Ziel
DURING THE PAST FOUR YEAR DORA PROJECT, FOR THE FIRST TIME EXTENSIVE DATA HAVE BEEN OBTAINED WITH REGARD TO THE BENTHOS OF THE NEA-DUMPING AREA FOR RADIOACTIVE WASTE. THE BIOLOGICAL RESEARCH HAS BEEN ESPECIALLY FOCUSED TO DETERMINING THE NUMBERS AND THE BIOMASSES OF BOTH THE MEIO- AND MACROFAUNA AS REPORTED IN RUTGERS VAN DER LOEFF & LAVALEYE (1986).
DUE TO THE NEED OF FURTHER AFTER-CARE OF THE DUMPING-AREA AND DUE TO THE ESTABLISHED GAPS OF KNOWLEDGE ARISEN PARTLY THROUGH THE INNOVATING CHARACTER OF THE RESEARCH (FOR THE FIRST TIME AN INVENTORY OF A DEEP SEA AREA WAS SET UP AT SUCH A SCALE) AND PARTLY THROUGH THE DROPPING OUT OF SOME SUB-PROJECTS DURING PREVIOUS EXPEDITIONS, IT IS PROPOSED TO PROLONG THIS PROJECT FOR ANOTHER TWO YEARS.
IN THE FRAMEWORK OF THE AFTER-CARE, ATTENTION WILL BE PAID IN PARTICULAR TO THE TYPE AND QUALITY (A.O. RADIONUCLIDES CONTENT) OF THE FAUNA BOTH ON THE DUMPSITE AND ALONG A TRANSECT IN THE DIRECTION DOWNSTREAM FROM THE DUMPSITE. FURTHERMORE THE KNOWLEDGE OF THE FOOD-WEB WILL BE ENLARGED ALLOWING A BETTER USE OF THE ALREADY COLLECTED AND STILL TO BE COLLECTED DATA IN ANALYSES OF RISKS FOR FAUNA IN AND AROUND THE DUMPSITE. BY DOING THIS ON THE LONG TERM MORE RELIABLE RESULTS ARE TO BE EXPECTED FOR FORECASTING. BESIDES, THE HITHERTO SAMPLED AREA WILL BE COMPARED WITH OTHER AREAS WHICH WILL LEAD TO THE EVALUATION OF THE BIOLOGICAL CHARACTER OF THE DUMP SITE IN COMPARISON TO OTHER DEEP SEA AREAS.
The relative richness of the benthic fauna and meiofauna of the dumpsite and its surroundings seemed to be relatively high in comparison with other deep sea studies in the east Atlantic. Macrofauna richness was difficult to assess, as a wide variation in screen size has been used in other deep sea studies in the Atlantic. From a comparison with the Narzog transect stations, it is concluded that the dumpsite is not exceptional within the hilly deep sea area southwest of the Porcupine Abbyssal Plain. It is clearly not the richest area as station 33 has a much higher benthos density and biomass.
1) COMPARISON OF THE MEIO- AND MACROFAUNA OF THE DUMPING AREA WITH THE FAUNA OF THE DOWNSTREAM DEEP SEA AREAS.
THE DUMPSITE ITSELF IS BY NOW ONE OF THE BEST INSPECTED DEEP SEA AREAS WITH REGARD TO THE MEIO- AND MACROFAUNA. HOWEVER, LITTLE IS KNOWN ABOUT THE DISTANT AREAS WHERE POSSIBLY RADIOACTIVE MATERIAL, SET FREE FROM THE DUMPSIDE MAY TURN UP. IT IS BESIDES NECESSARY TO COMPARE THE RICHES AND BIOLOGICAL SIGNIFICANCE OF THE DUMPSITE WITH THE ONE OF OTHER DEEP SEA AREAS. FOR THAT PURPOSE A TRANSECT WILL BE DRAWN IN THE NORTHWARD DIRECTION. IT IS PROPOSED, DEPENDENT ON THE AVAILABLE SHIP TIME, TO SAMPLE WITH A BOXCORER 8 TO 12 STATIONS AT DIFFERENT DISTANCES FROM THE DUMPING AREA. THE MEIO- AND MACROFAUNA OF THESE SAMPLES WILL BE INVESTIGATED LIKE IT HAS BEEN DONE IN THE DORA PROGRAMME. THE PO-210 AND PU-239+240 WILL EQUALLY BE DETERMINED. IN BEHALF OF THE FURTHER AFTER-CARE, SAMPLES EARLIERLY TAKEN AT THE DUMPSITE WILL BE CAREFULLY COMPARED WITH THE NEW SAMPLES.
