biodiversity in aquatic systems. objective(s): swbat describe the various types of organisms in...

Chapter 8:Aquatic BiodiversityBiodiversity in Aquatic Systems

C8Aquatic Environments: Types, components and limiting factors

Objective(s): • SWBAT describe the various types of organisms

in aquatic ecosystems. • SWBAT compare and contrast the major types of

plankton. • SWBAT explain some of the physical and

chemical characteristics of water. • SWBAT describe what factors limit life at

different depths in aquatic life zones. • SWBAT compare and contrast the coastal zone

and open sea.


Objective(s):• SWBAT differentiate between the various saltwater life

zones, including what types of organisms and places found in our country.

• SWBAT describe what types of impacts human activities have on aquatic life zones, particularly, the coastal zone.

• SWBAT describe the life zones found in freshwater lakes.

• SWBAT describe the different types of lakes.• SWBAT discuss what seasonal changes occur in

temperate lakes.• SWBAT summarize the major characteristics of

fresh water streams and rivers.

C8Aquatic Environments: Types, components and limiting factors• Aquatic Life Zones: aquatic equivalent of biomes. • Two Major Types of Aquatic Life Zones:•Marine (Estuaries, coastlines, coral reefs, marshes and swamps)• Freshwater (Lakes, ponds, streams, rivers, & inland wetlands)

• Major types of organisms found in different aquatic environments is determined by salinity.

C8 Aquatic Environments: Types, components and limiting factors

Major Types of Organisms in Aquatic Ecosystems:1. Plankton: free floating

and/or weak swimmers2. Nekton: strong swimming

consumers (fish, whales)3. Benthos: bottom dwellers

(barnacles, crabs, worms)4. Decomposers: break down

organic matter

C8 Aquatic Environments: Types, components and limiting factors3 Categories of Plankton:1. Phytoplankton: free-floating microscopic

cyanobacteria and many types of algae. **supports most aquatic food chains and food web**

2. Nanoplankton: very small photosynthetic plankton also termed ultraplankton

3. Zooplankton: mixture of nonphotosynthetic consumers


Physical and Chemical Properties of Water:1. Buoyancy: upward force exerted by a fluid, that

opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid.

2. Water provides a medium for dispersing gametes (sometimes long distances to begin new colonies)

3. Water is readily available; No adaptations for conserving water necessary

4. Filters out UV light5. Dilutes pollutants: surface of bottom sediments

tend to have concentrated levels of these pollutants.


Species and Habitat Diversity • The properties of water allow for a variety of

organisms not found on land.• Fluidity of water allows for less pronounced and

physical boundaries between aquatic life zones than in terrestrial ecosystems. **Counting and managing populations of aquatic organisms is more difficult**

• Endemism: restriction of a species to one location or habitat (less common in water than on land)


Trophic Structure and Food Web:1. Open water aquatic

systems: most plants are microscopic phytoplankton that float in water column

2. Aquatic food chains and food webs are more complex and have more trophic levels than terrestrial ecosystems.

C8 Aquatic Environments: Types, components and limiting factorsPopulation Characteristics: • Most aquatic species have a high reproductive rate

and short life cycles (exceptions include many whale species)

• Most aquatic species separate from their parents earlier in life than terrestrial species (exceptions include many whale species)

• Some populations are isolated and specific to the location they inhabit (for example, certain isolated lakes have species not found anywhere else on earth)


What factors limit life at different depths in the aquatic life zones?• Most aquatic life zones can be divided into

three layers: surface, middle and bottom.• Environmental factors that determine the

types and numbers of organisms found in the three major layers include:

• Temperature• Access to sunlight for photosynthesis• Dissolved oxygen content• Availability of nutrients


What factors limit life at different depths in the aquatic life zones?• Upper surface layer (euphotic zone):

Photosynthesis is confined to this layer, algal cells and clay/silt particles filter the light out so it does not reach the lower layers

• Ample nutrient supply in shallow water of streams, ponds, and ocean. The open ocean is in short supply of such nutrients (phosphates, nitrates, iron)

C8 Saltwater Life Zones

• Oceans are split up into two major life zones:• Coastal Zone• Open Sea

• Coastal Zone: warm, nutrient-rich shallow waters that extend from the high tide mark on land to the gently sloping shallow edge of the continental shelf**easily influenced by human activities on land**

• Open Sea: ocean beyond continental shelf.

