Energy flows

Energy Flow

By

Dr. Md. Shafiqur RahmanUMK

Energy flow

Energy flow is the capture of solar energy through photosynthesis, which is the process used by green plants to convert radiant energy from the sun into organic compounds such as glucose.

Energy flow

With the known exception of organisms that live along thermal vents in the deep ocean floor, all organisms--including humankind--nurture themselves, directly or indirectly, on the products of photosynthesis.

Energy flow

Energy flow can increase in a given area by lengthening one or more legs of the triangle that forms the base of solar conversion of the energy tetrahedron: length of the growing season, volume of plants, or leaf area. All of these factors are related to other ecosystem processes such as the water cycle, mineral cycles, and community dynamics.

Energy flow

We can increase energy flow into food crops, fiber, and forage by lengthening the growing season (with irrigation, for example). We can increase the volume and leaf area of plants (by adding nitrogen fertilizer, for example). However, long-term solutions to low energy flow must take into account all of the ecosystem processes, and must enhance biodiversity as well.

Energy flow

Most of the food we eat comes from simple food chains derived from human-controlled agricultural ecosystems. For example, the beef we eat comes from a cow that ate corn or grass . The corn or grass received its energy from the sun.

Energy flow

In natural ecosystems, a hawk may eat a snake that may have received its energy from a mouse, a frog, or a rabbit. If it ate a mouse, that mouse may have consumed seeds from any number of plants. None of these food chains is exactly alike, which makes studying energy transfer complex.

Energy flow

The food chain begins with producers, organisms such as green plants, that can make their own food. Through photosynthesis, producers convert solar energy to chemical energy, energy in the chemical bonds of the food. Of all the energy a plant receives from the sun

Energy flow

Plants are eaten by consumers, which are organisms that cannot make their own food. Herbivores are consumers that eat only producers. Consumers that prey on other consumers are called carnivores. If an animal can get its energy by ingesting either producers or consumers, it is an omnivore.

Energy flow

The amount of energy that is transferred from one organism to the next varies in different food chains. Generally, about ten percent of the energy from one level of a food chain makes it to the next.

Energy flow

Because energy is "lost" with each successive link, there must be enough energy in the organisms to allow for this loss and still have enough energy remaining for the consumers in the next level.

Energy flow

Decomposers, such as, bacteria, fungi, and small animals such as ants and worms, eat nonliving organic matter. Decomposers cycle, nutrients back into food chains and the remaining potential energy in unconsumed matter is used and eventually dissipated as heat. Therefore, decomposers are an integral component of all ecosystems (First and Second Laws of Thermodynamics).

Energy flow

In food chains there are many alternate routes through which energy can flow, creating integrated, complex food webs. Through agriculture, humans have simplified food chains so the energy flow is more direct

Energy flow

Species interactions include relationships like pollination, mutualism, predation, and decomposition. Plants and animals in an environment interact with each other in various ways. For example, plants may depend on insects or birds to pollinate flowers and on earthworms to aerate the soil; animals may depend on plants for food or shelter.

Energy flow

The interaction of living and nonliving components affects the qualities and characteristics of an ecosystem. These interactions can influence the climate within the area (often called a micro-climate). For example, in a forest tall trees block the sunlight resulting in a shady moist under story where only certain plants can live.

Energy Flow and Chemical Cycling

Every ecosystem is characterized by two fundamental phenomena:

Energy flow:- Begins when producers absorb solar energy- Make organic nutrients via photosynthesis- Organic nutrients are used by themselves & by

othersChemical cycling- The pathways by which chemicals

circulate through the ecosystems, involve both living (biotic) and non-living (geologic) components.

• A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment.[1] They are used to build and repair tissues, regulate body processes and are convOrganic nutrients erted to and used as energy.

