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Electron Transport System (ETS) Assay in the Atlantic Ocean

This dataset comprises measurements of microbial community respiration, derived from electron transport system (ETS) activity assays, in discrete water samples collected with Niskin bottles. ETS activity (mmol O2 m⁻³ d⁻¹) was determined enzymatically as a proxy for aerobic microbial and planktonic respiration, and respiratory oxygen consumption (RO2, mmol O2 m⁻³ d⁻¹) was subsequently calculated by applying respiration-to-ETS conversion factors of 0.75 for samples from the epipelagic zone and 0.086 for samples from the mesopelagic zone. Each of the 219 sampling stations was additionally assigned to an open-ocean biogeochemical province following the classification of Reygondeau et al. (2018). Samples were collected at depths ranging from 5 m to 4539 m water depth during thirteen research cruises carried out between November 2006 and April 2025: RODA-I (2006), RODA-II (2007), CAIBEX and CAIBOX (2009), HOTMIX and PUMP (2014), FLUXES I (2017), TRATLEQ1/M158 (2019), e-IMPACT1 and e-IMPACT2 (2022), APERO (2023), MICOLOR2 (2024) and OceanICU (2025). The combined geographical coverage extends across the eastern boundary upwelling system off northwest Africa (Canary Upwelling System, Cape Blanc, Canary Eddy Corridor), the North Atlantic Subtropical Gyre, the equatorial Atlantic, and a transect across the eastern South Atlantic and equatorial Atlantic between Walvis Bay (Namibia) and the Canary Islands; the HOTMIX cruise additionally sampled the eastern Mediterranean Sea before transiting into the Atlantic.

GTS Bulletin: FQMM80 EDZW - Forecast (details are described in the abstract)

The FQMM80 TTAAii Data Designators decode as: T1 (F): Forecast T1T2 (FQ): Other shipping A1A2 (MM): Mediterranean area (Remarks from Volume-C: WEATHER AND SEA BULLETIN FOR THE MEDITERRANEAN SEA (IN ENGLISH))

Quantitative Untersuchungen der sensibilisierten Photooxydation von gesaettigten Kohlenwasserstoffen in Oberflaechenfilmen auf Meerwasser

Gesaettigte Kohlenwasserstoffe ebenso wie Alkylaromaten werden bei Anwesenheit von Sauerstoff und geeigneten Sensibilisatoren (aromatische Ketone, Chinone) durch natuerliches Sonnenlicht zu Carbonylverbindungen abgebaut. Durch Modelluntersuchungen unter quasi-natuerlichen Bedingungen wurde gefunden, dass durch Kettenfragmentierung homologe Reihen entstehen, deren niedermolekulare Glieder Aceton, Acetaldehyd und Formaldehyd die hoeheren Homologen hinsichtlich ihrer Konzentration ueberwiegen. Zur Anreicherung hoeherer Homologen aus Meerwasser werden Sorptionsharze verwendet. Die Analytik stuetzt sich auf chromatographische Methoden und Massenspektrometrie. Fuer quantitative Untersuchungen wird als Reaktionsmedium steril-filtriertes Meerwasser benutzt, welches man nach Zugabe geringer Mengen des zu untersuchenden Kohlenwasserstoffes knapp unterhalb der Meeresoberflaeche natuerlichem Sonnenlicht aussetzt. Da bei sensibilisierten Reaktionen in verduennten, waessrigen Loesungen der molekulare Extinktionskoeffizient, welcher zur Bestimmung der Quantenausbeute erforderlich ist, schwer zu bestimmen ist, wird die Absorption des Substrates durch chemische Actinometer (p-Nitroacetophenon/Pyridin) ermittelt.

Aerosole aus dem asiatischen Monsun in der oberen Troposphäre: Quellen, Alterung, Auswirkungen

