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Stream Organisms

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Stream Organisms Uni1: Module 4, Lecture 4 – PowerPoint PPT presentation

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Title: 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
  • 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.

7
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
Attached and benthic populations
  • 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.

Hoffman Image Gallery
Hoffman Image Gallery
University of Wisconsin Botanical Images
Collection
9
Seasonal succession in periphyton communities
  • 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

www.urbanrivers.org/web_images/diatoms.gif
10
Distribution of autotrophs Lakes vs rivers
11
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
Macrophyte growth forms
  • Emergents banks and shoals
  • Floating-leaved stream margins
  • Free-floating slow (tropical) rivers
  • Submerged midstream (limited by light
    penetration, current speed, and substrate type)

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
Basic macrophyte structure
  • 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).

16
Patchy distribution of macrophytes
  • Macrophyte distribution and abundance changes
    annually

www.glifwc.org/
17
Macrophyte consumers
  • 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.

http//images.fws.gov/
www.epa.gov/25water/exotic/slide15.jpg
http//www.fcsc.usgs.gov/posters/Nonindigenous/Non
indigenous_Crustaceans/nonindigenous_crustaceans.h
tml
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
Insects
  • Adaptation to life in streams and rivers
  • Introduction to taxonomy
  • General life cycle
  • Introduction to functional roles

20
Morphological adaptations to running water
Adaptation Significance Representative Groups and Structures Comments
Dorsoventrally Flat Allows crawling in slow current boundary layer on substrate Odonata Gomphidae Trichoptera - Glossosoma
Streamlining Fusiform body minimizes resistance to current Ephemeroptera Baetis Diptera - Simulium Relatively rare body form
Reduced projecting structures Reduces resistance to current Ephemeroptera - Baetis Large lateral structures exist in some groups
Suckers Attach to smooth surfaces Diptera - Blephariceridae Rare adaptation
Friction Pads Increased contact reduces chances of being dislodged Coleoptera - Psephinus
21
Morphological adaptations to running water
Adaptation Significance Representative Groups and Structures Comments
Small size Allows use of slow-current boundary layer on top of substrate Stream animals are smaller than stillwater relatives
Silk and sticky secretions Attachment to stones in swift current Diptera Simulium Trichoptera - Hydropsychidae
Ballast Cases made of large stones Trichoptera - Goera
Attachment claws /dorsal processes Stout claws aid in attachment to plants Ephemeroptera - Ephemerella
Reduced power of flight Prevents emigration from small habitats Plecoptera - Allocapnia Reduces dispersal ability
Hairy bodies Keeps sand/soil particles away while burrowing Ephemeroptera - Hexagenia Allows water flow over body
Hooks or Grapples Attachment to rough areas of substrates Coleoptera - Elmidae
22
Classification of insects

Common Name Human Canada Goose Lake Darner Dragonfly Giant water bug
Kingdom Animalia Animalia Animalia Animalia
Phylum Chordata Chordata Arthropoda Arthropoda
Class Mammalia Aves Insecta Insecta
Order Primate Anseriformes Odonata Hemiptera
Family Hominidae Anatidae Aeshnidae Belostomatidae
Genus Homo Branta Aeshna Lethocerus
species sapiens canadensis eremita americanus
Author Scudder (Leidy)
www.usask.ca/biology/skabugs/idclass/classify.html
23
Aquatic insect orders
Order Number of North American aquatic species (estimated) Larvae Adults
Ephemeroptera (mayflies) 572
Odonata (dragonflies and damselflies) 357
Plecoptera (stoneflies) 582
Trichoptera (caddisflies) 1215
www.usask.ca/biology/skabugs/
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24
Aquatic insect orders
Order Number of North American aquatic species (estimated) Larvae Adults
Diptera (flies and midges) 4662
Hemiptera (true bugs) 410
Coleoptera (beetles) 1842
www.usask.ca/biology/skabugs/
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25
Aquatic insect orders
Order Number of North American aquatic species (estimated) Larvae Adults
Megaloptera (alderflies and dobsonflies) 43
Neuroptera (spongilla flies) 6
Lepidoptera (moths) 635
Hymenoptera (parasitic wasps) 55
www.usask.ca/biology/skabugs/
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26
Life cycles of aquatic Insects
Holometabolous
Hemimetabolous
  • Holometabolous insects pass through a complete
    metamorphosis that consists of four stages
  • 1) Egg gt immature (larva) gt Pupa gt Adult
  • 2) During pupal stage adult characteristics
    develop
  • 3) Examples include caddisflies and dipterans
    such as blackflies

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

fig. 14.2, p. 179 from Allan and Cushing
28
Hemimetabolous life cycle
www.usask.ca/biology/skabugs/lifecycle/insectlifec
ycle.html
29
Holometabolous life cycle
  • Complete metamorphosis in the caddisfly
    Hydropsyche sp.
  • Larva
  • Pupa
  • Adult

www.usask.ca/biology/skabugs/lifecycle/insectlifec
ycle.html
www.usask.ca/biology/skabugs/lifecycle/insectlifec
ycle.html
Adult
www.usask.ca/biology/skabugs/lifecycle/insectlifec
ycle.html
30
Life cycle length
  • 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).

31
Ecological roles
  • Macroinvertebrates play a variety of roles in
    food webs.

Fig. 4.9, p.53 in Allan and Cushing, 2001
32
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
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
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
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
Annelids (leeches and aquatic worms)
Molluscs (clams, mussels, and snails)
Crustaceans (crayfish, amphipods, and mites)
http//www.usask.ca/biology/skabugs/
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