Anne L. Soerensen
Water column profiles of mercury (Hg) and methylmercury (MeHg). The dataset includes observations on Total Hg, Hgᴵᴵ, Hg⁰, MeHg and other chemical compounds and physical properties in the Baltic Sea and Kattegat. Data was collected during six cruises in the Baltic Sea - three in the southern Baltic Sea and Kattegat with SMHI onboard the R/V Aranda (Sep 2014, July 2015, July 2016), three in the northern Baltic Sea with Umeå Science Centre onboard the Swedish Coast Guard's ship Kustbevakning (Sep 2014, Aug 2015, Aug 2016). Data are from water samples collected during the cruises. The data provides a baseline for total Hg and speciated Hg in summer and early fall in the Baltic Sea.
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Citation
Anne L. Soerensen (2018) Baltic Sea water column mercury profiles 2014–2016. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/soerensen-2018-mercury-1
References
Soerensen, A.L., A.T. Schartup, A. Skrobonja, S. Bouchet, D. Amouroux, V. Liem-Nguyen, E. Björn (2018), Deciphering the role of water column redoxclines on methylmercury cycling using speciation modeling and observations from the Baltic Sea, Global Biogeochemical Cycles, https://doi.org/10.1029/2018GB005942
Soerensen, A.L., A. Schartup, A. Skrobonja, E. Björn (2017). Organic matter drives high interannual variability in methylmercury concentrations in a subarctic coastal sea, Environmental Pollution 229, 531-538, https://doi.org/10.1016/j.envpol.2017.06.008
Soerensen, A.L., A. Schartup, E. Gustafsson, B. G. Gustafsson, E. Undeman, E. Björn (2016), Eutrophication increases phytoplankton methylmercury concentrations in a coastal sea – a Baltic Sea case study, Environmental Science and Technology 50(21), 11787-11796, https://doi.org/10.1021/acs.est.6b02717
Data description
The dataset is included in one xlsx file having the following data columns: Cruise, Year, Station, Depth [m], Latitude [Degrees], Longitude [Degrees], THg [pM], Hgᴵᴵ [pM], Hg⁰ [pM], MeHg [fM], MeHgdissolved [fM], MeHg/THg [%], Hg⁰/THg [%], km [/d], kd [/d], kdphoto [/d], kdphoto [m²/E], Turbidity, Temperature [℃], Salinity, Oxygen [mL/L], Oxygen [% saturation], H₂S [µM], pH, PO₄ [µM], Total P [µM], NO₂ [µM], NO₃ [µM], NH₄ [µM], Total N [µM], SiO₃ [µM], Chlorophyl A [µg/L]. For ancillary data numbers in italic are averages of measurements at depths above and below the given depth. When mercury observations are below level of detection (LOD), LOD x 0.5 is given. The data represent water profiles taken from the ship during the cruises. THg: total Hg (Hgᴵᴵ+Hg⁰+MeHg), Hgᴵᴵ: inorganic divalent Hg, Hg⁰: elemental gaseous Hg, MeHg: methyl-Hg. Dimethyl-Hg was measured in July 2016 but was always below detection limit (2 fM).
Comments
Methylmercury (MeHg) is a neurotoxin and the only mercury (Hg) species that biomagnifies in aquatic biota. Hg is classified as a contaminant of major health concern by WHO and is a leading toxin in the Baltic Sea food web. In the Baltic Sea monitoring efforts have focused on measuring total Hg concentrations. However, there is no direct relationship between total Hg load to the system and MeHg levels in biota. This disconnect suggests that other important processes control the variability of MeHg formation, bioaccumulation and biomagnification in the Baltic Sea. In this project we have used a combination of field work and laboratory and modelling studies to improve our understanding of the impact of eutrophication and climate change on mercury concentrations in the Baltic Sea water column and food web.
Ancillary data (all physical and chemical parameters other than mercury) are compiled from data available online at the Swedish Meteorological and Hydrological Institute.