• Aquatic BiomesBroad aquatic ecological associations can be characterized by their physical environment, chemical environment, geological features, photosynthetic organisms, and heterotrophs

97% oceans2% glaciers1% lakes, rivers, streams

Precipitationover land

Transportover land

Solar energy

Net movement ofwater vapor by wind

Evaporationfrom ocean

Percolationthroughsoil

Evapotranspirationfrom land

Runoff andgroundwater

Precipitationover ocean

LakesCoral reefsRiversOceanicpelagic andbenthic zonesEstuariesIntertidal zones

Tropic ofCancer

EquatorTropic ofCapricorn

30ºN

30ºS

fresh water or salt water (marine)Oceans cover about 75% of Earth’s surface and have an enormous impact on the biosphere

Inland aquatics

“Areas of marsh, fen, peatland, or water, whether natural or artificial, permanent or temporary, static or flowing, fresh, brackish, or salt, including areas of marine water, the depth of which at low tide does

not exceed 6 meters”

International Union for the Conservation of Nature

ENSC 2400 will cover the intertidal in Marine Biomes lecture

Running water flows down• Standing water – LENTIC systems

• Flowing water – LOTIC systems

Lakes

Oligotrophic lakes Eutrophic Lakes

Fig. 52-18d

A headwater stream in the GreatSmoky Mountains

Streams and Rivers

The Mississippi River far fromits headwaters

CurrentLifeEffect of damming

Fig. 52-18c

Okefenokee National Wetland Reserve in Georgia

Wetlands

Fig. 52-18f

An estuary in a low coastal plain of Georgia

Estuaries

Fig. 52-16a

Littoralzone Limnetic

zone

Photiczone

PelagiczoneBenthic

zoneAphoticzone

Rooted and floating aquatic plants live in the shallow and well-lighted littoral zoneLimnetic zone is too deep

Stratification - Dimictic example, effects oxygen and nutrient levels in water

Winter

4º4º4º

4ºC

4º 4º

Spring Summer Autumn

Thermocline

4º4º4º

4ºC

4º 4º4º4º

4º4ºC

2º 0º

4ºC5º6º

8º18º20º22º

Hydrology and wetland diversity• Climate (rainfall, temperature, seasonality)• Geomorphology (soils, geology, relief)

Impact defined by the water budget where the volume of water depends on

PrecipitationInterceptionSurface flow

Groundwater in and outflowTidal flow

Water budgets• General

• Marsh – Borders open water (rivers, estuaries), high energy, may be tidal, no OM buildup, plenty of dissolved O2

• Swamp – Occur in depressions, low energy, OM buildup – peat formation, low O2

• Bog- On level groundhigh rain, low evaporation,low energy, organic sediment,high water table

PrecipitationInterceptionSurface flow

Groundwater in and outflowTidal flow

Permanence and periodicityHydroperiod:Frequency of inundation

tidal marsh groundwater fed (constant)vernal poolseasonal rapid flooding from rain or

meltwater

Hydrology factors and results

High energy • Streams, rivers, tidal

marshes• High dissolved O2• High flushing• Open cycling• Erosion dominant• Not much organic matter• High primary productivity• Benthic invertebrates

Low Energy• Swamps and bogs and lakes

• Low dissolved O2• Low flushing• Closed nutrient cycling• Sedimentation dominant• Organic matter accumulates• Variable Primary Productivity• Benthic/planktonic inverts.

Human impacts• Water removal for human use– Wetlands drained, rivers

dammed, groundwater depleted

– Sustainable water usage requires considering the needs of the environment

– Global warming effects on montaine snow

Environmental factors

• Light, Temperature, Dissolved O2, pH, Salinity, Nutrients, Stratification

Light

• Light penetration depth determines how deep photosynthesis can occur

• Penetration of light into the water depends on color of the water and turbidity– Color – caused by dissolved substances from

decaying organic matter – Turbidity – from suspended materials (clay, algae)• Depends on flow, erosion, rainfall rate

Human Impacts - Light

• Clearing vegetation – increased sediment, less shading, quicker photodegradation of organic matter

• Runoff from impermeable surfaces (roads)• Nutrients in sediments cause algal blooms,

clog gills, increase turbidity for other aquatic vegetation

Temperature and Dissolved O2

Temperature• Temperature more variable

due to shallower depth• Changes seasonally or daily• Affects stratification,

metabolism • Affects dissolved O2• Human impacts include:

– Tree clearing reduces shading– Warm/cold water pollution

release from power plants or dams

Dissolved O2 (DO)• Depends on energy of

system, temp, photosynthesis, and stratification

• Used during respiration and decomposition

• Fish kills occur when DO is low – Secondary human impacts

due to effects on other things like temperature

pH (acidity), Salinity

pH• Decreases due to decomposition• Reduces wetland metabolism at

extremes (peat or limestone bogs)

• Human impacts include acid rain (Nox, SO2) from power generation , acid sulfate soils in depleted waters.

• Lowered pH increases availability of heavy metals which then kills fish

• Heavy metal waters can pollute groundwater

Salinity• Salts

– Fresh water, brackish, sea water, salt marsh, hypersaline

• Changes in salt concentration affect osmoregulation of animals

pH (acidity), Salinity

pH• Decreases due to decomposition• Reduces wetland metabolism at

extremes (peat or limestone bogs)

• Human impacts include acid rain (Nox, SO2) from power generation , acid sulfate soils in depleted waters.

• Lowered pH increases availability of heavy metals which then kills fish

• Heavy metal waters can pollute groundwater

Salinity• Salts

– Fresh water, brackish, sea water, salt marsh, hypersaline

• Changes in salt concentration affect osmoregulation of animals

• Human impacts: secondary salinity (removal of deeper rooted perennials with shallow rooted annuals, or through irrigation ) causes salts from the soil to rise and stay in surface soil. Then runoff adds salinity to waterways.

Fig. 55-14c

Decomposers

N2 in atmosphere

Nitrification

Nitrifyingbacteria

Nitrifyingbacteria

Denitrifyingbacteria

Assimilation

NH3 NH4 NO2

NO3

+ –

–

Ammonification

Nitrogen-fixingsoil bacteria

Nitrogen-fixingbacteria

Fig. 55-14d

Leaching

Consumption

Precipitation

Plantuptakeof PO4

3–

Soil

Sedimentation

Uptake

Plankton

Decomposition

Dissolved PO43–

Runoff

Geologicuplift

Weatheringof rocks

Lakes

Oligotrophic lakes Eutrophic Lakes

• When excess nitrogen and phosphorus is discharged from the watershed, massive algal blooms develop which result in the depletion of dissolved oxygen.

Eutrophication

A Dead Zone 6,000-7,000 sq miles develops

Pollution