Water type quantification in the Skagerrak, the Kattegat and off the Jutland west coast

SummaryAn extensive data series of salinity, nutrients and coloured dissolved organic material (CDOM) was collected in the Skagerrak, the northern part of the Kattegat and off the Jutland west coast in April each year during the period 1996–2000, by the Institute of Marine Research in Norway. In this month, after the spring bloom, German Bight Water differs from its surrounding waters by a higher nitrate content and higher nitrate/phosphate and nitrate/silicate ratios. The spreading of this water type into the Skagerrak is of special interest with regard to toxic algal blooms. The quantification of the spatial distributions of the different water types required the development of a new algorithm for the area containing the Norwegian Coastal Current, while an earlier Danish algorithm was applied for the rest of the area. From the upper 50m a total of 2227 observations of salinity and CDOM content have been used to calculate the mean concentration of water from the German Bight, the North Sea (Atlantic water), the Baltic Sea and Norwegian rivers. The Atlantic Water was the dominant water type, with a mean concentration of 79%, German Bight Water constituted 11%, Baltic Water 8%, and Norwegian River Water 2%. At the surface the mean percentages of these water types were found to be 68%, 15%, 15%, and 3%, respectively. Within the northern part of the Skagerrak, closer to the Norwegian coast, the surface waters were estimated to consist of 74% Atlantic Water, 20% Baltic Water, and 7% Norwegian River Water. The analysis indicates that the content of German Bight Water in this part is less than 5%

Release of artificially reared 0-group coastal cod (Gadus morhua L.) in a landlocked fjord in western Norway

In 1983 and 1984 about 14 000 seven month old pond or basin reared coastal cod were tagged and released in Heimarkspollen and Osen in Western Norway. In May 1984 fishing in the release areas was initiated and local fishermen were asked to report recaptures. Growth of released cod was at least as good as growth of wild cod in the area. The 1983 release contributed about 30% of this yearclass in Osen and about 50% in Heimarkspollen. The 1984 release contributed about 80% of this yearclass in Heimarkspollen. There seems to be no difference in food preference between released and wild cod. The reared cod are very stationary

Declining size-at-harvest in Norwegian salmon aquaculture: Lice, disease, and the role of stunboats

Sea cages used for fish farming are typically open to the environment, making the grow-out phase a race against the accumulation of infections. In Norway, farmed Atlantic salmon (Salmo salar) suffer outbreaks of salmon lice (Lepeophtheirus salmonis), which by law must be managed, and comorbid infections that weaken salmon and increase the risk of mortality following delousing treatments. To understand the role of louse management on size-at-harvest, we analysed monthly data from 1054 salmon farms over a 10-year period. Mean weight at harvest declined 6.6% (−310 g) from 2012 to 2021, with the smallest size-at-harvest occurring in months when delousing treatments were reported. In 2021, size-at-harvest was 3.4% smaller during treatment vs. non-treatment months. There is a pattern of increasing responsiveness to louse outbreaks over time, with delousing treatments preferred for small fish and harvesting preferred for large fish. There are also several lines of evidence suggesting that potential post-treatment mortalities are sometimes diverted to harvest statistics. Treatments tend to lead to higher relative mortality in the following month, except when a harvest was also reported during the treatment month. Stunboats are harvesting vessels equipped with stunning, bleeding and chilling systems, and anecdotally, are preferred for ‘emergency’ harvests. We found that stunboat visits were disproportionately associated with harvests of small fish during 2018–2021. Moreover, stunboats often visited during treatment months without any harvest being reported, consistent with accounts of stunboats standing by during risky operations to salvage moribund fish if necessary. Because harvests and mortalities are reported monthly, it is not clear how often harvests during treatment months reflect (i) harvesting of vulnerable fish as an alternative to treating, or (ii) risky treatments that produce moribund fish. However, if the latter is common, mortality statistics will underestimate the health and welfare risks of delousing treatments.publishedVersio

Matrix metalloproteinase-9 mediated shedding of syndecan-4 in glomerular endothelial cells

Background - Diabetic nephropathy is the most common cause of end‐stage renal failure in the western world and Asia. The mechanisms are not fully elucidated, but disruption of glomerular endothelial glycocalyx and shedding of its components including syndecans has been implicated. Aims - We hypothesize that reduced glomerular filtration in diabetes is caused by disruption of endothelial glycocalyx in glomeruli, including increased shedding of syndecan‐4. The aim of this study was to determine the effects of experimental diabetic conditions by means of hyperglycemia and IL‐1β exposure on syndecan‐4 shedding in GEnC, and to investigate regulation of shedding by sheddases. Results - We found that in GEnC the expression of syndecan‐4 is higher than that of the other syndecans. In polarized GEnC, apical shedding of syndecan‐4 and syndecan‐4 gene expression was increased by 60% after IL‐1β‐stimulation, but not affected by hyperglycemic conditions. This was accompanied by a 50% increase in MMP9 gene expression in IL‐1β‐stimulated cells but not hyperglycemia. MMP9 knockdown reduced syndecan‐4 shedding by 50%. Conclusion - IL‐1β but not hyperglycemia increases the shedding of syndecan‐4 from GEnC in an MMP9‐dependent manner. This provides a potential mechanism of GEnC damage in diabetes and other inflammatory conditions

