Report from the SMHI monitoring cruise

Johan Kronsell Swedish Meteorological and Hydrological Institute Oceanographic Laboratory Dnr: S/Gbg-1-73 1-9- Report from the SMHI monitoring cruise with R/V Dana Survey period: 1-9- - 1-9-7 Principal: Swedish Meteorological and Hydrological Institute (SMHI), Swedish Agency for Marine and Water Management (SwAM) SUMMARY The cruise, which is part of the Swedish pelagic monitoring program, visited the Sound, the Baltic Proper and parts of the Kattegat. In the Kattegat, Anholt E represents the entire sea area since neither N1 nor Fladen were sampled. This is otherwise done during a regular monitoring cruise. Due to limited ship time in combination with a recent fishing survey covering the Skagerrak and the Kattegat where some hydrographical sampling was done, the main focus of the expedition was to visit sampling stations in the Baltic Proper. As during the most recent expedition, which was in May, the surface water temperature was above normal at all visited stations, except for the station REF M1V1 where the surface water temperature was normal. No monitoring cruises have been done during the summer due to technical problems on R/V Aranda. Nutrients in the form of dissolved inorganic nitrogen (DIN) in the surface water were generally below limit of quantification, which is normal for the season. For dissolved inorganic phosphorus (DIP) the levels were normal for the season. The silicate concentrations were normal or above normal for the season. The next regular cruise was scheduled to take place from th to 7 th of September, but was cancelled half ways, and stopped in Lysekil. Adress: Sven Källfelts Gata 1 71 Västra Frölunda Telefon: 11-9 E-post: johan.kronsell@smhi.se WWW: http://www.smhi.se/

RESULTS The cruise was conducted aboard the Danish research vessel Dana. It started in Fredrikshavn the nd of September and ended at the same port the 7 th of September. The winds were mostly moderate. During the expedition, no zooplankton sampling was conducted due to technical issues. No stations were visited in the Skagerrak, and in the Kattegat the only visited station was Anholt E. In total 1 stations were sampled during the cruise. The Skagerrak and the Kattegat had been sampled in late August by R/V Dana during a fishing survey, and a report from that cruise will be published. This report is based on data that have passed a first quality control. When data are published at the National Oceanographic Data Centre some values might have changed after further quality controls have been performed. Data from this cruise will be published as soon as possible on the data centre s webpage, normally within a week after the cruise. Downloadable data can be found here: http://www.smhi.se/klimatdata/oceanografi/havsmiljodata (only available in Swedish). The Kattegat and the Sound The sea surface temperature was above normal for the season, 1.1 C in the Kattegat and 17. C in the Sound. The salinity in the surface water of the Kattegat was above normal for the season and in the Sound it was normal. Measured values were about psu and 1 psu respectively. Nutrients in the form of dissolved inorganic nitrogen, DIN (the sum of nitrate, nitrite and ammonia) were below limit of quantification in the surface water, which is normal for the season. Concentrations of dissolved inorganic phosphorus, DIP, were normal for the season in the Sound, and below normal in the Kattegat. The silicate concentrations were lower than normal in the Kattegat, but normal in the Sound. Oxygen levels in the deep water of the Kattegat and the Sound were normal for the season. In the bottom water at Anholt E the oxygen level was measured to 3.7 ml/l, and at W Landskrona it was measured to 3.3 ml/l. Fluorescence measurements from the CTD indicated low plankton activity.

The Baltic Proper The surface water temperature was above normal at all visited offshore stations, and varied between 1. and 19. C. At the coastal station REF M1V1 between Öland and the mainland the surface water temperature was 1.3 C and this is normal for the season. Surface water salinity was normal for the season and varied from. to.1 psu, lowest in the northern part and highest in southwest. A distinct thermocline was found at -3 meters depth, and a halocline was present at -7 meters depth at the deepest stations. Levels of DIN and DIP in the surface water were low, which this is normal for the season. The dissolved inorganic nitrogen in the surface was depleted and below limit of quantification. Surface water concentrations of silicate were normal or above normal, it varied from 7.9 to 1.3 µmol/l, highest concentrations in the southwest. Acute hypoxia (oxygen < ml/l) was found at the bottom of the Arkona Basin. The Bornholm Basin and the Eastern and Western Gotland Basin had anoxic conditions from 7- meters depth. Fluorescence measurements from the CTD showed low plankton activity. Figure 1. Transect showing dissolved oxygen and salinity from the Sound through the Baltic Proper to the Eastern Gotland Basin.

