Chapter 8 | Surface Water Quality (Organisms used as Indicators of Pollution) Flashcards
Can be used to determined the overall quality of an aquatic ecosystem
Biological communities (fish and freshwater macroinvertebrates)
used to evaluate short and long-term trends in water quality
Biological communities (fish and freshwater macroinvertebrates)
it show the existing status of a water body whether it is clean or polluted
Short-term trends
it shows if conditions are getting better or worse over time.
Long-term trends
are placed into
categories based on their tolerance to pollution and are
used as indicator organisms in evaluating the health of
streams
Fish and benthic macroinvertebrates
three main categories of pollution tolerance
- Intolerant
- Intermediate
- Tolerant
sensitive to poor stream conditions
Intolerant
moderately tolerant to degraded habitat
and water quality
Intermediate
most tolerant to degraded habitat and water
quality
Tolerant
not always the limiting factor in the
presence or absence of aquatic organisms
Water quality
also
plays a key role in the whether an organism inhabits a water
body
Physical habitat
It is indicated when the number of
tolerant organisms exceed that of intermediate species and intolerant species are absent
Poor water quality
It have a larger number of species with fewer individuals per species, increased variety, and a
balanced system
Good quality stream
It includes a few species with numerous individuals, lacks variety, and is unbalanced
Unhealthy community
Freshwater macroinvertebrates can indicate the following:
•Long-term water quality trends.
•Impacts of various pollutants.
•Impact of changes to the physical habitat.
•Improvements or declines in water quality.
Freshwater macroinvertebrates are used as indicators of water
quality for what reasons?
•Important component of virtually all aquatic ecosystems.
•Found in all types of aquatic habitats.
•Relatively easy to collect.
•Have different levels of tolerance to environmental disturbance.
•Most are sedentary or move over a small area.
•The kind of organisms and number present in a stream is well correlated with recent past and present conditions.
•Life cycles and taxonomy of most groups are well documented.
Freshwater fish are used as indicators of water pollution for what reasons?
•Live in water for entire life and have long life spans.
•Easy to identify in the field because of established key characteristics of fish species.
•Relatively easy to collect with the proper equipment.
•Wide range of tolerance levels, from very sensitive to very tolerant of environmental
disturbance.
•Distribution, life histories, and pollution tolerances of many species are well documented.
•Fish communities are persistent and can recover from natural disturbances.
Freshwater fish can indicate the following about water pollution:
•Long-term and short-term water quality trends.
•Impacts of various pollutants.
•Impact of changes to the physical habitat.
•Improvements or declines in water quality