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Microplastics (MP) including tire wear particles (TWP) occur ubiquitously in the environment. However, there are knowledge gaps about mass-based concentrations, transport, and effects of these contaminants in the marine boundary layer. The latter includes air, sea surface microlayer (SML) and underlying water (ULW). The SML covers most of the ocean's surface with a predominantly organic film of a thickness up to 1000 µm. Here, a remote-controlled catamaran simultaneously sampled air, SML and ULW (1 m depth) from three Swedish fjords characterized by varying anthropogenic impacts (urban environment, industrial site and natural conservation area). Superior aim was to generate knowledge about the vertical transport of MP in these fjords. Potential enrichment of certain polymer types between SML and underlying water body was evaluated. Polymers were determined by pyrolysis-gas chromatography-mass spectrometry and quantified by polymer specific backbone-related clusters indicated by prefix "C". Clusters such as polyethylene (C-PE), polypropylene (C-PP), polyethylene terephthalate (C-PET) and polymethyl methacrylate (C-PMMA) were analyzed. Furthermore, samples were scanned for car and truck tire wear particles (CTT & TTT). MP occurred in water samples with concentrations up to 10.8 µg/L. Most prominent MP types were C-PMMA, CTT and C-PET. Average MP mass load was higher in fjords influenced by an urban environment (8.5 µg/L SML and 6.0 µg/L ULW) and an industrial site (6.6 µg/L SML and 7.3 µg/L ULW). The fjord in the natural conservation area was averagely contaminated with 1.8 µg/L SML and 2.0 µg/L ULW. An enrichment in the SML was observed for C-PE, C-PP, C-PET and CTT. In the ULW C-PMMA and C-PC were enriched. Concentrations in air samples reached up to 0.05 µg MP/m³ and were dominated by C-PET and C-PC. As for the water samples, the air from urban environment and the industrial site showed elevated concentration than those from remote areas. Also see: https://micro2022.sciencesconf.org/426880/document, In MICRO 2022, Online Atlas Edition: Plastic Pollution from MACRO to nano

Transparent exopolymer particles (TEPs) exhibit the properties of gels and are ubiquitously found in the world oceans. TEPs may enter the atmosphere as part of sea-spray aerosol. Here, we report number concentrations of TEPs with a diameter > 4.5 µm, hence covering a part of the supermicron particle range, in ambient aerosol and cloud water samples from the tropical Atlantic Ocean as well as in generated aerosol particles using a plunging waterfall tank that was filled with the ambient seawater. The ambient TEP concentrations ranged between 7×102 and 3×104 #TEP m−3 in the aerosol particles and correlations with sodium (Na+) and calcium (Ca2+) (R2=0.5) suggested some contribution via bubble bursting. Cloud water TEP concentrations were between 4×106 and 9×106 #TEP L−1 and, according to the measured cloud liquid water content, corresponding to equivalent air concentrations of 2–4×103 #TEP m−3. Based on Na+ concentrations in seawater and in the atmosphere, the enrichment factors for TEPs in the atmosphere were calculated. The tank-generated TEPs were enriched by a factor of 50 compared with seawater and, therefore, in-line with published enrichment factors for supermicron organic matter in general and TEPs specifically. TEP enrichment in the ambient atmosphere was on average 1×103 in cloud water and 9×103 in ambient aerosol particles and therefore about two orders of magnitude higher than the corresponding enrichment from the tank study. Such high enrichment of supermicron particulate organic constituents in the atmosphere is uncommon and we propose that atmospheric TEP concentrations resulted from a combination of enrichment during bubble bursting transfer from the ocean and a secondary TEP in-situ formation in atmospheric phases. Abiotic in-situ formation might have occurred from aqueous reactions of dissolved organic precursors that were present in particle and cloud water samples, whereas biotic formation involves bacteria, which were abundant in the cloud water samples. The ambient TEP number concentrations were two orders of magnitude higher than recently reported ice nucleating particle (INP) concentrations measured at the same location. As TEPs likely possess good properties to act as INPs, in future experiments it is worth studying if a certain part of TEPs contributes a fraction of the biogenic INP population.

