Contrasting Patterns of Phytoplankton Assemblages in Two Coastal Ecosystems in Relation to Environmental Factors (Corsica, NW Mediterranean Sea)

Abstract

Corsica Island is a sub-basin of the Northwestern Mediterranean Sea, with hydrological features typical of both oligotrophic systems and eutrophic coastal zones. Phytoplankton assemblages in two coastal ecosystems of Corsica (the deep Bay of Calvi and the shallow littoral of Bastia) show contrasting patterns over a one-year cycle. In order to determine what drives these variations, seasonal changes in littoral phytoplankton are considered together with environmental parameters. Our methodology combined a survey of the physico-chemical structure of the subsurface water with a characterization of the phytoplankton community structure. Sampling provided a detailed record of the seasonal changes and successions that occur in these two areas. Results showed that the two sampled stations presented different phytoplankton abundance and distribution patterns, notably during the winter-spring bloom period. Successions in pico-, nano-, and microphytoplankton communities appeared mainly driven by differences in the ability to acquire nutrients, and in community-specific growth rates. Phytoplankton structure and dynamics are discussed in relation to available data on the Northwestern Mediterranean OPEN ACCESS Diversity 2014, 6 297 Sea. These results confirm that integrated monitoring of coastal areas is a requisite for gaining a proper understanding of marine ecosystems.

Seasonal and spatial variability of dimethylsulfoniopropionate (DMSP) in the Mediterranean seagrass Posidonia oceanica

“…Furthermore, there is a permanent background DMSP stock of 600 mol m −2 corresponding to winter time DMSP leaf content (2 mol g dw −1 ) and leaf biomass (300 g dw m −2 ), that is still 60 higher than the maximum yearly stock related to phytoplankton. The yearly maximum DMSP content of phytoplankton we estimated is anyway most probably largely over-estimated since the dominant diatoms during the spring phytoplankton bloom reported in the Bay of Revellata by Garrido et al (2014) have DMSP:Chl-a ratios much lower than the average value used above such as Chaetoceros didynus and Chaetoceros socialis or even DMSP cellular quota that are below detection limit such as Chaetoceros decipiens and Chaetoceros simplex (Keller et al, 1989).…”

“…Within, the P. oceanica canopy, phytoplankton material was found to be mostly detrital, and living cells corresponded to cyanobacteria that are characterized by low DMSP content (Table 1). Further, in August, when DMSPd measurements were carried out, Chl-a in surface waters were extremely low, typically <0.2 g L −1 (own data not shown; Garrido et al, 2014). Hence, it is possible that DMSPd could accumulate more within the canopy than what is typically observed in the planktonic community of surface waters.…”

The Community Structure of Phytoplankton in Seagrass Ecosystem and its Relationship with Environmental Characterstics

“…The phytoplanktons whose original habitat was offshore came from fishing boats and were carried by ballast water or stucked to the hull. Garrido et al (2014) also found that many non-littoral species were also found at the enclosed mariculture area at Corsica, in the Mediterranean Sea.…”

“…and Melosira sp. This group dominated the seashore area, particularly the areas which had mariculture activities in them (Garrido et al, 2014;George & Atakpa, 2015;Akter et al, 2015). The group which had a low abundance consisted of 12 species.…”

Are red mullet efficient as bio-indicators of mercury contamination? A case study from the French Mediterranean

“…First, phytoplanktonic communities in Corsica are dominated by nano-and picophytoplankton, just as in all oligotrophic zones (Garrido et al, 2014). Heimbürger et al (2010) showed that Hg methylation is enhanced in the presence of nano-and picophytoplankton.…”