Planktonic food web structure at a coastal time-series site: I. Partitioning of microbial abundances and carbon biomass

Abstract

Biogeochemistry in marine plankton communities is strongly influenced by the activities of 38 microbial species. Understanding the composition and dynamics of these assemblages is 39 essential for modeling emergent community-level processes, yet few studies have examined all 40 of the biological assemblages present in the plankton, and benchmark data of this sort from time-41 series studies are rare. Abundance and biomass of the entire microbial assemblage and 42 mesozooplankton (>200 μm) were determined vertically, monthly and seasonally over a 3-year 43 period at a coastal time-series station in the San Pedro Basin off the southwestern coast of the USA. All compartments of the planktonic community were enumerated (viruses in the femtoplankton size range [0.02-0.2 μm], bacteria + archaea and cyanobacteria in the picoplankton size range [0.2-2.0 μm] phototrophic and heterotrophic protists in the nanoplanktonic [2-20 μm] and microplanktonic [20-200 μm] size ranges, and mesozooplankton [>200 μm]. Carbon biomass of each category was estimated using standard conversion factors. Plankton abundances varied over seven orders of magnitude across all categories, and total carbon biomass averaged approximately 60 μg C l-1 in surface waters of the 890 m water column over the study period. Bacteria + archaea comprised the single largest component of biomass (>1/3 of the total), with the sum of phototrophic protistan biomass making up a similar proportion. Temporal variability at this subtropical station was not dramatic. Monthly depthspecific and depth-integrated biomass varied 2-fold at the station, while seasonal variances were generally <50%. This study provides benchmark information for investigating long-term environmental forcing on the composition and dynamics of the microbes that dominate food web structure and function at this coastal observatory.

Dynamics of Sediment Microbial Functional Capacity and Community Interaction Networks in an Urbanized Coastal Estuary

“…Additionally, significant correlations were observed between depth and several OTUs classified as Chloroflexi, Delta- and Gammaproteobacteria, Bacteriodetes, Gemmatimonadetes and Acidobacteria. Depth also served as a proxy of other unmeasured physicochemical environmental factors (e.g., light, pressure, and a redox gradient) along the land-sea transect ( Caron et al, 2017 ).…”

Global Systematic Review of Methodological Approaches to Analyze Coastal Shelf Food Webs

“…Destructive sampling techniques were mostly fisheries-based, using various types of benthic and pelagic fisheries tools, such as beam trawls (Jennings et al, 2002;Brind'Amour et al, 2009;Bell et al, 2016), otter trawls (Koulouri et al, 2015;Bell et al, 2016), plankton nets (Blachowiak-Samolyk et al, 2007;Anjusha et al, 2013;Caron et al, 2017), fyke nets (Thollot et al, 1999;Bergström et al, 2016), gillnets (Di Beneditto et al, 2012;Prado et al, 2014;Donadi et al, 2017), seine nets (Faye et al, 2011), bottom dredges (Jennings et al, 2001), crab traps (Mancinelli et al, 2013), and eel traps (Heldal et al, 2018). Other particular sampling techniques included infauna sampling with VanVeen and Smith-McIntyre grabs (Soto and Escobar-Briones, 1995;Dunton et al, 2012;Whalen et al, 2013;Lovvorn et al, 2015;Tu et al, 2015;Misic et al, 2016) and USNEL box corer (Tselepides et al, 2000), scraping of rocky surfaces with chisel for the collection of algae and benthic invertebrates (Lin et al, 1999;Kroeker et al, 2011), manual hand collection of macroinvertebrates by means of SCUBA diving (Tewfik et al, 2005;O'Gorman et al, 2008;Wing et al, 2018), as well as experimental dynamite fishing (Hansen et al, 2012).…”

Microbial Competition in the Subpolar Southern Ocean: An Fe–C Co-limitation Experiment

“…Photosynthetic pico-nanoplankton cell abundance was converted to carbon biomass using constant cell-to-carbon conversion factors based on the literature. Conversion factors used were, respectively 255 and 2590 fgC cell −1 for the cyanobacterium Synechococcus and for picoeukaryotes (Buitenhuis et al, 2012), and 183 fgC cell −1 for nanoeukaryotes (Caron et al, 1994(Caron et al, , 2017. We assume the cyanobacterium Synechococcus represented the majority of the resident cyanobacteria.…”