Aquatic Ecology Life of the Wet Things. Marine vs. Fresh Marine = Salt water –Estuaries, Coastlines, Coral reefs, Coastal marshes, Deep ocean Freshwater.

Aquatic Ecology

Life of the Wet Things

Marine vs. Fresh

• Marine = Salt water– Estuaries, Coastlines, Coral reefs,

Coastal marshes, Deep ocean

• Freshwater = Non-salty water– Lakes, Ponds, Stream, Rivers, Inland

wetlands

Major Types of Aquatic Life

• Plankton – Free floating

• Nekton – Strong swimming

• Benthos – Bottom dwelling

Advantages of Living in Water

• Natural buoyancy– Less energy spent on support

• Usually limited fluctuations of temperature

• Nutrients usually available

• Waste/toxins diluted

Limiting Factors of Life at Different Depths

• Three major zones– Surface

– Middle

– Bottom


• Life limited by following factors at different depths– Temperature

– Sunlight

– DO

– Nutrients


• Temperature drops as depth increases


• Sunlight can only penetrate about 100ft (30m)– Euphotic Zone


• DO– Varies by temperature and depth

– Comes mostly from atmosphere

– Can be added to by producers

– Depleted by consumers



• Nutrients– Affected by upwelling

– Phosphorus (phosphates) most limiting in freshwater

– Nitrogen (nitrates) most limiting in saltwater

Saltwater Life Zones

• Importance of oceans– 71% of planet– Heat sink– Major role in hydrologic cycle– Has a somewhat large influence in the

earth’s weather patterns• Ok, not so large, more like HUGE

– Gigantic reservoir for CO2


• Two major life zones– Coastal Zone

• On top of the continental shelf• 10% of ocean/90% of ocean life• High primary and net productivity

– Open Ocean




• Estuaries and Tidal Zones– Salt and freshwater mix

• Temperature and salinity vary– Runoff– Tidal flow

• Huge cleaning affect on environment


• Coastal Wetlands– Covered by salt water most of the year

– Breeding grounds/habitat for wildlife

– Filters waste/toxin

– Buffers shores against damage

– Bays, Mud flats, Salt marshes


• Rocky and Sandy Shores– Intertidal Zone

• Between low and high tide

– Rocky shores• Pounded by waves, but still lots of life

– Barrier beaches• Life must dig


• Human impact on coastal zones– 2/3 of human life live within 100 miles of

a coast

– California has lost 91% of its original coastal wetlands


• Coastal wetlands very vulnerable to pollution– Easy to trap pollutants

• Coral reefs decreasing due to human destruction


• Open ocean– Three life zones based on penetration of

sunlight• Euphotic• Bathyal• Abyssal


• Euphotic– Photosynthesis takes place

– Low nutrients

– High DO


• Bathyal and abyssal zones– COLD– Low DO– High nutrients– Life includes

• Deposit feeders• Filter feeders

– Tragedy of Commons

Things to Remember While Googling

• Its abyssal, not abysmal.

Freshwater Life Zones

• Dissolved salt <1% by volume

• Two types– Standing

– Flowing


• About 1% of earth’s surface, but 41% of known fish


• Closely connected to their surrounding terrestrial biomes.– Why?


• Dissolved salt <1% by volume

• Two types– Standing

– Flowing


• About 1% of earth’s surface, but 41% of known fish


• Closely connected to their surrounding terrestrial biomes.– Why?

Freshwater Lakes

• Lake Zones

Freshwater Lakes

• Littoral zone– Shallow– Near shore– Rooted plants stop growing outside the zone– Rich in nutrients– High in biological diversity

• Rooted plants, decomposers, and the usual suspects

Freshwater Lakes

• Limnetic zone– Like the euphotic zone

– Enough light for photosynthesis• Limits depth of limnetic zone

– Starting with plankton, simple food web

Freshwater Lakes

• Profundal zone– Deep, open water

– Too deep for photosynthesis

– Fish only

Freshwater Lakes

• Benthic zone– It’s the bottom.

– Mostly decomposers and detritus-feeders

Types of Freshwater Lakes

• Two types– Oligotrophic

– Eutrophic


• Oligotrophic– Poorly nourished

Freshwater Lakes


• Oligotrophic– Deep with steep

sides

– Crystal-clear blue or green water


• Eutrophic– Well-nourished

Freshwater Lakes


• Eutrophic– Lots of nutrients for producers

• Nitrates and phosphates

– Usually shallow and murky

– During summer, bottom may have low DO

Season Changes in Lakes

• Water is cool, especially when frozen– Makes water unique

– Also helps lakes survive wickedly cold winters• Wickedly meaning not like “Mr. Williamson,

it’s cold in here” or “It’s freezing outside in the F-quad”



• Lake layers– Epiliminon

– Thermocline

– Hypoliminon


• Winter– Top layer freezes

• Insulates lower layers from “wicked” cold• DO ok in epiliminon, not so good in

hypoliminon



• Spring– Ice melts and warms, reaching max

density

– Sinks forcing nutrient rich water from bottom• Helped by winds

– Spring overturn



• Summer– VERY definite stratification

– Causes bottom to loose DO and nutrients



• Fall– Epiliminon cools and becomes more

dense

– Sinks, causing cooler, nutrient rich water to rise

– DO good everywhere

Freshwater Streams and Rivers

• Consists of runoff

• Watershed


• Three zones– Headwater or source zone

– Transition zone

– Flood plain zone


• Source zone– Cold water

– Fast moving

– Lots of DO

– Organisms well adapted to environment




• Transition zone– Deeper channels

– Slower water

– Warmer water


• Flood plain zone– Slow moving

– Murky


• Importance of inland wetlands– Food source and habitats

– Improved water quality

– Reduced flooding and erosion

– Replenish groundwater


• Human impact– Loss of wetlands due to

• Agriculture (80%)• Mining• Forestry• Oil/gas extraction• Urban development


• Mitigation banking– Replacing lost wetlands with equal area

of sime type• Doesn’t work well


• Best course of action– Prevention

Aquatic Life Zones

• Why are they important?

• How do humans impact them?

• How does species diversification relate?

Aquatic Ecology Life of the Wet Things. Marine vs. Fresh Marine = Salt water –Estuaries, Coastlines, Coral reefs, Coastal marshes, Deep ocean Freshwater.

Documents

saltwater slide

dwelling slide

environment slide

freshwater life zones

human life

saltwater life zones

saltwater life zones

life barrier beaches