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RAJESH NAYAK
IMPORTANT ENVIRONMENT NOTES FROM WIKIPEDIA
ECOSYSTEM SERVICES
Humankind benefits in a multitude of ways from ecosystems.
Collectively, these benefits are becoming known as ecosystem
services.
Ecosystem services are regularly involved in the provisioning of
clean drinking water and the decomposition of wastes.
the ecosystem services concept itself was popularized by the
Millennium Ecosystem Assessment (MA) in the early 2000s.
ecosystem services into four broad categories: provisioning,
such as the production of food and water; regulating, such as the
control of climate and disease; supporting, such as nutrient cycles
and crop pollination; and cultural, such as
spiritual and recreational benefits. "
the benefits people obtain from ecosystems. Four Categories
Supporting services
include services such as nutrient recycling, primary production
and soil formation.
These services make it possible for the ecosystems to provide
services such as food supply, flood regulation and water
purification
Provisioning services "Products obtained from ecosystems"
food (including seafood and game), crops, wild foods, and
spices
raw materials (including lumber, skins, fuel wood, organic
matter, fodder, and fertilizer)
genetic resources (including crop improvement genes, and health
care)
water
minerals (including diatomite)
medicinal resources (including pharmaceuticals, chemical models,
and test and assay organisms)
energy (hydropower, biomass fuels)
ornamental resources (including fashion, handicraft, jewelry,
pets, worship, decoration and souvenirs like furs, feathers,
ivory, orchids, butterflies, aquarium fish, shells, etc.)
Regulating services
"Benefits obtained from the regulation of ecosystem
processes"
carbon sequestration and climate regulation
waste decomposition and detoxification
purification of water and air
pest and disease control
Cultural services
"Nonmaterial benefits people obtain from ecosystems through
spiritual enrichment, cognitive development, reflection,
recreation, and aesthetic experiences"
cultural (including use of nature as motif in books, film,
painting, folklore, national symbols, architect, advertising,
etc.)
spiritual and historical (including use of nature for religious
or heritage value or natural)
recreational experiences(including ecotourism, outdoor sports,
and recreation)
science and education (including use of natural systems for
school excursions, and scientific discovery)
Ecosystem-Based Adaptation (EbA)
Ecosystem-Based Adaptation or EbA is an emerging strategy for
community development and environmental management that seeks to
use an ecosystem services framework to help communities adapt to
the effects of climate
change.
The Convention on Biological Diversity currently defines
Ecosystem-Based Adaptation as the use of biodiversity and ecosystem
services to help people adapt to the adverse effects of climate
change, which includes the use of sustainable management,
conservation and restoration of ecosystems, as part of an overall
adaptation strategy that takes into account
the multiple social, economic and cultural co-benefits for local
communities
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RAJESH NAYAK
Estuarine and coastal ecosystems are both marine ecosystems.
An estuary is defined as the area in which a river meets the sea
or the ocean.
The waters surrounding this area are predominantly salty waters
or brackish waters; and the incoming river water is dynamically
motioned by the tide.
An estuary strip may be covered by populations of reed (or
similar plants) and/or sandbanks (or similar form or land)
Buffer Zones
Coastal and estuarine ecosystems act as buffer zones against
natural hazards and environmental disturbances, such as floods,
cyclones, tidal surges and storms.
The role they play is to [absorb] a portion of the impact and
thus [lessen] its effect on the land.
Wetlands, for example, and the vegetation it supports trees,
root mats, etc. retain large amounts of water (surface water,
snowmelt, rain, groundwater) and then slowly releases them back,
decreasing the likeliness of floods.
Mangrove forests protect coastal shorelines from tidal erosion
or erosion by currents; a process that was studied after the 1999
cyclone that hit India.
Villages that were surrounded with mangrove forests encountered
less damages than other villages that werent protected by
mangroves
BLUE CARBON
Blue carbon is the carbon captured by the world's oceans and
coastal ecosystems. The carbon captured by living organisms in
oceans is stored in the form of biomass and sediments from
mangroves, salt marshes and seagrasses.
The rates of blue carbon sequestration and storage capacities in
ecosystems are comparable to (and often higher than) those in
carbon-rich terrestrial ecosystems such as tropical rainforests or
peatlands.
Unlike most terrestrial systems, which reach soil carbon
equilibrium within decades, deposition of carbon dioxide in coastal
ecosystem sediment can continue over millennia.
However, when these coastal ecosystems are degraded or destroyed
they can become carbon dioxide sources due to the oxidization of
biomass and organic soil. coastal ecosystems do contain substantial
amounts of carbon, and because this
carbon is in danger of being released, they are important in
mitigating climate change.
However, the rate of loss of mangroves, sea grasses and salt
marshes (driven mostly by human activities) is estimated to be
among the highest of any ecosystem on the planet, prompting
international interest in managing them more
effectively for their carbon benefits.
Sperm whales increase the levels of primary production and
carbon export to the deep ocean by depositing iron rich faeces into
surface waters of the Southern Ocean.
The iron rich faeces causes phytoplankton to grow and take up
more carbon from the atmosphere.
When the phytoplankton dies, it sinks to the deep ocean and
takes the atmospheric carbon with it.
By reducing the abundance of sperm whales in the Southern Ocean,
whaling has resulted in an extra 2 million tonnes of carbon
remaining in the atmosphere each year.
Carbon sequestration
is the process of capture and long-term storage of atmospheric
carbon dioxide (CO2).
Carbon sequestration describes long-term storage of carbon
dioxide or other forms of carbon to either mitigate or defer global
warming and avoid dangerous climate change.
It has been proposed as a way to slow the atmospheric and marine
accumulation of greenhouse gases, which are released by burning
fossil fuels.
Biosequestration or carbon sequestration through biological
processes affects the global carbon cycle.
Examples include major climatic fluctuations, such as the Azolla
event, which created the current Arctic climate.
Such processes created fossil fuels, as well as clathrate and
limestone.
By manipulating such processes, geoengineers seek to enhance
sequestration.
Peat bogs are a very important carbon store.
By creating new bogs, or enhancing existing ones, carbon can be
sequestered.
Wetland soil is an important carbon sink; 14.5% of the worlds
soil carbon is found in wetlands, while only 6% of the worlds land
is composed of wetlands.
Ocean iron fertilization is an example of such a geoengineering
technique.
Iron fertilization attempts to encourage phytoplankton growth,
which removes carbon from the atmosphere for at least a period of
time.
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RAJESH NAYAK
This technique is controversial due to limited understanding its
complete effects on the marineecosystem, including side effects and
possibly large deviations from expected behavior.
Such effects potentially include release of nitrogen oxides, and
disruption of the ocean's nutrient balance.
Natural iron fertilisation events (e.g., deposition of iron-rich
dust into ocean waters) can enhance carbon sequestration. Sperm
whales act as agents of iron fertilisation when they transport iron
from the deep ocean to the surface during prey
consumption and defecation.
Sperm whales have been shown to increase the levels of primary
production and carbon export to the deep ocean by depositing iron
rich feces into surface waters of the Southern Ocean.
The iron rich feces causes phytoplankton to grow and take up
more carbon from the atmosphere.
When the phytoplankton dies, some of it sinks to the deep ocean
and takes the atmospheric carbon with it.
By reducing the abundance of sperm whales in the Southern Ocean,
whaling has resulted in an extra 2 million tonnes of carbon
remaining in the atmosphere each year.
Bio-energy with carbon capture and storage (BECCS)
BECCS refers to biomass in power stations and boilers that use
carbon capture and storage.
The carbon sequestered by the biomass would be captured and
stored, thus removing carbon dioxide from the atmosphere.
This technology is sometimes referred to as bio-energy with
carbon storage, BECS, though this term can also refer to the carbon
sequestration potential in other technologies, such as biochar
Landfills also represent a physical method of sequestration.
Biochar is charcoal created by pyrolysis of biomass waste.
The resulting material is added to a landfill or used as a soil
improver to create terra preta.
Biogenic carbon is recycled naturally in the carbon cycle.
Pyrolysing it to biochar renders the carbon relatively inert so
that it remains sequestered in soil.
Further, the soil encourages bulking with new organic matter,
which gives additional sequestration benefit.
Carbon carousel
uses panels that, after being depleted of CO2 in the
regeneration chamber, exit this chamber and enter the carousel.
The carousel rotates the CO2-sorbent panels through the air,
collecting CO2 all the while, until the CO2-saturated panels reach
the point of entry to the regeneration chamber.
The regeneration process provides new panels for the exit to the
recovery process.
Carbon capture and storage (CCS) (or carbon capture and
sequestration)
is the process of capturing waste carbon dioxide (CO2) from
large point sources, such as fossil fuel power plants, transporting
it to a storage site, and depositing it where it will not enter the
atmosphere, normally an
underground geological formation.
