Temperate lakes experience variation in mixing and stratification that affects the distributions, activities, abundances, and diversity of plankton communities. We examined temporal and vertical changes in the composition of planktonic microorganisms (including Bacteria and Archaea) in oligotrophic Flathead Lake, Montana. Using a combination of approaches that included 16S rRNA gene sequencing and flow cytometric determination...

Quantifying phytoplankton composition is critical to predicting marine ecosystem structure and function. DNA meta‐barcoding and high‐performance liquid chromatography (HPLC) pigment analysis are two widely used methods for assessing phytoplankton composition; however, comparing their performance has been done only rarely. Here, we integrate DNA meta‐barcoding and HPLC pigment observations to determine eukaryotic phytoplankton...

Summary Coral reefs are highly productive ecosystems with distinct biogeochemistry and biology nestled within unproductive oligotrophic gyres. Coral reef islands have often been associated with a nearshore enhancement in phytoplankton, a phenomenon known as the Island Mass Effect (IME). Despite being documented more than 60 years ago, much remains unknown about the extent and drivers of IMEs. Here we utilized 16S rRNA gene met...

Sinking particulate organic matter controls the flux of carbon (C) from the surface ocean to the deep sea. Microorganisms actively colonize particles, but the extent to which microbial metabolism influences particle export remains uncertain. We conducted experiments to quantify rates of bacterial production (derived based on 3 H‐leucine incorporation) and dark C‐fixation (based on 14 C‐bicarbonate assimilation) associated with...

Bacteria and archaea are key contributors to deep-sea biogeochemical cycles and food webs. The disruptions these microbial communities may experience during and following polymetallic nodule mining in the Clarion-Clipperton Zone (CCZ) of the North Pacific Ocean could therefore have broad ecological effects. Our goals in this synthesis are to characterize the current understanding of biodiversity and biogeography of bacteria an...

Mesoscale eddies, prominent physical processes in the stratified ocean gyres, affect community composition and metabolic rates of both phytoplankton and heterotrophic bacterioplankton (free‐living bacterial and archaeal) communities. We hypothesized that in situ differences in organic matter production would predispose bacterioplankton communities from cyclonic vs. anticyclonic eddies toward metabolic capabilities better suite...

Summary Primers targeting the 16S small subunit ribosomal RNA marker gene, used to characterize bacterial and archaeal communities, have recently been re‐evaluated for marine planktonic habitats. To investigate whether primer selection affects the ecological interpretation of bacterioplankton populations and community dynamics, amplicon sequencing with four primer sets targeting several hypervariable regions of the 16S rRNA ge...