1. 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

2. Aquatic Biomes charaterized primarily by their physical environment rather than be climate often layered with regard to  light penetration  temperature  community structure

3. 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

4. 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

5. 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

7. Lakes lake environment generally classified on basis of 3 physical criteria: 1. light penetration  photic / aphotic 2. distance from shore / depth of water  littoral / limnetic 3. open water / bottom  pelagic / benthic

10. Lakes standing bodies of water range from ponds a few square meters in area to lakes covering thousands of square kilometers

11. Lakes: Oligotrophic

12. Lakes: Eutrophic

13. 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

14. Phytoplankton

15. Lakes: Heterotrophs Limnetic Zone:  small, drifting heterotrophs or zooplankton (graze on phytoplankton) Benthic Zone:  assorted invertebrates (species depends on O 2 content)  Fishes live in all zones that have sufficient O 2

16. Zooplankton

17. 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 O 2 *high filter capacity: both nutrients & pollutants

19. Wetlands: Autotrophs among most productive biomes in world water-saturated soils great for plants  Lily pads  Cattails  Sedges  Tamaracks  Black spruce

20. Wetlands: Heterotrophs diverse community of invertebrates, birds, reptiles, amphibians, and mammals Herbivores:  crustaceans  aquatic insect larvae  muskrats Carnivores:  dragonflies  frogs  alligators  herons

21. Streams: Physical Environment most prominent characteristic: their current stratified into vertical zones

22. Streams: Physical Environment Headwaters:  generally cold, clear  turbulent, & swift Downstream:  generally warmer  more turbid

23. 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

24. 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

25. Estuary: Photosynthetic Organisms saltmarsh grasses & algae (including phytoplankton) are major producers

26. 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

27. 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

29. Intertidal Zones: Chemical Environment O 2 & nutrient levels generally high & renewed with each turn of the tides

30. 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

31. 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

32. Ocean Pelagic Zone open blue waters mixed constantly by wind & ocean currents photic zone extends deeper here (water is clearer)

33. Oceanic Pelagic Zone: Chemical Environment O 2 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

34. Oceanic Pelagic Zone: Geologic Features covers ~70% Earth’s surface average depth = 4,000 m deepest point: 10,000 m

35. Pelagic Zone: Photosynthetic Organisms phytoplankton (including photosynthetic bacteria) dominate due to vast area this zone covers: ~50% of all photosynthesis on Earth by them

36. 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

38. Pelagic Zone: Heterotrophs also include free-swimming animals:  large squid  fishes  sea turtles  marine mammals

39. 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 30°C found in deep seas 200 -1,500 m deep  as much diversity as shallow reef

40. Deep Sea Coral Reef

41. Shallow Coral Reef

42. Coral Reef: Chemical Environment require high O 2 levels

43. 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

44. 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