The aim is to prevent the release of large quantities of CO2
into the atmosphere (from fossil fuel use in power generation and
other industries).
It is a potential means ofmitigating the contribution of fossil
fuel emissions to global warming and ocean acidification.
Bio-energy with carbon capture and storage (BECCS)
is a greenhouse gas mitigation technology which produces
negative carbon dioxide emissions by combining bioenergy (energy
from biomass) use with geologic carbon capture and storage.
The concept of BECCS is drawn from the integration of trees and
crops, which extract carbon dioxide (CO2) from the atmosphere as
they grow, the use of this biomass in processing industries or
power plants, and the application of carbon capture and storage via
CO2 injection into geological formations.
There are other non-BECCS forms of carbon dioxide removal and
storage that include technologies such as biochar, carbon dioxide
air capture and biomass burial.
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RAJESH NAYAK
It was pointed out in the IPCC Fourth Assessment Report by the
Intergovernmental Panel on Climate Change (IPCC) as a key
technology for reaching low carbon dioxide atmospheric
concentration targets.
Bio-energy is derived from biomass which is a renewable energy
source and serves as a carbon sink during its growth.
During industrial processes, the biomass combusted or processed
re-releases the CO2 into the atmosphere.
The process thus results in a net zero emission of CO2, though
this may be positively or negatively altered depending on the
carbon emissions associated with biomass growth, transport and
processing, see below under environmental
considerations.
Carbon capture and storage (CCS) technology serves to intercept
the release of CO2 into the atmosphere and redirect it into
geological storage locations.
CO2 with a biomass origin is not only released from biomass
fuelled power plants, but also during the production of pulp used
to make paper and in the production of biofuels such as biogas and
bioethanol.
The main technology for CO2 capture from biotic sources
generally employs the same technology as carbon dioxide capture
from conventional fossil fuel sources.
Broadly, three different types of technologies exist:
post-combustion, pre-combustion, and oxy-fuel combustion.
A negative carbon dioxide emission or negative emission
or a process that is carbon negative gives a permanent removal
of the greenhouse gas carbon dioxide from Earth's atmosphere.
It is considered the direct opposite of carbon dioxide emission,
hence its name.
It is the result of carbon dioxide removal technologies, such as
bio-energy with carbon capture and storage, biochar, direct air
capture or enhanced weathering.
Negative emissions is different from reducing emissions, as the
former produces an outlet of carbon dioxide from Earth's
atmosphere, whereas the latter decreases the inlet of carbon
dioxide to the atmosphere.
Both have the same momentary net effect, but for achieving
carbon dioxide concentration levels below present levels, such as
350 ppm, negative emissions are critical.
Also for meeting higher concentration levels, negative emissions
are increasingly considered to be crucial as they provide the only
possibility to fill the gap between needed reductions to meet
mitigation targets and global emission
trends.
Carbonic acid
is a chemical compound with the chemical formula H2CO3
(equivalently OC(OH)2).
It is also a name sometimes given to solutions of carbon dioxide
in water (carbonated water), because such solutions contain small
amounts of H2CO3.
In physiology, carbonic acid is described as volatile acid or
respiratory acid, because it is the only acid excreted as a gas by
the lungs.
Carbonic acid, which is a weak acid, forms two kinds of salts,
the carbonates and the bicarbonates.
In geology, carbonic acid causes limestone to dissolve producing
calcium bicarbonate which leads to many limestone features such as
stalactites and stalagmites.
Carbonic acid is one of the polyprotic acids:
It is diprotic - it has two protons, which may dissociate from
the parent molecule.
Thus, there are two dissociation constants, the first one for
the dissociation into the bicarbonate (also called hydrogen
carbonate) ion HCO3.
Kelps
are large seaweeds (algae) belonging to the brown algae
(Phaeophyceae) in the order Laminariales.
There are about 30 different genera.
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RAJESH NAYAK
Kelp grows in underwater "forests" (kelp forests) in shallow
oceans.
The organisms require nutrient-rich water with temperatures
between 6 and 14 C (43 and 57 F).
They are known for their high growth rate the genera Macrocystis
and Nereocystiscan grow as fast as half a metre a day, ultimately
reaching 30 to 80 metres Giant kelp can be harvested fairly easily
because of its surface canopy and
growth habit of staying in deeper water.
Bongo kelp ash is rich in iodine and alkali.
In great amount, kelp ash can be used in soap and glass
production.
Mangroves
are various large and extensive types of trees up to medium
height and shrubs that grow in salinecoastal sediment habitats in
the tropics and subtropicsmainly between latitudes 25 N and 25
S.
The word is used in at least three senses: (1) most broadly to
refer to the habitat and entire plant assemblage or mangal, for
which the terms mangrove forest biome, mangrove swamp and mangrove
forest are also used, (2) to
refer to all trees and large shrubs in the mangrove swamp, and
(3) narrowly to refer to the mangrove family of plants,
the Rhizophoraceae, or even more specifically just to mangrove
trees of the genus Rhizophora.
The mangrove biome, or mangal, is a distinct saline woodland or
shrubland habitat characterized bydepositional coastal
environments, where fine sediments (often with high organic
content) collect in areas protected from high-energy wave
action.
The saline conditions tolerated by various mangrove species
range from brackish water, through pure seawater (30 to 40 ppt
(parts per thousand)), to water concentrated by evaporation to over
twice the salinity of ocean seawater (up to 90
ppt)
Red mangroves,
which can survive in the most inundated areas, prop themselves
above the water level with stilt roots and can then absorb air
through pores in their bark (lenticels).
Black mangroves
live on higher ground and make many pneumatophores (specialised
root-like structures which stick up out of the soil like straws for
breathing) which are also covered in lenticels.
These "breathing tubes" typically reach heights of up to 30 cm,
and in some species, over 3 m.
The four types of pneumatophores are stilt or prop type, snorkel
or peg type, knee type, and ribbon or plank type.
Knee and ribbon types may be combined with buttress roots at the
base of the tree.
The roots also contain wide aerenchyma to facilitate transport
within the plants.
A salt marsh or saltmarsh,
also known as a coastal salt marsh or a tidal marsh, is a
coastal ecosystem in the upper coastal intertidal zone between land
and open salt water or brackish water that is regularly flooded by
the tides.
It is dominated by dense stands of salt-tolerant plants such as
herbs, grasses, or lowshrubs.
These plants are terrestrial in origin and are essential to the
stability of the salt marsh in trapping and binding sediments.
Salt marshes play a large role in the aquatic food web and the
delivery of nutrients to coastal waters.
They also support terrestrial animals and provide coastal
protection.
Salt marshes occur on low-energy shorelines in temperate and
high-latitudes which can be stable or emerging, or submerging if
the sedimentation rate exceeds the subsidence rate.
Commonly these shorelines consist of mud or sand flats (known
also as tidal flats or abbreviated to mudflats) which are nourished
with sediment from inflowing rivers and streams.
These typically include sheltered environments such as
embankments, estuaries and the leeward side of barrier islands and
spits.
In the tropics and sub-tropics they are replaced by mangroves;
an area that differs from a salt marsh in that instead of
herbaceous plants, they are dominated by salt-tolerant trees.
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RAJESH NAYAK
Most salt marshes have a low topography with low elevations but
a vast wide area, making them hugely popular for human
populations.
Salt marshes are located among different landforms based on
their physical and geomorphological settings.
Such marsh landforms include deltaic marshes, estuarine,
back-barrier, open coast, embayment and drowned-valley marshes.
Salt marshes are sometimes included in lagoons, and the
difference is not very marked;
A swamp
is a wetland that is forested. Many swamps occur along large
rivers where they are critically dependent upon natural water level
fluctuations.
Other swamps occur on the shores of large lakes.
Some swamps have hammocks, or dry-land protrusions, covered by
aquatic vegetation, or vegetation that tolerates periodic
inundation.
The two main types of swamp are "true" or swamp forests and
"transitional" or shrub swamps.
In the boreal regions of Canada, the word swamp is colloquially
used for what is more correctly termed a bog or muskeg.
The water of a swamp may be fresh water, brackish water or
seawater.
Some of the world's largest swamps are found along major rivers
such as the Amazon, the Mississippi, and the Congo.
Swamps and other wetlands have traditionally held a very low
property value compared to fields, prairies, or woodlands.
They have a reputation for being unproductive land that cannot
easily be utilized for human activities, other than perhaps hunting
and trapping.
Farmers, for example, typically drained swamps next to their
fields so as to gain more land usable for planting crops.
Myristica swamps
are a type of freshwater swamp forest predominantly composed of
species of Myristica.