PARTICIPANTS Name From Anna-Kerstin Thell Chief Scientist SMHI Sara Johansson SMHI Johan Kronsell SMHI Kristin Andreasson SMHI APPENDICES - Track chart - Table over stations, sampled parameters and number of sampling depths - Map showing bottom oxygen concentrations - Vertical profiles for regular monitoring stations - Monthly average surface water plots for regular monitoring stations

F RR1 F9 RR RR7 BO3 F13 F1 F1 Sydostbrotten US Ulvödjupet US3 USB US7 MS MS F SR1A SR3 SR SS9 SR F Solovjeva F33 Grundkallen BY3 Tröskeln Ålands Hav LL1 BY7 LL17 LL1 BY /LL19 BY1 BY3/LL BY3 GF9 GF Blå Jungfrun Läsö ränna 9 Ålborg bugt L:a Middelgrund N1 Falkenberg Laholm-3 (YG) St Middelgrund RefM1V1 Kullen 9 Kattegatt SW BY39 Vågboj Knolls grund BY13 BY9 BY19 BY11 Hanöbukten Hanöbukten-KBV 1 Stevns klint BY3 Stolpe tröskel BY7 PL-P3 PL-P1

Date: 1-1- Time: 7: ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Ship: DA Year: 1 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Ser Cru Stat Proj Stat Lat Lon Start Start Bottom Secchi Wind Air Air WCWI CZPP No No T T S S P D D H P P N N N A N A S H C C no no code name date time depth depth dir vel temp pres elac hohp de btl e e a a h o o h t t t t m t l i u o o yyyymmdd hhmm m m C hpa aove loy m m l l x x s o o r r r o o k o m m m tueo apt p p t t y y s t i a z n t y 3 u n n hdsb o - s t t p b c b c b c s t t t t t t i v s l d l d l d i a s m i p t 91 9 KAEX9 BAS... ANHOLT E.13 1. 19 13 17. 17 113 x--- 1 - x - x - x x - x - x x x x - - x - x - 9 9 SOCX39 BAS... W LANDSKRONA. 1. 193 11 1. 1 999 x--- 9 - x - x - x x - x - x x x x - - x - x - 93 9 BPSA BAS... BY1 1.1 1317.9 193 73 7 9 1. 1 13 x--- - x - x - x x - x - x x x x - - x - x - 9 9 BPSA3 BAS... BY ARKONA.1 1. 193 1 1.7 13 113 x--- - x - x - x x - x - x x x x - - x - x - 9 9 BPSA BAS... W HAMMER ODDE 1. 13.13 193 13 1 17.9 13 73 ---- - x - x - - x - - - - - - - - - - - x - 9 9 BPSB BAS... BY CHRISTIANSÖ. 119. 193 1 9 7 1.1 1 13 x--- 1 - x - x - x x x x - x x x x - - x - - x 97 9 BPSB7 BAS... BY BORNHOLMSDJ 1.1 19.1 193 191 7 17. 11 999 x--- 1 - x - x - x x x x - x x x x - - x - x - 9 9 BPSE11 BAS... BCS III-1 33.1 1. 19 9 7 1. 11 133 x--- 1 - x - x - x x x x - x x x x - - x - x - 99 9 BPEX13 BAS... BY1 3.1 193.1 19 11 139 1.7 11 113 x--- 1 - x - x - x x x x - x x x x - - x - x x 9 9 BPEX1 BAS... BY1 GOTLANDSDJ 71.71.1 19 1 3 1 1. 11 73 x--- - x - x - x x x x - x x x x - - x - x - 91 9 BPEX BAS... BY FÅRÖDJ 79.91 19.9 19 19 3 17.7 11 999 x--- 17 - x - x - x x x x - x x x x - - x - - - 9 9 BPWX3 BAS... BY3 NORRKÖPINGSDJ 1.11 17. 19 199 3 17.7 11 13 x--- 17 - x - x - x x x x - x x x x - - x - x - 9 9 BPWX BAS... BY3 KARLSÖDJ 7.9 17.1 19 1 1 3 7 1. 1 113 x--- 1 - x - x - x x x x - - - x x - - - - x x 9 9 BPWK1 BAS... REF M1V1.31 11.1 19 1 3 1.3 1 999 x--- - x - x - x x - x - - - x x - - - - - x 9 9 BPSH BAS... HANÖBUKTEN 37. 1. 19 7 17.9 11 13 x--- 11 - x - x - x x x x - - - x x - - - - x x

Bottom water oxygen concentration (ml/l) Ship: Dana Date: 19-19 Series: 91-9 N 9 N N 7 N N N N 3.7.9 3.3 H S H S H S 1. 1.39 H S H S H S H S H S H S 3 1 1 3 ml/l 9 E 11 E 13 E 1 E 17 E 19 E 1 E 3 E E 7 E

STATION ANHOLT E SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 3 1 1 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1 1 1 O saturation % 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= m) 1 O ml/l 1 O ml/l 1 3 7 9 1 11 1 Month 19 199 199 1 1 Year

Vertical profiles ANHOLT E September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 3 3 3 1 1 1 3 1 PO mol/l 1 1 1 3 3 3.. 1. 1 1 1 3

STATION W LANDSKRONA SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 1 1 1 3 7 9 1 11 1 1 3 7 9 1 11 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= m) 1 O ml/l 1 O ml/l 1 3 7 9 1 11 1 Month 19 199 199 1 1 Year

Vertical profiles W LANDSKRONA September Mean 1-1 St.Dev. 1-9-3 Oxygen ml/l 1 1 1 3 3 3 1 1 1 3 1 PO mol/l 1 1 1 3 3 3.. 1. 1.. 1 1 1 3

