1,721,664 research outputs found
Accumulation of Gel Particles in the Sea-Surface Microlayer during an Experimental Study with the Diatom Thalassiosira weissflogii
Full text linkSince the early 80’s, the sea-surface microlayer (SML) has been hypothesized as being a gelatinous film. Recent studies have confirmed this characteristic, which confers properties that mediate mass and energy fluxes between ocean and atmosphere, including the emission of primary organic aerosols from marine systems. We investigated SML thickness and composition in five replicate indoor experiments between September and December 2010. During each experiment, the SML and underlying seawater were sampled from four seawater tanks: one served as control, and three were inoculated with Thalassiosira weissflogii grown in chemostats at 180, 380 and 780 ppm pCO2. We examined organic material enrichment factors in each tank, paying particular attention to gel particles accumulation such as polysaccharidic Transparent Exopolymer Particles (TEP) and the proteinaceous Coomassie Stainable Particles (CSP). While previous studies have observed carbohydrates and TEP enrichment in the microlayer, little is yet known about proteinaceous gel particles in the SML. Our experiments show that CSP dominate the gelatinous composition of the SML. We believe that the enrichment in CSP points to the importance of bacterial activity in the microlayer. Bacteria may play a pivotal role in mediating processes at the air-sea interface thanks to their exudates and protein content that can be released through cell disruption
Marvelous Marine Microgels: On the Distribution and Impact of Gel-Like Particles in the Oceanic Water-Column
Full text linkThree-dimensional hydrogels of organic polymers have been suggested to affect a variety of processes in the ocean, including element cycling, microbial ecology, food-web dynamics, and air-sea exchange. However, their abundance and distribution in the ocean are hardly known, strongly limiting an assessment of their global significance. As a consequence, marine gels are often disregarded in biogeochemical or ecosystem models. Here, we demonstrate the widespread abundance of microgels in the ocean, from the surface to the deep sea. We exhibit size spectra of two major classes of marine gels, transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP) for three different ocean regimes: (a) Polar Seas, (b) Eastern Boundary Upwelling Systems, and (c) the oligotrophic open ocean. We show the variations of TEP and CSP over the water-column, and compare them to dissolved organic carbon (DOC). We also discuss how the observed distributional patterns inform about productivity and particle dynamics of these distinct oceanic regimes. Finally, we exploit current research topics, where consideration of microgels may give new insight into the role of organic matter for marine biogeochemical processes
Biopolymer composition and surface activity in the surface waters in Eckernförde bay in summer 2018
No full textDuring two crusies in June (AL510) and September (AL516) 2018, a data set (N=76) from the sea surface microlayer (SML) was compiled in Eckernförde Bay, Germany. SML samples were collected with the glass plate technique. Reference samples from the underlying water (ULW) at an approx. depth of 20cm were collected with the help of a bottle. Total and dissolved hydrolysable amino acids, combined carbohydrates and dissolved organic carbon were analyzed to describe surfactant dynamics (based on phase-sensitive AC voltammetry). Flow cytometry provided additional information on bacteria and phytoplankton community composition. This data set resolves dynamics on short temporal (diurnal sampling ) and local scales (within an area of 50km^2)
Dissolved Organic Matter in the Upwelling System off Peru from METEOR cruises M136 and M138
No full textAmino acid and carbohydrate patterns in particulate carbon of different size-fractions across Fram Strait during POLARSTERN cruise PS107
No full textAmino acids (AA) and carbohydrates (CHO) are produced by phytoplankton as part of the particulate organic carbon (POC) fraction, and are subsequently consumed by smaller heterotrophs. We investigated changes in quantity and quality of individual AA and CHO in three size-fractions of POC (< 10 um, 0.7 - 10 um, 0.2 - 0.7 um) at three stations in the Fram Strait during annual Hausgarten sampling cruise PS107
Dissolved organic matter measurements off Peru during METEOR cruise M93 from CTD
No full textConcentrations of dissolved organic carbon (DOC), total dissolved nitrogen (TDN), amino acids and carbohydrates.Values with <0.01 are below detection limit. Detection limit is 2 nM for amino acids , 10 nM for carbohydrates, 1µM for DOC and 2 µM for TDN
Master track of ALKOR cruise AL635 in 1 sec resolution (zipped, 36 MB)
No full textRaw data acquired by position sensors on board RV Alkor during expedition AL635 were processed to receive a validated master track which can be used as reference of further expedition data. During AL635 data from the Seapath 330 system, the Furuno GP-170 and the Furuno GP-150 GPS receivers were used to calculate the mastertrack. Data were downloaded from DAVIS SHIP data base (http://dship.bsh.de) with a resolution of 1 sec. Processing and evaluation of the data is outlined in the data processing report. Processed data are provided as a master track with 1 sec resolution derived from the position sensors' data selected by priority and a generalized track with a reduced set of the most significant positions of the master track
Respiration and production measurements of POLARSTERN cruise PS126
No full textThe water samples for the incubation experiment were collected on the RV Polarstern at the LTER HAUSGARTEN 79N and -5 W to 11 E on 31 May and 21 June 2021. The parameters include inorganic nutrients, oxygen, oxygen respiration, INT reduction, primary production (PP), bacterial production (BP), prokaryote and viral abundance. Inorganic nutrients include nitrate, nitrite, siliate, and phosphorus. Oxygen and oxygen respiration were analyzed using Winkler titration. INT reduction is the in vivo Iodo-Nitro-Tetrazolium (INT) salt reduction. PP was determined on board the ship using the 14C-incorporation method and BP was measured using 3h-leucine and the microcentrifuge method. Bacteria and viral abundance were measured on a flow cytometer (Cytoflex, Beckman Coulter, USA). The purpose of data collection was to understand the rates of phytoplankton and bacteria across the Fram Strait
Enrichment factors (EF) of TEP and CSP in the SML with and without bubbling of the water column in Aelotron experiment 2014
No full textBiological carbon pump efficiency in the Humboldt current system off Peru: flux coefficients
No full textPotential drivers of export flux attenuation: relationship between carbon export flux and satellite-derived primary production28 (PP, during period of deployment), export flux attenuation coefficient (Martin-b) and biochemical parameters indicative of particle quality as obtained in the deepest trap of each deployment. The particle interceptor traps were deployed six times (T1, T2, T3, T4, T6, T7) at different locations off Peru (12.0°S-14.6°S and 77.3°W-78.6°W) during the RV METEOR cruises M136 and M138 at four times in April and two times in June 2017
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