These are found in two localities in India. Myristica swamps
have adapted to inundation by way of stilt roots and knee
roots.
Myristica swamps are found in the Uttara Kannada district of
Karnataka State and in the southern parts of Kerala State.
The Millennium Ecosystem Assessment (MA)
is a major assessment of the effects of human activity on the
environment.
It popularized the term ecosystem services, the benefits gained
by humans from ecosystems.
Niche
"the set of biotic and abiotic conditions in which a species is
able to persist and maintain stable population sizes.
The ecological niche is a central concept in the ecology of
organisms and is sub-divided into the fundamental and the realized
niche.
The fundamental niche is the set of environmental conditions
under which a species is able to persist.
Termite mounds with varied heights of chimneys regulate gas
exchange, temperature and other environmental parameters that are
needed to sustain the internal physiology of the entire colony.
Biomes are larger units of organization that categorize regions
of the Earth's ecosystems, mainly according to the structure and
composition of vegetation.
There are different methods to define the continental boundaries
of biomes dominated by different functional types of vegetative
communities that are limited in distribution by climate,
precipitation, weather and other environmental
variables.
Biomes include tropical rainforest, temperate broadleaf and
mixed forest, temperate deciduous forest, taiga, tundra, hot
desert, and polar desert.
Other researchers have recently categorized other biomes, such
as the human and oceanic micro biomes.
To a microbe, the human body is a habitat and a landscape.
Micro biomes were discovered largely through advances in
molecular genetics, which have revealed a hidden richness of
microbial diversity on the planet.
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RAJESH NAYAK
The oceanic micro biome plays a significant role in the
ecological biogeochemistry of the planet's oceans.
Community ecology is the study of the interactions among a
collections of species that inhabit the same geographic area.
Research in community ecology might measure primary production
in a wetland in relation to decomposition and consumption
rates.
This requires an understanding of the community connections
between plants (i.e., primary producers) and the decomposers (e.g.,
fungi and bacteria), or the analysis of predator-prey dynamics
affecting amphibian biomass.
Food webs and trophic levels are two widely employed conceptual
models used to explain the linkages among species. Interspecific
interactions such as predation are a key aspect of community
ecology.
A food web is the archetypal ecological network. Plants capture
solar energy and use it to synthesize simple sugars during
photosynthesis.
As plants grow, they accumulate nutrients and are eaten by
grazing herbivores, and the energy is transferred through a chain
of organisms by consumption.
The simplified linear feeding pathways that move from a basal
trophic species to a top consumer is called the food chain.
The larger interlocking pattern of food chains in an ecological
community creates a complex food web.
Food webs are a type of concept map or a heuristic device that
is used to illustrate and study pathways of energy and material
flows.
A trophic level (from Greek troph, , troph, meaning "food" or
"feeding") is "a group of organisms acquiring a considerable
majority of its energy from the adjacent level nearer the abiotic
source."
Links in food webs primarily connect feeding relations or
trophism among species.
Biodiversity within ecosystems can be organized into trophic
pyramids, in which the vertical dimension represents feeding
relations that become further removed from the base of the food
chain up toward top predators, and the
horizontal dimension represents the abundance or biomass at each
level.
When the relative abundance or biomass of each species is sorted
into its respective trophic level, they naturally sort into a
'pyramid of numbers'.
Species
are broadly categorized as autotrophs (or primary producers),
heterotrophs (or consumers), and Detritivores (or decomposers).
Autotrophs are organisms that produce their own food (production
is greater than respiration) by photosynthesis or
chemosynthesis.
Heterotrophs are organisms that must feed on others for
nourishment and energy (respiration exceeds production).[5]
Heterotrophs can be further sub-divided into different
functional groups, including primary consumers (strict
herbivores),secondary consumers (carnivorous predators that feed
exclusively on herbivores) and tertiary consumers
(predators that feed on a mix of herbivores and predators).
Omnivores do not fit neatly into a functional category because
they eat both plant and animal tissues.
It has been suggested that omnivores have a greater functional
influence as predators, because compared to herbivores they are
relatively inefficient at grazing.
Trophic levels are part of the holistic or complex systems view
of ecosystems.
Each trophic level contains unrelated species that are grouped
together because they share common ecological functions, giving a
macroscopic view of the system.
While the notion of trophic levels provides insight into energy
flow and top-down control within food webs, it is troubled by the
prevalence of omnivory in real ecosystems.
This has led some ecologists to "reiterate that the notion that
species clearly aggregate into discrete, homogeneous trophic levels
is fiction."
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RAJESH NAYAK
Nonetheless, recent studies have shown that real trophic levels
do exist, but "above the herbivore trophic level, food webs are
better characterized as a tangled web of omnivores."
A keystone species is a species that is connected to a
disproportionately large number of other species in the
food-web.
Keystone species have lower levels of biomass in the trophic
pyramid relative to the importance of their role.
The many connections that a keystone species holds means that it
maintains the organization and structure of entire communities.
The loss of a keystone species results in a range of dramatic
cascading effects that alters trophic dynamics, other food web
connections, and can cause the extinction of other species.
Sea otters (Enhydra lutris) are commonly cited as an example of
a keystone species because they limit the density of sea urchins
that feed on kelp.
If sea otters are removed from the system, the urchins graze
until the kelp beds disappear and this has a dramatic effect on
community structure.
[92] Hunting of sea otters, for example, is thought to have
indirectly led to the extinction of
the Steller's Sea Cow (Hydrodamalis gigas).
While the keystone species concept has been used extensively as
a conservation tool, it has been criticized for being poorly
defined from an operational stance.
It is difficult to experimentally determine what species may
hold a keystone role in each ecosystem.
Furthermore, food web theory suggests that keystone species may
not be common, so it is unclear how generally the keystone species
model can be applied
Complexity is understood as a large computational effort needed
to piece together numerous interacting parts exceeding the
iterative memory capacity of the human mind.
Global patterns of biological diversity are complex.
This bio complexity stems from the interplay among ecological
processes that operate and influence patterns at different scales
that grade into each other, such as transitional areas or Eco tones
spanning landscapes.
Complexity stems from the interplay among levels of biological
organization as energy and matter is integrated into larger units
that superimpose onto the smaller parts. "What were wholes on one
level become parts on a higher one."
Small scale patterns do not necessarily explain large scale
phenomena, otherwise captured in the expression (coined by
Aristotle) 'the sum is greater than the parts'"
Complexity in ecology is of at least six distinct types:
spatial, temporal, structural, process, behavioral, and
geometric."
From these principles, ecologists have identified emergent and
self-organizing phenomena that operate at different environmental
scales of influence, ranging from molecular to planetary, and these
require different explanations at each
integrative level.
Ecological complexity relates to the dynamic resilience of
ecosystems that transition to multiple shifting steady-states
directed by random fluctuations of history.
Long-term ecological studies provide important track records to
better understand the complexity and resilience of ecosystems over
longer temporal and broader spatial scales.
Holism remains a critical part of the theoretical foundation in
contemporary ecological studies.
Holism addresses the biological organization of life that
self-organizes into layers of emergent whole systems that function
according to non-reducible properties.
This means that higher order patterns of a whole functional
system, such as an ecosystem, cannot be predicted or understood by
a simple summation of the parts.
"New properties emerge because the components interact, not
because the basic nature of the components is changed.
Behavioural ecology
All organisms can exhibit behaviours.
Even plants express complex behaviour, including memory and
communication.
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RAJESH NAYAK
Behavioural ecology is the study of an organism's behaviour in
its environment and its ecological and evolutionary
implications.
Ethology is the study of observable movement or behaviour in
animals.
This could include investigations of motile sperm of plants,
mobile phytoplankton, zooplanktons wimming toward the female egg,
the cultivation of fungi by weevils, the mating dance of a
salamander, or social gatherings of amoeba.
Cognitive ecology
Cognitive ecology integrates theory and observations from
evolutionary ecology and neurobiology, primarily cognitive science,
in order to understand the effect that animal interaction with
their habitat has on their cognitive systems and
how those systems restrict behavior within an ecological and
evolutionary framework.
"Until recently, however, cognitive scientists have not paid
sufficient attention to the fundamental fact that cognitive traits
evolved under particular natural settings.
With consideration of the selection pressure on cognition,
cognitive ecology can contribute intellectual coherence to the
multidisciplinary study of cognition."
As a study involving the 'coupling' or interactions between
organism and environment, cognitive ecology is closely related to
enactivism, a field based upon the view that "...we must see the
organism and environment as bound together
in reciprocal specification and selection.
Social ecology
Social ecological behaviours are notable in the social insects,
slime moulds, social spiders, human society, and naked mole-rats
where eusocialism has evolved.
