LAKE ECOLOGY Unit 1: Module 2/3 Part 2 - Organisms January 2004
Jan 04, 2016
LAKE ECOLOGY
Unit 1: Module 2/3 Part 2 - Organisms January 2004
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s2
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-s3
Modules 2/3 outline
1. Introduction2. Major groups of organisms; metabolism3. Basins and morphometry4. Spatial and temporal variability – basic
physical and chemical patchiness (habitats)5. Major ions and nutrients 6. Management – eutrophication and water
quality
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s4
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-s5
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-s6
Dead stuff = detritusLiving things = plankton
Animals = zooplankton
Plants = phytoplankton
Bacteria = bacterioplankton
Internal = autocthonous(produced in the lake)External = allocthonous
(washed in from watershed)
Those that go where the water takes them
http://www.saskschools.ca
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s7
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-s8
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-s9
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-s10
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-s11
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.microscopy-uk.org.ukhttp://www.susqu.edu/biology/algae/
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s12
Plants – phytoplankton – major groups 2
Blue-greens – cyanobacteria “inedible” (less-edible); bloom/scum forming; N2-
fixers; P-storage; toxic forms
NRRI image
Aphanizomenon Aphanizomenon
NRRI Image
“Annie” “Fannie”
http://microbes.limnology.wisc.edu/outreach/importance.php
“Mike”
Microcystis Microcystis Chroococcus Chroococcus
Anabaena Anabaena
Aphanizomenon Aphanizomenon
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s13
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-s14
Algae – major growth forms
colonialcolonial
unicellularunicellular
filamentousfilamentous
scumscum
branched branched
unicellunicell
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s15
Too much can yield a nasty bloom
•http://microbes.limnology.wisc.edu/outreach/importance.php
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s16
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-s17
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-s18
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-s19
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-s20
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-s21
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-s22
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-s23
Macrophytes- floating leaved
Floating-leaved macrophytes
NRRI image
Watermeal Watermeal (Wolffia)(Wolffia)Water liliesWater lilies duckweedduckweed
duckweedduckweed
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s24
Macrophytes- submergent
Submergent macrophytes
MilfoilMilfoil
water celerywater celery
curly-leaved pondweed
PotamogetonPotamogeton
(pondweed) (pondweed)
CharaChara (an alga)(an alga)
Isoetes (quillwort)Isoetes (quillwort)
Pondweed?Pondweed?
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s25
Higher aquatic plants (macrophytes)- emergent
Emergent macrophytes
Pitlake emergent vegetationMead Xmas tree bloom
reeds cattails bulrushes Spirodella
carnivorous
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s26
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-s27
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-s28
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
Microbes – importance
9b.jpg
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s29
Ciliated protozoans Rotifers Crustaceans
Cladocerans Copepods
Migrating benthos (Mysids, Neomysids, Diaporeia, etc)
Insects
Zooplankton – Major groups
http://www.biosci.ohio-state.edu/~eeob/eeob405/labs/protista.html
VorticellaVorticella
KeratellaKeratellahttp://www.stetson.edu/~kwork/favorite.htm
amphipodamphipod cyclopoidcyclopoid
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s30
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
HolopediumHolopediumChydorusChydorusBosminaBosmina
DaphniaDaphnia
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s31
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
calanoidcalanoidcyclopoidcyclopoid harpacticoidharpacticoid
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s32
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
Kellicottia
PolyarthraKeratella
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s33
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
Zooplankton - ciliated protozoans
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s34
Zooplankton – ciliated protozoans
© www.micrographia.com
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s35
• Predatory & filter feeding insects• Raptorial predators• Amphipods & migrating benthos• Includes:
• Mysids (oppossum shrimp), • Diaporeia and other amphipods (sideswimmers/scuds;
Hyallela for toxicity testing)• Chaoborus (phantom midge extremely predacious)
Leptodora
Mysid Chaoborus Scuds
Diporeia
Big zooplankton - diversity
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s36
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-s37
Benthos – wormsBenthos – worms
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s38
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, well-
oxygenated 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-s39
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 FWSTop minnow – WI DNR image
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s40
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
SurvivorshipMortalityPopulation yield
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s41
Fish – thermal guilds - coldwater
Coldwater prefer temperatures
below 15 C Upper lethal
temperature is ~ 24 C Includes trout,
salmon, sculpins
brook troutbrook trout
chinook salmonchinook salmon
sculpinsculpin
http://www.gen.umn.edu/research/fish
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s42
Coolwater Prefer temps between
18 and 23 C Upper lethal temp is
~31-32 C Includes perch,
walleye, suckers
Fish – thermal guilds - coolwater
http://www.gen.umn.edu/research/fish
http://www.cnr.vt.edu/efish/families/clupeidae.html
suckersucker
walleyewalleye
perchperch
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s43
Fish – thermal guilds - warmwater
Warmwater Prefer temps above 25 C Upper lethal temperature exceeds 33 C Includes basses and sunfish
http://www.gen.umn.edu/research/fish
bluegillbluegill large mouth basslarge mouth bass
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s44
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-s45
Food webs - sublime
Probably more realistic ecologically, but perhaps useless to managers
But be aware of not-so-obvious complexities
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s46
Microbial loop
Food and energy transfers in lakes
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s47
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-s48
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-s49
Energy metabolism - Autotrophic
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)
DICCO2: dissolved inorganic carbon
POCParticulate organic carbon
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s50
Energy metabolism - Heterotrophic
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
POC + DOCParticulate + dissolved organic carbon
DICDissolved inorganic carbon
Developed by: R.Axler and C. Hagley Draft Updated: January 13 , 2004 U1-m2/3Part2-s51
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-s52