Die Asian Tropopause Aerosol Layer (ATAL), eine Schicht mit erhöhtem Aerosolgehalt, tritt jedes Jahr von Juni bis September in 14-18 km Höhe in einem Gebiet auf, das sich vom Mittelmeer bis zum westlichen Pazifik erstreckt. Hinsichtlich der Zusammensetzung der Partikel, sowie ihrer Bedeutung für die Strahlungsbilanz in dieser klimasensitiven Höhenregion bestehen große Unsicherheiten. Die bisher einzigen Flugzeugmessungen aus dem Zentrum der ATAL wurden 2017 im Rahmen der StratoClim Kampagne von Kathmandu aus gewonnen. Dabei entdeckten wir mit Hilfe des Infrarotspektrometers GLORIA auf dem Forschungsflugzeug Geophysica, dass feste Ammoniumnitrat (AN) â€Ì Partikel einen beträchtlichen Teil der Aerosolmasse ausmachen. Diese zählen zu den effizientesten Eiskeimen in der Atmosphäre. Zudem zeigte die gleichzeitige Messung von Ammoniakgas (NH3) durch GLORIA, dass dieses Vorläufergas durch starke Konvektion in die obere Troposphäre verfrachtet wird. Im Rahmen der PHILEAS-Kampagne schlagen wir eine gemeinsamen Betrachtung von atmosphärischen Modellsimulationen und Messungen vor, um die Zusammensetzung, Ursprung, Auswirkungen und Verbleib der ATAL-Partikel zu untersuchen â€Ì insbesondere im Hinblick auf ihre Prozessierung sowie ihren Einfluss auf die obere Troposphäre und die untere Stratosphäre der nördlichen Hemisphäre. Messungen von monsunbeeinflussten Luftmassen über dem östlichen Mittelmeer sowie über dem nördlichen Pazifik werden es uns erlauben, Luft mit gealtertem Aerosol- und Spurengasgehalt zu analysieren und damit die StratoClim-Beobachtungen aus dem Inneren des Monsuns zu komplementieren. Um dabei die wahrscheinlich geringeren Konzentrationen an Aerosol und Spurengasen zu quantifizieren, schlagen wir vor, die GLORIA-Datenerfassung von NH3 und AN u.a. durch die Verwendung neuartiger spektroskopischer Daten zu verbessern. Ferner werden wir die Analyse der GLORIA-Spektren auf Sulfataerosole sowie deren Vorläufergas SO2 auszudehnen. Auf der Modellseite werden wir das globale Wetter- und Klimamodellsystem ICON-ART weiterentwickeln, um die ATAL unter Einbeziehung verschiedener Aerosoltypen (Nitrat, Ammonium, Sulfat, organische Partikel, Staub) zu simulieren â€Ì unter Berücksichtigung der hohen Eiskeimfähigkeit von festem AN. Modellläufe werden durchgeführt, um einerseits einen globalen Überblick über die Entwicklung der ATAL 2023 zu gewinnen und zudem detaillierte, auf die relevanten Kampagnenperioden zugeschnittene, wolkenauflösende Informationen über die Aerosol-Wolken-Strahlungs-Wechselwirkungen zu erhalten. Über die direkte Analyse der PHILEAS-Kampagne hinausgehend wird diese Arbeit die Grundlage für eine verbesserte Analyse von Aerosolparametern aus GLORIA-Beobachtungen früherer und zukünftiger HALO-Kampagnen sowie aus Satellitenbeobachtungen legen. Darüber hinaus wird sie ICON-ART, einem der zentralen Klimamodellsysteme in Deutschland die Simulation von Aerosolprozessen sowie Aerosol/Wolken-Wechselwirkungen im Zusammenhang mit der ATAL ermöglichen.

The influence of seawater pH on U/ Ca ratios in the scleractinian cold-water coral Lophelia pertusa

The increasing pCO2 in seawater is a serious threat for marine calcifiers and alters the biogeochemistry of the ocean. Therefore, the reconstruction of past-seawater properties and their impact on marine ecosystems is an important way to investigate the underlying mechanisms and to better constrain the effects of possible changes in the future ocean. Cold-water coral (CWC) ecosystems are biodiversity hotspots. Living close to aragonite undersaturation, these corals serve as living laboratories as well as archives to reconstruct the boundary conditions of their calcification under the carbonate system of the ocean. We investigated the reef-building CWC Lophelia pertusa as a recorder of intermediate ocean seawater pH. This species-specific field calibration is based on a unique sample set of live in situ collected L. pertusa and corresponding seawater samples. These data demonstrate that uranium speciation and skeletal incorporation for azooxanthellate scleractinian CWCs is pH dependent and can be reconstructed with an uncertainty of ±0.15. Our Lophelia U / Ca-pH calibration appears to be controlled by the high pH values and thus highlighting the need for future coral and seawater sampling to refine this relationship. However, this study recommends L. pertusa as a new archive for the reconstruction of intermediate water mass pH and hence may help to constrain tipping points for ecosystem dynamics and evolutionary characteristics in a changing ocean.

Seawater carbonate chemistry and maximum growth rates of Skeletonema marinoi and Alexandrium ostenfeldii, toxin composition of Alexandrium ostenfeldii in a laboratory experiment

Phytoplankton populations can display high levels of genetic diversity that, when reflected by phenotypic variability, may stabilize a species response to environmental changes. We studied the effects of increased temperature and CO2 availability as predicted consequences of global change, on 16 genetically different isolates of the diatom Skeletonema marinoi from the Adriatic Sea and the Skagerrak (North Sea), and on eight strains of the PST (paralytic shellfish toxin)-producing dinoflagellate Alexandrium ostenfeldii from the Baltic Sea. Maximum growth rates were estimated in batch cultures of acclimated isolates grown for five to 10 generations in a factorial design at 20 and 24 °C, and present day and next century applied atmospheric pCO2, respectively. In both species, individual strains were affected in different ways by increased temperature and pCO2. The strongest response variability, buffering overall effects, was detected among Adriatic S. marinoi strains. Skagerrak strains showed a more uniform response, particularly to increased temperature, with an overall positive effect on growth. Increased temperature also caused a general growth stimulation in A. ostenfeldii, despite notable variability in strain-specific response patterns. Our data revealed a significant relationship between strain-specific growth rates and the impact of pCO2 on growth-slow growing cultures were generally positively affected, while fast growing cultures showed no or negative responses to increased pCO2. Toxin composition of A. ostenfeldii was consistently altered by elevated temperature and increased CO2 supply in the tested strains, resulting in overall promotion of saxitoxin production by both treatments. Our findings suggest that phenotypic variability within populations plays an important role in the adaptation of phytoplankton to changing environments, potentially attenuating short-term effects and forming the basis for selection. In particular, A. ostenfeldii blooms may expand and increase in toxicity under increased water temperature and atmospheric pCO2 conditions, with potentially severe consequences for the coastal ecosystem.