Ocean Zones

C8 Saltwater Life ZonesCoastal Zone:

• Less than 10% of the ocean’s area contains 90% of all marine species

• Nutrients flow from land• Very High Primary Productivity (due to

ample sunlight and nutrients from land)• Provides a variety of habitats for marine life:

• Bottom can be muddy, sandy, or rocky• Shorelines can vary from smooth sandy beaches

to jagged rocky cliffs• Coastal wetlands vary from mangrove forests to

saltwater marshes

• Water depth varies from a few centimeters to kilometers

C8 Saltwater Life ZonesCoastal Wetlands: Mangrove Forests


Coastal Wetlands: Saltwater Marsh

San Francisco Bay

Humboldt

C8 Saltwater Life ZonesCoastal Zones: Rocky Beaches

Monterey CA

Humboldt

7-2 Saltwater Life ZonesCoastal Zones: Sandy Beaches

Florida

Humboldt: Clam Beach

C8 Saltwater Life ZonesCoastal Zone: Estuaries & Wetlands• Estuary: a partially enclosed area of coastal

water where sea water mixes with fresh water and nutrients from rivers, streams and runoff from land. An ecotone.

• Coastal Wetlands: land areas covered with water all or part of the year associated with estuaries include, river mouths, inlets, bays, sounds, mangrove forest swamps in tropical water.

• Temperature and salinity levels vary in estuaries and wetlands due to the daily rhythm of the tides, seasonal variations in the flow of fresh water into the estuary, and unpredictable rates of freshwater inflow due to natural disasters.

Estuaries & Wetlands


Coastal Zone: Estuaries & WetlandsEcological and Economic Services Provided:• Helps maintain the quality of coastal waters by

diluting, filtering, and settling out sediments, excess nutrients and waste

• Breeding grounds and habitat for a variety of water fowl and other wildlife.

• Helps protect lives and property from flooding; absorbs and slows the flow of water

• Recreation area

C8 Saltwater Life ZonesCoastal Zone: Estuaries & WetlandsMajor Human Impacts:• Wetlands

• Dredging• Run off from land• Airborne Pollutants• Filling in for Coastal Development• Contamination from industrial and sewage discharges

• Mangrove Forests • Industrial logging for timber and fuelwood• Conversion to ponds for raising fish and rice fields and

other agriculture• Urban development

C8 Saltwater Life ZonesCoastal Zone: Rocky & Sandy Shores• Intertidal Zone: Area between low and high tides.

This is a stressful zone to inhabit due to extreme change in conditions daily as they tides comes in and out.

• Organisms must avoid:• Being swept away or crushed by incoming waves• Being immersed at high tides• Drying out at low tide• Changing levels of salinity based on runoff

Rocky Intertidal Zone

Steep sloping rocky beaches often pounded by large waves

Rocky Intertidal Zone

Sandy Shores (Barrier Beaches)

Gently sloping sandy beaches. Most organisms are hidden and include crabs, lugworms, clams, ghost shrimp, Sand dollars and flounder. Microalgae present as main photoautotroph.