• include carbohydrates, fats, proteins (or their building blocks, amino acids), and vitamins. Inorganic chemical compounds such as dietary minerals, water, and oxygen may also be considered nutrients.[

Natural Organic Matter (NOM)

Natural organic matter is present throughout the ecosystem. After degrading and reacting, it can then move into soil and mainstream water via waterflow. NOM forms molecules that contain nutrients as it passes through soil and water. It provides nutrition to living plant and animal species. NOM acts as a buffer, when in aqueous solution, to maintain a less acidic pH in the environment

Energy flow Through an Ecosystem

Ecosystems consists of 2 parts: biotic and abiotic component-Energy flows from sun to producer to

consumer to decomposer-Much energy is converted to heat as it moves

from one organism to another

Chemical CyclingThe pathways by which chemicals circulate through ecosystems:-Involve both living(biotic) and nonliving (geologic)Components.- Known as bio-geochemical cycle.• The water Cycle• Carbon Cycle• Phosphorus Cycle• Nitrogen Cycle

Chemical CyclingThe pathways by which chemicals circulate through ecosystems:-Involve both living(biotic) and nonliving (geologic)Components.- Known as bio-geochemical cycle.• The water Cycle• Carbon Cycle• Phosphorus Cycle• Nitrogen Cycle

The Water CycleIs the cycle of evaporation and

condensation that controls the distribution Earth’s water as it evaporates from the bodies of water, condenses, precipitates and returns those bodies of water

The Water Cycle

The Water Cycle

As water travels through the water cycle, some water will become part of The Global Conveyer Belt and can take up to 1,000 years to complete this global circuit. It represents in a simple way how ocean currents carry warm surface waters from the equator toward the poles and moderate global climate.

The Water Cycle

The Water Cycle (also known as the hydrologic cycle) is the journey water takes as it circulates from the land to the sky and back again.

The Water Cycle

The Sun's heat provides energy to evaporate water from the Earth's surface (oceans, lakes, etc.). Plants also lose water to the air (this is called transpiration). The water vapor eventually condenses, forming tiny droplets in clouds. When the clouds meet cool air over land, precipitation (rain, sleet, or snow) is triggered, and water returns to the land (or sea).

The Water Cycle

Some of the precipitation soaks into the ground. Some of the underground water is trapped between rock or clay layers; this is called groundwater. But most of the water flows downhill as runoff (above ground or underground), eventually returning to the seas as slightly salty water.

Importance of the ocean in the water cycle

Oceans cover about 70% of the Earth's surface and contain roughly 97% of the Earth's water supply. Ocean plays a key role in this vital cycle of water with holds 97% of the total water on the planet; 78% of global precipitation occurs over the ocean, and it is the source of 86% of global evaporation.

WHY ARE THE OCEANS SALTY?

As water flows through rivers, it picks up small amounts of mineral salts from the rocks and soil of the river beds. This very-slightly salty water flows into the oceans and seas. The water in the oceans only leaves by evaporating (and the freezing of polar ice), but the salt remains dissolved in the ocean - it does not evaporate. So the remaining water gets saltier and saltier as time passes.

The planet is approximately 71% water and contains (5) five oceans, including the Arctic, Atlantic, Indian, Pacific and Southern.

Five oceans

Importance of Hydrological cycle (water cycle)

Earth is a truly unique in its abundance of water. Water is necessary to sustaining life on Earth, and helps tie together the Earth's lands, oceans, and atmosphere into an integrated system. Precipitation, evaporation, freezing and melting and condensation are all part of the hydrological cycle - a never-ending global process of water circulation from clouds to land, to the ocean, and back to the clouds. Contd.

Importance of Hydrological cycle (water cycle)

This cycling of water is intimately linked with energy exchanges among the atmosphere, ocean, and land that determine the Earth's climate and cause much of natural climate variability. The impacts of climate change and variability on the quality of human life occur primarily through changes in the water cycle.

Contd.

Importance of Hydrological cycle (water cycle)

The fresh water that we use and its continuous replacement is a result of the water cycle. The earth have limited amount of fresh water and if water that evaporate never return back to earth, we would not be living now. One can live longer without food than without water.

The carbon cycle

Is the bio-geochemical cycle by which carbon is exchanged among the biosphere, geo-sphere, hydrosphere& atmosphere and recycled & reused throughout the biosphere and all the organisms.