Mediterranean Karst Aquifer Map 1:5,000,000 (MEDKAM)

Karst aquifers constitute important freshwater resources, but are challenging to manage and to protect, because of their unique hydraulic structure and behaviour, representing continuous challenges for research and development. Karst aquifers are widespread and contribute to freshwater supply of most Mediterranean countries and many cities are supplied by karst water, e.g., Rome, Vienna, Montpellier and Beirut. These land surfaces correspond to the main recharge zones of karst aquifers, which are often hydraulically connected over large areas and are highly vulnerable to contamination. The preparation of the Mediterranean Karst Aquifer Map (MEDKAM) generally followed the workflow used for the World Karst Aquifer Map (WOKAM). A new lithological classification has been developed for the MEDKAM, similar to that of the WOKAM, which groups the geological units into four meaningful hydrogeological units: 1). Karst aquifers in sedimentary and metamorphic carbonate rocks. 2). Karst aquifers in evaporite rocks. 3). Various hydrogeological settings in other sedimentary and volcanic formations (karst aquifers are possibly present at depth). 4). Local, poor and shallow aquifers in other metamorphic rocks and igneous rocks (no karst aquifers present at depth).

Lipid class composition of mesopelagic fish from the North Atlantic Ocean and the Western Mediterranean Sea

Mesopelagic fish collected during 3 field campaigns in 2020 were analysed for their lipid content. The sampling was conducted on 5 main locations; 2 stations in the Western Mediterranean Sea (September/October), 4 stations in the North Atlantic off the Iberian Peninsula (October), 4 stations in the Irminger Sea (July), 5 stations in the Iceland Basin (July) and 4 stations in the Northern Norwegian Sea (May). The fish were collected at distinct depth intervals, with different trawl types depending on the vessel. The database consists of 28 mesopelagic fish species belonging to 9 families and 5 genera. For each record, length and wet weight of the fish analysed is recorded with the wax ester (WE), triacylglycerol (TAG) and phospholipid (PL) values as % of total lipids (TL). Each data record is associated with information on the sampling location, geographic coordinates, month and year of sample collection, sampling gear and depth, taxonomic ranks (phylum, class, order, family), and number and replicates analysed. The lipids were extracted following Folch's extraction method (Folch et al. 1957), which was implemented on whole fish or a weighted sub-sample of a homogenized whole fish. Individual lipid classes were separated by Thin Layer Chromatography (TLC). A lipid sample was spotted onto silica-coated quartz rods, (chromarods; SES GmbH) and the lipid classes separated by development in two solvent systems: hexane/diethyl ether/acetic acid (60:17:0.2, by volume) followed by hexane/diethyl ether (96:4 vol/vol). The analysis was performed using an Iatroscan MK 5 TLC-FID analyser.

GTS Bulletin: FQMM60 EDZW - Forecast (details are described in the abstract)

The FQMM60 TTAAii Data Designators decode as: T1 (F): Forecast T1T2 (FQ): Other shipping A1A2 (MM): Mediterranean area (Remarks from Volume-C: WEATHER AND SEA BULLETIN FOR THE MEDITERRANEAN SEA (IN GERMAN))

Seawater carbonate chemistry and benthic marine community during experiments, 2011

<p>Ocean acidification is predicted to impact all areas of the oceans and affect a diversity of marine organisms. However, the diversity of responses among species prevents clear predictions about the impact of acidification at the ecosystem level. Here, we used shallow water CO2 vents in the Mediterranean Sea as a model system to examine emergent ecosystem responses to ocean acidification in rocky reef communities. We assessed in situ benthic invertebrate communities in three distinct pH zones (ambient, low, and extreme low), which differed in both the mean and variability of seawater pH along a continuous gradient. We found fewer taxa, reduced taxonomic evenness, and lower biomass in the extreme low pH zones. However, the number of individuals did not differ among pH zones, suggesting that there is density compensation through population blooms of small acidification-tolerant taxa. Furthermore, the trophic structure of the invertebrate community shifted to fewer trophic groups and dominance by generalists in extreme low pH, suggesting that there may be a simplification of food webs with ocean acidification. Despite high variation in individual species' responses, our findings indicate that ocean acidification decreases the diversity, biomass, and trophic complexity of benthic marine communities. These results suggest that a loss of biodiversity and ecosystem function is expected under extreme acidification scenarios.</p>

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