Social behaviours include reciprocally beneficial behaviours
among kin and nest mates and evolve from kin and group
selection.
Kin selection explains altruism through genetic relationships,
whereby an altruistic behaviour leading to death is rewarded by the
survival of genetic copies distributed among surviving
relatives.
The social insects, including ants, bees and wasps are most
famously studied for this type of relationship because the male
drones are clones that share the same genetic make-up as every
other male in the colony.
In contrast, group selectionists find examples of altruism among
non-genetic relatives and explain this through selection acting on
the group, whereby it becomes selectively advantageous for groups
if their members express altruistic
behaviours to one another.
Groups with predominantly altruistic members beat groups with
predominantly selfish members.
Bumblebees and the flowers theypollinate have coevolved so that
both have become dependent on each other for survival.
Molecular ecology
The important relationship between ecology and genetic
inheritance predates modern techniques for molecular analysis.
Molecular ecological research became more feasible with the
development of rapid and accessible genetic technologies, such as
the polymerase chain reaction (PCR).
The rise of molecular technologies and influx of research
questions into this new ecological field resulted in the
publication Molecular Ecology in 1992.
Molecular ecology uses various analytical techniques to study
genes in an evolutionary and ecological context.
In 1994, John Avise also played a leading role in this area of
science with the publication of his book, Molecular Markers,
Natural History and Evolution.
Newer technologies opened a wave of genetic analysis into
organisms once difficult to study from an ecological or
evolutionary standpoint, such as bacteria, fungi and nematodes.
Molecular ecology engendered a new research paradigm for
investigating ecological questions considered otherwise
intractable.
Molecular investigations revealed previously obscured details in
the tiny intricacies of nature and improved resolution into probing
questions about behavioural and biogeographical ecology.
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RAJESH NAYAK
For example, molecular ecology revealed promiscuous sexual
behaviour and multiple male partners in tree swallows previously
thought to be socially monogamous.
In a biogeographical context, the marriage between genetics,
ecology and evolution resulted in a new sub-discipline called
phylogeography.
The architecture of the inflorescencein grasses is subject to
the physical pressures of wind and shaped by the forces of natural
selection facilitating wind-pollination (anemophily).
Agroecology
the study of ecological processes that operate in agricultural
production systems.
The prefix agro- refers to agriculture.
Bringing ecological principles to bear in agroecosystems can
suggest novel management approaches that would not otherwise be
considered.
The term is often used imprecisely and may refer to "a science,
a movement, [or] a practice."
Agroecologists study a variety of agroecosystems, and the field
of agroecology is not associated with any one particular method of
farming, whether it be organic,integrated, or conventional;
intensive or extensive.
Although it has much more common thinking and principles with
some of the before mentioned farming systems.
Cultural ecology
the study of human adaptations to social and physical
environments.
Human adaptation refers to both biological and cultural
processes that enable a population to survive and reproduce within
a given or changing environment.
This may be carried out diachronically (examining entities that
existed in different epochs), or synchronically (examining a
present system and its components).
The central argument is that the natural environment, in small
scale or subsistence societies dependent in part upon it, is a
major contributor to social organization and other human
institutions.
Chemical ecology
is the study of chemicals involved in the interactions of living
organisms.
It focuses on the production of and response to signalling
molecules (i.e. semiochemicals) and toxins.
Chemical ecology is of particular importance among ants and
other social insects including bees, wasps, and termites as a means
of communication essential to social organization.
In addition, this area of ecology deals with studies involving
defensive chemicals which are utilized to deter potential predators
or pathogens, which may attack a wide variety of species.
Other aspects of chemical ecology deal with chemical responses
of organisms to abiotic factors such as temperature and radiation.
Primary production is the production of organic matter from
inorganic carbon sources.
Overwhelmingly, this occurs through photosynthesis.
The energy incorporated through this process supports life on
earth, while the carbon makes up much of the organic matter in
living and dead biomass, soil carbon and fossil fuels.
It also drives the carbon cycle, which influences global climate
via the greenhouse effect.
Through the process of photosynthesis, plants capture energy
from light and use it to combine carbon dioxide and water to
produce carbohydrates and oxygen.
The photosynthesis carried out by all the plants in an ecosystem
is called the gross primary production (GPP).
The carbon and energy incorporated into plant tissues (net
primary production) is either consumed by animals while the plant
is alive, or it remains uneaten when the plant tissue dies and
becomes detritus.
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In terrestrial ecosystems, roughly 90% of the NPP ends up being
broken down by decomposers. The remainder is either consumed by
animals while still alive and enters the plant-based trophic
system, or it is consumed after it has died, and
enters the detritus-based trophic system.
In aquatic systems, the proportion of plant biomass that gets
consumed by herbivores is much higher.
In trophic systems photosynthetic organisms are the primary
producers.
The organisms that consume their tissues are called primary
consumers or secondary producersherbivores.
Organisms which feed on microbes (bacteria and fungi) are termed
microbivores.
Animals that feed on primary consumerscarnivoresare secondary
consumers. Each of these constitutes a trophic level.
[18]
The sequence of consumptionfrom plant to herbivore, to
carnivoreforms a food chain.
Real systems are much more complex than thisorganisms will
generally feed on more than one form of food, and may feed at more
than one trophic level.
Carnivores may capture some prey which are part of a plant-based
trophic system and others that are part of a detritus-based trophic
system (a bird that feeds both on herbivorous grasshoppers and
earthworms, which consume detritus).
Real systems, with all these complexities, form food webs rather
than food chains.
The carbon and nutrients in dead organic matter are broken down
by a group of processes known as decomposition.
This releases nutrients that can then be re-used for plant and
microbial production, and returns carbon dioxide to the atmosphere
(or water) where it can be used for photosynthesis.
In the absence of decomposition, dead organic matter would
accumulate in an ecosystem and nutrients and atmospheric carbon
dioxide would be depleted.
Decomposition processes can be separated into three
categoriesleaching, fragmentation and chemical alteration of dead
material.
As water moves through dead organic matter, it dissolves and
carries with it the water-soluble components.
These are then taken up by organisms in the soil, react with
mineral soil, or are transported beyond the confines of the
ecosystem (and are considered "lost" to it).
Newly shed leaves and newly dead animals have high
concentrations of water-soluble components, and include sugars,
amino acids and mineral nutrients.
Leaching is more important in wet environments, and much less
important in dry ones.
The chemical alteration of dead organic matter is primarily
achieved through bacterial and fungal action.
Fungal hyphae produce enzymes which can break through the tough
outer structures surrounding dead plant material.
They also produce enzymes which break down lignin, which allows
to them access to both cell contents and to the nitrogen in the
lignin.
Fungi can transfer carbon and nitrogen through their hyphal
networks and thus, unlike bacteria, are not dependent solely on
locally available resources.
Decomposition rates vary among ecosystems.
The rate of decomposition is governed by three sets of
factorsthe physical environment (temperature, moisture and soil
properties), the quantity and quality of the dead material
available to decomposers, and the nature of the microbial
community itself.
Temperature controls the rate of microbial respiration; the
higher the temperature, the faster microbial decomposition occurs.
It also affects soil moisture, which slows microbial growth and
reduces leaching.
Freeze-thaw cycles also affect decompositionfreezing
temperatures kill soil microorganisms, which allows leaching to
play a more important role in moving nutrients around.
This can be especially important as the soil thaws in the
Spring, creating a pulse of nutrients which become available.
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Decomposition rates are low under very wet or very dry
conditions.
Decomposition rates are highest in wet, moist conditions with
adequate levels of oxygen.
Wet soils tend to become deficient in oxygen (this is especially
true in wetlands), which slows microbial growth. In dry soils,
decomposition slows as well, but bacteria continue to grow (albeit
at a slower rate) even after soils become too dry
to support plant growth.
When the rains return and soils become wet, the osmotic gradient
between the bacterial cells and the soil water causes the cells to
gain water quickly.
Under these conditions, many bacterial cells burst, releasing a
pulse of nutrients. Decomposition rates also tend to be slower in
acidic soils.
Soils which are rich in clay minerals tend to have lower
decomposition rates, and thus, higher levels of organic matter.
The smaller particles of clay result in a larger surface area
that can hold water.
The higher the water content of a soil, the lower the oxygen
content and consequently, the lower the rate of decomposition.
Clay minerals also bind particles of organic material to their
surface, making them less accessibly to microbes.[20]
Soil disturbance like tilling increase decomposition by
increasing the amount of oxygen in the soil and by exposing new
organic matter to soil microbes
When natural resource management is applied to whole ecosystems,
rather than single species, it is termed ecosystem management.
Although definitions of ecosystem management abound, there is a
common set of principles which underlie these definitions.