The carbon cycle

The carbon cycle

The carbon cycle

Carbon is the backbone of life on Earth. We are made of carbon, we eat carbon, and our civilizations—our economies, our homes, our means of transport—are built on carbon. We need carbon, but that need is also entwined with one of the most serious problems facing us today: global climate change.

The carbon cycle

Forged in the heart of aging stars, carbon is the fourth most abundant element in the Universe. Most of Earth’s carbon—about 65,500 billion metric tons—is stored in rocks. The rest is in the ocean, atmosphere, plants, soil, and fossil fuels.

Carbon Cycle - Photosynthesis

Photosynthesis is a complex series of reactions carried out by algae, phytoplankton, and the leaves in plants, which utilize the energy from the sun. The simplified version of this chemical reaction is to utilize carbon dioxide molecules from the air and water molecules and the energy from the sun to produce a simple sugar such as glucose and oxygen molecules as a by product. The simple sugars are then converted into other molecules such as starch, fats, proteins, enzymes, and DNA/RNA i.e. all of the other molecules in living plants. All of the "matter/stuff" of a plant ultimately is produced as a result of this photosynthesis reaction.

Carbon Cycle - Photosynthesis

Nitrogen Cycle

Nitrogen is both the most abundant element in the atmosphere and, as a building block of proteins and nucleic acids such as DNA, a crucially important component of all biological life. The nitrogen cycle is a complex biogeochemical cycle in which nitrogen is converted from its inert atmospheric molecular form (N2) into a form that is useful in biological processes.

Nitrogen Cycle

Nitrogen Cycle

Nitrogen fixation

Atmospheric nitrogen occurs primarily in an inert form (N2) that few organisms can use; therefore it must be converted to an organic - or fixed - form in a process called nitrogen fixation. Most atmospheric nitrogen is 'fixed' through biological processes

Nitrification

While ammonia can be used by some plants, most of the nitrogen taken up by plants is converted by bacteria from ammonia - which is highly toxic to many organisms - into nitrite (NO2

-), and then into nitrate (NO3-). This

process is called nitrification, and these bacteria are known as nitrifying bacteria.

Assimilation

Nitrogen compounds in various forms, such as nitrate, nitrite, ammonia, and ammonium are taken up from soils by plants which are then used in the formation of plant and animal proteins.

Ammonification

When plants and animals die, or when animals emit wastes, the nitrogen in the organic matter reenters the soil where it is broken down by other microorganisms, known as decomposers. This decomposition produces ammonia which is then available for other biological processes.

Denitrification

Nitrogen makes its way back into the atmosphere through a process called denitrification, in which nitrate (NO3

-) is converted back to gaseous nitrogen (N2). Denitrification occurs primarily in wet soils where the water makes it difficult for microorganisms to get oxygen. Under these conditions, certain organisms - known as denitrifiying bacteria - will process nitrate to gain oxygen, leaving free nitrogen gas as a byproduct.

PHOSPHORUS CYCLE

Phosphorus enters the environment from rocks or deposits laid down on the earth many years ago. The phosphate rock is commercially available form is called apatite. Other deposits may be from fossilized bone or bird droppings called guano

Phosphorus Cycle

Phosphorus Cycle

When plant materials and waste products decay through bacterial action, the phosphate is released and returned to the environment for reuse.

Phosphorus Cycle

Phosphate is incorporated into many molecules essential for life such as ATP, adenosine triphosphate, which is important in the storage and use of energy. It is also in the backbone of DNA and RNA which is involved with coding for genetics.

Human Inputs to the Phosphorus Cycle

Human Inputs to the Phosphorus Cycle

Plants may not be able to utilize all of the phosphate fertilizer applied, as a consequence, much of it is lost form the land through the water run-off. Animal wastes or manure may also be applied to the land as fertilizer. If misapplied on frozen ground during the winter, much of it may lost as run-off during the spring thaw. In certain area very large feed lots of animals, may result in excessive run-off of phosphate and nitrate into streams.

Human Inputs to the Phosphorus Cycle

Other human sources of phosphate are in the out flows from municipal sewage treatment plants. Without an expensive tertiary treatment, the phosphate in sewage is not removed during various treatment operations. Again an extra amount of phosphate enters the water.