AQUATIC ECOLOGY CHAPTER 7a – TEST 5
I. Aquatic Environments: -Aquatic Life Zones = Biomes -Organisms that are found in life zones are determined by Salinity. 1. Marine (Saltwater): • Ocean, coral reefs, coastal marshes • Freshwater: • Rivers, lakes, streams, wetlands
A. Main Types of Organisms in aquatic life zones: 1. Plankton: -Weak swimming and free-floating (ex: types of algae) -3 categories: Phyto(surface), Zoo, Nano
2. Nekton: -Strong Swimming consumer (Fish, turtles, sharks and whales)
3. Benthos: -Bottom dwelling…. (Oysters, sea star, worms, lobster & crabs)
4. Decomposers (Mostly Bacteria): -Break down organic compounds
BUOYANCY: Provides support Allows vertical movement Reduces the need for large supportive structures B. Benefits of Life in the Water:
2) THERMOSTAT ACTION: Keeps organisms from drying out Protects from major temperature changes.
5)DILUSION OF TOXIC MATERIAL Filtering of waste • DISSOLVING CAPABILITY: • Dissolves nutrients and makes them readily available. • UV PROTECTION: • Protects against harmful radiation
C. Limiting Factors In Aquatic Environments: *Factors that determine the number and types of organisms that live in certain aquatic life zones. - Temperature - Sunlight - Dissolved oxygen - Nutrients
2. Sunlight: -Most important at the surface, or EUPHOTIC ZONE, where photosynthesis occurs -The amount of sunlight can be affected by depth and excessive algal growth • Temperature: -Tends to have an effect on or to be affected by all the other factors.
3. Dissolved Oxygen -The amount of oxygen dissolved in the water. -Affected by these factors … *Temperature -Holds more at low temperatures *Number of Producers (add O2) *Number of Consumers (remove O2) *Number of aerobic decomposers * Many fish die when D.O. drops below 5 ppm
A Dead Zone caused by a lowering of dissolved oxygen in the water is referred to as hypoxia.
4. Nutrients: -Found in ample supplies in shallow water -Lacking in open ocean except where there areUPWELLINGS Seasonal mixing of deep nutrient waters that are brought to the surface.
II. Key Roles Of Oceans: • -Oceans play many vital roles on the planet… • Help to regulate climate • 2. Greatest total amt. of productivity across the world • 3. Provide a source of many natural resources & habitat for animals and plants • 4. Disperse/Dilute human produced wastes and has • -Two major “Ocean Life Zones”: coastal andopen ocean
1. COASTAL ZONE -Nutrient rich, shallow water -Extends from high tide mark to *CONTINENTAL SHELF -Contains 90% of all marine species -Most ecosystems w/in zone have high primary productivity A. Ocean Life Zones
Costal zones can be broken into various other areas… Estuaries and Coastal Wetlands A.Estuary- Partially enclosed area of coastal water where sea and fresh waters mix. B.Coastal Wetlands- associated with Estuaries that are water covered all or part of the year. Can further include INLETS,BAYS,SOUNDS,MARSHES
Chesapeake Bay Facts • Chesapeake Bay Facts • LENGTH: 200 miles. • WIDTH: varies: 4 miles at the Bay Bridge to 30 miles at the mouth of the Potomac River. • DEPTH: average depth is 21 feet, maximum depth is 175 feet near Bloody Point, Md. • MILES OF SHORELINE: 11,000 miles. (The same as the distance from New York to Los Angeles and back to New York.) • SURFACE AREA OF SHORELINE: 4,400 square miles. • WATERSHED: 64,000 square miles in 6 states and Washington, D.C. • The Chesapeake Bay is the largest estuary in the United States. • There are 15,000 streams covering 100,000 miles that feed into the Bay. (That's four times around the world!) • There are 600,000 acres of marshlands (wetlands). Marshlands and adjoining woodlands provide a natural habitat for over 2,700 species of plants and animals. • 90% of the Bay’s fresh water comes from l0 major river systems, and 50% of it comes from the Susquehanna River. The Bay provides more blue crabs than anywhere in the world. • *The industry of Chicken farming has been blamed the most in degrading the Bay • *The pollution that received the most blame for the degradation of the Bay is pollution from run off within the waters that supply the bay
Functions of Estuaries and Coastal Wetlands Breeding ground for aquatic organisms and habitat for water fowl Maintain water quality by diluting and filtering Food Production Recreational activities Protects mainland from flooding Most coastal wetlands that are lost are used for urban development
Covered with mangrove forest swamps. • Mangrove tree species has the ability to live in salt water.
