Contribution of benthic microalgae to the temporal variation in phytoplankton assemblages in a macrotidal system

Abstract

Suspended marine benthic microalgae in the water column reflect the close relationship between the benthic and pelagic components of coastal ecosystems. In this study, a 12-year phytoplankton time-series was used to investigate the contribution of benthic microalgae to the pelagic system at a site along the French-Atlantic coast. Furthermore, all taxa identified were allocated into different growth forms in order to study their seasonal patterns. The highest contribution of benthic microalgae was observed during the winter period, reaching up to 60% of the carbon biomass in the water column. The haptobenthic growth form showed the highest contribution in terms of biomass, dominant in the fall-winter period when the turbidity and the river flow were high. The epipelic growth form did not follow any seasonal pattern. The epiphytic diatom Licmophora was most commonly found during summer. As benthic microalgae were found in the water column throughout the year, the temporal variation detected in the structure of pelagic assemblages in a macrotidal ecosystem was partly derived from the differentiated contribution of several benthic growth forms.

Impact of Chronic and Massive Resuspension Mechanisms on the Microphytobenthos Dynamics in a Temperate Intertidal Mudflat

“…Taxonomic identification was performed at the class to species level. Class and species were associated to a full or partial benthic growth and pelagic growth form according to the classification given in Hernández Fariñas et al (). Counts (number of cells per liter) were used to determine the contribution of each forms.…”

Effect of Light Intensity and Light Quality on Diatom Behavioral and Physiological Photoprotection

“…The only species that had not yet been described for this site was Navicula meeulmansii. However, N. meeulmansii has only recently been described as a cosmopolitan species tolerating wide range of salinities (Mertens et al, 2014), which may have been previously described as Navicula phyllepta or Navicula microdigitoradiata in the other studies from this ecosystem (Méléder et al, 2007;Hernández Fariñas et al, 2017). These epipelic diatoms are known to photo-regulate using both physiological and behavioral photoprotection (Cartaxana et al, 2011;Laviale et al, 2015).…”

Remote Sensing-Driven Pacific Oyster (Crassostrea gigas) Growth Modeling to Inform Offshore Aquaculture Site Selection

“…Strong spatial gradients in the turbidity of the water column have been observed, with highly turbid conditions [TSM typically > 10 g m −3 , and up to more than an order of magnitude higher (Gernez et al, 2017)] in parts of the intertidal zone related to tidal-and wind-driven resuspension of surface sediment at shallower water depths, and relatively clear conditions offshore (Gernez et al, 2014). A predominant intertidal-offshore gradient similar to that of turbidity also exists for Chl-a concentration, related to the contribution of microphytobenthos resuspension at shallow depths (Hernández Fariñas et al, 2017), as well as nutrient loading in the nearshore environment via river discharge and overland runoff, and subsequent dilution and progressive uptake by phytoplankton toward the offshore environment. Chla concentration in Bourgneuf Bay has been reported to span several orders of magnitude, and typically ranges from 0.1 mg m −3 to occasionally > 5 mg m −3 offshore (data from the French Observation and Monitoring program for Phytoplankton and Hydrology in coastal waters database (REPHY, 2017); Bois de la Chaise large sampling site) to ∼1-30 mg m −3 across the intertidal zone (Barillé-Boyer et al, 1997;Dutertre et al, 2009;Gernez et al, 2017).…”