Temperate coastal marine waters are often thermally stratified from spring through fall but can be dynamic and disrupted by tidal currents and wind‐driven upwelling. These mixing events introduce deeper, cooler water with a higher partial pressure of CO2 (pCO2) and its associated microbial communities to the surface. Anecdotally, these events impact shellfish hatcheries and farms, warranting improved understanding of changes in composition and activity of marine microbial communities in relation to environmental processes. To characterize both compositional and functional changes associated with abiotic factors, here, we generate a reference metatranscriptome from the Strait of Georgia over representative seasons and analyze metatranscriptomic profiles of the microorganisms present within intake water containing different pCO2 levels at a shellfish hatchery in British Columbia from June through October. Abiotic factors studied include pH, temperature, alkalinity, aragonite, calcite, and pCO2. Community composition changes were observed to occur at broad taxonomic levels and most notably to vary with temperature and pCO2. Functional gene expression profiles indicated a strong difference between early (June–July) and late summer (August–October) associated with viral activity. The taxonomic data suggest this could be due to the termination of cyanobacteria and phytoplankton blooms by viral lysis in the late season. Functional analysis indicated fewer differentially expressed transcripts associated with abiotic variables (e.g., pCO2) than with the temporal effect. Microbial composition and activity in these waters vary with both short‐term effects observed alongside abiotic variation and long‐term effects observed across seasons. The analysis of both taxonomy and functional gene expression simultaneously in the same samples by environmental RNA (eRNA metatranscriptomics) provided a more comprehensive view for monitoring water bodies than either would in isolation.

Temperate coastal marine waters are often thermally stratified from spring through fall, but can be dynamic and disrupted by tidal currents and wind-driven upwelling. These mixing events introduce deeper, cooler water with a higher partial pressure of CO2 (pCO2), and its associated microbial communities to the surface. Anecdotally, there have been concerns that these changes in water quality as well as in microbial composition and activity may be involved in mass mortality events of Pacific oysters (Crassostrea gigas) on the East Coast of Vancouver Island, British Columbia. Therefore, improved understanding of the composition and microbial activity of marine waters associated with seasons and abiotic variables may be useful in managing these mortality events. To characterize both compositional and functional changes associated with abiotic factors, here we generate a reference metatranscriptome from the Strait of Georgia over the representative seasons and analyze metatranscriptomic profiles of the microorganisms present within intake water containing different pCO2 levels at a shellfish hatchery in British Columbia from June through October. Abiotic factors studied include pH, temperature, alkalinity, aragonite, calcite and pCO2. Community composition changes were observed to occur at broad taxonomic levels, and most notably to vary with temperature and pCO2. Functional gene expression profiles indicated a strong difference between early (June-July) and late summer (August-October) associated with viral activity. The taxonomic data suggests this could be due to the termination of cyanobacteria and phytoplankton blooms by viral lysis in the late season. Functional analysis indicated fewer differentially expressed transcripts associated with abiotic variables (e.g., pCO2) than with the temporal effect. Microbial composition and activity in these waters varies with both short-term effects observed alongside abiotic variation as well as long-term effects observed across seasonal changes, as captured in the samples analyzed here. The analysis of both taxonomy and functional gene expression simultaneously in the same samples (i.e., metatranscriptomics) provided a more comprehensive view for monitoring water bodies than either would in isolation.

The southwestern part of Foxe Basin is a little known region of the Canadian Arctic, being difficult to access during the summer because of heavy and unpredictable ice conditions. Surveys of birds and marine mammals in the area were carried out by lightweight expeditions in the summers of 1994 and 1995, using sea-kayaks, as well as a Peterhead boat from the nearest community, at Repulse Bay. The area supports important populations of narwhal, bowhead whales and walrus, as well as significant concentrations of shorebirds, common eiders, black guillemots, and perhaps one third of the world's Thayer's gulls. New information was obtained on the status and abundance of these species and novel observations were made on the feeding ecology and breeding phenology of the gulls.

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