Project description:An Autonomous Underwater Vehicle (AUV) and large volume underwater pumps were used to collect microbial biomass from offshore waters of the Sargasso Sea, from surface waters and into the deep ocean. Seawater collection was performed along a transect in the western North Atlantic Ocean beginning near Bermuda and ending off the coast of Massachusetts, capturing metabolic signatures from oligotrophic, continental margin, and productive coastal ecosystems.
Project description:The available energy and carbon sources for prokaryotes in the deep ocean remain still largely enigmatic. Reduced sulfur compounds, such as thiosulfate, are a potential energy source for both auto- and heterotrophic marine prokaryotes. Shipboard experiments performed in the North Atlantic using Labrador Sea Water (~2000 m depth) amended with thiosulfate led to an enhanced prokaryotic dissolved inorganic carbon (DIC) fixation.
Project description:Pelagic sediments from the subtropical South Atlantic Ocean contain geographically extensive Oligocene ooze and chalk layers that consist almost entirely of the calcareous nannofossil Braarudosphaera. Poor recovery and the lack of precise dating of these horizons in previous studies has limited the understanding of the number of acmes, their timing and durations, and therefore their likely cause. Here we present a high-resolution, astronomically tuned stratigraphy of Braarudosphaera oozes (29.5-27.9 Ma) from Ocean Drilling Program Site 1264 in the southeastern Atlantic Ocean. We identify seven episodes with highly abundant Braarudosphaera. Four of these acme events coincide with maxima and three with minima in the ~110 and 405-kyr paced eccentricity cycles. The longest lasting acme event corresponds to a pronounced minimum in the ~2.4-Myr eccentricity cycle. In the modern ocean, Braarudosphaera occurrences are limited to shallow marine and neritic settings, and the calcified coccospheres of Braarudosphaera are probably produced during a resting stage in the algal life cycle. Therefore, we hypothesize that the Oligocene acmes point to extensive and episodic (hyper) stratified surface water conditions, with a shallow pycnocline that may have served as a virtual seafloor and (partially/temporarily) prevented the coccospheres from sinking in the pelagic realm. We speculate that hyperstratification was either extended across large areas of the South Atlantic basin, through the formation of relatively hyposaline surface waters, or eddy contained through strong isopycnals at the base of eddies. Astronomical forcing of atmospheric and/or oceanic circulation could have triggered these conditions through either sustained rainfall over the open ocean and adjacent land masses or increased Agulhas Leakage.
Project description:Surface seawater samples collected from the Atlantic Ocean. Three types of samples were collected: seawater inside a patch of Sargassum ('in'), seawater in the downstream slick of Sargassum ('slick'), and seawater outside the patch ('out'). Samples were collected by hand from a small boat, and DOM was extracted using solid phase extraction with Bond Elut PPL cartridges. Both positive and negative ion mode data are available.
Project description:Black spots, which deteriorate quality of Atlantic salmon fillets represent a significant problem for commercial aquaculture. These areas are characterized with accumulation of melanomacrophages, occasional formation of granulomas and substitution of skeletal muscle with connective tissue. Transcriptome analysis was performed to elucidate the origin and the character of inflammation in the melanized foci of skeletal muscle.