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Ecology 15 Freshwater, Marine and Wetland Systems Global Climate Change Ralph Kirby.

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Presentation on theme: "Ecology 15 Freshwater, Marine and Wetland Systems Global Climate Change Ralph Kirby."— Presentation transcript:

1 Ecology 15 Freshwater, Marine and Wetland Systems Global Climate Change Ralph Kirby

2 Freashwater and Estuarine Ecosystems Water that falls on land and does not enter the soil or evaporate must create surface water systems Gravity forms streams then rivers These create basins, ponds, lakes floodplains and wetlands Watershed –Area of land drained by a stream or river Catchment –Ponds, lakes and wetlands that retain water for a long time Lotic –Flowing water ecosystems StreamsRiversLentic –Nonflowing water ecosystems PondsLakes Inland wetlands

3 Lakes and Ponds Multiple origins –Glacial –Tectonic –Subsidence –From rivers and streams by silting up –Animals –Humans Inland depression holding standing water –Large range of depths 1 meter to 2000 meters –Large range of sizes 1000 square kilometers 1000 square kilometers Ponds have rooted plants over most of area Lake and pond ecosystems have well defined boundaries –Dependent on light and therefore depth Affected by silt and phytoplankton Oxygen limitation –Littoral zone Where light reaches the botomn –Limnetic zone Where light penetrates, but not to botomn –Frofundal zone Water where light does not support photosynthesis –Benthic zone Bottom zone


5 Littoral Zone –Greatest diversity –Specialization –Many animal species –Provides a large input of organic matter into the whole system

6 Limnetic Zone Dominated by planktonic organisms –Phytoplankton –Zooplankton Seasonal variations Limited by light Phytoplankton limits it’s own light –Thus limnetic zone become shallower as summer progresses Phytoplankton specialiation based on depth and temperature Zooplankton can usually move and therefore may laos be stratified Spring and Autumn turnovers move plankton downwards and organic matter upwards Fish are usually top predators –Influenced by food supply, oxygen and temperature

7 Profundal Zone Limited life –Lack of oxygen –Lack of light –Low temperature Some fish Some plankton, especially zooplankton

8 Benthic Zone Where decomposition occurs Great biological activity Dominated by anaerobic microorganisms As it approaches the surface, it changes –Influence of plants, water movement, light, etc

9 Eutrophication Input of organic matter can change structure of a lake Increases plankton Decreases oxygen Changes temperature profile Affects Epiimnion Human intervention is very important in this –Can occur naturally –Fertilizers and addition of exotic species can also cause this

10 Flowing Water Communities Velocity is very important Geography determines the structure and speed of flow Speed usually higher nearer the sources Speed is reduced on entering a larger body of water –Silt drop Life adapts to the speed of the stream


12 Four major feeding groups in a stream community Flowing water systems are a continuous community Flowing water systems change from the headwaters to the mouth –Vegetation changes –Plankton changes –Animals change

13 Dams have a major effect on flowing water system –Create lakes –Slows water flow Changes spiraling –Reduce flooding –Removes silt –Multiple Dams can compound effects –Three Gorges Project Freshwater eventually joins the marine environment –Estuary –Sediment drop –Mixed environment –Salinity –Water flow in both directions

14 Marine Ecosystems Zonation and Stratification –Pelagic Zone Photic zone –Light Mesopelagic –Light limited Bathypelagic –Dark Neritic province – Continental Shelf Oceanic province –Benthic Zone

15 System varies with season and latitude

16 Surface of pelagic –Phytoplankton dominates Great diversity in species and size –Zooplankton major herbivore –Bacteria also important –Fish very important in Nekton province

17 Benthos Unique World –Surface and subsurface living organisms –Energy from decomposition –Energy from hydrothermal vents Black smokers –300-450 o C White smokers –+300 o C High in minerals Hyperthermophilic organisms –Bacteria –Worms

18 Seashores Rocky shore –Complex environment Wave action –Attachment Tides –How often Oxygen High diversity Sandy or muddy shores –Harsh No place to attach Life is hidden Based on organic matter

19 Rocky Shore

20 Sandy shore

21 Complexity of a coastal ecosystem

22 Coral Reefs High productivity Very high diversity Mixture of coastal and deepwater system

23 Wetlands Area covered with water and supporting aquatic plants Very wide variety of types –Vary with periodicity of flooding –Vary with saturation –Vary with oxygen availability –Salinity –Geography





28 Global Environmental Changes Evidence



31 Results



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