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- ItemInterfacial photochemistry at the ocean surface is a global source of organic vapors and aerosols([London] : Nature Publishing Group UK, 2018) BrĂĽggemann, Martin; Hayeck, Nathalie; George, ChristianThe surface of the oceans acts as a global sink and source for trace gases and aerosol particles. Recent studies suggest that photochemical reactions at this air/water interface produce organic vapors, enhancing particle formation in the atmosphere. However, current model calculations neglect this abiotic source of reactive compounds and account only for biological emissions. Here we show that interfacial photochemistry serves as a major abiotic source of volatile organic compounds (VOCs) on a global scale, capable to compete with emissions from marine biology. Our results indicate global emissions of 46.4-184 Tg C yr-1 of organic vapors from the oceans into the marine atmosphere and a potential contribution to organic aerosol mass of more than 60% over the remote ocean. Moreover, we provide global distributions of VOC formation potentials, which can be used as simple tools for field studies to estimate photochemical VOC emissions depending on location and season.
- ItemModeling Ice Shelf/Ocean Interaction in Antarctica: A Review(Rockville, MD : The Oceanography Society, 2016) Dinniman, Michael; Asay-Davis, Xylar; Galton-Fenzi, Benjamin; Holland, Paul; Jenkins, Adrian; Timmermann, RalphThe most rapid loss of ice from the Antarctic Ice Sheet is observed where ice streams flow into the ocean and begin to float, forming the great Antarctic ice shelves that surround much of the continent. Because these ice shelves are floating, their thinning does not greatly influence sea level. However, they also buttress the ice streams draining the ice sheet, and so ice shelf changes do significantly influence sea level by altering the discharge of grounded ice. Currently, the most significant loss of mass from the ice shelves is from melting at the base (although iceberg calving is a close second). Accessing the ocean beneath ice shelves is extremely difficult, so numerical models are invaluable for understanding the processes governing basal melting. This paper describes the different ways in which ice shelf/ocean interactions are modeled and discusses emerging directions that will enhance understanding of how the ice shelves are melting now and how this might change in the future.
- ItemDiscovery of chitin in skeletons of non-verongiid Red Sea demosponges(San Francisco, California, US : PLOS, 2018) Ehrlich, Hermann; Shaala, Lamiaa A.; Youssef, Diaa T. A.; Żółtowska- Aksamitowska, Sonia; Tsurkan, Mikhail; Galli, Roberta; Meissner, Heike; Wysokowski, Marcin; Petrenko, Iaroslav; Tabachnick, Konstantin R.; Ivanenko, Viatcheslav N.; Bechmann, Nicole; Joseph, Yvonne; Jesionowski, TeofilMarine demosponges (Porifera: Demospongiae) are recognized as first metazoans which have developed over millions of years of evolution effective survival strategies based on unique metabolic pathways to produce both biologically active secondary metabolites and biopolymer-based stiff skeletons with 3D architecture. Up to date, among marine demosponges, only representatives of the Verongiida order have been known to synthetize biologically active substances as well as skeletons made of structural polysaccharide chitin. This work, to our knowledge, demonstrates for the first time that chitin is an important structural component within skeletons of non-verongiid demosponges Acarnus wolffgangi and Echinoclathria gibbosa collected in the Red Sea. Calcofluor white staining, FTIR and Raman analysis, ESI-MS, SEM, and fluorescence microscopy as well as a chitinase digestion assay were applied in order to confirm, with strong evidence, the finding of α-chitin in the skeleton of both species. We suggest that, the finding of chitin within these representatives of Poecilosclerida order is a promising step in the evaluation of these sponges as novel renewable sources for both biologically active metabolites and chitin, which are of prospective application for pharmacology and biomedicine.
- ItemCorrelation networks from flows. The case of forced and time-dependent advection-diffusion dynamics(San Francisco, CA : Public Library of Science (PLoS), 2016) Tupikina, L.; Molkenthin, N.; LĂłpez, C.; Hernández-GarcĂa, E.; Marwan, N.; Kurths, J.
- ItemWe need biosphere stewardship that protects carbon sinks and builds resilience(Washington, DC : National Acad. of Sciences, 2021) Rockström, Johan; Beringer, Tim; Hole, David; Griscom, Bronson; Mascia, Michael B.; Folke, Carl; Creutzig, Felix[no abstract available]