Export of calcium carbonate corrosive waters from the East Siberian Sea
The Siberian shelf seas are areas of extensive biogeochemical transformation of organic matter, both of marine and terrestrial origin. This in combination with brine production from sea ice formation results in a cold bottom water of relative high salinity and partial pressure of carbon dioxide (pCO2). Data from the SWERUS-C3 expedition compiled on the icebreaker Oden in July to September 2014 show the distribution of such waters at the outer shelf, as well as their export into the deep central Arctic basins. Very high pCO2 water, up to ∼ 1000 µatm, was observed associated with high nutrients and low oxygen concentrations. Consequently, this water had low saturation state with respect to calcium carbonate down to less than 0.8 for calcite and 0.5 for aragonite. Waters undersaturated in aragonite were also observed in the surface in waters at equilibrium with atmospheric CO2; however, at these conditions the cause of under-saturation was low salinity from river runoff and/or sea ice melt. The calcium carbonate corrosive water was observed all along the continental margin and well out into the deep Makarov and Canada basins at a depth from about 50 m depth in the west to about 150 m in the east. These waters of low aragonite saturation state are traced in historic data to the Canada Basin and in the waters flowing out of the Arctic Ocean north of Greenland and in the western Fram Strait, thus potentially impacting the marine life in the North Atlantic Ocean.
Contrasting composition of terrigenous organic matter in the dissolved, particulate and sedimentary organic carbon pools on the outer East Siberian Arctic Shelf
Fluvial discharge and coastal erosion of the permafrost-dominated East Siberian Arctic delivers large quantities of terrigenous organic carbon (Terr-OC) to marine waters. The composition and fate of the remobilized Terr-OC needs to be better constrained as it impacts the potential for a climate–carbon feedback. In the present study, the bulk isotope (δ13C and Δ14C) and macromolecular (lignin-derived phenols) composition of the cross-shelf exported organic carbon (OC) in different marine pools is evaluated. For this purpose, as part of the SWERUS-C3 expedition (July–September 2014), sediment organic carbon (SOC) as well as water column (from surface and near-bottom seawater) dissolved organic carbon (DOC) and particulate organic carbon (POC) samples were collected along the outer shelves of the Kara Sea, Laptev Sea and East Siberian Sea. The results show that the Lena River and the DOC may have a preferential role in the transport of Terr-OC to the outer shelf. DOC concentrations (740–3600 µg L−1) were 1 order of magnitude higher than POC (20–360 µg L−1), with higher concentrations towards the Lena River plume. The δ13C signatures in the three carbon pools varied from −23.9 ± 1.9 ‰ in the SOC, −26.1 ± 1.2 ‰ in the DOC and −27.1 ± 1.9 ‰ in the POC. The Δ14C values ranged between −395 ± 83 (SOC), −226 ± 92 (DOC) and −113 ± 122 ‰ (POC). These stable and radiocarbon isotopes were also different between the Laptev Sea and the East Siberian Sea. Both DOC and POC showed a depleted and younger trend off the Lena River plume. Further, the Pacific inflow and the sea-ice coverage, which works as a barrier preventing the input of “young” DOC and POC, seem to have a strong influence in these carbon pools, presenting older and more enriched δ13C signatures under the sea-ice extent. Lignin phenols exhibited higher OC-normalized concentrations in the SOC (0.10–2.34 mg g−1 OC) and DOC (0.08–2.40 mg g−1 OC) than in the POC (0.03–1.14 mg g−1 OC). The good relationship between lignin and Δ14C signatures in the DOC suggests that a significant fraction of the outer-shelf DOC comes from “young” Terr-OC. By contrast, the slightly negative correlation between lignin phenols and Δ14C signatures in POC, with higher lignin concentrations in older POC from near-bottom waters, may reflect the off-shelf transport of OC from remobilized permafrost in the nepheloid layer. Syringyl ∕ vanillyl and cinnamyl ∕ vannillyl phenol ratios presented distinct clustering between DOC, POC and SOC, implying that those pools may be carrying different Terr-OC of partially different origin. Moreover, 3,5-dihydroxybenzoic acid to vanillyl phenol ratios and p-coumaric acid to ferulic acid ratios, used as a diagenetic indicators, enhanced in POC and SOC, suggesting more degradation within these pools. Overall, the key contrast between enhanced lignin yields both in the youngest DOC and the oldest POC samples reflects a significant decoupling of terrestrial OC sources and pathways.
Kvicksilver i kalkade och sura sjöar
Kalkning av sura sjöar minskar halterna av kvicksilver i fisk. I sura, okalkade sjöar är halterna högre men sjunker långsamt när vattnets pH återhämtar sig. När kalkningen upphör kan kvicksilverhalterna i insjöfisk öka igen. Det visar IKEU:s långa tidsserier för kvicksilver i abborre 1998-2015.
Provningsjämförelse / Proficiency Test 2016-3, Närsalter / NutrientsDownload
Provningsjämförelse / Proficiency Test 2016-2, Suspenderade ämnen / Suspended solids
Provningsjämförelse / Proficiency Test 2016-1, Metaller och spårämnen / Metals and Trace Elements
Provningsjämförelse/Proficiency Test 2015-4, Kommunalt och Skogsindustriellt avlopp/Municipal and Paper industry wastewater
Provningsjämförelse/Proficiency Test 2015-5, Jonbalans + Klorofyll/Ion Balance + Chlorophyll
Carbon and nitrogen stable isotopes within the Swedish national monitoring of contaminants in marine biota
This report gives an overview of spatial variation in carbon (δ13C) and nitrogen (δ15N) stable isotopes in different fish species in the Baltic Sea. The study also tries to investigate if differences in contaminants between sites and among species can be partly explained by nitrogen stable isotopes. Moreover, as a first attempt to understand the spatial trends in terms of biogeochemistry we look at the relationship between stable isotopes in fish and salinity as well as between stable isotopes and the ratio of total nitrogen to total phosphorus.
The results in this study shows that there were some clear difference between the Baltic Proper and the West Coast for cod, eelpout, and herring in δ15N and the results also showed clear spatial variations in δ13C with more negative values in the most northern parts of the Baltic Sea. In addition, different clusters of herring was seen, which coincided with the different regions in the Baltic – Bothnian Bay, Bothnian Sea and Baltic Proper. The observed geographical patterns in stable isotope ratios indicate that regional processes set the foodweb baseline of δ13C and δ15N.
Significant differences in the concentration of CB-153 between herring and cod disappeared when the the two species were adjusted for δ15N. The data in this report is limited to one year. Additional data will tell if stable isotopes can be confidently used as an important co-variable that can explain some of the between-year variation in contaminant concentrations, hence making samples among stations and species more comparable and increase the statistical power to detect trends and geographical differences.