Aquatic Biodiversity

How much of saltwater and freshwater ecosystem covers the earth’s surface?

three-fourths

What are saltwater (marine) ecosystems?

oceans, estuaries, coasts and shorelines, coral reefs, and mangrove swamps

What are freshwater ecosystems?

Lakes, rivers and streams, inland wetlands

What five factors affect the types of organisms found in aquatic ecosystems? 

Salinity, light, dissolved oxygen, dissolved nutrient concentrations, water temperature

Define salinity

the amount of various salts dissolved in water (esp.sodium chloride)

What are high salinity aquatic ecosystems?

oceans, estuaries, costal wetlands, and coral reefs

referred to as marine or saltwater

What are freshwater ecosystems?

lakes, ponds, streams, rivers, and inland wetlands

low salinities

What does the depth to wish light penetrate determine?

Photosynthesis and aquatic vegetation

Define dissolved oxygen

concentrations are usually higher near the surface and tend to be very low near the bottom

Why are ocean important?

because 71% of the earth is covered with water and ocean account for 97% of that

capable of receiving all the land runoff plus man’s wastes and dilute them

their effect upon climate

home to a quarter million species of plants and animals

What are the three major ocean life zones?

Coastal zone

Open sea

Ocean bottom

What is the coastal zone?

a relatively warm, nutrient-rich, shallow part of the ocean that extends from high-tide mark on land to the edge of the continental shelf

Only accounts for 10% of the total oceans and 90% of life

Where is the coastal zone?

All the water above the continental shelf

What is an estuary? 

a zone along a coastline where freshwater from rivers and streams runoff from the land and mix with seawater 

Why are estuaries (bay) significant?

more productive than any other ecosystems

are nursery grounds

What are seagrass beds?

In bay (no longer there)

grow underwater in shallow areas

support a variety of marine species

stabilize shorelines

reduce wave impact

Define wetlands

land that is flooded all or part of the year with fresh or salt water

What are local coastal wetlands?

ex: salt marshes

What do the coastal wetlands in tropical and subtropical areas have?

mangrove trees

What are the ecological and economic services of estuaries and coastal wetlands? 

coastal aquatic systems maintain water quality bu filtering toxic pollutants, excess plant nutrients, sediments

absorb other pollutants 

provide habitats

reduce storm damage and coast erosions 

What coastal zones are in New England and Pacific Northwest?

rocky shores 

What is a intertidal zone?

region between high and low tide

What do the barrier island and their sand dunes do?

protect the wetlands on the bay side

protect low-lying coastal areas from flooding and other damaging effects of storms and hurricanes

ecological services threaten the land

What do coastal zones in tropical and subtropical areas have?

coral reefs

What are coral reefs made up of?

An animal that is made up of calcium deposits from the coral

Habitats for one-fourth of all marine species

What has affected coral reefs?

ocean warming

soil erosion

algae growth from fertilizer runoff

mangrove destruction

coral reef bleaching

rising sea levels

increased UV exposure from ozone depletion

using cyanide and dynamite to harvest coral and reef fish

coral removal for building material, aquariums, and jewelry

damage from anchors, ships, and tourist divers

Where is the Open sea? 

beyond the continental shelf 

accounts for 90% of ocean area and only 10% of its marine life

What are the three vertical zones of the open sea?

Euphotic zone

Bathyal zone

Abyssal zone

All based on sun

What is the euphotic zone?

Phytoplankton

nutrients levels low (unless upwelling)

dissolved oxygen levels high

And have a limited amount of sunlightwhere photosynthesis can occur

What is the Bathyal zone?

Dimly lit

Zooplankton and small fishes

What is the Abyssal zone? 

Dark and cold

High levels of nutrients

little dissolved oxygen

Major threats to marine systems

Coastal development

overfishing

use of fishing trawlers

runoff of nonpoint source pollution

point source pollution

habitat destruction

introduction of invasive species

climate change from human activities

pollution of coastal wetlands and estuaries

What is the largest estuary in the U.S?

Chesapeake Bay in Maryland and has been polluted since 1960 

What caused the pollution in the chesapeake bay? 

point and nonpoint source raised pollution + phosphate and nitrate levels too high + excess sediments from runoff and decreased vegetation + oysters a keystone species was greatly reduced 

What are Freshwater ecosystems?

standing bodies of freshwater: lakes, reservoirs, ponds, freshwater wetlands

flowing freshwater systems: streams, rivers

What is a lake?

large, natural bodies of standing freshwater 

When are lakes formed?

when water from precipitation, land runoff, or groundwater fills a depression in the earth, due to glaciation, earthquakes, volcanic activity, or giant meteorites

What are the four major zones that lakes have?

Littoral zone

Limnetic zone

Profundal zone

Benthic zone

What is the Littoral zone? 

shallow water near shore where sunlight penetrates to the bottom 

rooted plants grow 

high biodiversity: turtles, frogs, crayfish, fish 

What is the Limnetic zone? 

Open, surface sunlight area away from shore 

Enough light for photosynthesis 

Some larger fish

What is the Profundal zone? 

Is the deep, open water region, not penetrated by sunlight 

Too dark for photosynthesis 

What is the Benthic zone? 

Is the bottom of the lake

What are reservoirs?

Are human created bodies of standing freshwater usually built behind a dam

are built for hydroelectric power, irrigation, and human consumption

What are Oligotrophic lakes?

lakes with low supply of plant nutrients

deep, cloud, clear water, with a little plant or animal life

What are Eutrophic lakes?

lakes with high levels of plant nutrients

shallow, warm, and cloudy, with large populations of plants and fish

What are Mesotrophic lakes?

lakes with moderate amounts of plant nutrients

What is eutrophication? 

the physical, chemical, and biological changes in a lake due to excessive nutrients enrichment 

What causes eutrophication?

human activities, especially agriculture, fertilizer runoff, sewage, etc.

What is surface water?

precipitation that has not infiltrated the ground

Where does surface water go? 

runs off into streams, lakes, rivers, wetlands, etc. 

What is watershed?

is the land area that delivers runoff water, sediment, and dissolved substances to a major river and its tributaries

The three phases of water flow 

Begins as cold, clear, fast water, and is usually shaded by trees (source zone) 

Gets deeper, warmer, less turbulent, with less oxygen (transition zone)

Becomes much wider, slower, meandering, carrying sediments into the wetlands and estuaries (flooplain zone)

Define freshwater wetlands

swamps, bogs, marshes, etc. that are. flooded all or part of the year with freshwater

What ecological and economic services do freshwater wetlands provide?

Filter and degrade toxic wastes

Reduce flooding and erosion

Help to replenish streams and recharge groundwater aquifers

Biodiversity

Food and timber

Recreation areas