lecture 4b- macroinvertebrates Flashcards
what are the two macro invertebrate food sources in aerobic environments?
- aerobic bacteria
- benthonic periphyton
what is the main invertebrate food source in anaerobic environments?
-anaerobic benthic microbes
Give the 8 major types of organic pollution in descending order
- pig slurry
- cattle slurry
- effluent drianage from slurry stores
- dilute dairy parlor and yard wasting
- milk
- untreated domestic sewage
- treated domestic sewage
- household products
how is organic pollution measured?why?
-via the distribution of macroinvertebrates, due to their high sensitivity to pollution
how do high levels of solid particles in rivers impact macro invertebrates?
-can clog invertebrate gills, which reduces their ability to obtain oxygen.
what are the impacts of high nutrient inflow on macroinvertebrates?
-this causes a boost in microbial acitvity, often leading to algae blooms and eutrophication. This reduces the avaliable food source for macroinvertebrates, as the loss of oxygen causes species to die off
what are the main components of organic pollution?(4)
-POC
-DOC
-ammonium
-phosphorous
(you should be able to explain why these are bad for macroinvertebrates)
how is organic pollution controlled? (2)
- via controlling the components of household products (eg. phosphorous free products)
- controlling the release of treated sewage
what defines macroinvertebrate sensitivity? (when theres lots of organic pollution)
-oxygen acquisition
What are the two ways macroinvertebrates acquire oxygen?
- spiracles
- gills
which oxygen acquisition feature is better for oxygen acquisition? why?
-spiracles, which are less subject to clogging than gills. This means that they are less impacted by solid particles in the water, and are less likely to be impacted
why are gills bad in polluted rivers?
- they are more subject to clogging than spiracles, especially when located externally and unprotected.
- this reduces their ability to acquire oxygen
what are the two effects of river sewage on river biota?
- increased suspended solids
- reduced oxygen levels
what are the two impacts of suspended solid inputs from organic sewage?
- clogging of macro invertebrate gills
- browness of water from humic materials resulting in reduces light penetration and algae photosynthesis. This reduces populations all along the aquatic food web.
what are the impacts of sewage inputs on aquatic system oxygen levels?
- increased microbial activity due to DOC, N and P inputs
- increase in biomass causes HIGH BIOLOGICAL OXYGEN DEMAND (BOD) and macroinvertebrates are often out competed for oxygen sources and die off
- levels of bacteria and “sewage fungus” increase these use of oxygen
Besides using oxygen, what is the impact of increased sewage fungus on macroinvertebrates?
-sewage fungus traps macroinvertebrates within it, causing them to die
how do macroinvertebrates respond to unfavourable pollution levels?
- they move
- overcompensate to try and acquire more oxygen, and die
what are the forms of macroinvertebrates? (3 forms relating to pollution levels)
-clean water sensitive
-midpollution tolerant
severe pollution tolerant
why type of larvae are a major proportion of macroinvertebrates?
-fly larvae
Name the four studied macroinvertebrates lacking a pupa development stage?
- stonefly
- mayfly
- damselfly
- dragonfly
what is incomplete when aquatic larvae have no pupa stage?
-metamorphism is incomplete
why are stone,may,dragon and damselflys sensitive to organic pollution?
-they all have gills
give description of plecopetra (stoneflys) (tail, gills, protection techniques)
- lives 1-4 years
- gills at the base of the abdomen and has two pronged tail (identifying characteristic)
- gills situated at: abdomen, neck and thorax
- external gills leave them subject to clogging
how to plecopetra acquire oxygen? why do they move away from low oxygen sites?
- do “press ups” to bring oxygen towards gills, which causes lots of physical exertion
- remove themselves in low oxygen conditions as too many press ups could kill them
describe ephemeroptera (mayfly) key characteristics
- larvae live fro 1-2 years
- gills located laterally on the thorax, and highly subject to clogging
- tail is three pronged and very distinctive
why are the baetis mayfly genus less sensitive?
-gills are enclosed in casing,protecting the gills from clogging
what is the latin name for dragonfly and damselflys?
-odonata
describe odante
- live for 2-3 years
- main defense mechanism is chemical cues.as the smell of dead relatives acts as an early warning system for predators and poor water quality
- dragonflys have no obvious gills or tails, damselflys have obvious three pronged tail
how do dragonflys acquire oxygen?
via pumping from gills in the oxygen, allowing them to acquire more
what type of larve fly undergoes complete metamorphism?
-caddisfly
give information of caddis flys
-5-7 larvae stages
-soft bodies, and inhabit cases
-have gills on trachea so are subject to clogging (external abdomen gills)
feed by producing silk feeding nets that catch prey, but these are also subject to clogging
-different geni have a range of tolerance to different environmental conditions
-75% are cased
-
what are the two types of silk nets produced by caddisflys, and which clogs quicker?
- philopatmus (larger, clogs quicker)
- hydropsyche (smaller, clogs slower)
Give information on adderflies (Megaloptera). Cover distribution, water tolerance, and gills
- have a pupa stage so fully metamorphose
- have gills on the ABDOMEN, but these are protected in casing so are less subject to clogging
- gills used for locomotion
- protected gills means they are less sensitive, so can be found in regions of poorer water quality
- no tail
what is the difference between true flies and other fly larvae (eg. Mayfly,stone fly). Give an example of true flys
- “non true flies” do not have jointed limbs (look like maggots)
- DIPETERA
What are the three Diptera groups?
- Tipulidae (crane flys)
- Simuliidae (Black flys)
- Chironomidae (non biting midges)
what type of fly larvae are the most tolerant to organic pollution
-diptera
describe the characteristics of Tipulidae. Give key identification feature
- -thick worm like maggot
- functional spiracle with 6 tail like appendages. key identification feature.
- mosquito eaters
describe the characteristics of simuliidae. give key identification characteristic
- black,green,brown,grey in colour
- fat “swelled” bottom key for identification
give key characteristics of Chiromomidae.
- larvae up to 30 mm long
- most tolerant of the diptera larvae
- tolerant of low oxygen levels (but not anoxic)
- have spiracles that are not subject to clogging
