Ecologicalintegrity refers to the status of an ecosystem remaining undisturbedor natural. In other words, ecological integrity is the ability ofthe ecosystem to maintain and support a diverse community of microand macro organisms as well as the natural ecosystems. Some of thethree aspects of a river that contribute towards its integrityinclude the physical integrity, chemical integrity, and biologicalintegrity. An interference with any of these aspects reduces thehealth of the river, which in turn results in the degradation of theaquatic life.
Q.2:Macrovertebrates as useful indicators of stream health
Thereare many factors that make aquatic macrovertebrates good indicatorsof stream health. First, these macrovertebrates occupy a central rolein the aquatic system’s food chain, which means that they areeasily affected by the chemical, physical, and biological aspects ofthe stream. Secondly, aquatic macrovertebrates spend their entirelife in the water, which means that they cannot escape pollution.This makes them good indicators of both the long-term and theshort-term pollution occurrences. Third, aquatic macrovertebratesare easy to identify and sample, which makes the process of assessingthe stream health faster and cheap. Fourth, aquatic macrovertebratesindicates cumulative effects of pollution, which makes them suitableto asses all events of pollution that have occurred for a long time.Fifth, some of the aquatic macrovertebrates are intolerant topollution, which increases the possibility of detecting even theslightest changes in the integrity of the stream.
Q.3:How to use macrovertebrates to infer the stream health
Thehealth of the stream can be inferred by conducting a biologicalassessment, which involves the evaluation of different conditions ofa given water body. This is accomplished by collecting representativesamples of a biological community that spends its life in the waterbody and then comparing the biological indicators with conditionsthat would be expected based on the reference sites. Some of the keybiological indicators that can be used to assess the health of astream include crayfish, fish, macrophytes, and periphyton amongothers. Different metrics of the biological conditions providequantitative information about the past and the present impacts ofanthropogenic stress on the aquatic system. Each individual metric isacts as measure of sample’s conditions relative to a givenreference site. Some of the metrics that can be used to infer thehealth of a stream include the relative richness, total taxonrichness, and percentage occurrence of anomalies among others.
Q.4:Diatoms and their usefulness as indicators of water quality
Diatomsare macroscopic algae that are found in semi-aquatic and aquatichabitats. Diatoms are unicellular organisms with some yellow-brownchloroplast that increase their capacity to carryout photosynthesis.Diatoms are preferred as indicators of water quality because they actas the primary producers. This means that their response to changesin the water conditions is a good indicator of events taking place atthe interface between chemotrophic response and the aquaticenvironment in which they live in. For example, a change in differentbiological factors (such as pH, salinity, and nutrients) results in arapid reproduction of diatoms. These changes in the growth rate ofdiatoms can be used as indicators of some interference with theintegrity of the water body.
Q.5:cosmopolitan species of diatom
Astatement that diatom are cosmopolitan means that they are found inmany nations. This happens because the environmental conditions indifferent countries and parts of the world (such as Africa, Europe,and Australia) allow the same species of diatom to grow. This is canenhance the process of biological assessment of the quality of waterbodies in the world because the results of the assessment can becompared across countries, provinces, and continents.