Pg. 170 Figure 8-10

C8 Saltwater Life ZonesCoastal Zone: Barrier Islands• Long, thin, low offshore islands of sediment that

generally run parallel to the shore.• Help protect mainland, estuaries and marshes

from the energy of approaching storm waves.• High risk of storm damage (flooding, severe erosion)• Ex: Ocean City MD, Atlantic City NJ, and Miami Beach

Barrier IslandsCoastal Zone: Barrier Islands• Currents running parallel

to the beaches transport sand from one place to another

C8 Saltwater Life ZonesCoastal Zone: Coral Reefs• Form in warm coastal waters of the tropics and

subtropics.• Area of high biodiversity • Organisms fall into 3 main groups:

• Attached Organisms: Give reef structure (corals, algae, sponges)

• Fishes• Small Organisms that bore into, attach to, or hide within the

reef’s hiding places

C8 Saltwater Life ZonesCoastal Zone: Coral Reefs

C8 Saltwater Life ZonesCoastal Zone: Coral ReefsVulnerable to Damage Due to:• Slow Growth• Disrupted easily (slight changes in salinity and temperature)• Thrive only in clear, warm shallow waters with constant high

salinity)• Small Temperature Range

C8 Saltwater Life ZonesCoastal Zone: Coral ReefsVulnerable to Damage Due to:• Corals can only live in water with a temperature of

18-30° C (64-86° F)• If temperature exceed this range for too long coral

bleaching can occur • Coral Bleaching: corals expel their symbiotic algae

(zooxantheallae) causing a reduction in photosynthesis and overall health.


Coastal Zone: Coral ReefsThreats to Biodiversity of Coral Reefs Due to

Human Impact:• Deposition of eroded soil produced by land development, deforestation, agriculture, mining, and dredging• Runoff of fertilizers promote overgrowth of algae which reduces sunlight available to polyps.• Potential flooding from seal level rise due to global warming• Oil Spills• Physical damage from tourist divers, anchors, trash and boat collisions with the reef• Destruction of mangroves

C8 Saltwater Life ZonesOpen Sea• Sharp increase in water depth at the edge of the continental shelf begins the open sea.• Based on light penetration there are three main vertical zones:• Euphotic Zone: Lighted upper layer where photosynthesis occurs.• Bathyal Zone: Dimly lit middle zone that does not contain photoautotrophs due to lack of light but does contain zooplankton and small fish that migrate to the Euphotic zone at night to eat. •Abyssal Zone: Dark, lower zone that is very cold with little dissolved oxygen. Plenty of nutrients available.

C8 Saltwater Life ZonesEuphotic Zone• Nutrient levels low• Levels of Dissolved

Oxygen are high• Inhabited large, fast

swimming predatory fish

C8 Salt Water Life Zones

C8 Saltwater Life ZonesBathyal Zone: • Small fish, squid, octopi and zooplankton

inhabit this zone.

C8 Saltwater Life ZonesAbyssal Zone:• Dead and decaying

organisms fall to the ocean floor to feed decomposers and scavengers

• Overall average primary productivity and net primary productivity per unit of area are low in the open sea

C8 Freshwater Life ZonesFresh water life zones: water with a dissolved salt concentration of less than 1% by volume accumulates on or flows through the surface of terrestrial biomes.• Two major types:

• Standing (lentic) bodies of fresh water (lakes, ponds, inland wetlands)• Flowing (lotic) systems such as rivers and

streams• Runoff from land provides freshwater life zones with

a constant input of organic material, inorganic nutrients, and pollutants.

C8 Freshwater Life ZonesLakes: large natural bodies of standing fresh water formed when precipitation, runoff, or groundwater seepage fills depressions in the Earth’s surface. • Causes of Depressions where Lakes form:• Glaciation (The Great Lakes)• Crustal Development • Volcanic Activity (Crater Lake, OR)

• Ponds are shallow and typically only have one zone because light penetrates the water the whole way to the bottom.

C8 Freshwater Life Zones


4 Distinct Zones of Lakes:• Littoral Zone: shallow, sunlit waters near the

shore to the depth at which rooted plants stop growing.

• Limnetic Zone: open, sunlit surface water layer away from the shore that extends to the depth penetrated by sunlight. Main area of photosynthesis in a lake.

