Spatial and temporal dynamics of nano‐ and pico‐size particulate organic matter (POM) in a coastal megatidal marine system

Abstract

Surface water samples of size-selected seston (0.7-20 lm) were collected from April 2013 to September 2013 at three similar coarse-sand benthic habitats. Additionally, seston sampling was performed at a fixed location throughout a complete tidal cycle (2014). A combination of fatty acid (FA), isotope, and flow cytometry analyses were used to determine the quality and quantity of nano-and pico-sized particulate organic matter (POM). High variability was found between fatty acid replicate samples. Similar temporal patterns were observed at two sheltered sites, while the exposed site displayed less pronounced seasonal changes. Lower concentrations of 16C and 18C polyunsaturated fatty acids were found during low tide sampling. Globally, POM was dominated by picoeukaryotes, with concentrations exceeding 50,000 cells mL 21 , and (16:4x3 1 18:3x3)/Rx3 is proposed as novel biomarker of picoeukaryotes in this region.

Cultured eastern oysters (Crassostrea virginica): retention and assimilation of picophytoplankton using a multi-biomarker approach

“…The MPB is characterized by high spatial variability at microscale (Spilmont et al, 2011) with fairly stable biofilms at a large scale in estuaries (Brito et al, 2013). Those general isotopic results are in agreement with numerous studies on oyster's food sources discrimination (Pernet et al, 2012;Moynihan et al, 2016). Stable isotopes analysis can provide time-integrated information (long term) on food sources, averaging the natural environment variability in dietary components (Pernet et al, 2012).…”

Trophic cues promote secondary migrations of bivalve recruits in a highly dynamic temperate intertidal system

“…Water was pre‐filtered through a 20‐μm mesh to focus on nano‐ and pico‐sized particulate organic matter (Moynihan et al. ), which are preferentially retained by early bivalve recruits (Raby et al. ).…”

“…The detailed analysis method is described in Moynihan et al. (). Fatty acid methyl esters were quantified by gas chromatography analysis (Varian 3800) using a flame ionization detector.…”

“…Four replicates of four liters of surface water were sampled 2 h after low tide at about 200 m from the study site (48°52 0 51.5″ N 1°50 0 09.8″ W) during each sampling period for fatty acid composition determination and for flow cytometry analyses. Water was pre-filtered through a 20-lm mesh to focus on nano-and pico-sized particulate organic matter (Moynihan et al 2016), which are preferentially retained by early bivalve recruits (Raby et al 1997). Samples were then filtered onto precombusted GF/F 47-mm microfiber filters (Whatman) that were stored at À80°C until fatty acid analyses.…”

“…Lipids associated with sediment and water-column samples were extracted according to the modified Bligh and Dyer (1959) method (Meziane et al 2006). The detailed analysis method is described in Moynihan et al (2016). Fatty acid methyl esters were quantified by gas chromatography analysis (Varian 3800) using a flame ionization detector.…”