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E Ortegaretuerta - One of the best experts on this subject based on the ideXlab platform.
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Transparent Exopolymer Particle tep distribution and in situ prokaryotic generation across the deep mediterranean sea and nearby north east atlantic ocean
Progress in Oceanography, 2019Co-Authors: E Ortegaretuerta, Ignacio P Mazuecos, Isabel Reche, Josep M Gasol, Xose Anton Alvarezsalgado, Marta Alvarez, Maria F Montero, Javier AristeguiAbstract:Abstract Transparent Exopolymer Particles (TEP) play a key role in ocean carbon export and structuring microbial habitats, but information on their distribution across different ocean basins and depths is scarce, particularly in the dark ocean. We measured TEP vertical distribution from the surface to bathypelagic waters in an east-to-west transect across the Mediterranean Sea (MedSea) and the adjacent North East Atlantic Ocean (NEA), and explored their physical and biological drivers. TEP ranged from 0.6 to 81.7 µg XG eq L−1, with the highest values in epipelagic waters above the deep chlorophyll maximum, and in areas near the Gibraltar and Sicily Straits. TEP were significantly related to particulate organic carbon (POC) in all basins and depth layers (epipelagic vs. deep), but the contribution of TEP to POC was higher in the NEA (85%, 79% and 67% in epi-, meso- and bathypelagic waters, respectively) than in the MedSea (from 53% to 62% in epipelagic waters, and from 45% to 48% in meso- and bathypelagic waters), coinciding with higher carbon to nitrogen particulate organic matter ratios in the NEA. The TEP connectivity between epipelagic waters and mesopelagic waters was less straightforward than between mesopelagic waters and bathypelagic waters, with a 23% and 55% of the variance in the relationship between layers explained respectively. Prokaryotes were found to be a likely net source of TEP as inferred by the significant direct relationship observed between prokaryotic heterotrophic abundance and TEP. This assumption was confirmed using experimental incubations, where prokaryotes produced TEP in concentrations ranging from 0.7 (Western Mediterranean, bathypelagic) to 232 (Western Mediterranean, mesopelagic) µg XG eq. L−1 day−1.
Javier Aristegui - One of the best experts on this subject based on the ideXlab platform.
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Transparent Exopolymer Particle tep distribution and in situ prokaryotic generation across the deep mediterranean sea and nearby north east atlantic ocean
Progress in Oceanography, 2019Co-Authors: E Ortegaretuerta, Ignacio P Mazuecos, Isabel Reche, Josep M Gasol, Xose Anton Alvarezsalgado, Marta Alvarez, Maria F Montero, Javier AristeguiAbstract:Abstract Transparent Exopolymer Particles (TEP) play a key role in ocean carbon export and structuring microbial habitats, but information on their distribution across different ocean basins and depths is scarce, particularly in the dark ocean. We measured TEP vertical distribution from the surface to bathypelagic waters in an east-to-west transect across the Mediterranean Sea (MedSea) and the adjacent North East Atlantic Ocean (NEA), and explored their physical and biological drivers. TEP ranged from 0.6 to 81.7 µg XG eq L−1, with the highest values in epipelagic waters above the deep chlorophyll maximum, and in areas near the Gibraltar and Sicily Straits. TEP were significantly related to particulate organic carbon (POC) in all basins and depth layers (epipelagic vs. deep), but the contribution of TEP to POC was higher in the NEA (85%, 79% and 67% in epi-, meso- and bathypelagic waters, respectively) than in the MedSea (from 53% to 62% in epipelagic waters, and from 45% to 48% in meso- and bathypelagic waters), coinciding with higher carbon to nitrogen particulate organic matter ratios in the NEA. The TEP connectivity between epipelagic waters and mesopelagic waters was less straightforward than between mesopelagic waters and bathypelagic waters, with a 23% and 55% of the variance in the relationship between layers explained respectively. Prokaryotes were found to be a likely net source of TEP as inferred by the significant direct relationship observed between prokaryotic heterotrophic abundance and TEP. This assumption was confirmed using experimental incubations, where prokaryotes produced TEP in concentrations ranging from 0.7 (Western Mediterranean, bathypelagic) to 232 (Western Mediterranean, mesopelagic) µg XG eq. L−1 day−1.
Josep M Gasol - One of the best experts on this subject based on the ideXlab platform.
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Transparent Exopolymer Particle tep distribution and in situ prokaryotic generation across the deep mediterranean sea and nearby north east atlantic ocean
Progress in Oceanography, 2019Co-Authors: E Ortegaretuerta, Ignacio P Mazuecos, Isabel Reche, Josep M Gasol, Xose Anton Alvarezsalgado, Marta Alvarez, Maria F Montero, Javier AristeguiAbstract:Abstract Transparent Exopolymer Particles (TEP) play a key role in ocean carbon export and structuring microbial habitats, but information on their distribution across different ocean basins and depths is scarce, particularly in the dark ocean. We measured TEP vertical distribution from the surface to bathypelagic waters in an east-to-west transect across the Mediterranean Sea (MedSea) and the adjacent North East Atlantic Ocean (NEA), and explored their physical and biological drivers. TEP ranged from 0.6 to 81.7 µg XG eq L−1, with the highest values in epipelagic waters above the deep chlorophyll maximum, and in areas near the Gibraltar and Sicily Straits. TEP were significantly related to particulate organic carbon (POC) in all basins and depth layers (epipelagic vs. deep), but the contribution of TEP to POC was higher in the NEA (85%, 79% and 67% in epi-, meso- and bathypelagic waters, respectively) than in the MedSea (from 53% to 62% in epipelagic waters, and from 45% to 48% in meso- and bathypelagic waters), coinciding with higher carbon to nitrogen particulate organic matter ratios in the NEA. The TEP connectivity between epipelagic waters and mesopelagic waters was less straightforward than between mesopelagic waters and bathypelagic waters, with a 23% and 55% of the variance in the relationship between layers explained respectively. Prokaryotes were found to be a likely net source of TEP as inferred by the significant direct relationship observed between prokaryotic heterotrophic abundance and TEP. This assumption was confirmed using experimental incubations, where prokaryotes produced TEP in concentrations ranging from 0.7 (Western Mediterranean, bathypelagic) to 232 (Western Mediterranean, mesopelagic) µg XG eq. L−1 day−1.