A fundamental principle is the long-term sustainability of the
production of goods and services by the ecosystem;
"intergenerational sustainability [is] a precondition for
management, not an afterthought".
It also requires clear goals with respect to future trajectories
and behaviors of the system being managed.
Other important requirements include a sound ecological
understanding of the system, including connectedness, ecological
dynamics and the context in which the system is embedded.
Other important principles include an understanding of the role
of humans as components of the ecosystems and the use of adaptive
management.
While ecosystem management can be used as part of a plan for
wilderness conservation, it can also be used in intensively managed
ecosystems (see, for example,agroecosystem and close to nature
forestry).
Ecosystem ecology studies "the flow of energy and materials
through organisms and the physical environment".
It seeks to understand the processes which govern the stocks of
material and energy in ecosystems, and the flow of matter and
energy through them.
The study of ecosystems can cover 10 orders of magnitude, from
the surface layers of rocks to the surface of the planet.
An aquatic ecosystem
an ecosystem in a body of water.
Communities of organisms that are dependent on each other and on
their environment live in aquatic ecosystems.
The two main types of aquatic ecosystems are marine ecosystems
and freshwater ecosystems.
The intertidal zone is the area between high and low tides; in
this figure it is termed the littoral zone.
Other near-shore (neritic) zones can include estuaries, salt
marshes, coral reefs, lagoons and mangrove swamps.
In the deep water, hydrothermal vents may occur where
chemosynthetic sulfur bacteria form the base of the food web.
There are three basic types of freshwater ecosystems:
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Lentic: slow moving water, including pools, ponds, and
lakes.
Lotic: faster moving water, for example streams and rivers.
Wetlands: areas where the soil is saturated or inundated for at
least part of the time.
Lake ecosystems can be divided into zones.
One common system divides lakes into three zones.
The first, the littoral zone, is the shallow zone near the
shore. This is where rooted wetland plants occur.
The offshore is divided into two further zones, an open water
zone and a deep water zone.
In the open water zone (or photic zone) sunlight supports
photosynthetic algae, and the species that feed upon them.
In the deep water zone, sunlight is not available and the food
web is based on detritus entering from the littoral and
photic zones.
The off shore areas may be called the pelagic zone, and the
aphotic zone may be called the profundal zone.
Inland from the littoral zone one can also frequently identify a
riparian zone which has plants still affected by the
presence of the lakethis can include effects from windfalls,
spring flooding, and winter ice damage.
The production of the lake as a whole is the result of
production from plants growing in the littoral zone, combined
with
production from plankton growing in the open water.
Wetlands can be part of the lentic system, as they form
naturally along most lakeshores, the width of the wetland and
littoral zone being dependent upon the slope of the shoreline
and the amount of natural change in water levels, within
and among years.
Often dead trees accumulate in this zone, either from windfalls
on the shore or logs transported to the site during floods.
This woody debris provides important habitat for fish and
nesting birds, as well as protecting shorelines from erosion.
Two important subclasses of lakes are ponds, which typically are
small lakes that intergrade with wetlands, and
water reservoirs.
Over long periods of time, lakes, or bays within them, may
gradually become enriched by nutrients and slowly fill in
with organic sediments, a process called succession.
When humans use the watershed, the volumes of sediment entering
the lake can accelerate this process.
The addition of sediments and nutrients to a lake is known as
eutrophication.
The major zones in river ecosystems are determined by the river
bed's gradient or by the velocity of the current.
Faster moving turbulent water typically contains greater
concentrations of dissolved oxygen, which supports greater
biodiversity than the slow moving water of pools.
These distinctions form the basis for the division of rivers
into upland and lowland rivers.
The food base of streams within riparian forests is mostly
derived from the trees, but wider streams and those that lack
a canopy derive the majority of their food base from algae.
Anadromous fish are also an important source of nutrients.
Environmental threats to rivers include loss of water, dams,
chemical pollution and introduced species.
A dam produces negative effects that continue down the
watershed.
The most important negative effects are the reduction of spring
flooding, which damages wetlands, and the retention of
sediment, which leads to loss of deltaic wetlands.
Wetlands are dominated by vascular plants that have adapted to
saturated soil.
There are four main types of wetlands: swamp, marsh, fen and bog
(both fens and bogs are types of mire).
Wetlands are the most productive natural ecosystems in the world
because of the proximity of water and soil. Hence
they support large numbers of plant and animal species.
Due to their productivity, wetlands are often converted into dry
land with dykes and drains and used for agricultural
purposes.
The construction of dykes, and dams, has negative consequences
for individual wetlands and entire watersheds.
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Their closeness to lakes and rivers means that they are often
developed for human settlement.
Once settlements are constructed and protected by dykes, the
settlements then become vulnerable to land subsidence and
ever increasing risk of flooding.
Marine ecosystems
the largest of Earth's aquatic ecosystems.
They include oceans, salt marshes, intertidal zones, estuaries,
lagoons, mangroves, coral reefs, the deep sea, and the sea
floor.
They can be contrasted with freshwater ecosystems, which have a
lower salt content.
Marine waters cover two-thirds of the surface of the Earth.
Such places are considered ecosystems because the plant life
supports the animal life and vice versa. See food chains.
Marine ecosystems are very important for the overall health of
both marine and terrestrial environments.
According to the World Resource Centre, coastal habitats alone
account for approximately 1/3 of all marine biological
productivity, and estuarine ecosystems (i.e., salt marshes,
seagrasses, mangrove forests) are among the most productive
regions on the planet.
In addition, other marine ecosystems such as coral reefs,
provide food and shelter to the highest levels of marine diversity
in the world.
Marine ecosystems usually have a large biodiversity and are
therefore thought to have a good resistance against invasive
species.
However, exceptions have been observed, and the mechanisms
responsible in determining the success of an invasion are not yet
clear
Large marine ecosystems (LMEs)
are regions of the world's oceans, encompassing coastal areas
from river basins and estuaries to the seaward boundaries
ofcontinental shelves and the outer margins of the major ocean
current systems.
They are relatively large regions on the order of 200,000 km or
greater, characterized by distinct bathymetry, hydrography,
productivity, and trophically dependent populations.
The system of LMEs has been developed by the US National Oceanic
and Atmospheric Administration (NOAA) to identify areas of the
oceans for conservation purposes.
The objective is to use the LME concept as a tool for enabling
ecosystem-based management to provide a collaborative approach to
management of resources within ecologically-bounded transnational
areas.
This will be done in an international context and consistent
with customary international law as reflected in 1982 UN Convention
on the Law of the Sea.
LME-based conservation is based on recognition that the worlds
coastal ocean waters are degraded by unsustainable fishing
practices, habitat degradation,eutrophication, toxic pollution,
aerosol contamination, and emerging diseases, and
that positive actions to mitigate these threats require
coordinated actions by governments and civil society to recover
depleted fish populations, restore degraded habitats and reduce
coastal pollution.
Although the LMEs cover only the continental margins and not the
deep oceans and oceanic islands, the 64 LMEs produce 95% of the
world's annual marine fishery biomass yields.
Most of the global ocean pollution, overexploitation, and
coastal habitat alteration occur within their waters.
NOAA has conducted studies of principal driving forces affecting
changes in biomass yields for 33 of the 64 LMEs, which have been
peer-reviewed and published in ten volumes.
Freshwater ecosystems
are a subset of Earth's aquatic ecosystems.
They include lakes and ponds, rivers, streams,springs, and
wetlands.
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They can be contrasted with marine ecosystems, which have a
larger salt content.
Freshwater habitats can be classified by different factors,
including temperature, light penetration, and vegetation.
Freshwater ecosystems can be divided into lentic ecosystems
(still water) and lotic ecosystems (flowing water).
Limnology (and its branch freshwater biology) is a study about
freshwater ecosystems. It is a part of hydrobiology.
Original efforts to understand and monitor freshwater ecosystems
were spurred on by threats to human health (ex. Cholera outbreaks
due to sewage contamination).
Early monitoring focussed on chemical indicators, then bacteria,
and finally algae, fungi and protozoa.
A new type of monitoring involves differing groups of organisms
(macroinvertebrates,macrophytes and fish) and the stream conditions
associated with them.
Current biomonitering techniques focus mainly on community
structure or biochemical oxygen demand.
Responses are measured by behavioural changes, altered rates of
growth, reproduction or mortality.
Macro invertebrates are most often used in these models because
of well known taxonomy, ease of collection, sensitivity to a range
of stressors, and their overall value to the ecosystem. Most of
these measurements are difficult to extrapolate
on a large scale, however.
The use of reference sites is common when assessing what a
healthy freshwater ecosystem should look like.
Reference sites are easier to reconstruct in standing water than
moving water.
