| Plattform Platform |
Reise-Nr. Cruise-No. |
Zeitraum Period |
Projekt Project |
Arbeitsgebiet Working area |
|---|---|---|---|---|
| Alkor | AL616 | 18.07.2024 - 09.08.2024 | Mecklenburg Bight Baltic Sea |
| Fahrtleiter Chief Scientist | Institut Institute | Auslaufhafen Port of departure | Einlaufhafen Port of return | Stationskarte Station map | Schiffsroute Trackchart |
|---|---|---|---|---|---|
| Sommer Stefan | Helmholtz Centre for Ocean Research Kiel (GEOMAR) | Kiel | Kiel |
Ziel der Reise / Objectives of Cruise:
Within the BMBF funded second phase of the DAM project "Ausschluss mobiler grund-beruhrender Fischerei (MGF) in marinen Schutzgebieten der Ostsee" Phase II (MGF-Ostsee-II) - an experimental field study has been conducted to determine the effects of bottom trawling on the benthic ecosystem of the German coastal Baltic Sea. An area characterized with low fishing activity has been selected in the Mecklenburger bight about 5 km north of the town Kuhlungsborn based on geo-acoustic and sedimentological criteria. In a part of this area referred to as High Impact area, high intensity trawling was simulated by performing several trawls, whereas in another area of similar size the sediments were not disturbed and served as a Control site. Both areas were repeatedly investigated over a period of 3 weeks using biogeochemical sediment analyses, in situ benthic flux measurements and visual seafloor inspection to determine changes of the benthic ecosystem in response to the trawling impact. A further area has been assigned to perform biogeochemical analyses in sediment push cores taken by divers from specific sediment features in and around trawl mark tracks caused by the otter boards during trawling. In addition to the benthic working program, physico-chemical investigations were carried out of the suspension particle plume generated during trawling as well as seafloor imaging to decipher the degree of disturbance and redistribution of sediments possibly affecting benthic communities. Including RV ALKOR four research vessels participated in this trawling experiment. On RV ELISABETH MANN BORGESE (chief scientist Prof. Klaus Jurgens, Leibniz-Institut fur Ostseeforschung, Warnemunde, IOW) sediments were sampled for biological analyses (macrobenthos, meiobenthos, protozoans, microbenthos). Scientists on the fishery RV CLUPEA (chief scientist Dr. Daniel Oesterwind, Thunen Institut fur Ostseefischerei) carried out trawling and investigated the effects of trawling on fish. Diving operations were performed using the RV LIMANDA and the small tender KLASHAHN (chief scientist Dr. Stefan Forster, University Rostock). Seabed morphology was investigated by Peter Feldens (IOW).
Messungen / Measurements
| Institut Institute |
Wissenschaftler Scientist |
Anzahl Number |
Einheit Unit |
Typ der Messungen Type of measurements |
Kommentar Comments |
Daten im DOD Data in DOD |
|---|---|---|---|---|---|---|
| GEOMAH | Sommer Stefan | 6 | deployment | D71 Current profiler (e.g. ADCP) |
Current Profiler upward looking deployed on the Deep-Sea Rover Pants Rhei (DSR) | no |
| GEOMAH | Sommer Stefan | 3 | survey | D90 Other physical oceanographic measurements |
Measurement of the particle concentration and particle size spectra in the sediment plume caused by the trawling using a LISST sensor implemented in the towed camera and sensor system XOFOS (X Ocean Floor Observation System) | no |
| GEOMAH | Dale Andrew | 38 | deployment | G04 Core-soft bottom (no. of cores) |
Sediment samples using the multiple corer (MUC) for geochemical and biogeochemical analyses | no |
| GEOMAH | Sommer Stefan | 18 | survey | G08 Bottom photography |
Visual sea floor inspection using the towed camera- sensor system XOFOS (X Ocean Floor Observation System) | no |
| GEOMAH | Sommer Stefan | 6 | deployment | G71 In-situ sea floor measurements |
Repeated in situ benthic flux measurements of oxygen using GEOMAR Deep-Sea Rover Pants Rheinland | no |
| GEOMAH | Sommer Stefan | 10 | deployment | G71 In-situ sea floor measurements |
In situ benthic flux measurements of oxygen, nutrients, TA, DIC using the GEOMAR BIGO type Lander (Biogeochemical Observatory) | no |
| GEOMAH | Sommer Stefan | 6 | deployment | H10 CTD-Stations |
Deployments of a CTD water rosette for physical measurements (salinity, temperature, density, oxygen, turbidity, chl.a) in the water column | no |
| GFZPO | Kallmeyer Jens | 35 | deployment | H90 Other chemical oceanographic measurements |
35S radioactive tracer incubations to measure the microbial sulfate reduction in the sediment | no |
| GEOMAH | Sommer Stefan | 6 | deployment | R03 Robotic vehicle deployments |
Deployment of the Deep-Sea Rover Pants Rhei (DSR) for in situ benthic oxygen flux measurements. | no |