Modeled Buoyancy of eggs and larvae of the deep-sea shrimp Aristeus antennatus (Crustacea: Decapoda) in the northwestern Mediterranean Sea

Information on the buoyancy of eggs and larvae from deep-sea species is rare but necessary for 30 explaining the position of non-swimming larvae in the water column. Due to embryonic 31 morphology and ecology diversities, egg buoyancy has important variations within one species and 32 among other ones. Nevertheless, it has hardly been explored if this buoyancy variability can be a 33 strategy for deep-sea larvae to optimize their transport beyond their spawning areas. In the 34 northwestern Mediterranean Sea, protozoea and mysis larvae of the commercial deep-sea shrimp 35 Aristeus antennatus were recently found in upper layers, but to present, earlier stages like eggs and 36 nauplii have not been collected. Using a Lagrangian transport model and larval characteristics, we 37 evaluate the buoyancy and hydrodynamic effects on the transport of A. antennatus larvae in the 38 northwestern Mediterranean Sea. The transport models suggested that 75% of buoyant eggs 39 released between 500 and 800 m depth (i.e., known spawning area), reached the upper water layers 40 (0-75 m depth). Then, according to the modeled larval drifts, three spawning regions were defined 41 in the studied area: 1) the northern part, along a continental margin crossed by large submarine 42 canyons; 2) the central part, with two circular circulation structures (i.e., eddies); and 3) the 43 southern part, with currents flowing through a channel. The number of larvae in the most upper 44 layer (0-5 m depth) was higher if the larval transport model accounted for the ascent of eggs and 45 nauplii (81%) instead of eggs reaching the surface before hatching (50%). The larvae reaching the 46 most water upper layer (0-5 m depth) had higher rates of dispersal than the ones transported below 47 the surface layer (deeper than 5 m depth). The results of larval dispersal simulations have 48 implications for the understanding of A. antennatus larval ecology and for management decisions 49 related to the shrimp fisheries in the northwestern Mediterranean S

Matrix metalloproteinase-9 mediated shedding of syndecan-4 in glomerular endothelial cells

Background - Diabetic nephropathy is the most common cause of end‐stage renal failure in the western world and Asia. The mechanisms are not fully elucidated, but disruption of glomerular endothelial glycocalyx and shedding of its components including syndecans has been implicated. Aims - We hypothesize that reduced glomerular filtration in diabetes is caused by disruption of endothelial glycocalyx in glomeruli, including increased shedding of syndecan‐4. The aim of this study was to determine the effects of experimental diabetic conditions by means of hyperglycemia and IL‐1β exposure on syndecan‐4 shedding in GEnC, and to investigate regulation of shedding by sheddases. Results - We found that in GEnC the expression of syndecan‐4 is higher than that of the other syndecans. In polarized GEnC, apical shedding of syndecan‐4 and syndecan‐4 gene expression was increased by 60% after IL‐1β‐stimulation, but not affected by hyperglycemic conditions. This was accompanied by a 50% increase in MMP9 gene expression in IL‐1β‐stimulated cells but not hyperglycemia. MMP9 knockdown reduced syndecan‐4 shedding by 50%. Conclusion - IL‐1β but not hyperglycemia increases the shedding of syndecan‐4 from GEnC in an MMP9‐dependent manner. This provides a potential mechanism of GEnC damage in diabetes and other inflammatory conditions

Carbon export is facilitated by sea urchins transforming kelp detritus

With the increasing imperative for societies to act to curb climate change by increasing carbon stores and sinks, it has become critical to understand how organic carbon is produced, released, transformed, transported, and sequestered within and across ecosystems. In freshwater and open-ocean systems, shredders play a significant and well-known role in transforming and mobilizing carbon, but their role in the carbon cycle of coastal ecosystems is largely unknown. Marine plants such as kelps produce vast amounts of detritus, which can be captured and consumed by shedders as it traverses the seafloor. We measured capture and consumption rates of kelp detritus by sea urchins across four sampling periods and over a range of kelp detritus production rates and sea urchin densities, in northern Norway. When sea urchin densities exceeded 4 m−2, the sea urchins captured and consumed a high percentage (ca. 80%) of kelp detritus on shallow reefs. We calculated that between 1.3 and 10.8 kg of kelp m−2 are shredded annually from these reefs. We used a hydrodynamic dispersal model to show that transformation of kelp blades to sea urchin feces increased its export distance fourfold. Our findings show that sea urchins can accelerate and extend the export of carbon to neighboring areas. This collector–shredder pathway could represent a significant flow of small particulate carbon from kelp forests to deep-sea areas, where it can subsidize benthic communities or contribute to the global carbon sink