Preserved indicators such as diatom valves, macrophyte pollen,
insect chitin and fish scales can be used to establish a reference
ecosystem representative of a time before large scale human
disturbance.
Common chemical stresses on freshwater ecosystem health include
acidification, eutrophication and copper and pesticide
contamination.
A lake ecosystem
includes biotic (living) plants, animals and micro-organisms, as
well as abiotic (nonliving) physical and chemical interactions.
Lake ecosystems are a prime example of lentic ecosystems.
Lentic refers to stationary or relatively still water, from the
Latin lentus, which means sluggish.
Lentic waters range from ponds to lakes to wetlands, and much of
this article applies to lentic ecosystems in general. Lentic
ecosystems can be compared with lotic ecosystems, which involve
flowing terrestrial waters such as rivers and
streams.
Together, these two fields form the more general study area of
freshwater or aquatic ecology.
Lentic systems are diverse, ranging from a small, temporary
rainwater pool a few inches deep to Lake Baikal, which has a
maximum depth of 1740 m.
The general distinction between pools/ponds and lakes is vague,
but Brown states that ponds and pools have their entire
bottom surfaces exposed to light, while lakes do not.
In addition, some lakes become seasonally stratified (discussed
in more detail below.) Ponds and pools have two regions: the
pelagic open water zone, and the benthic zone, which comprises the
bottom and shore regions.
Since lakes have deep bottom regions not exposed to light, these
systems have an additional zone, the profundal.
These three areas can have very different abiotic conditions
and, hence, host species that are specifically adapted to live
there.
Water striders are predatory insects which rely on surface
tension to walk on top of water.
They live on the surface of ponds, marshes, and other quiet
waters.
They can move very quickly, up to 1.5 m/s.
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Important abiotic factors
Light, Temperature, Wind, Chemistry
Lentic system biota
Algae, including both phytoplankton and periphyton are the
principle photosynthesizers in ponds and lakes. Phytoplankton are
found drifting in the water column of the pelagic zone.
Many species have a higher density than water which should make
them sink and end up in the benthos.
To combat this, phytoplankton have developed density changing
mechanisms, by forming vacuoles and gas vesicles or by changing
their shapes to induce drag, slowing their descent.
A very sophisticated adaptation utilized by a small number of
species is a tail-like flagellum that can adjust vertical position
and allow movement in any direction.
Phytoplankton can also maintain their presence in the water
column by being circulated in Langmuir rotations.
Periphytic algae, on the other hand, are attached to a
substrate. In lakes and ponds, they can cover all benthic surfaces.
Both types of plankton are important as food sources and as oxygen
providers
Aquatic plants live in both the benthic and pelagic zones and
can be grouped according to their manner of growth: 1) emergent =
rooted in the substrate but with leaves and flowers extending into
the air, 2) floating-leaved = rooted in the
substrate but with floating leaves, 3) submersed = growing
beneath the surface and 4) free-floating macrophytes = not
rooted in the substrate and floating on the surface
These various forms of macrophytes generally occur in different
areas of the benthic zone, with emergent vegetation nearest the
shoreline, then floating-leaved macrophytes, followed by submersed
vegetation.
Free-floating macrophytes can occur anywhere on the systems
surface.
Aquatic plants are more buoyant than their terrestrial
counterparts because freshwater has a higher density than air.
This makes structural rigidity unimportant in lakes and ponds
(except in the aerial stems and leaves).
Thus, the leaves and stems of most aquatic plants use less
energy to construct and maintain woody tissue, investing that
energy into fast growth instead.
In order to contend with stresses induced by wind and waves,
plants must be both flexible and tough.
Light, water depth and substrate types are the most important
factors controlling the distribution of submerged aquatic
plants.
Macrophytes are sources of food, oxygen, and habitat structure
in the benthic zone, but cannot penetrate the depths of the
euphotic zone and hence are not found there
Zooplankton are tiny animals suspended in the water column.
Like phytoplankton, these species have developed mechanisms that
keep them from sinking to deeper waters, including drag-inducing
body forms and the active flicking of appendages such as antennae
or spines
Remaining in the water column may have its advantages in terms
of feeding, but this zones lack of refugia leaves zooplankton
vulnerable to predation.
In response, some species, especially Daphnia sp., make daily
vertical migrations in the water column by passively sinking to the
darker lower depths during the day and actively moving towards the
surface during the night.
Also, because conditions in a lentic system can be quite
variable across seasons, zooplankton have the ability to switch
from laying regular eggs to resting eggs when there is a lack of
food, temperatures fall below 2 C, or if predator
abundance is high.
These resting eggs have a diapause, or dormancy period that
should allow the zooplankton to encounter conditions that are more
favorable to survival when they finally hatch.
The invertebrates that inhabit the benthic zone are numerically
dominated by small species and are species rich compared to the
zooplankton of the open water.
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They include Crustaceans (e.g. crabs, crayfish, and shrimp),
molluscs (e.g. clams and snails), and numerous types of
insects.
These organisms are mostly found in the areas of macrophyte
growth, where the richest resources, highly oxygenated water, and
warmest portion of the ecosystem are found.
The structurally diverse macrophyte beds are important sites for
the accumulation of organic matter, and provide an ideal area for
colonization.
The sediments and plants also offer a great deal of protection
from predatory fishes
Very few invertebrates are able to inhabit the cold, dark, and
oxygen poor profundal zone.
Those that can are often red in color due to the presence of
large amounts of hemoglobin, which greatly increases the amount of
oxygen carried to cells.
Because the concentration of oxygen within this zone is low,
most species construct tunnels or borrows in which they can hide
and make the minimum movements necessary to circulate water
through, drawing oxygen to them without
expending much energy
The ecosystem of a river is the river viewed as a system
operating in its natural environment, and includes biotic(living)
interactions amongst plants, animals and micro-organisms, as well
as abiotic (nonliving) physical and chemical
interactions.
River ecosystems are prime examples of lotic ecosystems. Lotic
refers to flowing water, from the Latin lotus, washed.
Lotic waters range from springs only a few centimeters wide to
major rivers kilometers in width.
Much of this article applies to lotic ecosystems in general,
including related lotic systems such as streams and springs.
Lotic ecosystems can be contrasted with lentic ecosystems, which
involve relatively still terrestrial waters such as lakes and
ponds.
Together, these two fields form the more general study area of
freshwater or aquatic ecology.
The following unifying characteristics make the ecology of
running waters unique from that of other aquatic habitats.
Flow is unidirectional.
There is a state of continuous physical change.
There is a high degree of spatial and temporal heterogeneity at
all scales (microhabitats).
Variability between lotic systems is quite high.
The biota is specialized to live with flow conditions.
Energy sources can be autochthonous or allochthonous.
Autochthonous
energy sources are those derived from within the lotic
system.
During photosynthesis, for example,primary producers form
organic carbon compounds out of carbon dioxide and inorganic
matter.
The energy they produce is important for the community because
it may be transferred to higher trophic levels via consumption.
Additionally, high rates of primary production can introduce
dissolved organic matter (DOM) to the waters.
Another form of autochthonous energy comes from the
decomposition of dead organisms and feces that originate within the
lotic system.
In this case, bacteria decompose the detritus or coarse
particulate organic material (CPOM; >1 mm pieces) into fine
particulate organic matter (FPOM;
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In addition, terrestrial animal-derived materials, such as feces
or carcasses that have been added to the system are examples of
allochthonous CPOM.
The CPOM undergoes a specific process of degradation.
When leaf fallen into a stream?
First, the soluble chemicals are dissolved and leached from the
leaf upon its saturation with water.
This adds to the DOM load in the system.
Next, microbes such as bacteria and fungi colonize the leaf,
softening it as the mycelium of the fungus grows into it.
The composition of the microbial community is influenced by the
species of tree from which the leaves are shed (Rubbo and Kiesecker
2004).
This combination of bacteria, fungi, and leaf are a food source
for shredding invertebrates, which leave only FPOM after
consumption.
These fine particles may be colonized by microbes again or serve
as a food source for animals that consume FPOM. Organic matter can
also enter the lotic system already in the FPOM stage by wind,
surface runoff, bank erosion,
or groundwater.
Similarly, DOM can be introduced through canopy drip from rain
or from surface flows.
A wetland is a land area that is saturated with water, either
permanently or seasonally, such that it takes on the
characteristics of a distinct ecosystem.
The primary factor that distinguishes wetlands from other land
forms or water bodies is the
characteristic vegetation of aquatic plants, adapted to the
unique hydric soil.
Wetlands play a number of roles in the environment, principally
water purification, flood control, carbon sink and
shoreline stability.
Wetlands are also considered the most biologically diverse of
all ecosystems, serving as home to a wide range of plant
and animal life.