OceanRep OceanRep Startseite Kontakt Schnellsuche Einfache Suche Erweiterte Suche Blättern Autor Forschungsbereich Publikationsart Jahr Studiengang Neuzugänge Artikel – begutachtet Alle Über uns GEOMAR Bibliothek Open Access Policies Grundsätze Hilfe FAQs Statistik Impressum Biofilm-like habitat at the sea-surface: A mesocosm study, Cruise No. POS537, 14.09.2019 – 04.10.2019, Malaga (Spain) – Cartagena (Spain) - BIOFILM . Logged in as Heidi Düpow Einträge verwaltenManage recordsManage shelvesProfilGespeicherte SuchenBegutachtungAdminLogout - Tools Wurl, Oliver, Mustaffa, Nur Ili Hamizah, Robinson, Tiera-Brandy, Hoppe, Jennifer, Jaeger, Leonie, Striebel, Maren, Heinrichs, Anna-Lena, Hennings, Laura Margarethe, Goncalves, Rodrigo, Ruiz Gazulla, Carlota und Ferrera, Isabel (2020) Biofilm-like habitat at the sea-surface: A mesocosm study, Cruise No. POS537, 14.09.2019 – 04.10.2019, Malaga (Spain) – Cartagena (Spain) - BIOFILM . Open Access . POSEIDON Berichte . University of Oldenburg, Oldenburg, 35 pp. [img] Text Cruise_Reports_POS537_final.pdf - publizierte Version Available under License Creative Commons: Attribution 4.0. Download (2417Kb) | Vorschau Abstract Biofilm-like properties can form on sea surfaces, but an understanding of the underlying processes leading to the development of these biofilms is not available. We used approaches to study the development of biofilm-like properties at the sea surface, i.e. the number, abundance and diversity of bacterial communities and phytoplankton, the accumulation of gel-like particles and dissolved tracers. During the expedition POS537 we used newly developed and free drifting mesocosms and performed incubation experiments. With these approaches we aim to investigate the role of light and UV radiation as well as the microbes themselves, which lead to the formation of biofilms. With unique microbial interactions and photochemical reactions, sea surface biofilms could be biochemical reactors with significant implications for ocean and climate research, e.g. with respect to the marine carbon cycle, diversity of organisms and oceanatmosphere interactions.

Ice-nucleating particles (INPs) in the troposphere can form ice in clouds via heterogeneous ice nucleation. Yet, atmospheric number concentrations of INPs (NINP) are not well characterized, and, although there is some understanding of their sources, it is still unclear to what extend different sources contribute or if all sources are known. In this work, we examined properties of INPs at Cabo Verde (a.k.a. Cape Verde) from different environmental compartments: the oceanic sea surface microlayer (SML), underlying water (ULW), cloud water and the atmosphere close to both sea level and cloud level. Both enrichment and depletion of NINP in SML compared to ULW were observed. The enrichment factor (EF) varied from roughly 0.4 to 11, and there was no clear trend in EF with ice-nucleation temperature. NINP values in PM10 sampled at Cape Verde Atmospheric Observatory (CVAO) at any particular ice-nucleation temperature spanned around 1 order of magnitude below −15 ∘C, and about 2 orders of magnitude at warmer temperatures (>-12 ∘C). Among the 17 PM10 samples at CVAO, three PM10 filters showed elevated NINP at warm temperatures, e.g., above 0.01 L−1 at −10 ∘C. After heating samples at 95 ∘C for 1 h, the elevated NINP at the warm temperatures disappeared, indicating that these highly ice active INPs were most likely biological particles. INP number concentrations in PM1 were generally lower than those in PM10 at CVAO. About 83±22 %, 67±18 % and 77±14 % (median±standard deviation) of INPs had a diameter >1 µm at ice-nucleation temperatures of −12, −15 and −18 ∘C, respectively. PM1 at CVAO did not show such elevated NINP at warm temperatures. Consequently, the difference in NINP between PM1 and PM10 at CVAO suggests that biological ice-active particles were present in the supermicron size range. NINP in PM10 at CVAO was found to be similar to that on Monte Verde (MV, at 744 m a.s.l.) during noncloud events. During cloud events, most INPs on MV were activated to cloud droplets. When highly ice active particles were present in PM10 filters at CVAO, they were not observed in PM10 filters on MV but in cloud water samples instead. This is direct evidence that these INPs, which are likely biological, are activated to cloud droplets during cloud events. For the observed air masses, atmospheric NINP values in air fit well to the concentrations observed in cloud water. When comparing concentrations of both sea salt and INPs in both seawater and PM10 filters, it can be concluded that sea spray aerosol (SSA) only contributed a minor fraction to the atmospheric NINP. This latter conclusion still holds when accounting for an enrichment of organic carbon in supermicron particles during sea spray generation as reported in literature.

