Decrease in the abundance and viability of oceanic phytoplankton due to trace levels of complex mixtures of organic pollutants

Changes in the Synechococcus Assemblage Composition at the Surface of the East China Sea Due to Flooding of the Changjiang River

“…For example, the Changjiang River discharge, in addition to carrying nutrients, also carries large amounts of heavy metals (e.g., Cu, Cd, Zn) and organic matter (e.g., polychlorinated benzenes) into the ECS due to anthropogenic activities [41,42]. Hence, it can be deduced that the input of contaminants should increase greatly after a flooding event [16,42,43] and, in turn, damage Synechococcus growth [44][45][46]. In addition, Tsai et al (2010) found that large numbers of nanoflagellates usually occur in the CDW during large plume periods [47].…”

Phytoplankton lysis predicts dissolved organic carbon release in marine plankton communities

“…The results presented show that the high DOC release rates by phytoplankton in the oligotrophic ocean are not supported by healthy cells but, rather, by dying ones, as suspected long ago (Duursma, 1963). Evidence for high lysis rates (Agustí et al, 1998(Agustí et al, , 2001Hayakawa et al, 2008) and a high percentage of dying or compromised cells (Agustí, 2004;Alonso-Laita and Agustí, 2006;Lasternas et al, 2010;Llabrés and Agustí, 2011;Hayakawa et al, 2008) as characteristic properties of phytoplankton communities in the oligotrophic ocean is accumulating in parallel to an increased understanding of the multiple cellular and molecular mechanisms (Bidle et al, 2004) and environmental drivers (Llabrés and Agustí, 2006;Echeveste et al, 2010) responsible for these high mortality rates. Phytoplankton mortality is, therefore, a fundamental process shaping carbon flow in the oligotrophic ocean.…”

“…Moreover, the turnover of dead and compromised cells in the community is relatively fast (Marbá et al, 2007). Considerable research has also focused on the drivers of mortality, identifying a broad range of stresses causing mortality, particularly of the apparently more vulnerable picoautotrophs, such as UVB radiation (Llabrés and Agustí, 2006;Agustí and Llabrés, 2007;Llabrés et al, 2010), hydroxyl radicals (Llabrés and Agustí, 2012), viral infections (Suttle et al, 1990), accumulated damages and stresses (Llabrés and Agustí, 2011), nutrient limitation (Berges and Falkowski, 1998), persistent organic pollutants (Echeveste et al, 2010), and even bursts of gamma rays from extrasolar events (Peñate et al, 2010). There has also been considerable progress in our understanding in the cellular processes conducive to lysis rates (Biddle and Falkowski, 2004).…”

Contrasted effects of natural complex mixtures of PAHs and metals on oxygen cycle in a microbial mat

“…Contamination is rarely due to a single molecule but to a trail of pollutants sometimes at trace levels, which can nevertheless affect the diversity and function of organisms. Trace levels of natural complex mixtures of pollutants can have severe consequences on the diversity and function of microorganisms, with toxicity effects sometimes 1000 times higher than the toxicity expected for a single pollutant (Echeveste et al, 2010). In addition, artificial contamination often requires the use of solvents that can have a significant effect for the community.…”

“…The toxicity of a contaminant may also be modified by environmental conditions; solar radiation, particularly ultraviolet (UV) radiation, can increase the toxicity of PAH compounds by production of toxic intermediate products (Ankley et al, 1994;Woo et al, 2009). Therefore, to estimate the consequences of contaminants on biological models, it is imperative to consider the contamination in its entirety (Echeveste et al, 2010) in order to better simulate the conditions of exposure to contaminants encountered by organisms in polluted environments. The response to a contamination depends on the adaptation mechanisms that microorganisms can develop to face pollution.…”