Wetlands occur naturally on every continent except Antarctica,
the largest including the Amazon River basin, the West
Siberian Plain and the Pantanal in South America.
The water found in wetlands can be freshwater, brackish,
orsaltwater
The main wetland types include swamps, marshes, bogs, and fens
and sub-types include mangrove, carr,pocosin,
and varzea.
The UN Millennium Ecosystem Assessment determined that
environmental degradation is more prominent within
wetland systems than any other ecosystem on Earth. International
conservation efforts are being used in conjunction
with the development of rapid assessment tools to inform people
about wetland issues.
Constructed wetlands can be used to treat municipal and
industrial wastewater as well as stormwater runoff, They may
also play a role in water-sensitive urban design.
The biota of a wetland system includes its vegetation zones and
structure as well as animal populations.
The most important factor affecting the biota is the duration of
flooding.
Other important factors include fertility and salinity.
In fens, species are highly dependent on water chemistry.
The chemistry of water flowing into wetlands depends on the
source of water and the geological material in which it
flows throughas well as the nutrients discharged from organic
matter in the soils and plants at higher elevations in slope
wetlands.
Biota may vary within a wetland due to season or recent flood
regimes.
Flora
There are four main groups of hydrophytes that found in wetland
systems throughout the world.
Submerged water plants.
This type of vegetation is found completely underwater.
Submerged wetland vegetation can grow in saline and fresh-water
conditions.
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Some species have underwater flowers, while others have long
stems to allow the flowers to reach the surface.
Submerged species provide a food source for native fauna,
habitat for invertebrates, and also possess filtration
capabilities.
Examples include seagrasses and eelgrass.
Floating water plants.
Floating vegetation is usually small although it may take up a
large surface area in a wetland system.
These hydrophytes have small roots and are only found in
slow-moving water with rich-nutrient level water Floating aquatic
plants are a food resource for avian species.
Examples include water lilies, lily pad and duckweed.
Emergent water plants.
Emergent water plants can be seen above the surface of the water
but whose roots are completely submerged.
Many have aerenchyma to transmit oxygen from the atmosphere to
their roots. Extensive areas of emergent plants are usually termed
marsh.
Examples include cattails (Typha) and arrow arum (Peltandra
virginica).
Surrounding trees and shrubs.
Forested wetlands are generally known as swamps.
The upper level of these swamps is determined by high water
levels, which are negatively affected by dams.
Some swamps can be dominated by a single species, such as silver
maple swamps around the Great Lakes.
Others, like those of the Amazon Basin, have large numbers of
different tree species. Examples include cypress (Taxodium) and
mangrove.
Fauna
Fish:
Fish are more dependent on wetland ecosystems than any other
type of habitat. 75% of the United States' commercial fish and
shellfish stocks depend solely on estuaries to survive.
Tropical fish species need mangroves for critical hatchery and
nursery grounds and the coral reef system for food.
Amphibians:
Frogs are the most crucial amphibian species in wetland
systems.
Frogs need both terrestrial and aquatic habitats in which to
reproduce and feed.
While tadpoles control algal populations, adult frogs forage on
insects.
Frogs are used as an indicator of ecosystem health due to their
thin skin which absorbs both nutrient and toxins from the
surrounding environment resulting in an above average extinction
rate in unfavorable and polluted environmental
conditions.
Reptiles:
Alligators and crocodiles are two common reptilian species.
Alligators are found in fresh water along with the fresh water
species of the crocodile.
The saltwater crocodile is found in estuaries and mangroves and
can be seen in the coastline bordering the Great Barrier Reef in
Australia.
The Florida Everglades is the only place in the world where both
crocodiles and alligators co-exist.
Snakes, lizards, goannas, and turtles also can be seen
throughout wetlands.
Snapping turtles are one of the many kinds of turtles found in
wetlands.
Mammals:
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Multiple small mammals as well as large herbivore and apex
species such as the Florida Panther live within and around
wetlands.
The wetland ecosystem attracts mammals due to its prominent seed
sources, invertebrate populations, and numbers of small reptiles
and amphibians.
Monotremes:
The platypus (Ornithorhynchus anatinus) is found in eastern
Australia living in freshwater rivers or lakes, and much like the
beaver creates dams, create burrows for shelter and protection.
The platypus swims through the use of webbed feet.
Platypuses feed on insect larvae, worms, or other freshwater
insects hunting mainly by night by the use of their bill.
They turn up mud on the bottom of the lake or river, and with
the help of the electroreceptors located on the bill, unearth
insects and freshwater insects.
The platypus stores their findings in special pouches behind
their bill and consumes its prey upon returning to the surface.
Insects and invertebrates:
These species total more than half of the 100,000 known animal
species in wetlands.
Insects and invertebrates can be submerged in the water or soil,
on the surface, and in the atmosphere.
Algae
Algae are diverse water plants that can vary in size, color, and
shape.
Algae occur naturally in habitats such as inland lakes,
inter-tidal zones, and damp soil and provide a dedicated food
source for animals, fish, and invertebrates. There are three main
groups of algae:
Plankton are algae which are microscopic, free-floating
algae.
This algae is so tiny that on average, if fifty of these
microscopic algae were lined up end-to-end, it would only measure
one millimetre.
Plankton are the basis of the food web and are responsible for
primary production in the ocean using photosynthesis to make food.
Filamentous algae are long strands of algae cells that form
floating mats.
Chara and Nitella algae are upright algae that look like a
submerged plant with roots.
List of wetland types
Wetland types:
AMarine and Coastal Zone wetlands
1. Marine waterspermanent shallow waters less than six metres
deep at low tide; includes sea bays, straits 2. Subtidal aquatic
beds; includes kelp beds, seagrasses, tropical marine meadows 3.
Coral reefs 4. Rocky marine shores; includes rocky offshore
islands, sea cliffs 5. Sand, shingle or pebble beaches; includes
sand bars, spits, sandy islets 6. Intertidal mud, sand or salt
flats 7. Intertidal marshes; includes saltmarshes, salt meadows,
saltings, raised salt marshes, tidal brackish and freshwater
marshes
8. Intertidal forested wetlands; includes mangrove swamps, nipa
swamps, tidal freshwater swamp forests 9. Brackish to saline
lagoons and marshes with one or more relatively narrow connections
with the sea 10. Freshwater lagoons and marshes in the coastal zone
11. Non-tidal freshwater forested wetlands
BInland wetlands
1. Permanent rivers and streams; includes waterfalls 2. Seasonal
and irregular rivers and streams
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3. Inland deltas (permanent) 4. Riverine floodplains; includes
river flats, flooded river basins, seasonally flooded grassland,
savanna and palm savanna 5. Permanent freshwater lakes (> 8 ha);
includes large oxbow lakes 6. Seasonal/intermittent freshwater
lakes (> 8 ha), floodplain lakes 7. Permanent saline/brackish
lakes 8. Seasonal/intermittent saline lakes 9. Permanent freshwater
ponds (< 8 ha), marshes and swamps on inorganic soils; with
emergent vegetation waterlogged for
at least most of the growing season
10. Seasonal/intermittent freshwater ponds and marshes on
inorganic soils; includes sloughs, potholes; seasonally flooded
meadows, sedge marshes
11. Permanent saline/brackish marshes 12. Seasonal saline
marshes 13. Shrub swamps; shrub-dominated freshwater marsh, shrub
carr, alder thicket on inorganic soils 14. Freshwater swamp forest;
seasonally flooded forest, wooded swamps; on inorganic soils 15.
Peatlands; forest, shrub or open bogs 16. Alpine and tundra
wetlands; includes alpine meadows, tundra pools, temporary waters
from snow melt 17. Freshwater springs, oases and rock pools 18.
Geothermal wetlands 19. Inland, subterranean karst wetlands
CHuman-made wetlands
1. Water storage areas; reservoirs, barrages, hydro-electric
dams, impoundments (generally > 8 ha) 2. Ponds, including farm
ponds, stock ponds, small tanks (generally < 8 ha) 3.
Aquaculture ponds; fish ponds, shrimp ponds 4. Salt exploitation;
salt pans, salines 5. Excavations; gravel pits, borrow pits, mining
pools 6. Wastewater treatment; sewage farms, settling ponds,
oxidation basins 7. Irrigated land and irrigation channels; rice
fields, canals, ditches 8. Seasonally flooded arable land, farm
land
A terrestrial ecosystem
is an ecosystem found only on landforms. Six primary terrestrial
ecosystems exist: tundra, taiga, temperate deciduous forest,
tropical rain forest, grassland and desert.
A community of organisms and their environment that occurs on
the land masses of continents and islands.
Terrestrial ecosystems are distinguished from aquatic ecosystems
by the lower availability of water and the consequent importance of
water as a limiting factor.