Human Impacts on Estuaries 53% have been destroyed in the USA Causes: Dredging, and filling Trap pesticides, heavy metals and other contaminants Sewage runoff Dam construction and river diversion California and Florida have lost most of their coastal wetlands.
C. Intertidal Zone Area of shoreline between low and high tides Sometimes thought of as the SWASH ZONE Stressful zone to live in - Swept away or crushed by waves - Immersed during high tides - High and Dry during low tides - Changing levels of salinity Most organisms have shells, dig in or hold onto something
1.Sandy Shores vs. Rocky Sandy Shores or Barrier Beaches -Show a variety of plant and animal -Most animals survive under the sand -Vegetation in “levels” among sand dunes *Sandy shores dominate the Eastern Atlantic coast. -Subject to: Violent storms Pollution from the land Over-harvesting Coastal development
Sand Dunes Ocean Beach Intensive recreation no building Primary Dune No direct passage or building Trough Limited recreation and walkways Secondary Dune No direct passage or building Back Dune Most suitable for development Bay or Lagoon Intensive recreation -Primary and Secondary Dunes play and important role in protecting the land -Development should only be behind the second strip of dunes Bay shore No filling Grasses or shrubs Taller shrubs Taller shrubs and trees Fig. 7.11, p. 161
Rocky Shores -Characterized by pounding waves -Often numerous tidal pools containing various organisms
D. Barrier Islands -Long, thin, low offshore islands of sediment that generally run parallel to the shore -Helps to protect mainland estuaries and coastal wetlands by dispersing storm waves -Constantly change shape and size EX. Atlantic City, Miami Beach, Outer Banks
E. Coral Reefs -Second only to tropical rain forest in biodiversity. -3 categories of organisms … *Attached *Fish *Organisms that bore, attach, or hide -Found only in the tropics -Usually colored by algae
- 65 countries protect 300 coral reefs as reserves/parks. Another 600 reefs have been recommended for protection.
Human Impacts on Coral Reefs Estimated that 10% have been seriously degraded by … Deposition of eroded soil Fertilizer runoff Chemical Pollution Coral bleaching-the killing of symbiotic algae(largest threat) Increased UV Destructive harvesting techniques Ecotourism damage
Coral Reefs Gray reef shark Producer to primary consumer Sea nettle Green sea turtle Fairy basslet Primary to secondary consumer Blue tangs Parrot fish Sergeant major Brittle star Hard corals Algae Banded coral shrimp Secondary to higher-level consumer Phytoplankton Symbiotic algae Coney Zooplankton Black basslet All consumer and producers to decomposers Sponges Moray eel Bacteria Fig. 7.13, p. 163
2. The Open Ocean 3 vertical zones based on sunlight penetration Euphotic Zone: Bathyal Zone: Abyssal Zone:
1. Euphotic Zone-High photosynthesis -Low nutrients -High dissolved oxygen -Large fish 2. Bathyal Zone -No/Little photosynthesis -Zooplankton abundant -Small migratory fish
3. Abyssal Zone -Low temps -Low dissolved oxygen -High nutrients
Ocean Zones Depth in meters High tide Sun Open Sea Low tide Coastal zone Sea level 0 50 Euphotic Zone Photosynthesis 100 Estuarine Zone Continental shelf 200 500 Bathyal Zone Continental 1,000 1,500 Slope 2,000 Abyssal Zone 3,000 Darkness 4,000 5,000 10,000
Salt marshes, mangrove forests, and sea-grass meadows, are being lost and degraded -Estimated that coastal wetlands have decreased by 53% over the last century -70% of world beaches are eroding -Bottom habitat is being degraded by trawlers + dredging. III. Human Impact on Marine Systems and Coastal Biomes: