Chapter 5 AQUATIC BIOMES

Transcription

1 Chapter 5 AQUATIC BIOMES 1

2 OUTLINE Marine Ecosystems Coasts - Sandy, Rocky, Salt Marsh, Mangrove Coral Reefs Open Ocean Hydrothermal Vents Freshwater Ecosystems - Lakes, Rivers, Wetlands Human Disturbance 2

3 MARINE ECOSYSTEMS Oceans cover 3/4 of Earth s surface. Photosynthesis is carried out by algae or free floating plants (phytoplankton). Greatest amount of photosynthesis near the coast where nutrients wash in. Organisms die and fall to sea floor where the nutrients are used in deep ocean ecosystems. Upwelling currents circulate nutrients from the ocean floor back to the surface. 3

4 MARINE ECOSYSTEMS VERTICAL STRATIFICATION is a key feature. Light and temperature decrease with depth and deep ocean species often grow slowly. Cold water holds more oxygen than warm water so productivity is often high in cold oceans such as the North Atlantic. Ocean systems classified: LITTORAL near/on shore PELAGIC - water column above the bottom BENTHIC - bottom 4

5 MARINE ORGANISMS Aquatic organisms are classified based on how they move: PLANKTON Float and are carried by ocean currents - Phytoplankton plants (algae, diatoms) - Zooplankton animals (eggs, larvae, jellies) NEKTON are able to swim (fish, whales, turtles, etc) NEUSTON organisms floating/moving on the surface of the water (man-of-war, water striders) BENTHOS - live on or in the bottom dig/crawl (clams, worms, sea stars, etc) 5

6 ZONES OF THE OCEAN LITTORAL ZONE Coastline or shore is called the. It is affected by tides. NERITIC ZONE away from shore, where light can penetrate bottom (shallow) PELAGIC ZONE is away from the coast and unaffected by tides. 6

7 TIDAL ZONES SUPRATIDAL above high tide INTERTIDAL between high and low tide SUBTIDAL under the low tide 7

8 SANDY BEACHES / BARRIER ISLANDS Narrow islands made of sand that form parallel to a coastline Provide protection from storms, waves, tides Since they are made of sand, they should not be built on, but they are. Oftentimes, storms destroy the buildings. examples: 8

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10 ROCKY SHORE Intertidal zone where organisms have adaptations to withstand exposure to air and can stick to the rocks against wave and current action. Exhibit vertical zonation. 10

11 TIDE POOLS Depressions in a rocky shoreline that are flooded at high tide but retain some water at low tide 11

12 ESTUARINE ENVIRONMENTS ESTUARY A bay or semi-enclosed body of water that forms where rivers and ocean waters mix. Form BRACKISH WATER - diluted salt water Estuaries have high productivity and are protected areas used by many marine organisms as nurseries and feeding grounds. ie: salt marsh & mangroves 12

13 SALT MARSH SALT MARSHES - coastal wetlands flooded by tidal waters TEMPERATE ESTUARY Nutrient rich & biologically diverse. 2/3 of marine fish and shellfish rely on estuaries for spawning and development. Threatened by sewage & agricultural pollutants from coastal cities 13

14 MANGROVES Mangroves are trees that grow in saltwater along tropical coastlines. a TROPICAL ESTUARY Help stabilize shoreline roots prevent erosion Nurseries for coral reef organisms Mangroves are cut for timber & aquaculture 14

15 CORAL REEFS Corals are aggregations of coral colonies Their calcium rich skeletons build up the reef. Corals have a mutualistic relationship with algae that produce food for the coral animals. Light must penetrate for algal photosynthesis. Therefore, corals live within the photic zone. Threatened by trash, sewage, urban runoff, industrial waste, introduced pathogens and global warming. One third of coral reefs have already been destroyed and 60% of the remaining reefs will probably be dead by 2030 ( 2006 UNESCO Conference). 15

16 Global warming causes CORAL BLEACHING in which corals expel their algal partners and then die. OCEAN ACIDIFICATION Reduces corals ability to create their calcium exoskeletons 16

17 ZONES OF THE OPEN OCEAN EPIPELAGIC ZONE or EUPHOTIC ZONE or PHOTIC ZONE Where enough light can penetrate up to 600 feet for photosynthesis to take place. Majority of biodiversity is here. 17