Transparent exopolymer particles (TEPs) are a major source for both organic matter (OM) and carbon transfer in the ocean and into the atmosphere. Consequently, understanding the vertical distribution of TEPs and the processes which impact their movement is important in understanding the OM and carbon pools on a larger scale. Additionally, most studies looking at the vertical profile of TEPs have focused on large depth scales from 5 to 1000 m and have omitted the near-surface environment. Results from a study of TEP enrichment in the sea surface microlayer (SML) in different regions (tropical, temperate) has shown that, while there is a correlation between TEP concentration and primary production (PP) on larger or seasonal scales, such relationships break down on shorter timescales and spatial scales. Using a novel small-scale vertical sampler, the vertical distribution of TEPs within the uppermost 2 m was investigated. For two regions with a total of 20 depth profiles, a maximum variance of TEP concentration of 1.39×106 µg XG eq2 L−2 between depths and a minimum variance of 6×102 µg XG eq2 L−2 was found. This shows that the vertical distribution of TEPs was both heterogeneous and homogeneous at times. Results from the enrichment of TEPs and Chl a between different regions have shown TEP enrichment in the SML to be greater in oligotrophic waters, when both Chl a and TEP concentrations were low, suggesting the importance of abiotic sources for the enrichment of TEPs in the SML. However, considering multiple additional parameters that were sampled, it is clear that no single parameter could be used as a proxy for TEP heterogeneity. Other probable biochemical drivers of TEP transport are discussed.

Transparent exopolymer particles (TEP) act as a major transport mechanism for organic matter (OM) to the sea surface microlayer (SML) via bubble scavenging, and into the atmosphere via bubble bursting. However, little is known about the effects of bubble scavenging on TEP enrichment in the SML. This study examined the effects of several bubbling conditions and algae species on the enrichment of TEP in the SML. TEP enrichment in the SML was enhanced by bubbling, with a larger impact from bubbling rate than bubble size and increasing enrichment over time. Depth profiles showed that any TEP aggregates formed in the underlying water (ULW) were rapidly (&lt, 2 min) transported to the SML, and that TEP was entrained in the SML by bubbling. Species experiments determined that the presence of different phytoplankton species and their subsequent release of precursor material further enhance the effectiveness of TEP enrichment via bubble scavenging.

We investigated the influence of solar radiation on biogeochemical parameters of the sea surface microlayer (SML), including the spectroscopic composition of FDOM, and biotic and abiotic parameters. We calculated the humification index, biological index, and recently produced material index from the ultraviolet spectra to characterize the dynamic environment of the SML. The humification index ranged from 4 to 14 in the SML and 14 to 22 in underlying water (ULW). An inverse relation for this index as a function of solar radiation was observed, indicating photochemical decomposition of complex molecules present in fluorescent dissolved organic matter (FDOM). The biological index (along Leg 2) ranged from 1.0 to 2.0 for the SML and 1.0 to 1.5 for ULW. The index for recently produced material ranged from 0.25 to 0.8 for the SML and 0.5 to 1.0 for ULW. The FDOM enrichment process of the SML was influenced by the photochemical decomposition of highly aromatic-like fluorophores, as indicated by the calculated indices. Fluorescence intensity increased for humic C peaks (>0.5 Raman units) in the North Sea samples and for humic M peaks (>1.0 Raman units) for Jade Bay. Spearman analysis for FDOM enrichment in the SML as a function of PAR (for Leg 2) showed a weak positive correlation (Rho = 0.676, n = 11, p = 0.022). Abundance of small photoautotrophic cells (Rho = 0.782, n = 11, p = 0.045) and of bacteria (Rho = 0.746, n = 11, p = 0.0082) also showed a positive correlation as a function of PAR. Overall, we found positive trends between the intensity of available light and the response of the constituents within the SML, highlighting the role of the surface microlayer as a distinctive habitat characterized by unique photochemical processes.