the zoobenthos

1. the zoobenthos

2. Question of the day: • A) We have considered phytoplankton and zooplankton communities dynamics a typical year in a(n) eutrophic lake in an agricultural landscape. Do these two stories match up? Sketch a graph that shows BOTH phytoplankton and zooplankton dynamics over the year (x = time, y = biomass). Label the major groups of phytoplankton and zooplankton. Also indicate changes in lake mixing patterns (stratification) and other factors that might influence zooplankton and phytoplankton biomass. • B) How might a good year for the reproduction of a fish with zooplanktivorous larvae impact the patterns you’ve sketched out? • C) How might a very large rainstorm in mid July impact the patterns you’ve sketched out?

3. (green) (diatoms)

4. Exam 2 (out of 104 pts) Exam 2 distribution 4 3 Number of individuals 2 1 0 60 64 68 72 76 80 84 88 92 96 100 Points ~B ~A ~C Ave: 85.5 (+- 10.6 Std Dev)

5. The benthos

6. Lecture outline • the organisms • taxonomy • trophic levels • feeding methods • distribution • ecosystems relations • sampling

7. Porifora Bryozoa Annelida Crustacea Mollusks Aquatic insects Simplest of the multi cellular phyla Colonial animals Freshwater sponges

8. Bryozoans • Porifora • Bryozoa • Annelida • Crustacea • Mollusks • Aquatic insects

10. Porifora Bryozoa Annelida Crustacea Mollusks Aquatic insects Oligochaeta- lake classification Leeches- some predatory, some detritivores Aquatic worms

11. www.biosci.ohio-state.edu/~eeob/ eeob405/labs/oligochaete.jp www-personal.umich.edu/~mjwiley/ www311/gammarus.jpg Tubifix worms

12. Porifora Bryozoa Annelida Crustacea Mollusks Aquatic insects Several major groups: crayfish amphipods isopods Several major groups:

13. www.vanninfo.no/sider/dn15/ images/Kap2/56.jpg Orconectes rusticus Trout Lake, WI K.A.Wilson 1998 www-personal.umich.edu/~mjwiley/ www311/gammarus.jpg

15. Porifora Bryozoa Annelida Crustacea Mollusks Aquatic insects snails bivalves 2 classes

16. Unionid mussels, Conn. River www.bio.umass.edu/biology/ conn.river/fwmussel.html Physella www.lrca.org/ Macrophysella.jpg

17. Depends upon fish as temporary host for glochidia dispersal Mussel life cycle www.ext.vt.edu/pubs/fisheries/ 420-014/cycle.gif

19. Porifora Bryozoa Annelida Crustacea Mollusks Aquatic insects 10 insect orders aquatic- terrestrial link most diverse/ best studied

20. Check out: http://www.waterbugkey.vcsu.edu/index.htm

21. Most are larvae with terrestrial adults

22. Taxonomy: extremely diverse • Porifora • Bryozoa • Aquatic worms • Crustacea (338 native crayfish taxa) • Mollusks (297 freshwater bivalve taxa) • Aquatic insects ( > 500 species in a single stream)

23. trophic levels carnivore herbivore detritivore

24. Feeding methods: collectors 1. filterers 2. gatherers both feed on decomposing fine particulate organic matter

25. Feeding methods: grazers and detritivores 3. scrapers graze on algae attached to stony and organic surfaces 4. shredders chew large organic particles

26. Feeding methods: carnivores 5. piercers Sieze and remove fluids from tissues 6. engulfers bite off chunks of prey or devour them completely

27. distribution • Within lake • Among lakes

28. within lake distribution littoral Factors: Substrate varied Oxygen lots Food resources varied Biotic interactions yes

29. within lake distribution Factors: Substrate uniform Oxygen limited Food resources uniform Biotic interactions few profundal

30. Profundal benthos

31. Benthos Abundance 1 2 3 4 Depth A: littoral zone B: thermocline C: profundal 1. Ultra Oligotrophic 2. Oligotrophic 3. Mesotrophic 4. Eutrophic among lake distribution

33. Among habitat distribution deposition erosion

34. among systems

36. Ecosystem relations • benthic production • benthic- pelagic energy transfer

37. 100 Pelagic 80 % Whole-lake Production 60 Benthic 40 29 3 15 20 Invertebrates Primary Producers Heterotrophic Bacteria 0 Pelagic vs. benthic production

38. 100 90 80 70 60 Zoobenthic production (% whole-lake) 50 40 30 20 10 0 0 5 10 15 20 25 30 35 40 Average depth (m)

39. What is the fate of all this benthic production? • Energy transfer through the food web • Links to terrestrial habitats

40. Fish Benthic Invertebrates Zooplankton Benthic Bacteria Bacterioplankton Phytoplankton Periphyton/ Macrophytes trophic transfers between benthic and pelagic habitats Between habitats Within habitats

41. 1 2 100 1 2 2 1 1 75 %Zoobenthos in Lake Trout diets 2 1 1 2 1 50 1 2 1 1 1 2 1 1 1 1 2 2 25 1 1 1 1 2 1 2 2 1 3 3 1 1 3 3 3 2 2 2 1 2 3 3 3 3 3 2 3 3 2 1 2 3 2 2 3 3 3 2 3 3 3 3 3 3 3 0 0.01 1 100 10000 1000000 Lake area (km2)

42. aquatic- terrestrial linkages

43. Insect life cycle Egg Various instars Winged adult or Egg  Larvae Pupae  Winged adult

44. Aquatic-terrestrial linkages Birds & bats Frogs & spiders

45. Sampling challenges • Macroinvertebrates habitat specific • Where to sample is tricky: • Sand, rocks, muck, leaves, macrophytes

46. Invertebrate Samplers

49. zoobenthos summary Tremendous diversity of benthic invertebrates A variety of factors influence their distribution Benthic production is an important component of the total energy in a lake ecosystem and linked terrestrial ecosystems Sampling is challenging because of the habitat-specific nature of invertebrates