Diatoms reveal freshwater pollution

May 04, 2010

Researchers in India have demonstrated that microscopic aquatic creatures could be used as the ecological equivalent of a canary in a coalmine for assessing inland freshwater lakes and ponds. Writing in the World Review of Science, Technology and Sustainable Development the team explains how diatoms respond badly to pollutants and sewage contamination.

Bijaya Kumar Padhi, Jnanendra Rath, and Pratap Kumar Padhy of the Visva-Bharati University, in Santiniketan, India, have looked at the ecological responses of diatoms to pollution and nutrient enrichment, caused by domestic and municipal sewage, in five freshwater ponds. Absent diatom species were present in some heavily polluted lakes, while raised levels of nutrients boost numbers of other species. They suggest that a Biological Index for Diatoms could be used as a simple biological method for monitoring water quality that avoids the need for sophisticated chemical analysis.

Rapid urbanization and economic development have resulted in unfavorable changes in the hydrology and ecology of freshwater systems, which are felt most acutely in the developing world. The researchers explain that the remediation and protection of freshwater ecosystems is increasingly important but water quality management requires reliable long-term data on water quality and how remediation work affects the water. Moreover, information about natural, baseline, conditions in undisturbed ponds, lakes and is needed against which polluted bodies of water undergoing remediation might be gauged.

Natural changes in environmental conditions, such as flow rate, water temperature, dissolved oxygen, and food resources exert direct control on the population dynamics of , which gives rise to characteristic biological communities within different ecosystems. However, pollution and other human activities also disturb these community profiles significantly and so can provide such a measure.

Diatoms are important contributors to the primary production in aquatic ecosystems, sitting at the bottom of the food chain. They are eukaryotic algae, commonly unicellular, although they do exist as filamentous colonies and are good indicators of the environmental integrity, the researchers explain. They have several advantages over other indicators, the team adds.

First, they are readily dispersed and can invade a variety of habitats. They are relatively easy to sample and such sampling has negligible impact on the ecosystem during collection. Their "response" time to variation in environmental conditions lies between bacteria (change hourly) and bigger invertebrates (change over the course of months). Finally, diatoms are sensitive to very subtle changes in environmental conditions and/or disturbances that may not visibly affect other communities, or may only affect other communities at greater levels of disturbance.

The team's evaluation of monitoring of five freshwater bodies was consistent with more conventional physical and chemical determinations carried out in parallel. Diatoms usually grow better in unpolluted ponds and streams and this preliminary investigation suggests that they could be useful for biological monitoring of pollution levels and ecosystem integrity in the short and potentially in the long-term once seasonal studies confirm the preliminary results.

Explore further: First large-scale carbon capture goes online in Canada

More information: "Diatoms for assessing the ecological condition of inland freshwater bodies" in World Review of Science, Technology and Sustainable Development, 2010, 7, 352-359

add to favorites email to friend print save as pdf

Related Stories

Climate Change Alters Base of Tahoe Food Web

Sep 29, 2008

(PhysOrg.com) -- UC Davis researchers at Lake Tahoe this week published the first evidence that climate change alters the makeup of tiny plant communities called algae, which are the very foundation of the ...

New species of diatom discovered

Dec 02, 2005

Lake Superior has a new native resident. It’s been hanging around the shore for years, but until now it was regarded as an intercontinental drifter, not a homegrown local. So say Rebecca Bixby of the University of Georgia ...

Environmental Change Impacts Oklahoma Rivers

Jan 25, 2010

(PhysOrg.com) -- Biodiversity in freshwater systems is impacted as much or more by environmental change than tropical rain forests, according to University of Oklahoma Professor Caryn Vaughn, who serves as director of the ...

Fuzzy logic water quality

Apr 17, 2008

A fuzzy logic approach to analyzing water quality could help reduce the number of people in the developing world forced to drink polluted and diseased water for survival. Writing in a forthcoming issue of the International Jo ...

Recommended for you

Report IDs 'major weaknesses' at nuclear-arms lab

4 hours ago

One of the nation's premier nuclear weapons laboratories is being called out by the inspector general of the U.S. Department of Energy for "major weaknesses" in the way it packaged contaminated waste before shipping it to ...

User comments : 0