STATION BY1 SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= m) 1 O ml/l 1 O ml/l 1 3 7 9 1 11 1 Month 19 199 199 1 1 Year

Vertical profiles BY1 September Mean 1-1 St.Dev. 1-9-3 Oxygen ml/l 1 1 1 1 1 1 3 3 3 3 3 3 1 1 1 1 1 PO mol/l 1 1 1 1 1 1 3 3 3 3 3 3.. 1. 1.. 1 1

STATION BY ARKONA SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= m) 1 O ml/l 1 O ml/l 1 3 7 9 1 11 1 Month 19 199 199 1 1 Year

Vertical profiles BY ARKONA September Mean 1-1 St.Dev. 1-9-3 Oxygen ml/l 1 1 1 1 1 1 3 3 3 3 3 3 1 1 1 1 1 PO mol/l 1 1 1 1 1 1 3 3 3 3 3 3.. 1. 1.. 1 1 3

STATION BY CHRISTIANSÖ SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= m) 1 O ml/l 1 3 7 9 1 11 1 Month 1 O ml/l 19 199 199 1 1 Year

Vertical profiles BY CHRISTIANSÖ September Mean 1-1 St.Dev. 1-9-3 Oxygen ml/l 1 1 1 3 3 3 7 7 7 1 1 1 1 1 PO mol/l 1 1 1 3 3 3 7 7 7 1 1 1

STATION BY BORNHOLMSDJ SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= m) 1 O ml/l 1 3 7 9 1 11 1 Month 1 O ml/l 19 199 199 1 1 Year

Vertical profiles BY BORNHOLMSDJ September Mean 1-1 St.Dev. 1-9-3 Oxygen ml/l 1 1 1 3 3 3 7 7 7 1 1 1 3 1 PO mol/l 1 1 1 3 3 3 7 7 7 1 1

STATION BCS III-1 SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= m) 1 O ml/l 1 3 7 9 1 11 1 Month O ml/l 19 199 199 1 1 Year

Vertical profiles BCS III-1 September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 3 3 3 7 7 7 1 1 1 1 PO mol/l 1 1 1 3 3 3 7 7 7 1 3 1 1 1 3

STATION BY1 SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= 1 m) 1 O ml/l 1 3 7 9 1 11 1 Month O ml/l 1 19 199 199 1 1 Year

Vertical profiles BY1 September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 1 1 1 1 1 1 1 PO mol/l 1 1 1 1 1 1 1 3 1 1

STATION BY1 GOTLANDSDJ SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= m) 1 O ml/l 1 3 7 9 1 11 1 Month O ml/l 1 19 199 199 1 1 Year

Vertical profiles BY1 GOTLANDSDJ September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 1 1 1 1 1 1 1 1 PO mol/l 1 1 1 1 1 1 1 3

STATION BY FÅRÖDJ SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= 17 m) 1 O ml/l 1 3 7 9 1 11 1 Month O ml/l 1 19 199 199 1 1 Year

Vertical profiles BY FÅRÖDJ September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 1 1 1 1 1 1 1 PO mol/l 1 1 1 1 1 1 1 1

STATION BY3 NORRKÖPINGSDJ SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= 17 m) O ml/l O ml/l 1 3 7 9 1 11 1 Month 19 199 199 1 1 Year

Vertical profiles BY3 NORRKÖPINGSDJ September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 1 1 1 1 1 1 1 PO mol/l 1 1 1 1 1 1 1 3 1 1

STATION BY3 KARLSÖDJ SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= 1 m) 1 O ml/l 1 O ml/l 1 3 7 9 1 11 1 Month 19 199 199 1 1 Year

Vertical profiles BY3 KARLSÖDJ September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 1 1 1 1 PO mol/l 1 1 1 1 3 1 1

STATION REF M1V1 SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 3 1. 1. 1. 1. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= 17 m) 1 O ml/l 1 O ml/l 1 3 7 9 1 11 1 Month 19 199 199 1 1 Year

Vertical profiles REF M1V1 September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 1 1 1 1 1 1 1 PO mol/l 1 1 1 1 1 1.. 1. 1 1 1

STATION HANÖBUKTEN SURFACE WATER (-1 m) 1 1 Annual Cycles Mean 1-1 St.Dev. 1 9 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 1. PO mol/l 1. 1 1. 1.. 1 3 7 9 1 11 1 1 3 7 9 1 11 1 3 1 O saturation % 1 1 1 1 7 1 3 7 9 1 11 1 1 3 7 9 1 11 1 OXYGEN IN BOTTOM WATER (depth >= 7 m) O ml/l 1 3 7 9 1 11 1 Month O ml/l 19 199 199 1 1 Year

Vertical profiles HANÖBUKTEN September Mean 1-1 St.Dev. 1-9- Oxygen ml/l 1 1 1 3 3 3 7 7 7 1 1 1 1 1 PO mol/l 1 1 1 3 3 3 7 7 7 1 1