ICM and IEO researchers have developed a simple, cheap and fast method to evaluate the Good environmental status of the ocean based on the analysis of the diversity of microorganisms.
A study published by scientists from the Institut de Ciències del Mar of Barcelona (ICM) and the Spanish Institute of Oceanography (IEO) proposes the use of a simple, cheap and fast method to evaluate the Good environmental status of the ocean based on the analysis of microbial biodiversity, which could facilitate monitoring programs that enforce the EU Marine Strategy Framework Directive.
This study is a step forward towards fulfilment of the EU Marine Strategy Framework Directive, which seeks to achieve the Good environmental status of European seas through the analysis and monitoring of a series of descriptors to quantify ecosystems health. The initial implementation of this directive has highlighted the technical difficulties in developing this monitoring and the need to develop innovative, simpler, cheaper and faster indicators and methods of analysis.
In this sense, this new article published in the specialized journal Marine Pollution Bulletin evaluates the use of new indicators based on microbial diversity which, thanks to the development and cheapening of mass sequencing techniques, could be useful in understanding the environmental status of the sea.
In the study, scientists have assessed whether the diversity of picoplankton (plankton a thousand times smaller than a millimeter) and nanoplankton (one hundred times smaller than a millimeter) is a useful bioindicator for determining Good environmental status. For this, six sampling areas were selected in different areas of the Catalan-Balearic Sea adjacent to territories with different uses: from urban to agricultural use, and also under the influence of rivers and groundwater.
"Plankton microorganisms respond very quickly to disturbances in the ecosystem such as the massive entry of nutrients or pollution, so they could be useful indicators of these impacts", states Isabel Ferrera, an IEO researcher and first author of the study.
However, although the results demonstrate the usefulness of these techniques, the authors warn of possible drawbacks that must be taken into account when considering microbial diversity as an indicator of the ecosystem’s health.
The great seasonal variability that plankton microorganism communities have naturally could be confused with changes caused by human impacts. Thus, to use this variable as an indicator of ecosystem’s health, its essential to know the natural seasonality of microbial diversity in each area.
Besides, human impacts such as massive nutrient discharge can occasionally lead to an increase in microbial biodiversity that could erroneously translate into an indicator of Good environmental status. For all this, the authors suggest that the use of these new indicators should be made not only considering the environmental conditions, but also in combination with the analysis of other communities of organisms.
"Given the importance of marine ecosystems for our human well-being, knowing how vulnerable they are to our impacts is essential. Monitoring programs must make it possible to know the condition of the sea and how it responds to the pressure exercised. Only in this way we will be able to manage the negative impacts that lead to environmental degradation of some areas and to keep them in good condition", concludes Esther Garcés, researcher at the ICM.