Increased barium levels in recent marine sediments from the Norwegian and Barents Seas suggest impact of hydrocarbon drilling and production

Barium (Ba) in recent marine sediments can originate from natural and anthropogenic sources including discharges from the oil and gas industry. In this study, we use data from the Norwegian and Barents Seas to assess whether Ba in recent marine sediments has increased due to these discharges. To account for Ba in detrital material, we normalise all samples with respect to aluminosilicate by calculating an enrichment factor. We use statistical modelling to control for parameters related to sedimentation. We present results that suggest increased Ba levels in recent sediments that coincide with the timing of hydrocarbon drilling and production. This is supported by geographical differences on a large scale that relate to proximity to hydrocarbon drilling and production. Among 243 sampling stations, we identify 73 locations exhibiting enrichment of Ba in the upper 6 of sediment. At these locations, Ba is 1.55 to 3.55 times higher than the levels that can be expected from the shale average when Ba in detrital matter is accounted for. Excess Ba is reported in sediment surface samples in areas important to fisheries like the Lofoten area and the western Barents Sea.publishedVersio

Radioactive substances in Norwegian farmed Atlantic salmon (Salmo salar)

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Distribution of natural and anthropogenic radionuclides in sediments from the Vefsnfjord, Norway

Areas in central Norway were heavily contaminated with fallout from the Chernobyl accident in 1986. In this study, we assess 137Cs in surface sediments and sediment cores collected in the Vefsnfjord in Nordland county. Concentrations of 137Cs in surface sediments ranged from 159 to 191 Bq kg−1 dry weight (d.w.). Sub-surface peaks of 137Cs were observed in all cores, with a maximum concentration of 432 Bq kg−1 d.w. Given that little is known about the distribution of naturally occurring radionuclides in Norwegian fjords and coastal areas, a better understanding of the total burden of radioactivity is important for the Norwegian fishing and aquaculture industries. Therefore, analyses of the natural radionuclides 40K, 226Ra, 228Ra and 210Pb were included in the study. Analyses of total sulphur (TS), total carbon (TC), total organic carbon (TOC) and grain size distribution have been performed to provide a sedimentologic context for interpreting the radionuclide results.publishedVersio

Kvikksølvinnhold i fisk og annen sjømat ved vraket av U-864 vest av Fedje

Denne rapporten viser resultater fra overvåkningen for Kystverket i 2016 av kvikksølv i sjømat ved ubåtvraket U-864 vest av Fedje. Vi analyserte prøver av brosme, taskekrabbe, lange, torsk, lyr, lusuer, sei, skjellbrosme, hågjel, svarthå, havmus, trollkrabbe og blyantkråkebolle. Femten av 92 brosmer hadde kvikksølvnivå over grenseverdien for mattrygghet, alle relativt stor fisk. Kvikksølvnivået i brosme var likevel ikke høyere enn bakgrunnsnivå for kysten av Vestlandet. Annen fisk og klokjøtt av krabbe hadde kvikksølvnivåer under gjeldende grenseverdier. Kvikksølvnivået i brunmat av taskekrabbe prøvetatt ved vraket av U-864 var noe forhøyet (ingen grenseverdi). Også trollkrabbe hadde relativt høye kvikksølvnivåer i hepatopankreas (fordøyelseskjertelen). Krabbe får trolig i seg metallisk kvikksølv fra det forurensede sedimentet som ikke akkumuleres i klokjøtt. Ingen av resultatene fra prøvetakingen i 2016 tyder på at arbeidet i juni med etablering av en støttefylling medførte økning i innholdet av kvikksølv i organismene.publishedVersio

North Sea Ecosystem Cruise Report_JH2022206

The North Sea Ecosystem cruise (NSEC) is a multi-purpose survey established to monitor distribution and interactions of several components that constitute the lower trophic levels of the pelagic food web including phytoplankton, zooplankton, fish eggs and fish larvae. The cruise is managed by the IMR projects Monitoring of climate and plankton in the North Sea Skagerrak (IMR 14920) and Early life history dynamics of North Sea Fishes (IMR 14917). The cruise provides horizontal and vertical distributions of physical and chemical oceanographic parameters and phytoplankton, zooplankton fish eggs and larvae community composition and structure in the northern North Sea and Skagerrak. Since 2020 the IMR plankton survey was expanded by adding the monitoring of an additional trophic level, microzooplankton. The survey area of the North Sea Ecosystem cruise 2021 covered the northern North Sea and the Skagerrak (57-60.8ºN, 2.2ºW- 8.6ºE). Sampling were made at pre-selected stations along the IMR standard hydrographic transects.North Sea Ecosystem Cruise Report_JH2022206publishedVersio

Inferring ecological separation from regional differences in radioactive caesium in harbour porpoises Phocoena phocoena

