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LAKE ECOLOGY Unit 1: Module 2/3 Part 2 - Organisms January 2004 Modules 2/3 overview Goal – Provide a practical introduction to limnology Time required – Two weeks of lecture (6 lectures) and 2 laboratories Extensions – Additional material could be used to expand to 3 weeks. We realize that there are far more slides than can possibly be used in two weeks and some topics are covered in more depth than others. Teachers are expected to view them all and use what best suits their purposes. Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s2 Modules 2/3 outline Introduction Major groups of organisms; metabolism Basins and morphometry Spatial and temporal variability – basic physical and chemical patchiness (habitats) 5. Major ions and nutrients 6. Management – eutrophication and water quality 1. 2. 3. 4. Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s3 2. Lake organisms Aquatic organisms may be classified as: Those that go where they choose Those that go where the water takes them Those that live on the lake bottom Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s4 Those that go where they choose Organism photos MN DNR MN DNR Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s5 Those that go where the water takes them Living things = plankton Dead stuff = detritus Animals = zooplankton Plants = phytoplankton Bacteria = bacterioplankton Internal = autocthonous (produced in the lake) External = allocthonous (washed in from watershed) http://www.saskschools.ca Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s6 Those that live on the lake bottom BENTHOS = animals crustaceans, worms molluscs, insects Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s7 Those that live on the lake bottom - cont. PLANTS higher plants (macrophytes) and attached algae (periphyton) NRRI image Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s8 Those that live on the lake bottom - cont. BACTERIA & FUNGI sewage sludge, aufwuchs (slime of algae, fungi, bacteria Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s9 Plants – phytoplankton – major habitats Algae Phytoplankton (float freely in the water) Periphyton (attached to aquatic vegetation, rocks, wood and other substrates) Benthic algae (grow on the lake bottom/sediments); also sometimes called periphyton Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s10 Plants – phytoplankton – major groups 1 Greens grass-like pigments; unicells, filaments, colonies; starch storage Diatoms silica walls, preserve well in lake sediments (paleolimnology); edible; high light and cool water; lipid storage http://www.susqu.edu/biology/algae/ Developed by: R.Axler and C. Hagley •http://www.microscopy-uk.org.uk Draft Updated: January 13 , 2004 U1-m2/3Part2-s11 Plants – phytoplankton – major groups 2 Blue-greens – cyanobacteria “inedible” (less-edible); bloom/scum forming; N2- fixers; P-storage; toxic forms “Annie” “Fannie” Aphanizomenon “Mike” Microcystis Chroococcus Aphanizomenon NRRI image Anabaena NRRI Image http://microbes.limnology.wisc.edu/ outreach/importance.php Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s12 Plants – phytoplankton – major groups 3 Dinoflagellates, cryptophytes, chrysophytes Edible Flagella - some can “migrate” to optimal light, temp Taxa-specific accessory pigments Bloom forming toxic tides (red and brown; harmful algal blooms; Pfisteria hysteria) NRRI Image Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s13 Algae – major growth forms unicellular unicell colonial branched scum filamentous Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s14 Too much can yield a nasty bloom •http://microbes.limnology.wisc.edu/outr each/importance.php Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s15 Phytoplankton – succession There are always many species abundant “somewhere” in the water column or littoral zone Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s16 Phytoplankton succession cont. Algal biomass is low in early spring due to low light and cool temperatures As sunlight increases diatom biomass will often increase due to high nutrients from turnover and spring runoff Greens do well as water warms, high light from long days Blue-greens do well in warmer water can store P some fix N2 most are “less edible” buoyancy helps with light Late summer-fall brings mixing and light-limitation, nutrient inputs, decreased grazing Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s17 Chlorophyll-a: a good estimator of algae The primary photosynthetic pigment in all plants “Easily” measured with a spectrophotometer or fluorometer Accessory pigments now used for estimating the major groups of algae Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s18 But increased algae isn’t always bad… Although increased algal growth results in decreased water clarity….. More food at base of food web leads to increased fish yield But not always the fish you want Schematic from NALMS. 1990. The lake and reservoir restoration guidance manual. 2nd edition. North American Lake Management Society and USEPA Office of Water, Washington, D.C. EPA-440/4-90-006 August 1990. Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s19 Attached algae – periphyton Periphyton is often categorized by the substrate on which it grows: Epilithic (rocks) Epiphytic (on plants) Epipelic (soft sediments) Epipsammic (sand) Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s20 Attached algae – periphyton cont. Ecological differences from phytoplankton Fixed depth re light, wave action and temperature zones Closer to sediment nutrient sources Exposed to higher levels of nutrients from watershed May act as biofilter on the sediments in unproductive lakes Interactions with macrophytes Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s21 Plants – macrophytes – growth forms • Floating-leaf: near-shore unless sheltered, rooted or floating roots • Submergent: rooted and growing underwater from shoreline to several meters deep; leaves may be floating • Emergent: above shoreline to about knee-deep; roots may be underwater but grow and flower aerially; tolerate fluctuating water levels; dense stands can dampen wave action http://aquat1.ifas.ufl.edu/\ Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s22 Macrophytes- floating leaved Floating-leaved macrophytes Watermeal (Wolffia) Water lilies duckweed duckweed NRRI image Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s23 Macrophytes- submergent Submergent macrophytes Isoetes (quillwort) Chara (an alga) water celery curly-leaved pondweed Pondweed? Milfoil Potamogeton (pondweed) Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s24 Higher aquatic plants (macrophytes)- emergent Emergent macrophytes reeds cattails Mead Xmas tree bloom bulrushes carnivorous Developed by: R.Axler and C. Hagley Spirodella Pitlake emergent vegetation Draft Updated: January 13 , 2004 U1-m2/3Part2-s25 Plants – macrophytes – key features Macrophytes are vascular (rooted) plants Often called “weeds” Can be excessive from nutrient enrichment – especially by exotic, invasive species at disturbed sites Difficult to re-establish once removed Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s26 Plants – macrophytes – key features Ecological importance: structural habitat & spawning site food for invertebrates, fish, and wildlife stabilize shoreline and bottom sediments important in nutrient cycling (sediment nitrogen and phosphorus) may light-limit phytoplankton in productive systems Prevent the spread of invasive species Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s27 Microbes – importance Bacterioplankton – Microbial loop: major food chain pathway through microzooplankton Nutrient (C, N, P) recyclers (water & sediments) Pathogens (disease-causing) Fecal coliform bacteria = indicator of human feces E.coli – more specific But – only a warm-blooded animal indicator Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s28 Zooplankton – Major groups Ciliated protozoans Rotifers Crustaceans Cladocerans Copepods Migrating benthos (Mysids, Vorticella http://www.biosci.ohiostate.edu/~eeob/eeob405/labs/protista.html Neomysids, Diaporeia, etc) Insects Keratella http://www.stetson.edu/~kwork/favorite.htm amphipod cyclopoid Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s29 Zooplankton – key features - cladocerans Cladocerans (e.g. water fleas) Size: 100 –300 microns Migration – can be ten’s of meters daily Slow moving (relative to copepods and hungry fish) Selective feeders (edible vs inedible algae) Parthenogenic – “r-selection”, rapid reproduction Very effective at clearing the water column Daphnia Bosmina Developed by: R.Axler and C. Hagley Chydorus Draft Updated: January 13 , 2004 Holopedium U1-m2/3Part2-s30 Zooplankton – key features - copepods Calanoids, Cyclopoids and Harpacticoids : Size: wide range overlaping cladocerans Cyclopoids often predatory Faster moving – less affected by fish predation Selective feeders (edible vs inedible algae) Many life stages and slower growing – “k-selection” Distributed more evenly over day, seasons, depth calanoid Developed by: R.Axler and C. Hagley cyclopoid harpacticoid Draft Updated: January 13 , 2004 U1-m2/3Part2-s31 Zooplankton - Rotifers Size: small <150 microns Some able to migrate 10’s of meters daily Slow moving but small size offers some protection from adult planktivorous fish Less selective feeders (algae, bacteria, protozoans, detritus); not well understood Parthenogenic – “r-selection”, rapid reproduction Keratella Kellicottia Polyarthra Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s32 Zooplankton - ciliated protozoans Protozoa - animal-like, single-celled organisms: amoebas, ciliates • The terms algae and phytoplankton are used for the more plant-like forms that are photosynthetic • euglenoids, cryptomonads, dinoflagellates • All these organisms together = Kingdom Protista • Not well studied – very important to bacterioplankton and nutrient cycling in unproductive systems Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s33 Zooplankton – ciliated protozoans © www.micrographia.com Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s34 Big zooplankton - diversity • • • • Predatory & filter feeding insects Raptorial predators Amphipods & migrating benthos Includes: Leptodora • Mysids (oppossum shrimp), • Diaporeia and other amphipods (sideswimmers/scuds; Hyallela for toxicity testing) • Chaoborus (phantom midge extremely predacious) Diporeia Mysid Chaoborus Developed by: R.Axler and C. Hagley Scuds Draft Updated: January 13 , 2004 U1-m2/3Part2-s35 Big zooplankton - ecology • Play an important role in fish-less lakes by structuring the smaller zooplankton communities through predation or competition • Some migrate hundreds of meters (mysids) from benthos • Extremely important as fish food in larger lakes Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s36 Benthos – worms Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s37 Fish The best known group of aquatic consumers Different species exploit different habitats (niches) Bass and pike are found in lakes that have beds of aquatic macrophytes suitable for spawning Walleyes, on the other hand, spawn on a gravel bottom. Lake trout live only in very clear lakes with cold, welloxygenated deep water In contrast, carp are adapted to warm turbid, low oxygen lakes with mucky, high organic matter bottoms Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s38 Fish – feeding guilds Most fish are somewhat opportunistic in their feeding habits but in general, the majority of the food they eat enables fishery biologists to place them into feeding guilds. Planktivores – consume zooplankton Benthivores – consume benthos Piscivores – consume fish Detritivores – consume organisms that live on detritus or mud (biofilm) Omnivores – consume a variety of foods opportunistically Walleye - drawn by Bob Savannah for the US FWS Top minnow – WI DNR image Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s39 Fish – thermal guilds Temperature is important to fish at all levels of biological organization. Temperature effects fish both: Individually Affects development and growth rates And at the population level Survivorship Mortality Population yield Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s40 Fish – thermal guilds - coldwater Coldwater prefer temperatures below 15 C Upper lethal temperature is ~ 24 C Includes trout, salmon, sculpins chinook salmon brook trout sculpin http://www.gen.umn.edu/research/fish Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s41 Fish – thermal guilds - coolwater Coolwater Prefer temps between 18 and 23 C Upper lethal temp is ~31-32 C Includes perch, walleye, suckers perch sucker walleye http://www.cnr.vt.edu/efish/families/clupeidae.html http://www.gen.umn.edu/research/fish Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s42 Fish – thermal guilds - warmwater Warmwater Prefer temps above 25 C Upper lethal temperature exceeds 33 C Includes basses and sunfish bluegill large mouth bass http://www.gen.umn.edu/research/fish Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s43 Food chains and webs - simple Organisms can be organized into food chains & food webs of varying complexity Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s44 Food webs - sublime Probably more realistic ecologically, but perhaps useless to managers But be aware of notso-obvious complexities Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s45 Food and energy transfers in lakes Microbial loop Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s46 Metabolism Organisms need: Energy source(s) Carbon for structure and for synthesizing enzymes, nucleic acids, sugars, lipids, etc Mineral nutrients – CHNOPS, trace metals Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s47 Metabolism Essentially two categories of metabolism: Autotrophic (self-feeding) – produce organic matter by yourself Heterotrophic (other-feeding) – eat living or dead organic matter Plants photosynthesize; most of their mineral nutrition is from the water (inorganic form) Animals eat mostly organic stuff Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s48 Energy metabolism - Autotrophic DIC POC CO2: dissolved inorganic carbon Particulate organic carbon Photosynthetic – using light energy to fix CO2 Plants (aerobic); certain anaerobic bacteria Chemosynthetic – using chemical energy to fix CO2 Certain aerobic bacteria (oxidize NH4, H2S, Fe+2, CH4, and more) Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s49 Energy metabolism - Heterotrophic POC + DOC DIC Particulate + dissolved organic carbon Dissolved inorganic carbon Aerobic respiration - uses O2 Algae, plants, animals, many bacteria Anaerobic fermentation - uses nitrate, sulfate, … Various groups of bacteria that may only survive in the absence of oxygen, or may switch their metabolism based on the presence or absence of oxygen Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s50 Trophic (feeding metabolism) terminology Oligotrophic – low nutrients and “productivity;” usually high clarity Mesotrophic – moderate nutrients, “productivity” and clarity Eutrophic – high nutrients and “productivity;” low clarity Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s51 Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s52