Stream Organisms

1. Stream Organisms Uni1: Module 4, Lecture 4

2. Objectives Students will be able to: • describe major characteristics of autotrophs. • categorize autotrophs types by location. • contrast seasonal variations in the growth of periphyton communities. • compare and contrast the four types of macrophytes. • define and provide examples of stream macroinvertebrates. • provide examples of morphological adaptations to water and interpret their significance. • diagram the life cycles of aquatic insects. • compare and contrast the functional roles of macroinvertebrates in organic matter processing.

3. Stream organisms • The slides on stream organisms are divided into three sections: • Autotrophs • Invertebrates • Fish

4. Autotrophs • Autotrophs are organisms that acquire materials from the environment and energy from sunlight in the process of producing organic matter. • Green plants, diatoms and filamentous algae, some bacteria, and some protists make up the autotrophs in lotic systems. • In contrast, heterotrophs, such as fungi or fish gain nutrients and energy by processing dead organic matter. • Functionally, autotrophs serve lotic communities by making organic energy available to consumer organisms at higher trophic levels. www.glifwc.org/

5. Benthic autotrophs • Benthic autotrophs grow on virtually all surfaces receiving light in flowing waters and are collectively referred to as the periphyton community. • Habitat specialization allows for classification of benthic autotrophs into groups; • Species that grow on stones (epilithon) • Species that grow on soft sediments (epipelon) • Species that grow on other plants (epiphyton)

6. Periphyton is a complex matrix of algae and heterotrophic microbes attached to submerged substrata in almost all aquatic ecosystems. It serves as an important food source for invertebrates and some fish, and it can be an important sorber of contaminants. www.duluthstreams.org/understanding/algae.html Periphyton

7. phytoflagellates (euglenophyta) www.cawthron.org.nz/periphyton_image.htm Periphyton components • Lotic phytoplankton include: • Algae • Protozoans • Cyanobacteria • These are small enough to remain suspended in the water column and be transported by currents. Biodidac Hoffman Image Gallery Hoffman Image Gallery

8. Many blue-green algae grow attached on the surface of rocks and stones (epilithic forms), on submerged plants (epiphytic forms) or on the bottom sediments (epipelic forms, or the benthos) of rivers. The epiphytic flora of lotic communities is usually dominated by diatoms and green algae, and blue-greens are of less importance in this community. green algae (chlorophyta) Biodidac blue-green algae (cyanobacteria) Diatoms Attached and benthic populations Hoffman Image Gallery Hoffman Image Gallery University of Wisconsin Botanical Images Collection

9. Diatoms dominate during the winter, spring, and early summer Green algae and cyanobacteria populations increase during the summer Benthic autotrophs tends to decrease during the summer as a result of increased shading, increasing again in fall Seasonal succession in periphyton communities www.urbanrivers.org/web_images/diatoms.gif

10. Image from Allan, Fig. 4.12, p. 105 Distribution of autotrophs: Lakes vs rivers

11. Photosynthesis • Light - Temperature • Nutrient - Chronic toxicity • Velocity • Washout • Velocity • Available substrate Turbulent diffusion Loading Algal biomass • Mortality • Acute toxicity • High temperature • Sinking • - Velocity • Stress Grazing Respiration/Excretion www.epa.gov/waterscience/pc/wqnews/algal.gif Algal primary productivity

12. Macrophytes • Westlake (1975a) identified four primary growth forms: • 1) Emergents occurring on river banks and shoals typically are rooted in soil that is near or below the waterline and have aerial leaves and reproductive structures; • 2) Floating-leaved species occupy margins of slow current areas, are rooted in submerged soils, and have aerial or floating leaves and reproductive structures; • 3) Free-floating species are typically not attached to the substrate and often form mats that entangle other species in slow flowing tropical rivers; • 4) Submerged species are rooted to the substrate, have submerged leaves, and are located in mid-channel to the point of insufficient light penetration.

13. Emergents: banks and shoals Floating-leaved: stream margins Free-floating: slow (tropical) rivers Submerged: midstream (limited by light penetration, current speed, and substrate type) Emergent cce.cornell.edu/onondaga/watersheds/images/milfoil.jpg Floating-leaved www.sthubertsisle.com/Lily%20pads.jpg Free-floating http://lakes.chebucto.org/VIEW/PIC/duckweed.jpg Submerged http://riverwoods.ces.fau.edu/riverwoods/display.ihtml?pic=../photos/birdseyenupharsm.jpg Macrophyte growth forms

14. Macrophyte growth forms • Aquatic macrophytes do not show adaptations to life in rivers and streams. • Consequently, they are limited to areas of little current and suitable substrate. • Most commonly these areas include; deltas, backwaters, pools, beaver impoundments, margins, banks, shoals, and contiguous wetlands.