Possible future scenarios for two major Arctic Gateways connecting Subarctic and Arctic marine systems: I. Climate and physical-chemical oceanography

We review recent trends and projected future physical and chemical changes under climate change in transition zones between Arctic and Subarctic regions with a focus on the two major inflow gateways to the Arctic, one in the Pacific (i.e. Bering Sea, Bering Strait, and the Chukchi Sea) and the other in the Atlantic (i.e. Fram Strait and the Barents Sea). Sea-ice coverage in the gateways has been disappearing during the last few decades. Projected higher air and sea temperatures in these gateways in the future will further reduce sea ice, and cause its later formation and earlier retreat. An intensification of the hydrological cycle will result in less snow, more rain, and increased river runoff. Ocean temperatures are projected to increase, leading to higher heat fluxes through the gateways. Increased upwelling at the Arctic continental shelf is expected as sea ice retreats. The pH of the water will decline as more atmospheric CO2 is absorbed. Long-term surface nutrient levels in the gateways will likely decrease due to increased stratification and reduced vertical mixing. Some effects of these environmental changes on humans in Arctic coastal communities are also presented.publishedVersio

ØKOKYST Subprogram Nordsjøen Nord, Annual Report 2018

Prosjektleder Trine DaleI ØKOKYST-delprogram Nordsjøen Nord ble deler av grunnprogrammet gjennomført i 2018. Prøvetakningen inkluderte 8 pelagiske stasjoner, 6 hardbunnstasjoner og 5 bløtbunnstasjoner, hvorav 2 pelagiske, 2 hardbunns og 1 bløtbunnstasjon var tilleggsundersøkelser (opsjoner). En stasjon fra Ferrybox er også inkludert i 2018-programmet. Det inngår 12 vannforekomster i delprogram Nordsjøen Nord, og 11 av disse ble prøvetatt i 2018. Tilstanden varierte fra «Dårlig» til «Meget god» i 2018. Vannforekomsten Maurangsfjorden fikk tilstand «Dårlig», og redusert tilstand var knyttet til kvalitetselementet makroalger. Vannforekomsten Aurlandsfjorden fikk tilstand «Moderat». Her var redusert tilstand knyttet til kvalitetselementet klorofyll-a. 5 av vannforekomstene fikk «God» tilstand, mens de resterende 4 fikk tilstand «Meget god».MiljødirektoratetpublishedVersio

Klimapåvirkning på viktige kystvannsarter

Vi beskriver statistisk nedskalering av det marine fysisk-biologiske klimaet for norskekysten under tre klimagassutslippscenarioer (SSP1-2.6, SSP2-4.5, SSP5-8.5). Resultatene inngår i beregningene for fremtidig habitatskvalitet for fem utvalgte marine arter langs norskekysten: kysttorsk, kongekrabbe, Atlantisk laks, stortare og drøbakkråkebolle. Resultatene indikerer at kongekrabbe vil hovedsakelig finnes i Nord-Norge, men habitatkvalitet vil synke frem til 2100. Kysttorsk vil kunne finnes langs hele norskekysten frem mot år 2100, men en nedgang i habitatkvalitet forventes uavhengig av klimascenario. For Atlantisk laks vil økte havtemperaturer gi redusert habitatskvalitet, men uavhengig av klimascenario vil kystsonen forbli egnet habitat. Habitatskvaliteten for stortare forventes å holde seg stabil i sørlige kystområder og øke i nordlige områder, men med en sterkere økning i temperatur mot slutten av århundret kan vi forvente nedgang eller lokal utryddelse i Sør-Norge avhengig av scenario. Habitatet for drøbakkråkebolle vil holde seg stabilt under utslippsscenarioene SSP1-2.6 og SSP2-4.5, men under SSP5-8.5 vil forsuring føre til sterk reduksjon i utbredelse. Disse resultatene kan gi forvaltningen bedre innsyn i hvordan kystsonen vil påvirkes forskjellig fra de åpne havområdene. En mer helhetlig tilnærming til forvaltning av kystsonen og havområdene vil kunne gi bedre mulighet til å fange opp endringer som skyldes klima og innføre tiltak som kan begrense den negative effekten av klimaendringer. Dette kan inkludere bærekraftig fiskeriforvaltning og opprettelse av marine verneområder.publishedVersionpublishedVersio