Overview of Phytoplankton Indicators and Biomarkers as Key-Tools for Trace Element Contamination Assessment in Estuaries

Abstract

Contamination of trace elements is still ubiquitous in estuaries. The main sources of trace element pollution are directly linked to anthropogenic activities commonly taking place in these coastal ecosystems. Trace element loading in and impacts on estuarine waters can be assessed and monitored by using indicator species equipped with efficient biomarkers of trace element stress. Phytoplankton, which are the primary producers at the base of estuarine food webs, can accumulate considerable amounts of trace elements, responding rapidly and proportionally to element availability changes in the environment. As such, phytoplankton provide potentially useful bioindicators with which to assess water quality and help evaluate the ecological state of polluted estuarine systems. Furthermore, several phytoplankton species are equipped with efficient biomarkers evidencing the damaging effect of trace elements which can also be used as key-tools for trace element pollution assessment. Although there is an emerging realization that phytoplankton can provide a valuable trace element-specific suite of indicators, a comprehensive identification of phytoplankton indicators and biomarkers for the early detection of element stress is generally lacking. This chapter gathers results obtained from our team over the past years, aiming to better understand trace element impacts on the phytoplankton communities and to deliver suitable phytoplankton indicators and biomarkers of element stress with potential application to element contaminated estuarine and coastal systems worldwide.