15. Success and maintenance of macrophyte populations in significant current can be attributed to a few adaptive characteristics. Tough, flexible stems and leaves; attachment by adventitious roots, rhizomes, or stolons; and vegetative reproduction characterize most lotic macrophyte species (Hynes, 1970; Westlake, 1975a). Stems and leaves Adventitious roots aquat1.ifas.ufl.edu/zizaqu2.jpg Basic macrophyte structure

16. Patchy distribution of macrophytes • Macrophyte distribution and abundance changes annually www.glifwc.org/

17. Even in streams that show high macrophyte productivity, a relatively small fraction of the streams total energy results from macrophyte production. The fate of this primary production includes herbivory, secretion of dissolved organic matter, and decomposition. Herbivory is carried out in large part by vertebrates, including waterfowl, manatee, grass carp, muskrat (Westlake, 1975b), and moose. Macrophyte consumers http://images.fws.gov/ www.epa.gov/25water/exotic/slide15.jpg http://www.fcsc.usgs.gov/posters/Nonindigenous/Nonindigenous_Crustaceans/nonindigenous_crustaceans.html

18. Stream invertebrates • Much of the aquatic life in streams is composed of benthic macroinvertebrates. • The term macroinvertebrate includes clams, crayfish, worms, and insects. • Macroinvertebrates do not have internal skeletons, are larger than 5 microns, and, typically, live on a stream substrate (bottom, woody debris, macrophyte, etc..) photo source: North American Benthological Society

19. Adaptation to life in streams and rivers Introduction to taxonomy General life cycle Introduction to functional roles Insects

20. Morphological adaptations to running water

21. Morphological adaptations to running water

22. Classification of insects www.usask.ca/biology/skabugs/idclass/classify.html

23. Aquatic insect orders www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/

24. Aquatic insect orders www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/

25. Aquatic insect orders www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/ www.usask.ca/biology/skabugs/

26. Holometabolous insects pass through a complete metamorphosis that consists of four stages: 1) Egg > immature (larva) > Pupa > Adult 2) During pupal stage adult characteristics develop 3) Examples include; caddisflies and dipterans such as blackflies Life cycles of aquatic Insects Holometabolous Hemimetabolous fig. 14.2, p. 179 from Allan and Cushing

27. Hemimetabolous insects pass through three stages in their life cycle: 1) Egg > Immature (nymph) > Adult 2) Adults are terrestrial 3) Examples include; stoneflies, mayflies, and dragonflies Life cycles of aquatic Insects Holometabolous Hemimetabolous fig. 14.2, p. 179 from Allan and Cushing

28. Hemimetabolous life cycle www.usask.ca/biology/skabugs/lifecycle/insectlifecycle.html

29. Holometabolous life cycle • Complete metamorphosis in the caddisfly Hydropsyche sp. • Larva • Pupa • Adult www.usask.ca/biology/skabugs/lifecycle/insectlifecycle.html www.usask.ca/biology/skabugs/lifecycle/insectlifecycle.html Adult www.usask.ca/biology/skabugs/lifecycle/insectlifecycle.html

30. Multivoltine – several generations per year Univoltine – one generation per year Semivoltine – one generation every 2-3 years Baetis sp., a common mayfly is noted to be univoltine at low elevation and warmer temperatures and semivoltine at high elevations and colder temperatures (Allan, 1995). www.mendozaflyshop.com/images/6_01.jpg Life cycle length

31. Ecological roles • Macroinvertebrates play a variety of roles in food webs. Fig. 4.9, p.53 in Allan and Cushing, 2001

32. A caddisfly of the family Limnephilidae www.oaa.pdx.edu/CAE/Programs/sti/pratt/feeding/inverts/shredder.html Macroinvertebrate functional roles in organic matter processing • Shredders • Dominant food • Vascular macrophyte tissue • Coarse particulate organic material (CPOM) • Wood • Feeding mechanisms • Herbivores - Chew and mine live macrophytes • Detritivores - Chew on CPOM • Representatives • Scathophagidae (dung flies) • Tipulidae (crane flies)

33. A blackfly of the family Simulidae A caddisfly of the family Hydroptilidae www.oaa.pdx.edu/CAE/Programs/sti/pratt/feeding/inverts/collector.html Macroinvertebrate functional roles • Collectors • Dominant food • Decompose fine particulate organic matter (FPOM) • Feeding mechanisms • Filterers - Detritivores • Gatherers - Detritivores • Representatives • Filterers • Hydropsychidae • Simulidae (black flies) • Gatherers • Elmidae (riffle beetles) • Chironomini • Baetis • Ephemerella • Hexagenia

34. A dipteran of the family Thaumaleidae www.oaa.pdx.edu/CAE/Programs/sti/pratt/feeding/inverts/scraper.html Macroinvertebrate functional roles • Scrapers • Dominant food • Periphyton (attached algae) • Material associated with periphyton • Feeding mechanisms • Graze and scrape mineral and organic surfaces • Representatives • Helicopsychidae • Psephenidae (water pennies) • Thaumaleidae (solitary midges) • Glossosoma • Heptagenia

35. A stonefly of the family Perlidae A “true bug” of the family Notonectidae www.oaa.pdx.edu/CAE/Programs/sti/pratt/feeding/inverts/predator.html Macroinvertebrate functional roles • Predators • Dominant food • Living animal tissue • Feeding mechanisms • Engulfers - Attack prey and ingest whole animals • Piercers - Pierce tissues, suck fluids • Representatives • Engulfers • Anisoptera (dragonflies) • Acroneuria • Corydalus (hellgrammites) • Piercers • Veliidae (water striders) • Corixidae (water boatmen) • Tabanidae (deerflies & horseflies)

36. Other macroinvertebrates http://www.usask.ca/biology/skabugs/ http://www.usask.ca/biology/skabugs/ http://www.usask.ca/biology/skabugs/ http://www.usask.ca/biology/skabugs/ http://www.usask.ca/biology/skabugs/ http://www.usask.ca/biology/skabugs/ http://www.usask.ca/biology/skabugs/