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Vorhaben: Verbesserung von Parametrisierungen des Licht- und Energieflusses durch Meereis im arktischen Ozean

Description: Das Projekt "Vorhaben: Verbesserung von Parametrisierungen des Licht- und Energieflusses durch Meereis im arktischen Ozean" wird vom Umweltbundesamt gefördert und von O.A.Sys - Ocean Atmosphere Systems GmbH durchgeführt. To be able to predict the physical conditions for the Arctic ecosystem in the ‚new Arctic', it is necessary to understand and parametrise the processes which determine the light and enery budget under the sea ice and snow under 'first year ice' conditions. For this we need a holistic approach that combines biology, optics, seaice and ocean physics, based on direct observations and remotely sensed information with numerical modelling. This is the overall goal of the joint project (with AWI, BAS and UCL) to which OASys contributes. Sea ice plays a fundamental role in the Arctic ecosystem through complex physical and bio-geochemical interactions and feedbacks. The sea ice matrix offers a protected habitat for microbial life, particularly for algae, which together with phytoplankton form the base of the Arctic marine food web, sustaining the sea ice associated macrofauna and part of the pelagic zooplankton. The growth of sea ice algae and phytoplankton depends in large parts on light availability, which is strongly dependent on the sea ice and under ice water properties. On the other hand, the ice underside provides a high variable and heterogeneous habitat for different ice-associated macrofauna, i.e. the zooplankton communities whose vertical migration is often triggered by food availability and periodic changes in light availability. As the Arctic is changing, it is no longer dominated by thick multi-year ice (MYI), but it is a regime dominated by thinner, more dynamic, first year ice (FYI). At the same time, the length of the melt season has increased, leading to earlier retreat and later ice formation, changes in snow accumulation and freshwater input to the Arctic Ocean. These changes have important implications for the in-ice and under-ice biota, influencing light availability, ocean properties, and the timing of sea ice algae and phytoplankton blooms. In other words, changes in sea ice can alter phenology of carbon supply to the ecosystem. We are still in the process of elucidating these complexities, but our fundamental understanding of ecosystem function, sea ice, and upper ocean processes in the Arctic Ocean has been overwhelmingly derived from a MYI setting, rather than the FYI dominated Arctic of recent years. As a result, our current state of knowledge and the validity of many of the parameterisations presently embedded in models become more questionable. For example, most GCMs use a formulation of sea ice light transmission for MYI. However, such treatment can lead to underestimation of the under-ice light conditions. Furthermore, recent measures have shown that the transition from a MYI to FYI summer ice cover corresponds to a 50% increase in light absorption in sea ice and an increase of 200% in light transmittance into the upper ocean. (abridged text)

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SupportProgram

Origin: /Bund/UBA/UFORDAT

Tags: Algenblüte ? Resorption ? Pelagial ? Arktisches Meereis ? Beleuchtung ? Fischer-Tropsch-Verfahren ? Kohlenstoff ? Phytoplankton ? Pflanzensamen ? Zooplankton ? Blei ? GC-MS ? Vereinigtes Königreich ? Optik ? Eisbedeckung ? Biologie ? Biozönose ? Eis ? Habitat ? Licht ? Meeresalgen ? Physik ? Sommer ? Süßwasser ? Arktis ? Meereis ? Globales Klimamodell ? Naturschutzgebiet ? Schnee ? Jahreszeit ? Algen ? Meeresgewässer ? Wasser ? Modellierung ? Ökosystemfunktion ? Arktisches Ökosystem ? Phänologie ? Biosystem ? Abdeckung ? Schutzgebiet ? Gesundheit ? Atmosphäre ? Umweltveränderung ? Bedarf ? Lebensmittel ? Physikalischer Vorgang ? Migration ? Nordpolarmeer ? Ökosystem ? Basen [chemisch] ? Vermehrung ? Bram-Verfahren ? Buchgrundstück ? Schmelzbad ? Adsox-Verfahren ?

Region: Hamburg

Bounding box: 9.99302° .. 9.99302° x 53.55073° .. 53.55073°

License: cc-by-nc-nd/4.0

Language: Deutsch

Organisations

Time ranges: 2018-07-01 - 2021-06-30

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