Lab 1: Stream Ecology Flashcards
Aquatic macroinvertebrates
animals without a backbone that live in the water and can be seen with the naked eye
Benthic
bottom-dwelling (where most stream dwelling macro invertebrates live
Riffles
typically the shallower, faster-flowing areas of a stream characterized by higher levels of dissolved oxygen and substrates such as stones and gravel that often create “white water”- where most benthic macro invertebrates are concentrated
Runs
fairly fast-flowing areas of a stream but a bit deeper and less turbulent
Pools
Deeper holes, often have a soft silty substrate, where the water is slow moving so it contains less oxygen
Arthropods (benthic macroinverebrate in NE Iowa streams)
insects
PHYLUM: arthropod: has an exoskeleton
Mollusks (benthic macroinverebrate in NE Iowa streams)
clams and snails
annelids (benthic macroinverebrate in NE Iowa streams)
segmented worms
Dominant forms of macro invertebrates in freshwater streams are…
aquatic insects in their immature forms
Five major groups of feeders
grazers/scrapers, shredders, collector-gatherers, collector-filterers, and predators
grazers/scrapers
feed on algae growing on surfaces
shredders
consume leaf litter and larger organic materials
collector-gatherers
collect find (<1mm) organic matter from the bottom
collector-filterers
collect fine (<1mm) organic matter from water
predators
eat and kill other organisms
What is the best biotic indicators for assessing overall stream health and why?
Macroinverebrates, especially immature aquatic insects, because they tend to use particular habitats reliably and are adapted for living in those habitats.
What limits survival of Macroinverebrates, especially immature aquatic insects?
Their survival is limited by the
-availability of food
-water temp
-levels of dissolved oxygen
-stream current
-presence or absence of predators
-depth and type of substrate
What is an early warning signs of stream degradation?
Benthic macroinverebrates populations changing because they change in response to the limiting factors of their survival
What is needed for a stream bioassessment?
The level of diversity of organisms collected and known pollution tolerance of the organisms collected
Who developed the “biotic index” to asses water quality by looking at where particular species were found in streams in Iowa?
The Iowa Department of Natural Resources (2010)
Taxa with a score of 3 are found…
in streams with NO organic pollution or nutrients (e.g. manure, sewage, nitrates)
Taxa with a score of 1 are found…
in highly polluted streams
Objectives of Lab 1
-collect environmental data (temp and dissolved oxygen) from one of two streams
-collect the benthic macroinveretbrates from a riffle in assigned stream
-ID all types of invertebrates present in sample
Materials used for lab 1
-knee boots
-D-net
-plastic wash basin
Many of organisms collected will be….
immature larval or nymph stages of insects (phylum: Arthropoda, class: Insecta)
Snails and clams are in the phylum…
Mollusca
segmented worms are in the phylum…
Annelida
Whats the most abundant benthic macroinvertebrate and what classifies them?
Insects
-3 body regions (head, thorax, abdomen) NOT 3 SEGMENTS
-one pair of antennae
-3 pairs of “true” legs attached to thorax
-may also have fleshy bumps on abdomen called ‘prolegs’
-adults have 0,1, or 2 pairs of wings
