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AQUATIC BIOMES. CHAPTER 4 SECTION 4 SC B-6 STUDENTS WILL DEMONSTRATE AN UNDERSTANDING OF THE INTERRELATIONSHIPS AMONG ORGANISMS & THE BIOTIC & ABIOTIC COMPONENTS OF THEIR ENVIRONMENT. Aquatic Biomes. charaterized primarily by their physical environment rather than be climate
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AQUATIC BIOMES CHAPTER 4 SECTION 4 SC B-6 STUDENTS WILL DEMONSTRATE AN UNDERSTANDING OF THE INTERRELATIONSHIPS AMONG ORGANISMS & THE BIOTIC & ABIOTIC COMPONENTS OF THEIR ENVIRONMENT
Aquatic Biomes • charaterized primarily by their physical environment rather than be climate • often layered with regard to • light penetration • temperature • community structure
Zonation in Aquatic Biomes light absorbed by water itself + photosynthetic organisms so…light intensity decreases rapidly with depth Photic Zone: sufficient light for photosynthesis Aphotic Zone: little light penetrates Pelagic Zone = photic zone + aphotic zone
Zonation in Aquatic Biomes • Abyssal Zone: • 2,000 – 6,000 m deep • Benthic Zone: • the bottom of all aquatic biomes, shallow or deep • Benthos: • communities of organisms that live in sand & sediments of the benthic zone
More Definitions • Detritus: • dead organic material that “rains” down from photic zone; food source for benthos • Thermocline: • narrow layer of water where there is an abrupt temperature change • separates the more uniformly warm upper layer from the uniformly cold deeper water • many temperate lakes undergo a semiannual mixing of their water
Lakes • lake environment generally classified on basis of 3 physical criteria: • light penetration • photic / aphotic • distance from shore / depth of water • littoral / limnetic • open water / bottom • pelagic / benthic
Lakes standing bodies of water range from ponds a few square meters in area to lakes covering thousands of square kilometers
Lakes: Photosynthetic Organisms • Littoral Zone: • shallow, well-lit waters close to shore • rooted & floating aquatic plants • Limnetic Zone: • waters too deep to support rooted plants • phytoplankton, including cyanobacteria
Lakes: Heterotrophs • Limnetic Zone: • small, drifting heterotrophs or zooplankton (graze on phytoplankton) • Benthic Zone: • assorted invertebrates (species depends on O2 content) • Fishes live in all zones that have sufficient O2
Wetlands habitat that is inundated by water (at least part of the year) & supports plants adapted to water-saturated soil due to high organic production by plants & decomposition by microbes: water & soil of wetlands periodically low in dissolved O2 *high filter capacity: both nutrients & pollutants
Wetlands: Autotrophs • among most productive biomes in world • water-saturated soils great for plants • Lily pads • Cattails • Sedges • Tamaracks • Black spruce
Wetlands: Heterotrophs • diverse community of invertebrates, birds, reptiles, amphibians, and mammals • Herbivores: • crustaceans • aquatic insect larvae • muskrats • Carnivores: • dragonflies • frogs • alligators • herons
Streams: Physical Environment most prominent characteristic: their current stratified into vertical zones
Streams: Physical Environment • Headwaters: • generally cold, clear • turbulent, & swift • Downstream: • generally warmer • more turbid
Estuary a transitional area between river & sea when high tide: salt water flows up estuary channel higher density sea water stays below lesser density freshwater
Estuary: Chemical Environment salinity varies from that of freshwater sea water & with rise & fall of tides nutrients from rivers make estuaries some of most productive biomes
Estuary: Photosynthetic Organisms saltmarsh grasses & algae (including phytoplankton) are major producers
Estuary: Heterotrophs abundant #’s of worms, oysters, crabs, & many fish many invertebrates & fishes use estuaries as breeding grounds crucial feeding grounds for birds & some marine mammals
Intertidal Zones are periodically submerged & exposed by the tides, 2x daily on most marine shores upper zones exposed to air for longer periods greater variation in temp & salinity changes in physical conditions from upper to lower zones limits the distribution of many organisms to particular strata
Intertidal Zones: Chemical Environment O2& nutrient levels generally high & renewed with each turn of the tides
Intertidal Zone: Photosynthetic Organisms high diversity & biomass of attached marine algae inhabit rocky intertidal zones much lower diversity & biomass in sandy intertidal zones with vigorous wave action sandy intertidal zones in protected bays or lagoons have rich beds of grass & algae
Intertidal Zone: Heterotrophs • animals here have multiple structural adaptations • rocky areas: ways to attach to hard surfaces • sandy areas: many bury themselves • feed on what tides bring them
Ocean Pelagic Zone open blue waters mixed constantly by wind & ocean currents photic zone extends deeper here (water is clearer)
Oceanic Pelagic Zone: Chemical Environment O2 levels generally high nutrient levels generally lower than in coastal waters tropical oceans: thermally stratified all year temperate & hi-latitude oceans have spring & fall turnover so generally nutrients renewed in photic zone
Oceanic Pelagic Zone: Geologic Features covers ~70% Earth’s surface average depth = 4,000 m deepest point: 10,000 m
Pelagic Zone: Photosynthetic Organisms phytoplankton (including photosynthetic bacteria) dominate due to vast area this zone covers: ~50% of all photosynthesis on Earth by them
Pelagic Zone: Heterotrophs • zooplankton most abundant group in this zone • graze on phytoplankton • includes: • protists • worms • copepods • shrimp-like krill • jellies • small larvae of invertebrates
Pelagic Zone: Heterotrophs • also include free-swimming animals: • large squid • fishes • sea turtles • marine mammals
Coral Reefs • formed largely from the calcium carbonate skeletons of corals • in photic zone of relatively stable tropical marine environments with high water clarity • sensitive to temps < 18 – 20° & > 30°C • found in deep seas 200 -1,500 m deep • as much diversity as shallow reef
Coral Reef: Chemical Environment require high O2 levels
Coral Reefs: Photosynthetic Organisms unicellular algae live w/in tissues of corals in mutualistic relationship: provides corals with organic molecules diverse multicellular red & green algae growing on reef also photosynthesize
Coral Reef: Heterotrophs dominant heterotroph: corals are a diverse group of cnidarians also high diversity of fishes & invertebrates overall nearly as diverse as tropical rainforest