Hinrichsen, Hans-Harald

OceanRep

                CRUISE REPORT: 08.4.-21.4.2011  R.V. Alkor                                                     Cruise No.:Al 371  General subject of research: Physical, chemical, biological and fishery oceanography               Port calls: Saßnitz  Leibniz-Institute-Department/CAU-Institute: Marine Ecology (Fishery Biology)/ Leibniz-Institute of Marine Sciences  Chief Scientist: Hans-Harald Hinrichsen  Number of Scientists: 12  Projects: AQUASHIFT, CAVIAR, EPOCA, DFG-Mnemiopsis-Project, CALMARO    Research programme  This multidisciplinary research cruise was conducted within the framework of different inter-and nationally funded projects:  The research focus in AQUASHIFT RECONN 2 is to develop a more general picture of the influence of climatic processes on Baltic sprat population development. This includes: (i) developing process models on adult sprat growth and reproduction based on available field data, and (ii) combining output from experiments, analyses of field data as well as modelling activities (RECONN 1) in a stage-based matrix population model (life table) approach in order to resolve the influence of climate processes on the overall stock dynamics of sprat.    CAVIAR is joint Danish/German research project which aims at a detailed analysis of the climate variability of the Baltic Sea area and to investigate its impact on bio/physical processes in the central Baltic Sea. Analysing the effect of regional climate variations on coupled bio/physical processes, past and future data sets will be utilized for coupled bio-physical modelling to investigate and compare the potential impact of future climate change, especially the effect of global warming on the spatial distribution, habitat utilisation and recruitment processes of central Baltic fish and zooplankton populations.  The overall goal of the EU FP7 Integrated Project EPOCA (European Project on OCean Acidification) is to advance our understanding of the biological, ecological, biogeochemical, and societal implications of ocean acidification. EPOCA aims to document the changes in ocean chemistry and biogeography across space and time and determine the sensitivity of marine organisms, communities and ecosystems to ocean acidification. The results of the impact of ocean acidification on marine ecosystems will be used to better understand and predict the responses of the Earth system to ocean acidification in order to assess uncertainties, risks and thresholds ("tipping points") related to ocean acidification at scales ranging from subcellular to ecosystem and local to global. Within EPOCA it is planned to investigate the impact of ocean acidification on the performance, reproduction and growth in marine organisms. One of the objectives is to identify the critical stages in the life cycle of functionally important marine organisms based on performance measures as indicators of sensitivity to ocean acidification. Furthermore, physiological mechanisms of performance, acclimation capacity and tipping points are to me analyzed. One of the key species in this study is the Baltic cod, Gadus morhua, which will be obtained during the cruises with the RV ALKOR. Results will be compared to other species and functional groups for quantification of the impact of ocean acidification.   The DFG-Mnemiopsis-Project focuses on the comb jelly Mnemiopsis leidyi (Ctenophora) which recently invaded North- and Baltic Sea. 18 mo after the first occurrence, populations frequently attain >500 individuals /m3, suggesting profound consequences for the pelagic food chain. This project will study the ‘‘paradox of invasions’: how and why are supposedly genetically uniform colonizing populations so successful? - We first determine the source region(s) of Mnemiopsis populations invading North and Baltic Sea, using high-resolution genetic markers. We are then interested in processes enhancing adaptive evolution, which would exacerbate the impact that M. leidyi has on native fish populations. Taking advantage of genetic samples collected very early after first occurrence, we follow the level of genetic diversity displayed by Mnemiopsis populations across the study area over time. We test the hypothesis that the invading population is genetically less diverse than the source, while older invaded areas such as Caspian/Black Sea reveal intermediate levels. In order to address whether invading Mnemiopsis undergoes rapid evolutionary adaptation in its novel environment, genetic divergence among populations will be quantified temporally and spatially using gene-linked SNP loci in combination with genome scans.   Another focus is an additional cryptic invasion by another comb jelly, Mertensia ovum. This species co-occurs with M.leidyi in the Bornholm basin.  The EU project CALMARO involves initial Training Network aims at improving the career perspectives of early researchers by offering structured training in the field of Calcification by Marine Organisms as well as providing complementary skills and exposing the researchers to other sectors including private companies. CalMarO comprises investigation of calcareous structures as well as calcification processes and the sensitivities to changes in environmental conditions at all scales ranging from cellular, organism, population to ecosystem, and regional to global levels.   Gears used:  Hydrography: CTD, Water sample rosette  Zooplankton and jelly fish: Babybongo-Net (50 and 150 µm), Multinet (1/4 m2; 50 µm), WP-2 (200 µm), Apstein (50 µm)  Ichthyoplankton: Bongo-Net (335 and 500 µm), Helgoland Larvalnet (500 µm), IKS80 (300 µm), Mulitnet (1/2 m2; 335 µm)   Fish: Young fish trawl   Hydroaccoustic: 38 and 200 kHz-ecosounder      Scientific crew:   - Hans-Harald Hinrichsen (Chief Scientist) IfM-Geomar Kiel  whole cruise  - Svend Mees     IfM-Geomar Kiel  whole cruise - Julian Döring    IfM-Geomar Kiel  whole cruise - Enno Prigge     IfM-Geomar Kiel  whole cruise - Lars Kruse     IfM-Geomar Kiel  whole cruise - Burkhard v. Dewitz    IfM-Geomar Kiel  whole cruise - Helena Hauss    IfM-Geomar Kiel  whole cruise - Isabel Keller     IfM-Geomar Kiel  whole cruise - Holger Haslob    IfM-Geomar Kiel  whole cruise - Hilda Nurlaeli    IfM-Geomar Kiel  whole cruise - Natascha Mortagli    IfM-Geomar Kiel  whole cruise - Viola Neumann    DTU AQUA, Denmark whole cruise   Report of cruise Al354 with technical details  Thursday 08/04/11 0800-1000 Loading of ship  1000              Steaming to Arkona Basin 1800  Prolongation of measurements due to bad weather conditions (up to 9 Bft.)  Friday 09/04/11  0000  Start with hydrographic, hydroaccoustic, plankton  Sampling and pelagic fishery in the Arkona Basin (St. H23, H22, H21, H18 and H17)  Friday 09/04/11 2200  Start with hydrographic, hydroaccoustic and plankton  sampling in the Bornholm Basin and in the Stolpe Trench (St. BB1-BB13, SF55, BB 23-26, BB14-16  Sunday 11/04/11 0600 Start with pelagic fishery in the northeast of the 1800 Continuation with hydrographic, hydroaccoustic and   plankton sampling in the Bornholm Basin (St.BB 23, 22, 17-21) Monday 12/04/11 0600 Start with pelagic fishery in the northwest of the Bornholm Basin (6 hauls) 1800  Continuation with hydrographic, hydroaccoustic and plankton sampling in the Bornholm Basin (St.BB 32, 31, 30, 34, 33, 42, 41, 40) Tuesday 13/04/11 0600 Start with pelagic fishery in the southwest of the Bornholm Basin (6 hauls) 1800  Continuation with hydrographic, hydroaccoustic and plankton sampling in the Bornholm Basin (St.BB 35, 39, 43-45, 38, 36-37, 28, 29) Wednesday 14/04/11 0900 Start with pelagic fishery in the southeast of the Bornholm Basin (5 hauls)  1900 Interruption of sampling and steaming to Saßnitz, consultation of hospital due to illness of a crew member, exchange of crew member Friday 15/04/11         1400  Leaving Saßnitz into direction central Bornholm Basin 2000 Continuation with hydrographic, hydroaccoustic and plankton sampling in the Bornholm Basin (small-scale resolution in vicinity of St. 23) Saturday 16/04/11 0600 Start with small-scale pelagic fishery in vicinity of St. 23 Bornholm Basin (7 hauls)    1700  Start with hydrographic, hydroaccoustic, plankton  sampling and pelagic fishery in the Gdansk Deep (St. GB 59, 60, 60a, 63, 58, 57, 56) Sunday 17/04/11 0600 Start with hydrographic, hydroaccoustic, plankton  sampling and pelagic fishery in the Southern Gotland Basin and the Stolpe trench (St. GB 72, 73, 79, 80, 81, 82, SF 51, 50, 49, 52, 53, 48, 47, 54, 46) Tuesday 19/04/11 1100 Continuation with hydrographic, hydroaccoustic and   plankton sampling in the Bornholm Basin (St.BB 27 and 23) Wednesday 20/05/10 0100  End of scientific program, Steaming to Kiel 2000  End of cruise Al371 in Kiel   Summary of cruise   Despite of relatively bad weather conditions at the verya beginning of the cruise, sampling could be performed as scheduled.   The physical measurements of this cruise were designed to investigate the quasi-synoptic three-dimensional distribution of temperature, salinity, oxygen and pH within the Arkona- and Bornholm Basin. The station grid in the Bornholm Basin covered the area enclosed by the 60 m isobath and was regularly spaced with a distance of 10 nm in N/S-and 8.5 nm in E/W-direction. Data of these physical observations will be used in future to analyse the three-dimensional distribution of biological parameters (e.g. zooplankton, fiah egg and larval abundance, fish abundance) with respect to variability of the physical environmental conditions.   The hydrographic measurements identified the permanent halocline in the Bornholm Basin in the depth range 45-55 meter increasing from east towards west. The water temperature of the mixed layer was around 2-3°C. In the more western part of the Bornholm Basin, below the halocline a very cold water body with temperatures was observed not exceeding 1.5°C. This relatively cold, well oxygenated water had a vertical extension down to the bottom. It originated from an inflow event of Kattegat and western Baltic water masses during winter 2010/2011. Within the deep water area of the eastern Bornholm Basin, oxygen values were below 2 ml/l with temperatures around 6°C and salinities not exceeding 17 psu. In comparison to hydrographic measurements available from previous cruises in 2010 within the central Baltic the hydrographic situation partly changed. The indication of newly inflowed water entering the Bornholm Basin, yields a relatively high probability of substantial water mass exchange between particular basins having an impact on environmental conditions in the Gdansk Deep and the southern Gotland Basin. Howeveer, at present, there is only low oxygen concentration in the near-bottom layers of the Gdansk Deep and the southern Gotland Basin, but parly above the required concentrations for successful cod spawning. The deep part of the southern Stolpe Trench has the most favourable spawning conditions from the halocline to the bottom, with oxygen concentrations larger than 2 ml/l.  The 500 µm samples from the Bongo have been checked for cod and sprat larvae on board. All fish larvae had been frozen at -80°C to enable evaluation of their nutritional status by RNA/DNA analysis in relation to otolith microstructure. The WP2 net was utilized to investigate the spatial distribution and the genetic markers of Mnemiopsis leydi and Mertensia ovum., on several stations a WP2-net and vertical as well as towed multinet hauls were performed (see Table 4).  43 pelagic fishery hauls were performed to determine the spatial distributions of sprat, cod and herring in the Bornholm Basin, the Gdansk Deep and the southern Gotland Basin. Length and weight distributions of sprat and herring were recorded as well as maturation stages on every fishery station. To describe the predation on ichthyoplankton by pelagic fish, herring and sprat stomachs have been sampled by pelagic trawling. Additionally, herring and sprat were frozen for bioenergetic analysis. For cod length and weight measurements were performed, maturation stages recorded and otoliths collected. Due to the relatively low water temperatures, the catch rates of cod were very low, indicating only low  spawning migration from the winter feeding grounds towards the spawning ground in the deep Bornholm Basin. From the cruise it was recognized that the spawning activity of sprat had also not fully started.   Due to the peculiar hydrographical conditions in the Central Baltic Sea with oxygen minimum zones in higher saline bottom layers, pelagic fish eggs regularly face hypoxic conditions during their development. Thus, the determination of the specific buoyancy potential of the most important pelagic fish eggs (cod, sprat, flounder eggs) is an important issue to deal with and has been analyzed during this cruise using two independent methods to assess the vertical egg distribution.   Vertically towed Helgoländer Larvalnet (HLN) were used to integrate the near bottom to surface water column and alive, unharmed fish eggs (cod, sprat, flounder) have been picked out, determined to species level, staged and size measured under stereomicroscopes. The eggs were inserted into freshly prepared density gradient columns and the density was calculated after the eggs had obtained their neutral buoyancy within 60 minutes in the stratified column equipped with specific calibrated density floats.    The second method to determine egg density values (=egg neutral buoyancy) was the strip spawning of running ripe female fish and immediate fertilization with sperm collected from running ripe males. Eggs were decanted to separate dead from alive fertilized ones and after 30min incubation time kept cool and dark for about 20 hours before subsamples were checked for normal developmental progress, staged, size measured and put into gradient columns. 60 min past insertion, density potential of the batch could be read in conjunction with the calibrated density floats. The majority of measurements were made in the Bornholm Basin, followed by some batches in the southern Gotland Basin and in the Gdansk Deep.                            Tables  Table1: Hydrographic stations Arkona Basin   Station Breite Länge H01 55  7.0 12 49.0 H02 55  4.0 13 16.0 H03 55 14.5 13 30.0 H04 55  7.0 13 30.0 H05 55  7.0 13 48.0 H06 55  9.0 14  2.0 H07 55  7.0 14 15.5 H08 55 22.0 14 21.5 H09 55 21.0 14 30.0 H10 55 20.0 14 39.5 H11 55 15.0 14 30.0 H12 55 10.5 14 25.0 H13 55  6.5 14 33.5 H14 55  4.5 14 21.0 H15 54 58.5 14 16.0 H16 54 52.0 14  2.0 H17 55  1.0 14  2.0 H18 54 56.5 13 47.0 H19 54 47.0 13 47.0 H20 54 47.0 13 30.0 H21 54 56.5 13 30.0 H22 54 57.5 13 15.0 H23 54 53.5 13  5.0 H24 54 48.5 13 15.0 H25 54 44.0 13  2.5 H26 54 