Ch. 8 Aquatic Biodiversity

Saltwater biome

oceans, estuaries, coasts, coral reefs, mangrove forest

Freshwater biome

lakes, rivers, streams, inland wetlands

Plankton

drifting aquatic (micro)organisms that can’t swim therefore relying on currents and waves

Nekton

strong swimmers (e.g. fish, turtles, and whales)

Benthos

bottom dwellers (e.g. oysters, sea stars, clams, lobsters, and crabs)

Importance of saltwater ecosystem

• Oxygen

• Rain/ water supply

• Seafood

• Climate regulation

Posidonia Oceanica Meadows

• Good bioindicator for sea bottom conditions

• Supports diverse ecosystems

• Carbon sink and oxygen pump

• Sediment stabilization

• Filtration

Tides

gravitational pull of the sun and moon

Coral Reefs

marine equivalent of tropical rainforests, living organisms that serve as the home for a lot of aquatic life

• thrive on solar energy

• like warm areas far away from the coast to avoid runoff

• participate in carbon cycling

• sustain aquatic biodiversity

3 vertical zones of the open sea

• Euphotic

• Bathyal

• Abyssal

Human Activities Degrading Marine Systems

• coastal development

• runoff of pollutants

• overfishing

• destruction of ocean bottom habitats

• introduction of invasive species

• tourism

Standing (lentic) systems of freshwater

lakes, ponds, inland wetlands

Flowing (lotic) systems of freshwater

streams and rivers

4 Life Zones of Lakes

• Littoral

• Limnetic

• Profundal

• Bentheic

Littoral zone

shallow water near shore where rooted plants grow; high biodiversity

Limnetic zone

open sunlight area away from shore; main photosynthetic zone

Profundal zone

deep water that is has too low oxygen and is too dark for photosynthesis

Benthic zone

lake bottom occupied by decomposers, detritus feeders, and some fish nourished primarily by dead matter

3 Life Zones of Streams/Rivers

• source

• transition

• floodplain

Source zone

• shallow, cold, clear, swiftly flowing headwater stream

• lots of mixing water with the atmosphere, poor in nutrients

Transition zone

• wider, deeper, warmer streams

• more nutrients with lower levels of oxygen

Floodplain zone

• wide, deep rivers that flow across flat valleys

• high temperatures and dissolved oxygen

Importance of Inland Wetlands

•  Filtering toxic wastes and pollutants

• Reducing flooding and erosion

• Sustaining stream flows during dry periods

•  Recharging groundwater aquifera

• Providing habitats for a variety of species

• Supplying valuable products

Human Effect on Freshwater Ecosystems

• flood-control destroys aquatic habitats

• cities and farms pollute water

• wetlands drained for human purposes