Geographic variation in the level of radioactive caesium-137 (Cs-137) was examined from the axial muscle of 36 harbour porpoises Phocoena phocoena obtained as bycatch from 5 locations along the coast of Norway, ranging from southern (North Sea) to northern (Barents Sea) Norway. Levels of Cs-137 in seawater and sediments have been found to differ along the coast of Norway due to distance from point sources, such as the Sellafield nuclear fuel reprocessing plant in Cumbria, UK (discharging into the Irish Sea) and outflow from the Baltic Sea, which contains significant amounts Of Cs-137 that originated in Chernobyl. Radioactive caesium is accumulated in muscle in a manner related to ambient levels in the environment through exposure and/or ingestion of contaminated prey items. Hence, we hypothesised that if harbour porpoises are philopatric, their muscle tissue would reflect concentrations Of Cs-137 in their area of residence. The levels found in harbour porpoise muscle were consistent with that found in the area from which they were caught. Porpoises from the Barents Sea had significantly lower levels of Cs-137 than porpoises from the west and south coasts of Norway, reflecting the concentration patterns of Cs-137 in the waters of those areas. This suggests ecological separation of harbour porpoises in these regions, and that porpoises are limited in their movements along the coast of Norway

Understanding source terms of anthropogenic uranium in the Arctic Ocean – First 236U and 233U dataset in Barents Sea sediments

This work reports the first dataset of 236U and 233U in sediment cores taken from the Barents Sea, with the aim to better understand the source terms of anthropogenic uranium in the Arctic region. Concentrations of 236U and 233U along with 137Cs, and 233U/236U atomic ratio were measured in six sediment profiles. The cumulative areal inventories of 236U and 233U obtained in this work are (3.50–12.7) × 1011 atom/m2 and (4.92–21.2) × 109 atom/m2, with averages values of (8.08 ± 2.93) × 1011 atom/m2 and (1.08 ± 0.56) × 1010 atom/m2, respectively. The total quantities of 236U and 233U deposited in the Barents Sea bottom sediments were estimated to be 507 ± 184 g and 7 ± 3 g, respectively, which are negligible compared to the total direct deposition of 236U (6000 g) and 233U (40–90 g) from global fallout in the Barents Sea. The integrated atomic ratios of 233U/236U ranging in (0.98–1.57) × 10−2 reflect the predominant global fallout signal of 236U in the Barents Sea sediments and the highest reactor-236U contribution accounts for 30 ± 14 % among the six sediment cores. The reactor-236U input in the Barents Sea sediments is most likely transported from the European reprocessing plants rather than related to any local radioactive contamination. These results provide better understanding on the source term of anthropogenic 236U in the Barents Sea, prompt the oceanic tracer application of 236U for studying the dynamics of the Atlantic-Arctic Ocean and associated climate changes. The 236U-233U benchmarked age-depth profiles seem to match reasonably well with the reported input function history of radioactive contamination in the Barents Sea, indicating the high potential of anthropogenic 236U-233U pair as a useful tool for sediment dating

Understanding source terms of anthropogenic uranium in the Arctic Ocean – First ²³⁶U and ²³³U dataset in Barents Sea sediments

This work reports the first dataset of 236U and 233U in sediment cores taken from the Barents Sea, with the aim to better understand the source terms of anthropogenic uranium in the Arctic region. Concentrations of 236U and 233U along with 137Cs, and 233U/236U atomic ratio were measured in six sediment profiles. The cumulative areal inventories of 236U and 233U obtained in this work are (3.50–12.7) × 1011 atom/m2 and (4.92–21.2) × 109 atom/m2, with averages values of (8.08 ± 2.93) × 1011 atom/m2 and (1.08 ± 0.56) × 1010 atom/m2, respectively. The total quantities of 236U and 233U deposited in the Barents Sea bottom sediments were estimated to be 507 ± 184 g and 7 ± 3 g, respectively, which are negligible compared to the total direct deposition of 236U (6000 g) and 233U (40–90 g) from global fallout in the Barents Sea. The integrated atomic ratios of 233U/236U ranging in (0.98–1.57) × 10−2 reflect the predominant global fallout signal of 236U in the Barents Sea sediments and the highest reactor-236U contribution accounts for 30 ± 14 % among the six sediment cores. The reactor-236U input in the Barents Sea sediments is most likely transported from the European reprocessing plants rather than related to any local radioactive contamination. These results provide better understanding on the source term of anthropogenic 236U in the Barents Sea, prompt the oceanic tracer application of 236U for studying the dynamics of the Atlantic-Arctic Ocean and associated climate changes. The 236U-233U benchmarked age-depth profiles seem to match reasonably well with the reported input function history of radioactive contamination in the Barents Sea, indicating the high potential of anthropogenic 236U-233U pair as a useful tool for sediment dating.publishedVersio

A Framework for Communicating Qualities of Indicators

There is a growing focus on ecosystem-based indicators and what qualities they need to satisfy. However, the qualities and the characteristics of the already existing indicators vary substantially. Due to both scientific and societal aspects, so will the future indicators. With a growing interest for participatory decision processes it is crucial that scientific advice or knowledge based on these indicators is transparent. Advice should therefore be presented in such a way that a manager or a citizen is able to judge the rigidity and the relevance of the scientific information. This will also improve the communication of uncertainty. A common framework for presenting indicators could clarify such aspects by addressing qualities associated with the scientific knowledge and societal concerns. Some relevant qualities are how well an indicator is able to detect a manmade change, the rigidity of the scientific knowledge, how well an indicator threshold reflects a danger, how useful an indicator is for decision-making and the characteristics of the uncertainty. In this paper we discuss what features should be addressed in the communication of scientific knowledge and how this can be communicated through a general framework. The framework and the discussion of its content will be illustrated by case studies on measured technetium-99 levels in lobster and on Ecological Quality Objectives (EcoQOs) for commercial fish stocks and harbor porpoise by-catch