18 ZONES OF THE OPEN OCEAN MESOPELAGIC ZONE 200 meters to 1000m Twilight Zone Large predators such as sharks and squid BATHYPELAGIC ZONE 1000 to 4000m Many organisms create light BIOLUMINESCENCE 18

19 ZONES OF THE OPEN OCEAN HADAL ZONE ABYSSAL ZONE m Extreme HYDROSTATIC PRESSURE Many benthic organisms feed on detritus and dead organisms that sank to the bottom Trenches that extend to 11,000+ meters Mariana Trench deepest place on earth. 19

20 HYDROTHERMAL VENT COMMUNITY This community contains tube worms, mussels, etc. supported by microbes that capture chemical energy from thermal vents on the ocean floor. These organisms are adapted to extreme temperatures (700 0 F) and intense hydrostatic pressure. 20

21 HYDROTHERMAL VENT COMMUNITY Bacteria (archaea) convert chemicals such as hydrogen sulfide and methane into glucose in a process called CHEMOSYNTHESIS. Mutualistic organisms such as clams, mussels, shrimp and tube worms house the archaea. 21

22 HYDROTHERMAL VENT COMMUNITY The intense heat dissolves metals and other inorganic substances from the rock. These form chimney-like structures called Smokers and metal rich sediments. 22

23 WETLANDS Land surface is saturated or covered with water at least part of the year. SWAMPS - Wetlands with trees. MARSHES - Wetlands without trees. BOGS & FENS - Waterlogged soils that tend to accumulate peat. Generally, nutrient poor with low productivity, but many unusual species. - BOGS are fed by precipitation - FENS are fed from groundwater Water usually shallow enough to allow full sunlight penetration, so the majority of wetlands have high productivity. 23

24 WETLANDS Conservation is very important due to rich biodiversity. Wetlands are the breeding grounds for birds and aquatic species. Make up less than 5% of land area, but contain 33% of endangered species. One of the greatest areas of concern for biologists. May gradually convert to terrestrial communities through succession Trap and filter water, and store runoff. About half of all original wetlands in the U.S. have been degraded over the past 250 years. 24

25 Wetlands Bog 25

26 FRESHWATER ECOSYSTEMS LAKES Freshwater lakes have distinct VERTICAL ZONES or VERTICAL STRATIFICATION. - EPILIMNION - warm upper layer - HYPOLIMNION - cold, deeper layer that does not mix - BENTHOS bottom - LIMNETIC ZONE - area in water that light penetrates - PROFUNDAL ZONE - area in water below light penetration 26

27 LAYERS OF A LAKE THERMOCLINE - distinctive temperature transition zone that separates upper layer and deeper layer. Layers overturn when seasons change in summer the top is warmer, in winter the bottom is warmer this mixes nutrients 27

28 PLANTS OF A LAKE EMERGENT PLANTS rooted on bottom but leaves and stems extend out of water. SUBMERGED PLANTS plants are completely under water EMERGENT PLANTS rooted on bottom with leaves and flowers on the surface 28

29 ANIMALS OF A LAKE FISH stay near center and deep in winter to avoid freezing. INSECTS generally live at the surface or in detritus. Larvae feed on plants, adults usually fly REPTILES/AMPHIBIANS hibernate in mud 29

30 PRODUCTIVITY OF A LAKE OLIGOTROPHIC lakes are those bodies of water that have a poor nutrient supply and little/no plant life MESOTROPHIC lakes are in between... EUTROPHIC lakes have a good nutrient supply and support high plant growth. 30

31 HUMAN DISTURBANCE ACID RAIN stay near center and deep in winter to avoid freezing. SEWAGE, THERMAL POLLUTION RUNOFF of fertilizers & detergents can cause EUTROPHICATION. 31

32 FLOWING WATER RIVERS / STREAMS SOURCE rain, meting ice, lakes. FLOODPLAIN FERTILE low lying areas surrounding a river DRAINAGE BASIN the total land area that drains into the river DELTA collection of sediments from the river generally fertile 32

33 FLOWING WATER RIVERS / STREAMS RIPARIAN ZONE contains water loving plants and animals adapted to both water and land. ie: reeds, sedges, cottonwood, willow, ie: musk rats, otters, turtles, amphibians 33

34 FLOWING WATER RIVERS / STREAMS MAJOR RIVER SYSTEMS Large rivers have drainage systems that incorporate wide continental areas. HUMAN DISTURBANCES include dams, irrigation, hydroelectric facilities, runoff, and industrial dumping 34