Copper and cadmium effects on growth and extracellular exudation of the marine toxic dinoflagellate Alexandrium catenella: 3D-fluorescence spectroscopy approach

Abstract

In this study, metal contamination experiments were conducted to investigate the effects of copper and cadmium on the growth of the marine toxic dinoflagellate Alexandrium catenella and on the production of dissolved organic matter (Dissolved Organic Carbon: DOC; Fluorescent Dissolved Organic Matter: FDOM). This species was exposed to increasing concentrations of Cu(2+) (9.93 × 10(-10)-1.00 × 10(-7)M) or Cd(2+) (1.30 × 10(-8)-4.38 × 10(-7)M), to simulate polluted environments. The drastic effects were observed at pCu(2+)=7.96 (Cu(2+): 1.08 × 10(-8)M) and pCd(2+)=7.28 (Cd(2+): 5.19 × 10(-8)M), where cyst formation occurred. Lower levels of Cu(2+) (pCu(2+)>9.00) and Cd(2+) (pCd(2+)>7.28) had no effect on growth. However, when levels of Cu(2+) and Cd(2+) were beyond 10(-7)M, the growth was totally inhibited. The DOC released per cell (DOC/Cell) was different depending on the exposure time and the metal contamination, with higher DOC/Cell values in response to Cu(2+) and Cd(2+), comparatively to the control. Samples were also analyzed by 3D-fluorescence spectroscopy, using the Parallel Factor Analysis (PARAFAC) algorithm to characterize the FDOM. The PARAFAC analytical treatment revealed four components (C1, C2, C3 and C4) that could be associated with two contributions: one, related to the biological activity; the other, linked to the decomposition of organic matter. The C1 component combined a tryptophan peak and a characteristic humic substances response, and the C2 component was considered as a tryptophan protein fluorophore. The C3 and C4 components were associated to marine organic matter production.

Impact of industrial pollution on recent dinoflagellate cysts in Izmir Bay (Eastern Aegean)

“…Some metals such as Hg, Cd, and Pb can be extremely toxic to vegetative cells (Okamoto et al, 1999). Metal toxicity might cause an inhibition of net growth, whereas lower levels of some metals (Cu and Cd) have no effect on cell growth (Herzi et al, 2013). These studies support and may explain the abundance of cysts, and reflect the relationship of metal level to their distribution in Izmir Bay.…”

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“…15: 543-554(2015) 551 et al, 1999). The lower levels of Cu and Cd do not have any significant effect on vegetative cell growth of phytoplankton species (Herzi et al, 2013). Some metal elements are important component in phytoplankton physiology and effects of metal toxicity on dinoflagellate life cycle is not well understood.…”

Do the levels of industrial pollutants influence the distribution and abundance of dinoflagellate cysts in the recently-deposited sediment of a Mediterranean coastal ecosystem?

“…Several laboratory studies have been conducted to date to test the degree of stress posed by metal contamination on vegetative cells. Contaminants affect the physiology of vegetative cells by acting on the levels of oxidative stress in cells (Okamoto and Colepicolo, 1998;Pinto et al, 2003) or by reducing their light-harvesting capacity and by inhibiting cell growth (Miao and Wang, 2006;Herzi et al, 2013). Under high levels of iron, cell Naple, Adriatic sea (Italy), Alfacs Bay (Spain) (Montresor, 1995;Bravo et al, 2006;Penna et al, 2010;Satta et al, 2013) Alexandrium minutum Halim * Paralytic shellfish toxins (Bravo et al, 2006) Harbour of Alexandria (Egypt), Catalonia, Arenys del mar (Spain); Ionian sea, Adriatic sea, Tyrrhenian sea, Olbia (Italy), Aegean Sea (Turkey) (Ismael and khadr, 2003;Anglès et al, 2010;Rubino et al, 2010;Penna et al, 2010;Aydin et al, 2011) Alexandrium catenella/tamarense (Whedon & Kofoid) Balech ** Paralytic shellfish toxins (Laabir et al, 2013) Aegean Sea (Turkey), Ionian Sea, Olbia, (Italy), Thau lagoon (France), Tarragona and Barcelona Harbours (Spain) (Bravo et al, 2006;Satta et al, 2010;Rubino et al, 2010;Aydin et al, 2011) Lingulodinium polyedrum (Stein) Dodge Lingulodinium sp ** Yessotoxin (Paz et al, 2004) Ionian Sea, Adriatic sea (Italy), Catalan sea, Arenys del mar, Alfacs and Fangar bays (Spain) Penna et al, 2010;Satta et al, 2010Satta et al, , 2013) Gonyaulax cf.…”

“…Chemical contaminants can affect negatively the metabolic activities of vegetative cells of various phytoplankton species, inhibiting their growth and survival at determined concentrations (e.g., Rai et al, 1998;Mosulén et al, 2003;Wang et al, 2005;Miao and Wang, 2006;Herzi et al, 2013). Until now, most of the ecotoxicological studies conducted on dinoflagellates investigated the effects of contaminants only on vegetative cells.…”