Uta Passow - One of the best experts on this subject based on the ideXlab platform.
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Aggregation and Sedimentation of Thalassiosira weissflogii (diatom) in a Warmer and More Acidified Future Ocean
PloS one, 2014Co-Authors: Shalin Seebah, Matthias S. Ullrich, Caitlin Fairfield, Uta PassowAbstract:Increasing Transparent Exopolymer Particle (TEP) formation during diatom blooms as a result of elevated temperature and pCO2 have been suggested to result in enhanced aggregation and carbon flux, therewith potentially increasing the sequestration of carbon by the ocean. We present experimental results on TEP and aggregate formation by Thalassiosira weissflogii (diatom) in the presence or absence of bacteria under two temperature and three pCO2 scenarios. During the aggregation phase of the experiment TEP formation was elevated at the higher temperature (20°C vs. 15°C), as predicted. However, in contrast to expectations based on the established relationship between TEP and aggregation, aggregation rates and sinking velocity of aggregates were depressed in warmer treatments, especially under ocean acidification conditions. If our experimental findings can be extrapolated to natural conditions, they would imply a reduction in carbon flux and potentially reduced carbon sequestration after diatom blooms in the future ocean.
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the characteristics and Transparent Exopolymer Particle tep content of marine snow formed from thecate dinoflagellates
Journal of Plankton Research, 1998Co-Authors: Alice L Alldredge, Uta Passow, H D HaddockAbstract:Abundant marine snow containing diatoms and detritus, but dominated by large, bio- luminescent thecate dinoflagellates and their temporary vegetative cysts, especially several species of the genus Gonyaulax, was observed at six stations in the Santa Barbara Channel, California, in 1989 and 1994. These aggregates were unusually cohesive and mucus rich, and contained 2-4 times more mass, paniculate organic carbon (POC), paniculate organic nitrogen (PON) and chlorophyll a per unit aggregate volume than more common types of marine snow formed from diatoms, fecal matter, larvacean houses or miscellaneous detritus. However, the relationship between aggregate size and the concentration of TEP (Transparent Exopolymer Particles which form the mucus matrix of most marine snow) was similar to that of other types of aggregates, suggesting that much of the copious gel-like material within dinoftagellate aggregates was not TEP. While this is the first report of abundant thecate dinoflagellates occurring within large, rapidly sinking marine aggregates, the data do not suppon the conclusion that mass aggregation and subsequent sedimentation of blooms is pan of the life history adaptations of thecate dinoflagellates, as it is for some diatoms. The high abundance of free-living dinoflagellate cells and temporary cysts, and the similar proportion of dinoflagellat es relative to other algal and chemical components in both aggregates and the surrounding seawater, indicate that the dinoflagellates were not differentially aggregating. Even so, passive accumulation of dinoflagellates in marine snow through aggregation processes may result in more rapid transport of dinoflagellate-generated material to the deep ocean, alter the nature of sinking paniculate matter following dinoflagellate blooms, and increase the nutritional value of marine snow as a food source for zooplankton and fish.
Jie Chen - One of the best experts on this subject based on the ideXlab platform.
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Transparent Exopolymer Particle production and aggregation by a marine planktonic diatom thalassiosira weissflogii at different growth rates
Journal of Phycology, 2015Co-Authors: Jie Chen, Daniel C. O. ThorntonAbstract:Transparent Exopolymer Particles (TEP) play an important role in the ocean carbon cycle as they are sticky and affect Particle aggregation and the biological carbon pump. We investigated the effect of growth rate on TEP production in nitrogen limited semi-continuous cultures of the diatom Thalassiosira weissflogii (Grunow) G. Fryxell & Hasle. Steady-state diatom concentrations and other indicators of biomass (chl a, and total carbohydrate) were inversely related to growth rate, while individual cell volume increased with growth rate. There was no change in total TEP area with growth rate; however, individual TEP were larger at high growth rates and the number of individual TEP Particles was lower. TEP concentration per cell was higher at higher growth rates. SYTOX Green staining showed that <5% of the diatom population had permeable cell membranes, with the proportion increasing at low growth rates. However, TEP production rates were greater at high growth rates, refuting our hypothesis that TEP formation is dependent on dying cells with compromised cell membranes in a diatom population. Measurements of Particle size distribution in the cultures using laser scattering showed that they were most aggregated at high growth rates. These results indicate a coupling between TEP production and growth rate in diatoms under N limitation, with fast growing T. weissflogii producing more TEP and aggregates.
