Wetlands and Aquatic Ecosystems: Types, Characteristics, and Importance, Slides of Ecology and Environment

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Wetlands

 In between fully aquatic and fully terrestrial ecosystems

 Standing water for at least part of the year

 Vegetation adapted to growing with submerged roots

Wetlands

 Classified by vegetation type:  Swamps – woody plants and shrubs  Marshes – reeds, rushes, other grasses  Bogs – sphagnum moss  Fens – sedges, rushes  Mangroves

Wetlands

 Perform services useful to humans

 Purify water by trapping sediments and breaking down toxic wastes and chemicals that run off agricultural land

 Serve as reservoirs that reduce the risk of flooding

Aquatic Ecosystems

 Water covers 71% of the Earth’s surface

Freshwater

 Only 1% of water is freshwater

 Only 0.3% of freshwater is available on the Earth’s surface, the rest is locked in glaciers, polar ice and underground aquifers

Freshwater Ecosystems

 Include:

 Standing water (ponds and lakes)  Flowing water (streams and rivers)

Lakes

Oligotrophic lake

Eutrophic lake

Lake Stratification

 In temperate zones, deep lakes are stratified in summer  Epilimnion – Surface layer, warm from solar radiation, least dense  Thermocline – Thin middle layer  Hypolimnion – Lower layer, cold, most dense

 Layers do not usually mix; less dense water floats on top of more dense water

Lake Stratification

 In winter, ice forms on the surface, maintaining a uniform temperature

 Overturn is repeated again in spring as the ice melts

Life Zones

 Lakes can be stratified into different life zones according to:  Amount of sunlight penetration  Nutrient levels  Temperature  Amount of dissolved oxygen

Streams & Rivers

 Bodies of water that move continuously in one direction

 May originate from springs, runoffs from melting snow or ice, or outlets of lakes

 Structure changes from their point of origin ( headwaters ) to where they empty into a larger body of water ( mouth )

Streams and Rivers

 Headwaters:

 Water is clear  Little sediment  Few nutrients  Channel is narrow  Rocky substrate  Water flows swiftly

Estuaries

 Partially enclosed body of water where freshwater and seawater mix

 River meets the ocean

 Salinity varies greatly

 Highly productive due to nutrients brought in by rivers

Estuaries

 High biodiversity

 These organisms must be able to adapt to changing salinity

 Estimated over half of all marine fishes require development in estuaries