HAUSGARTEN: Multidisciplinary investigations at a deep-sea, long-term observatory in the Arctic Ocean

The marine Arctic has played an essential role in the history of our planet over the past 130 million years and contributes considerably to the present functioning of Earth and its life. The global cycles of a variety of materials fundamental to atmospheric conditions and thus to life depend to a signifi cant extent on Arctic marine processes (Aargaard et al., 1999). The past decades have seen remarkable changes in key Arctic variables. The decrease of sea-ice extent and sea-ice thickness in the past decade is statistically signifi - cant (Cavalieri et al., 1997; Parkinson et al., 1999; Walsh and Chapman, 2001; Partington et al., 2003; Johannessen et al., 2004). There have also been large changes in the upper and intermediate layers of the ocean, which have environmental implications. For instance, the deep Greenland Sea has continued its decadal trend towards warmer and saltier conditions, with a corresponding decrease in oxygen content, refl ecting the lack of effective local convection and ventilation (Dickson et al., 1996; Boenisch et al., 1997). Changes in temperature and salinity and associated shifts in nutrient distributions will directly affect the marine biota on multiple scales from communities and populations to individuals, consequently altering food-web structures and ecosystem functioning (Benson and Trites, 2002; Moore, 2003; Schumacher et al., 2003; Wiltshire and Manly, 2004; Perry et al., 2005). Today, we do not know whether the severe alterations in abiotic parameters represent perturbations due to human impacts, natural long-term trends, or new equilibriums (Bengtson et al., 2004). Because Arctic organisms are highly adapted to extreme environmental conditions with strong seasonal forcing, the accelerating rate of recent climate change challenges the resilience of Arctic life (Hassol, 2004). The entire system is likely to be severely affected by changing ice and water conditions, varying primary production and food availability to faunal communities, an increase in contaminants, and possibly increased UV irradiance. The stability of a number of Arctic populations and ecosystems is probably not strong enough to withstand the sum of these factors, which might lead to a collapse of subsystems. To detect and track the impact of large-scale environmental changes in the transition zone between the northern North Atlantic and the central Arctic Ocean, and to determine experimentally the factors controlling deep-sea biodiversity, the German Alfred Wegener Institute for Polar and Marine Research (AWI) established the deepsea, long-term observatory HAUSGARTEN, representing the fi rst, and by now only, open-ocean, long-term station in a polar region

New technologies to study effects of physical disturbances at the sediment-water interface: The development of an Integrated Sediment Disturber (ISD)(Vortrag)

New, innovative technologies were developed and integrated within the EU-project COBO (Coastal Ocean Benthic Observatory) to investigate benthic responses to natural and anthropogenic impacts. The Alfred Wegener Institute for Polar and Marine Research (AWI) leads a work-package developing the so-called Integrated Sediment Disturber (ISD) to study the complex interactions between the biota and environmental perturbations and relaxations. The ISD carries three rotating fork-like disturber units able to rework the upper sediment layers at chosen time intervals. An Autonomous Positioning Drive allows the positioning of oxygen micro-sensors within and between the disturbed zones. A camera system continuously monitors all ISD actions. The ISD was deployed for a 2 months experiment in summer/autumn 2006. Sediment sampling has been carried out at the start, after one month and at the end of the long-term deployment. Scientific aims of the experiment are: to investigate benthic community function, with a focus on carbon and nutrient regeneration to investigate response to physical and chemical perturbation (organic additions, resuspension, anoxia) by benthic communities to examine functional resistance and resilience to single and combined pressure

Cruise report DISCOL 3. Sonne cruise 77 January 26 - February 27, 1992. Balboa/Panama - Balboa/Panama

Also: DISCOL-publication, no. 20Available from TIB Hannover: RR 1860(2)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

MAROPT. Entwicklung einer Sortiereinrichtung fuer das Macro-Flow-Planktometer zur analysegesteuerten Sortierung von Meeres- und Meeres- und Benthosorgansimen. Entwicklung einer Leerbilderkennung. Testserien mit einer Anlage zur Sortierung von Organismen aus Sediment und Planktronproben Erfolgskontrollbericht. Schlussbericht

In marine biology there is a lack of effective, automated techniques for analysis and sorting. For the Macro Flow Planktometer (MFP) developed during MAROPT I/II a sorting module should be developed to faciliate analysis-triggered sorting of organisms. For the subproject in Kiel an empty-image rejection device should be developed to filter useful images out of an analog video signal. A setup of the MFP with an electromechanical sorting module was constructed and build. The additional electronic circuitry for the sorting module was developed on an Eurocard board. For adjusting purposes a microscope with an LED flags illumination was added. Using eggs and larvae of artemia salina as test particles, a purity of the sorted fraction of more than 90% could be achieved. In Hamburg different fluorochromes have been tested. Propidium iodide has proved its suitability. A staining technique using this fluorochrome has been developed. For the fast sedimenting particles a new sample inlet was developed. An average of 86% of the organisms was separated from the sediment. For the realtime detection of empty video images the 'Primaspeed' Image processing board by Leutron Vision is employed. Empty-image detection is done by evaluating a histogram. If the number of white pixels exceeds a certain limit, the image is routed to the output, otherwise the output is blanked. (orig.)Available from TIB Hannover: F96B624+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman