Leibniz Institute for Baltic Sea Research Warnemünde

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1 INSTITUT FÜR OSTSEEFORSCHUNG WARNEMÜNDE an der Universität Rostock BALTIC SEA RESEARCH INSTITUTE Leibniz Institute for Baltic Sea Research C r u i s e R e p o r t r/v "Elisabeth Mann Borgese" Cruise- No. EZ / 1 / March April, 1 Western and Central Baltic Sea This report is based on preliminary data an der Universität Rostock Seestraße 1 D-111 Rostock- GERMANY

2 Monitoring Cruise No. EZ/1/ 1. Cruise No.: EZ / 1 /. Dates of the cruise: from March 1 to April 1. Particulars of the research vessel: Name: Elisabeth Mann Borgese Nationality: Germany Operating Authority: IOW. Geographical area in which ship has operated: western and central Baltic Sea. Dates and names of ports of call. Purpose of the cruise Monitoring cruise in the framework of HELCOM programme. Crew: Name of master: U. Scholz Number of crew: 11. Research staff: Chief scientist: Scientists: Engineers: Technicians: Dr. R. Feistel S. Jürgensmann J. Ruickoldt J. Donath, F. Pohl, Bi. Sadkowiak, A. Tschakste, S. Lage. Co-operating institutions: 1. Scientific equipment CTDO bathysonde, plankton net, Secchi disk EZ1 CR BMP Feistel.doc Page of 11

3 Monitoring Cruise No. EZ/1/ 11. General remarks and preliminary results The cruise of r/v Borgese from March till April 1 was carried out under mostly moderate wind (BF- ) conditions that prevailed at the eastern flank of the high-pressure cell Harry over the British Islands. Exceptions were caused by the lows Ellen and Fabiola that passed the Central Baltic from NW to SE between the morning of 1 March and the evening of April with wind speeds exceeding m/s and harsh sea states. Sample filtering and related optional station work requested for external scientific projects at TF1 for an expected duration of h was cancelled when the storm approached. Related work could be carried out at TF, partially under shelter of the Swedish coast in the NW, and caused an additional delay of approximately 1 h of the regular program. Surface water temperatures varied between. C in the Kiel Bight and. C north of Gotland. Air-temperature readings were in a similar range except 1 April when ice covered the ship s deck in the morning. Two preconditions were expected to influence the observation results, (i) the negligible inflow activity from the North Sea during all of 1 and two minor inflows in the first half of 11, and (ii) the recent significant inflow event of November/December 11. On the way from the Bornholm Deep to the Gotland Deep, a weak oxygen signal was observed in the near-bottom layer as far downstream as TF, a temperature signal preceding the actual inflow water could be registered already at TF, but TF appeared still unaffected by the recent inflow. For estimating the inflow progress velocity, a related station series was visited again on the ship s way back. As a result of the storms Ellen and Fabiola, a quite recently developed inflow layer with cold oxygenated water is visible at the stations TF11 (Arkona Basin) and TF1 (Bornholm Basin) between the repeated casts during the cruise, see the two magnified transects below. In this report, oxygen values marked with an asterisk* refer to raw sensor data that may be corrected by postprocessing after the cruise. In the Arkona Basin, TF11, the near-bottom salinity is significantly higher than in March 11 (Table ), the water column is well ventilated. In the Bornholm Basin, TF1, salinity in the deep water is only slightly higher than in the year before, but the oxygen concentration is markedly improved (although already slightly worse than in January 1). From about to m depth, oxygen drops sharply from about * ml/l to about * ml/l. The latter concentration is almost constant down to about m, below which it drops again to about * ml/l. That lowest layer has a temperature of about C. Down from m, the water column is warmer than C with a slow downward increase. In the Stolpe Channel, TF, the near-bottom salinity exceeds that of last year, which indicates some inflow that had lifted water over the Stolpe Sill. The oxygen situation is similarly good as in last year. Bottom ( m) water temperature is. C, salinity 1. psu, containing oxygen at a level of.* ml/l. In the South-Eastern Gotland Basin at TF, no HS was detected. Minimum oxygen concentration at the bottom ( m) is 1.* ml/l at a temperature of.1 C and a salinity of 1. psu. Lower than m depth, oxygen exceeds * ml/l. In the South-Eastern Gotland Basin at TF, no HS was detected. Minimum oxygen concentration at the bottom (11 m) is 1.* ml/l at a temperature of. C and a salinity of 11. psu. Lower than m depth, oxygen exceeds * ml/l. EZ1 CR BMP Feistel.doc Page of 11

4 Monitoring Cruise No. EZ/1/ In the South-Eastern Gotland Basin at TF, HS was detected below 1 m depth. At the bottom (1 m) HS is. ml/l, the temperature is.1 C and the salinity is 11. psu. In the South-Eastern Gotland Basin at TF, HS was detected below 1 m depth. At the bottom (1 m) HS is. ml/l, the temperature is. C and the salinity is 11. psu. In the Eastern Gotland Basin at TF1, H S is detected from 1 m downward with a maximum of -. ml/l. At the Farö Deep at TF, H S is detected from 1 m downward with a maximum of -1. ml/l, at the Landsort Deep, TF, from 1 m downward up to -1. ml/l, and at the Karlsö Deep, TF, only a minor HS value of -.1 ml/l could be measured in the bottom layer at 1 m. Rainer Feistel, scientist in charge Attachments: - station charts - tables of preliminary results (surface layer and near-bottom layer) - transects of T, S and O from Kiel Bight to Eastern Gotland Basin - two subsequent magnified transects east of the Bornholm Basin - near-bottom O/HS chart EZ1 / map all monitoring stations / 1 repeated stations Odense Lübeck DENMARK TF1 TF TF1 TF TF TF1 Gedser TF Fehmarn TF TF11 TF1 Kiel TF1 TF TFO Rostock GERMANY Kopenhagen Trelleborg Ystad SWEDEN TF1 TF1 TF1 BORNHOLM Ronne TF TF1 TF1 TF1 TF1 TF11 TF11 TF11 ABBoje TF111 TF11 TF11 TF1 Sassnitz TFO11 map 1 TF1 TF1 map Karlskrona TF Longitude [ ] TF1 TF1 TF1 Koszalin Kalmar Västervik ÖLAND TF POLAND TF TF TF Visby GOTLAND TF TF TF Gdynia Slite Gdansk TF TF TF TF limit 1 - /. - // scale - 1 TF TF TF TF TF1 TF Kalingrad Liepaja LATVIA Klaipeda Ventspils Department Physical Oceanography Jan Donath Leibniz Institute for Baltic Sea Research Latitude [ ] EZ1 CR BMP Feistel.doc Page of 11

5 Monitoring Cruise No. EZ/1/ EZ1 / map 1 monitoring stations / 1 repeated stations Kiel Odense TF TF1 Lübeck Fehmarn TF TF1 TF11 TF1 DENMARK Gedser TF TF TF1 TFO GERMANY Rostock Longitude [ ] Kopenhagen TF TF1 TF Trelleborg TF11 TF11 TF11 Ystad TFO11 Sassnitz Ronne BORNHOLM EZ1 / map monitoring stations / 1 repeated stations TF Karlskrona Kalmar TF1 TF1 TF1 Västervik ÖLAND TF TF TF TF Longitude [ ] Visby GOTLAND TF TF TF Slite TF TF TF TF TF1 TF1 TF1 TF1 TF1 TF111 ABBoje limit 1-1 /. - // scale - 1 TF11 TF11 TF1 TF1 TF1 TF1 TF1 1 Department Physical Oceanography Jan Donath Leibniz Institute for Baltic Sea Research TF TF TF TF TF TF1 TF limit 1 - / - // scale - 1 Liepaja Klaipeda Ventspils LATVIA Department Physical Oceanography Jan Donath Leibniz Institute for Baltic Sea Research Latitude [ ] Latitude [ ] EZ1 CR BMP Feistel.doc Page of 11

6 Monitoring Cruise No. EZ/1/ Table 1: Preliminary data of 1 from the surface layer ( m) of selected regions. Oxygen values from titration. In brackets, related data of March 11. Location / Station / Temp. Salinity O NO + PO SiO Date Number C psu ml/l Kiel Bight TF (.) (1.) (.) (.) (.1) (.) Mecklenburg Bight TF (.) (1.11) (.) (.) (.) (.) Lübeck Bight TF (.) (1.) (.) (.1) (.) (.) Darss Sill TF..1.1*..1 1 (1.) (.) (1.) (.1) (.1) (.) Arkona Basin TF11...*..1 1 (1.1) (.1) (1.) (.) (.) (11.) Bornholm Deep TF1.1..*..1 (1.) (.) (.) (.) (.) (1.) Stolpe Channel TF (1.) (.) (.) (.) (.) (1.) SE Gotland Basin TF (1.) (.) (.) (.) (.) (1.) Gotland Deep TF (.) (.) (.) (.) (.) (11.) Farö Deep TF (.) (.) (.) (.1) (.) (11.) Landsort Deep TF (.) (.) (.) (.) (.) (1.) Karlsö Deep TF (.1) (.) (.) (.) (.) (.) EZ1 CR BMP Feistel.doc Page of 11

7 Monitoring Cruise No. EZ/1/ Table : Preliminary data of 1 from the near-bottom layer of selected regions. Oxygen values from titration. Negative oxygen values are equivalents of H S. In brackets, related data of March 11. Location / Station / Depth Temp. Salinity O NO + PO SiO Date Number dbar C psu ml/l Kiel Bight..1 TF 1. (1.) 1. (1.). (.).1 (.).1 (.1) 1. (1.1) Mecklenburg Bight..1 TF1. (1.) 1. (1.). (.1).1 (.). (.) 1.1 (1.) Lübeck Bight..1 TF. (1.1) 1.1 (1.). (.). (.). (.1). (1.) Darss Sill..1 TF 1.1 (1.1) 1. (1.).* (.) (1.) (.1) (11.) Arkona Basin..1 TF11 1. (.) 1.1 (11.).* (.1) (.) (.) (1.) Bornholm Deep..1 TF1.1 (.) 1. (1.).* (.) (.) (.1) (.) Stolpe Channel..1 TF 1. (.) 1. (11.).1 (.). (.) 1. (1.). (.) SE Gotland Basin..1 TF. (.). (1.). (.). (.) 1. (.). (.) Gotland Deep..1 TF1. (.) 1.1 (1.1) -. (-.) (.). (.). (.1) Farö Deep 1..1 TF 1. (.) 11. (11.) -. (-1.) (.1). (.). (.) Landsort Deep 1..1 TF. (.) 1. (1.) -1. (-.) (.). (.). (.) Karlsö Deep 1..1 TF 1. (.).1 (1.). (-1.1). (.1). (.). (.) EZ1 CR BMP Feistel.doc Page of 11

8 Monitoring Cruise No. EZ/1/ EZ1 Kiel Bight - Gotland..1 1: :1 UTC TF TF1 TF1 TF11 TF1 TF TF TF1 TF TF11 TF11 TF11 TF1 TF1 TF1 TF1 TF1 TF1 TF1 TF TF1 TF1 TF TF TF TF TF TF TF TF TF TF1 TF TF TF Temperature [ C] Salinity [psu] srf Oxygen [ml/l] 1 1 Distance [n.m.] 1 Leibniz Institute for Baltic Sea Research, Department Physical Oceanography Jan Donath EZ1 CR BMP Feistel.doc Page of 11 1

9 Monitoring Cruise No. EZ/1/ EZ1 TF1 - TF Hinweg..1 : : UTC TF1 TF1 TF TF TF TF TF TF TF Temperature [ C] Salinity [psu] Oxygen [ml/l] Distance [n.m.] a.srf 1 Leibniz Institute for Baltic Sea Research, Department Physical Oceanography Jan Donath EZ1 CR BMP Feistel.doc Page of 11 1

10 Monitoring Cruise No. EZ/1/ EZ1 TF1 - TF Rückweg..1 : - 1: UTC TF1 TF1 TF TF TF TF TF TF TF Temperature [ C] Salinity [psu] Oxygen [ml/l] Distance [n.m.] b.srf 1 Leibniz Institute for Baltic Sea Research, Department Physical Oceanography Jan Donath EZ1 CR BMP Feistel.doc Page 1 of 11 1

11 Monitoring Cruise No. EZ/1/ EZ1 / map O monitoring oxygen bottom - concentration [ml/l] Kiel Odense. Lübeck Fehmarn.1 DENMARK. Gedser Rostock GERMANY Kopenhagen. Trelleborg.1 Ystad.1. Sassnitz SWEDEN BORNHOLM Ronne Karlskrona. Longitude [ ].. -1.(HS) -.(HS) -.1(HS) Kalmar Koszalin Västervik ÖLAND POLAND Visby GOTLAND 1. Gdynia Slite Gdansk limit 1 - /. - // scale (HS) -.(HS) -.(HS) Kalingrad Liepaja LATVIA Klaipeda Ventspils Department Physical Oceanography Jan Donath Leibniz Institute for Baltic Sea Research Latitude [ ] EZ1 CR BMP Feistel.doc Page 11 of 11