APES Chapter 8 - Aquatic Biodiversity

Key Concepts/Questions to Know:

8-1 What is the general nature of aquatic systems?

8-2 Why are marine aquatic systems important?

8-3 How have human activities affected marine ecosystems?

8-4 Why are freshwater ecosystems important?

8-5 How have human actives affected freshwater ecosystems?

Aquatic Systems cover

¾the of the earths surface with the ocean dominating - 71% of earths surface and freshwater with 2.2%

• Ocean divided into 4 large areas: Pacific, Atlantic, Indian and Arctic Oceans

• Pacific is the largest

KEY factors determining biodiversity in aquatic systems: **

1. Temp

2. Dissolved oxygen content

3. Availibility of food

4. Access to light and nutrients needed for photosynthesis

Aquatic Life Zones+ 2 major types

Saltwater and freshwater portions of the biosphere that can support life. Aquatic life zones are the counterpart of biomes

2 major aquatic zones are determines by salinity (amounts of various dissolved salts

1. Freshwater

2. Saltwater

Freshwater Life Zones

lakes, rivers, streams, inland wetlands

Saltwater/Marine Life Zones

Oceans and their bays, estuaries (mix of salt and fresh ), other costal ecosystems

4 Major Types of Aquatic Organisms:

1. Plankton

2. Nekton

3. Benthos

4. Decomposers

Plankton

free-flowing and weakly swimming. Types include:

• Phytoplankton - drifters photosyntheziers (lots of algea)

• Ultraplankton - even smaller than photo,

  huge populations of photosynthetic bacteria

  Photo and Ultra make up the producers and are the basis for the aquatic food chains and webs.

• Zooplankton - feed on photo and other zoo (jellyfish ex or a lot smaller)

Nekton

Strong Swimming Consumers like fish, turtles, and whales found in the pelagic zone.

Benthos

Bottom dwellers like oysters, clams, lobsters, crabs, worms.

Decomposers

Mostly Bacteria which break down organic compounds in the dead bodies and wastes of aquatic organisms.

Marine Abiotic Factors (repeat but important)**

Determine the type and # of organisms and various depths. Includes:

• Water temp and density

• Dissolved oxygen content

• Availability of food

• Availability of light and nutrients required for photosyn.

Photosynthesis is largely confined to the..

Upper layer of water (euphoric or photic zones ) because sunlight can penetrate. This depth for these zones is reduced due to algae blooms - eutrophication.

Coastal Zone

EX. Estuaries, coastal wetlands, coral reefs, barrier islands, + beaches

• Shallow

• Warm

• Nutrient Rich

• High Primary Productivity

  10% of area 90% of oceans species

• Extends from the high tide mark on land to the continental shelf

Estuaries

Where the river meets the sea

• Associated with coastal wetlands - really productive due to the nutrients from the rivers

Marine Life Zones - Refrence Diagram on Phone Dec 2

Euphotic Zone - warmer near-surface where Plankton and some Kekton live. Nutrients levels low but dissolved oxygen and sunlight high.

Bathyal Zone - dimly lit middle zone(little sunlight and does not contain any photosynthesized produces. Zoo and small fish populate this zone

Abyssal Zone - Dark + Cold, little dissolved oxygen. contain the Benthic. Most organism get their food from marine snow - showers of dead and decaying organisms

Pelagic

Open Sea

• NPP is low besides in upwelling areas however due to its surface coverage makes the largest contribution to the earths overall NPP

8-2 + 8-3 Why are marine aquatic systems important and how have we affected them?

saltwater systems drive major ecological and economical services and are irreplaceable reserves of biodiversity.

Marine Ecosystem Ecological Services:

• Climate moderation

• CO2 absorption

• nutrient cycling

• waste treatment

• reduced storm impact

• habitats

• genetic resources and biodiversity

• Scientific info

Marine Ecosystem Economic Services:

• Food

• Animal and pet feed

• pharmaceuticals

• Harbors and transpo.

• human habitat

• employment

• oil and natural gas

• minerals

Human Impact on Marine Ecosystems:

• ½ costal wetlands lost to agriculture and urban development + mangrove forests

• Beaches eroding due to higher sea levels and development

Human Impact on Coral Reefs:

• Ocean warming

• Ocean acidity

• soil erosion

• euthropication

• rising sea levels

• increaed UV exposure

• damage from fishing, diving…

• overfishing

8-4 + 8-5 What are the major types of freshwater systems and how have humans impacted them? NT

Water stands ( lentic) in some freshwater systems and flows(lotic) in others

• Surface water(flows or stored)

  Surface water that flows is called runoff.

• Watershed/drainage basin = land area that delivers runoff, sediment into a stream, lake or wetlands.

Lakes

Large natural bodies of standing water formed when precipitation, runoff, streams, rivers, and groundwater seepage fill depressions in the earths surface.

• Causes of depression glaciation, displacemnt of earths crust, volcanic activity

• Lakes have 4 zones

Lake stratification and Turnover

In the fall and spring, changing water temp can lead to mixing or “turnover” of water, oxygen, and nutrients.

Lake Types

Low Nutrient Lake = Oligotrophic

High Nutrient Lake = Eutrophic

In between these two extremes = Mesotrophic

Runoff

Surface water when it moves to streams or lakes.

Watershed/ Drainage Basin

land area that delivers runoff, sediment and dissolved substances to a stream or lake.

Water flows through 3 distinct zones:

1. Source (Ex. Sierra)

2. Transition (Ex. Foothills)

3. Floodplain (Ex. Delta)

Inland Wlands et

lands located away from coastal areas that are covered with fresh all or most of year - excluding lakes, reservoirs, and streams

• Ex. marshes, swamps, prairie potholes

Freshwater Systems Ecological Services:

• Climate moderation

• nutrient cycling

• flood control

• groundwater recharge

• habitats

• genetic resources and biodiversity

• scientific info

Freshwater Systems Economic Services:

• Food

• Drinking water

• irrigation water

• Hydroelectricity

• transport corridors

• recreation

• employment

Human Impacts on Freshwater Systems

• Diversion, restrict the flow of water - dams and canals

• Flood control levees and dikes - disconeenst rivers destroying habitabt

• Wetland and other habitat Destruction

• Pollutants from city and industry (including thermal pollution)

• Euthrophication

• Overuse: recreation, fishing, building

Island Biogeography

Geographical analyses of plant and animals species on islands

• Islands have been colonized in the past by new species arriving from elsewhere

Three Big Ideas Chapter 8

1. Differences in climate, based mostly on long-term differences in avg temp and precipitation, largely determines the types and locations of the earth’s biomes, grasslands, forests, and deserts.

2. Saltwater and freshwater aquatic systems cover almost ¾ of the earth’s surface and oceans dominate the planet.

3. The earth’s terrestrial and aquatic systems, provide important ecological and economic services, which are being degraded and disrupted by human activities.