Terrestrial ecosystems are characterized by greater temperature
fluctuations on both a diurnal and seasonal basis than occur in
aquatic ecosystems in similar climates.
The availability of light is greater in terrestrial ecosystems
than in aquatic ecosystems because the atmosphere is more
transparent in land than in water.
Gases are more available in terrestrial ecosystems than in
aquatic ecosystems.
Those gases include carbon dioxide that serves as a substrate
for photosynthesis, oxygen that serves as a substrate in aerobic
respiration, and nitrogen that serves as a substrate for nitrogen
fixation.
Terrestrial environments are segmented into a subterranean
portion from which most water and ions are obtained, and an
atmospheric portion from which gases are obtained and where the
physical energy of light is transformed into the
organic energy of carbon-carbon bonds through the process of
photosynthesis.
9. Terrestrial ecosystems occupy 55,660,000 mi (144,150,000 km),
or 28.26% of Earth's surface.
10. Although they are comparatively recent in the history of
life (the first terrestrial organisms appeared in the Silurian
period, about 425 million years ago) and occupy a much smaller
portion of Earth's surface than marine ecosystems,
terrestrial ecosystems have been a major site of adaptive
radiation of both plants and animals.
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11. Major plant taxa in terrestrial ecosystems are members of
the division Magnoliophyta (flowering plants), of which there are
about 275,000 species, and the division Pinophyta (conifers), of
which there are about 500 species.
12. Members of the division Bryophyta (mosses and liverworts),
of which there are about 24,000 species, are also important in some
terrestrial ecosystems.
13. Major animal taxa in terrestrial ecosystems include the
classes Insecta (insects) with about 900,000 species, Aves (birds)
with 8,500 species, and Mammalia (mammals) with approximately 4,100
species
14. Organisms in terrestrial ecosystems have adaptations that
allow them to obtain water when the entire body is no longer bathed
in that fluid, means of transporting the water from limited sites
of acquisition to the rest of the body, and means
of preventing the evaporation of water from body surfaces.
15. They also have traits that provide body support in the
atmosphere, a much less buoyant medium than water, and other traits
that render them capable of withstanding the extremes of
temperature, wind, and humidity that characterize
terrestrial ecosystems.
16. Finally, the organisms in terrestrial ecosystems have
evolved many methods of transporting gametes in environments where
fluid flow is much less effective as a transport medium.
17. The organisms in terrestrial ecosystems are integrated into
a functional unit by specific, dynamic relationships due to the
coupled processes of energy and chemical flow.
18. Those relationships can be summarized by schematic diagrams
of trophic webs, which place organisms according to their feeding
relationships.
19. The base of the food web is occupied by green plants, which
are the only organisms capable of utilizing the energy of the Sun
and inorganic nutrients obtained from the soil to produce organic
molecules.
20. Terrestrial food webs can be broken into two segments based
on the status of the plant material that enters them.
21. Grazing food websare associated with the consumption of
living plant material by herbivores.
22. Detritus food webs are associated with the consumption of
dead plant material by detritivores.
23. The relative importance of those two types of food webs
varies considerably in different types of terrestrial
ecosystems.
24. Grazing food webs are more important in grasslands, where
over half of net primary productivity may be consumed by
herbivores.
25. Detritus food webs are more important in forests, where less
than 5% of net primary productivity may be consumed by
herbivores.
The littoral zone
is the part of a sea, lake or river that is close to the
shore.
In coastal environments the littoral zone extends from the high
water mark, which is rarely inundated, to shoreline areas that are
permanently submerged.
It always includes this intertidal zone and is often used to
mean the same as the intertidal zone.
However, the meaning of "littoral zone" can extend well beyond
the intertidal zone.
In oceanography and marine biology, the idea of the littoral
zone is extended roughly to the edge of the continental shelf.
Starting from the shoreline, the littoral zone begins at the
spray region just above the high tide mark.
From here, it moves to the intertidal region between the high
and low water marks, and then out as far as the edge of
the continental shelf.
These three subregions are called, in order, the supralittoral
zone, the eulittoral zone and the sublittoral zone.
Supralittoral zone[edit]
The supralittoral zone (also called the splash, spray or
supratidal zone) is the area above the spring high tide line that
is regularly splashed, but not submerged by ocean water.
Seawater penetrates these elevated areas only during storms with
high tides.
Organisms here must cope also with exposure to fresh water from
rain, cold, heat and predation by land animals and seabirds.
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At the top of this area, patches of dark lichens can appear as
crusts on rocks. Some types
ofperiwinkles, Neritidae and detritus feeding Isopoda commonly
inhabit the lower supralittoral.
Eulittoral zone
The eulittoral zone (also called the midlittoral or
mediolittoral zone) is the intertidal zone also known as the
foreshore.
It extends from the spring high tide line, which is rarely
inundated, to the spring low tide line, which is rarely not
inundated.
The wave action and turbulence of recurring tides shapes and
reforms cliffs, gaps, and caves, offering a huge range of habitats
for sedentary organisms.
Protected rocky shorelines usually show a narrow almost
homogenous eulittoral strip, often marked by the presence of
barnacles.
Exposed sites show a wider extension and are often divided into
further zones.
Sublittoral zone
The sublittoral zone starts immediately below the eulittoral
zone. This zone is permanently covered with seawater and is
approximately equivalent to the neritic zone.
In physical oceanography, the sublittoral zone refers to coastal
regions with significant tidal flows and energy dissipation,
including non-linear flows, internal waves, river outflows and
oceanic fronts. In practice, this typically
extends to the edge of the continental shelf, with depths around
200 meters.
In marine biology, the sublittoral refers to the areas where
sunlight reaches the ocean floor, that is, where the water is never
so deep as to take it out of the photic zone.
This results in high primary production and makes the
sublittoral zone the location of the majority of sea life.
As in physical oceanography, this zone typically extends to the
edge of the continental shelf.
The benthic zone in the sublittoral is much more stable than in
the intertidal zone; temperature, water pressure, and the amount of
sunlight remain fairly constant.
Sublittoral corals do not have to deal with as much change as
intertidal corals. Corals can live in both zones, but they are more
common in the sublittoral zone.
Within the sublittoral, marine biologists also identify the
following:
The infralittoral zone is the algal dominated zone to maybe five
metres below the low water mark.
The circalittoral zone is the region beyond the infralittoral,
that is, below the algal zone and dominated by sessile animals
such as oysters.
A riparian zone or riparian area
is the interface between land and a river or stream.
Riparian is also the proper nomenclature for one of the fifteen
terrestrial biomes of the earth. Plant habitats and communities
along the river margins and banks are called riparian vegetation,
characterized by hydrophilic plants.
Riparian zones are significant in ecology, environmental
management, and civil engineering because of their role in soil
conservation, their habitatbiodiversity, and the influence they
have on fauna and aquatic ecosystems,
including grassland, woodland, wetlandor even non-vegetative. In
some regions the terms riparian woodland, riparian
forest, riparian buffer zone, or riparian strip are used to
characterize a riparian zone.
The word "riparian" is derived from Latin ripa, meaning river
bank.
Riparian zones may be natural or engineered for soil
stabilization or restoration.
These zones are important natural biofilters, protecting aquatic
environments from excessive sedimentation, polluted surface runoff
and erosion.
They supply shelter and food for many aquatic animals and shade
that is an important part of stream temperature regulation.
When riparian zones are damaged by construction, agriculture or
silviculture, biological restoration can take place, usually by
human intervention in erosion control and revegetation.
If the area adjacent to a watercourse has standing water or
saturated soil for as long as a season, it is normally termed a
wetland because of its hydric soil characteristics.
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Because of their prominent role in supporting a diversity of
species, riparian zones are often the subject of national
protection in a Biodiversity Action Plan.
These are also known as a "Plant or Vegetation Waste
Buffer".
A biodiversity action plan (BAP)
is an internationally recognized program addressing threatened
species and habitats and is designed to protect and restore
biological systems.
The original impetus for these plans derives from the 1992
Convention on Biological Diversity (CBD).
As of 2009, 191 countries have ratified the CBD, but only a
fraction of these have developed substantive BAP documents.
The principal elements of a BAP typically include: (a) preparing
inventories of biological information for selected species or
habitats; (b) assessing the conservation status of species within
specified ecosystems; (c) creation of targets
for conservationand restoration; and (d) establishing budgets,
timelines and institutional partnerships for implementing
the BAP.
Subsurface lithoautotrophic microbial ecosystems, or "SLIMEs"
(also abbreviated "SLMEs" or "SLiMEs"),
defined by Edward O. Wilson as "unique assemblages of bacteria
and fungi that occupy pores in the interlocking mineral grains of
igneous rock beneath Earth's surface.