44.0 12 47.5 H27 54 54.5 12 47.5 H28 54 50.0 12 37.0 H29 54 43.0 12 29.5 H30 54 37.0 12 17.0 H31 54 24.0 12 10.0 Table 2: Hydrographic stations Bornholm Basin   station latitude longitude Basin1 55 27.5 14 45 BB2 55 37.5 14 45 BB3 55 37.5 15 00 BB4 55 37.5 15 15 BB5 55 37.5 15 30 BB6 55 37.5 15 45 BB7 55 37.5 16 00 BB8 55 47.5 16 00 BB9 55 47.5 16 15 BB10 55 37.5 16 15 BB11 55 47.5 16 30 BB11a 55 47.5 16 45 BB11b 55 47.5 17 00 BB12 55 37.5 16 30 BB12a 55 37.5 16 45 BB12b 55 37.5 17 00 BB13 55 27.5 16 30 BB14 55 27.5 16 15 BB15 55 27.5 16 00 BB16 55 27.5 15 45 BB17 55 27.5 15 30 BB18 55 27.5 15 15 BB19 55 27.5 15 00 BB20 55 17.5 15 00 BB21 55 17.5 15 17 BB22 55 17.5 15 30 BB23 55 17.5 15 45 BB24 55 17.5 16 00 BB25 55 17.5 16 15 BB26 55 17.5 16 30 BB27 55 07.5 16 30 BB28 55 07.5 16 15 BB29 55 07.5 16 00 BB30 55 07.5 15 45 BB31 55 07.5 15 30 BB32 55 07.5 15 15 BB33 54 57.5 15 15 BB34 54 57.5 15 30 BB35 54 57.5 15 45 BB36 54 57.5 16 00 BB37 54 57.5 16 15 BB38 54 47.5 16 00 BB39 54 47.5 15 45 BB40 54 47.5 15 30 BB41 54 47.5 15 15 BB42 54 47.5 15 00 BB42b 54 47.5 14 45 BB43 54 37.5 15 15 BB43a 54 37.5 15 00 BB43b 54 37.5 14 45 BB44 54 37.5 15 30 BB45 54 37.5 15 45 BB  BB – Bornholm Basin                                         Table 3: Stolpe Trench, Gdansk Deep and Gotland Basin: CTD and IKS-80      At stations with * CTD and Bongo/Babybongo    Station Breite Länge Becken46* 55 14 16 48 SF47* 55 15 17 05 SF48* 55 14 17 22 SF49 55 15 17 35 SF50 55 14 17 55 SF51 55 29 17 55 SF52 55 25 17 35 SF53* 55 21 17 22 SF54* 55 21 17 05 SF55* 55 21 16 48 SF56 55 09 18 25 GD57 55 10 18 49 GD58 55 00 19 05 GD59 54 54 18 54 GD59a 55 00 18 41 GD60 54 49 19 08 GD60a 54 43 19 17 GD61 54 48 19 25 GD62 54 54 19 30 GD62a 55 00 19 30 GD63 54 54 19 12 GD64 55 00 19 21 GD65 55 10 19 16 GD66 55 10 19 38 GD67 55 19 19 42 GD68 55 19 19 26 GD69 55 18 19 06 GD70 55 23 18 43 GD71 55 23 18 19 GD72 55 37 18 19 GB73 55 37 18 43 GB74 55 37 19 11 GB75 55 37 19 26 GB76 55 38 19 56 GB76a 55 48 19 39 GB77 55 39 20 11 GB78 55 59 19 22 GB79 55 57 19 03 GB80 55 57 18 43 GB81 55 55 18 29 GB82 55 53 18 12 GB82a 56 50 19 10 GB83 55 15 18 37 GB84 56 15 19 00 GB85 56 15 19 30 GB86 56 32 20 22 GB86a 56 38 20 16 GB87 56 34 20 01 GB88 56 32 19 39 GB89 56 32 19 23 GB90 56 32 19 00 GB90a 56 32 18 46 GB91 56 42 19 00 GB92 56 42 19 30 GB93 56 42 20 00 GB94 56 55 20 24 GB95 56 55 19 54 GB96 56 55 19 35 GB97 56 55 19 14 GB98 56 55 18 55 GB99 57 10 19 25 GB100 57 09 19 42 GB101 57 09 20 00 GB102 57 10 20 29 GB102a 57 23 20 35 GB103a 57 22 20 23 GB104b 57 18 20 09 GB105 57 23 19 58 GB106a 57 22 19 28 GB107 57 36 19 44 GB108 57 54 19 50 GB109 57 55 20 10 GB110 57 45 20 30 GB111 57 37 20 15 GB  SF: Stolper Trench; GD: Gdansk Deep; GB: Gotland Basin           Table 4. Number and type of samples taken during AL371   Basin      Type   Number Arkona Basin     CTD    5       Watersampler   1         Fishery trawls   5       Helgoland Larvalnet  2  Bornholm Basin    CTD   60       WP2    8       Bongo/Babybongo 51         Multinet  12       Watersampler   2       Helgoland Larvalnet 10       Apstein net   6        Fishery trawls  30 Stolpe Trench     CTD    9         Bongo/Babybongo  6       IKS80    4       Helgoland Larvalnet  1       WP2    1 Gdansk and Southern Gotland Basin  CTD   13       IKS80   13       WP2    2       Helgoland Larvalnet  1       Fishery trawls   8                     Figures  Fig 1: Stations  Arkona Basin                      Fig 2: Stations  Bornholm Basin and Stolpe Trench                      Fig 3: Stations  Gdansk Deep and Gotland Basiin       

Cruise Report: 08.4.-21.4.2011 R.V. Alkor Cruise No.:Al 371

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