Transcript Mod2/3-B Lake Ecology

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
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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
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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
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Those that go where they choose
Organism photos
MN DNR
MN DNR
Developed by: R.Axler and C. Hagley
Draft Updated: January 13 , 2004
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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
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Those that live on the lake bottom
 BENTHOS = animals
 crustaceans, worms molluscs, insects
Developed by: R.Axler and C. Hagley
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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
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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
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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
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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
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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
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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
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Algae – major growth forms
unicellular
unicell
colonial
branched
scum
filamentous
Developed by: R.Axler and C. Hagley
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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
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Phytoplankton – succession
There are always many species abundant “somewhere” in the water
column or littoral zone
Developed by: R.Axler and C. Hagley
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Zooplankton – ciliated protozoans
© www.micrographia.com
Developed by: R.Axler and C. Hagley
Draft Updated: January 13 , 2004
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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
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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
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Benthos – worms
Developed by: R.Axler and C. Hagley
Draft Updated: January 13 , 2004
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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
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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
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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
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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
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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
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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
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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
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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
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Food and energy transfers in lakes
Microbial
loop
Developed by: R.Axler and C. Hagley
Draft Updated: January 13 , 2004
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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
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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
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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
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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
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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
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Developed by: R.Axler and C. Hagley
Draft Updated: January 13 , 2004
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