• Profundal Zone: deep open water where it is too dark for photosynthesis; oxygen levels are low.

• Benthic Zone: bottom of the lake; inhabited mostly by organisms that tolerate cool temperatures and low oxygen levels.


Types of Lakes (by nutrient load):• Oligotrophic Lake: new lake with a low

supply of plant nutrients. Often deep with steep banks.

• Eutrophic Lake: lake with large or excessive supply of nutrients (mostly nitrates and phosphates)

• Mesotrophic Lake: lake with a moderate supply of nutrients; between the two nutrient extremes od oligotrohpic lakes and eutrophic lakes.

• Fig 8-16, pg 175

C8 Types of Lakes

C8 Freshwater Life Zones• Liquid water is the most dense; due to this property deep lakes in temperate areas have a thermal stratification.


Seasonal Changes in Temperate Lakes

C8 Freshwater Life ZonesMajor Characteristics of Fresh water Streams and Rivers• Surface Water: Precipitation that

does not sink into the ground or evaporate

• Water Shed (Drainage Basin): Land area that delivers runoff, sediment and dissolved substances to a stream.

• Three major aquatic life zones with different environmental conditions: Source Zone, Transition Zone, and Floodplain Zone. Fig. 8-17

C8 Freshwater Life ZonesThree Major River Aquatic Life Zones • Source Zone – Narrow headland, or mountain

highland stream of cold, clear rushing water. Water rushes down over rock creating waterfalls and adding a lot of dissolved oxygen to the water. Algae and mosses attach to rocks and cold water (smaller) fish inhabit this zone.

C8 Freshwater Life ZonesThree Major River Aquatic Life Zones • Transition Zone – Head water streams

merge to form wider, deep streams. Gentle slope and warmer water allows more producers to inhabit this zone. A variety of fish inhabit this zone. Less oxygen dissolved than in source zone.

C8 Freshwater Life ZonesThree Major River Aquatic Life Zones • Floodplain Zone – Streams join into deeper, wider

rivers that meander across broad, flat valleys. Higher temperature and less dissolved oxygen than other two zones. Large populations of algae, cyanobacteria and other autotrophs. High concentration of mud and silt so water is murky.

C8 Freshwater Life ZonesRiver Watersheds:• Must be protected so that excessive nutrients,

fertilizers and other chemicals do not overload the river system.

C8 Freshwater Life ZonesInland Wetlands: lands covered with fresh water all or part of the time (excluding lakes, reservoirs and streams) and located away from the coastal areas. • Inland Wetlands include:• Marshes (few trees) • Swamps (dominated by trees and shrubs)• Prairie Potholes (depressions carved out by glaciers)• Floodplains (receive excess water during rainy seasons

and floods)• Bogs and Fens (waterlogged soils which accumulate peat)• Wet arctic tundra

• Seasonal Wetlands: only underwater or soggy for part of the year. (includes prairie potholes and floodplains)


Prairie Potholes - Minnesota

Cypress Swamp

Bog


Ecological and Economic Roles of Inland Wetlands:• Provide Food and habitats for fish, migratory waterfowl, shorebirds and other wildlife• Improves water quality by filtering, diluting and degrading toxic wastes, excess nutrients and sediments and other pollutants.• Reduce flooding and erosion by absorbing flood stormwater• Reduce CO2 in atmosphere by storing carbon within the plant community and soil.• Provides natural products (shellfish, berries, timber, etc)• Provides recreation activities (birdwatchers, photographers, boaters, anglers, etc)


Inland Wetlands

C8 Freshwater Life Zones Human Impacts on Inland Wetlands:• Many inland wetlands are drained, dredged, filled in,

or covered so area can be used for development, agriculture, mining, and oil & gas extraction.

• We have lost more than 50% of the inland wetlands in the United States.

biodiversity in aquatic systems. objective(s): swbat describe the various types of organisms in...

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