2. FURTHER STUDY OF THE DEEP SEA FOODWEB.
DURING THE DORA-PROJECT SOME RESEARCH WAS DONE ALREADY, THROUGH STUDY OF THE STOMACH CONTENT OF DEEP SEAFISHES AND THROUGH A DETAILED INVESTIGATION OF THE TROPHIC LEVELS INSIDE THE NEMATODES. THIS RESEARCH WILL BE EXTENDED TOWARDS SEVERAL ANIMAL GROUPS ENCOMPASSING MEGA-,MACRO-, AND MEIOFAUNA. PRACTICALLY, IT WILL COME TO THIS:
A) A FURTHER SEPARATION OF THE BENTHIC ANIMAL GROUPS IN SMALLER TAXONOMIC UNITS, MAKING EASIER THE SEPARATION IN DIFFERENT TROPHIC LEVELS. AMONG E.G. THE BIVALVES, THE TUNICATES AND POLYCHAETES, THERE EXIST BOTH TAXA WITH A CARNIVOROUS MENU AND TAXA WITH DEPOSIT OF FILTERFEEDING.
B) VISUAL STOMACH INSPECTION, ESPECIALLY OF THE MEGAFAUNA. THIS RESEARCH GIVES MORE SPECIALIZED INFORMATION ABOUT THE FOOD OF THE DIFFERENT SPECIES OF BENTHIC ORGANISMS THAN THE TAXO-MORPHOLOGICAL RESEARCH MENTIONED IN POINT A). IN PRACTICE, THIS CAN ONLY BE PERFORMED PROPERLY WITH SOMEWHAT LARGER ANIMAL SPECIES (MEGAFAUNA) LIKE FISHES, ANEMONES, STARFISHES AND TUNICATES. IMMUNOLOGICAL RESEARCH OF THE STOMACH CONTENT (IN COOPERATION WITH R.J. FELLER, USA) WILL GIVE FURTHER INFORMATION. THIS INFORMATION IS VERY IMPORTANT FOR THE RISK ANALYSES TO BE WORKED OUT LATER ON FOR THE DEEP SEA FAUNA OF THE DUMPING AREA.
THE RESEARCH MENTIONED IN A) CAN BE PERFORMED WITH THE STILL AVAILABLE MATERIAL OF THE DORA EXPEDITIONS. FOR THE STUDY OF POINT B), FRESH MATERIAL IS NEEDED TO BE OBTAINED PARTICULARLY BY TRAWLING. DEPENDENT OF THE SUCCESS OF THE SAILING PERIOD THIS SUBJECT CAN BE MORE OR LESS WORKED OUT.
3. QUANTITATIVE DETERMINATION OF MEGAFAUNA.
THIS WILL BE DONE WITH THE AID OF PHOTOGRAPHS OF THE SEA BOTTOM, TO BE TAKEN WITH DEEP SEA CAMERA MOUNTED ON AN AGASSIR TRAWL.
EXECUTION FIELDWORK
DURING AN EXPEDITION AT THE UNIVERSITY OF AMSTERDAM IN 1986 PART OF THE SAMPLES WERE TAKEN FOR THE PROGRAMME MENTIONED UNDER POINT 1 ABOVE. DURING ANOTHER EXPEDITION IN LATE 1987 OR EARLY 1988 FIVE EXTRA DAYS'LL BE AVAILABLE TO EXECUTE THE REMAINING PART OF THE PROGRAM
Wissenschaftliches Gebiet
- engineering and technologyother engineering and technologiesnuclear engineeringnuclear waste management
- engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsensorsoptical sensors
- natural scienceschemical sciencesnuclear chemistryradiation chemistry
- agricultural sciencesagricultural biotechnologybiomass
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