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Baleen from mysticete whales is a well-preserved proteinaceous material that can be used to identify migrations and feeding habits for species whose migration pathways are unknown. Analysis of δ 13 C and δ 15 N values from bulk baleen have been used to infer migration patterns for individuals. However, this approach has fallen short of identifying migrations between regions as it is difficult to determine variations in isotopic shifts without temporal sampling of prey items. Here, we apply analysis of δ 15 N values of amino acids to five baleen plates belonging to three species, revealing novel insights on trophic position, metabolic state and migration between regions. Humpback and minke whales had higher reconstructed trophic levels than fin whales (3.7–3.8 versus 3–3.2, respectively) as expected due to different feeding specialization. Isotopic niche areas between baleen minima and maxima were well separated, indicating regional resource use for individuals during migration that aligned with isotopic gradients in Atlantic Ocean particulate organic matter. Phenylanine δ 15 N values confirmed regional separation between the niche areas for two fin whales as migrations occurred and elevated glycine and threonine δ 15 N values suggested physiological changes due to fasting. Simultaneous resolution of trophic level and physiological changes allow for identification of regional migrations in mysticetes.

Continental shelves are a major source of iron (Fe) and manganese (Mn) to marine waters. Here, we investigate controls on benthic release of Fe and Mn and the impact on the water column in the Baltic Sea. We find high in situ benthic release rates of dissolved Fe and Mn at seasonally hypoxic sites (bottom water oxygen between 0–63 μmol L−1) receiving high inputs of organic matter. We find that benthic Fe and Mn release is sensitive to bottom water oxygen concentrations. Benthic Fe release is likely additionally controlled by Fe–sulfur redox chemistry in the surface sediment. For Mn, benthic release correlates positively with Mn oxide availability in the surface sediment. Benthic release contributes to high dissolved Fe and Mn concentrations in the water column and is amplified by repeated cycling of Fe and Mn between the sediment and overlying water through benthic release, oxidation in the water column, deposition as metal oxides, followed by reductive dissolution. Most water column Fe (∼ 80%) is present in particulate form near the seafloor. In contrast to Fe, a large percentage of the Mn remains dissolved (∼ 50%). We show that easily reducible Fe and Mn oxides are key forms of particulate Fe and Mn in suspended matter. The Baltic Sea represents a highly eutrophic, low oxygen end‐member when compared to other modern coastal systems. Our results imply that, upon continued eutrophication and deoxygenation of the coastal ocean, benthic release of dissolved Fe and Mn from continental shelves could become greater than previously thought.

[Image: see text] Oxygen depletion in coastal waters may lead to release of toxic sulfide from sediments. Cable bacteria can limit sulfide release by promoting iron oxide formation in sediments. Currently, it is unknown how widespread this phenomenon is. Here, we assess the abundance, activity, and biogeochemical impact of cable bacteria at 12 Baltic Sea sites. Cable bacteria were mostly absent in sediments overlain by anoxic and sulfidic bottom waters, emphasizing their dependence on oxygen or nitrate as electron acceptors. At sites that were temporarily reoxygenated, cable bacterial densities were low. At seasonally hypoxic sites, cable bacterial densities correlated linearly with the supply of sulfide. The highest densities were observed at Gulf of Finland sites with high rates of sulfate reduction. Microelectrode profiles of sulfide, oxygen, and pH indicated low or no in situ cable bacteria activity at all sites. Reactivation occurred within 5 days upon incubation of an intact sediment core from the Gulf of Finland with aerated overlying water. We found no relationship between cable bacterial densities and macrofaunal abundances, salinity, or sediment organic carbon. Our geochemical data suggest that cable bacteria promote conversion of iron monosulfides to iron oxides in the Gulf of Finland in spring, possibly explaining why bottom waters in this highly eutrophic region rarely contain sulfide in summer.

To monitor flat oyster reef restoration projects in offshore pilots innovative techniques with a focus on remote monitoring are needed. This will reduce the frequency with which offshore pilot study locations have to be visited. The valve gape monitor can potentially be used as an effective method to monitor survival and behaviour of the European flat oyster Ostrea edulis. This is an in situ device that continuously measures the opening and closing of the shell of live bivalves (valves) equipped with sensors. It has been successfully used in combination with other bivalve species. In this study, eight oysters Ostrea edulis from two different regions (Norway and the Netherlands (Grevelingen)) were fitted with valve gape sensors. Valve gape activity was monitored during different experimental conditions (tide simulation and starvation) under controlled conditions to test the applicability of the valve gape monitor to assist with monitoring of O. edulis reef restoration projects. No significant differences in valve gape activity of Norwegian oysters and oysters from the Grevelingen were detected under controlled conditions. Tide simulation did not appear to affect valve gape activity. However, the oysters were responsive to disturbances such as daily maintenance as well as starvation. Size frequency distribution of gape class clearly shows that fed individuals show longer periods of open valves and percentage closure is significantly higher in the starved oysters. Gape width is larger in fed conditions then in starved conditions. In addition, starved oysters open less wide when they open. These results indicate that food availability affects valve gape activity and the valve gape monitor can provide information on the behaviour and stress response of Ostrea edulis. In situ monitoring of flat oyster gape activity should incorporate environmental parameters such as Chl a, temperature, salinity, current speed and oxygen to provide insight into the environmental stressors on and/or the behavioural patterns of flat oysters.

Shallow coastal seas are subject to an increasing pressure by offshore operations. Further to a direct influence these operations impose on benthic and pelagic organisms, an indirect influence is caused by changes in sediment dynamics and morphodynamics. Temporal variations in SPM have a large effect on the timing and rate of primary production, thereby also affecting higher trophic levels. Field measurements along the Dutch coast indicate significant seasonal variations in concentrations of SPM (Suijlen and Duin, 2001; Witbaard et al., 2015). These seasonal variations originate from a marked seasonality in wind climate and the occurrence of storms. During storms, increases in SPM occur simultaneously in large parts of the Dutch coastal zone of the North Sea (Suijlen & Duin 2001), demonstrating that on short timescales, the vertical exchange between the sea bed and the water column is dominant. Model concepts with two discrete seabed layers (a fluffy top layer and a sandy lower layer) turned out to capture these fine sediment dynamics, see van Kessel et al. (2011). However, the underlying physical processes resulting in the water-bed exchange of fines are still to be unravelled. Therefore, this study aims to investigate the resuspension of fines from the bed during and after storms, accounting for the tidal variation due to the spring-neap tide cycle. This will lead to a more specific conceptualization and related parameterization of the water-bed exchange, thereby enabling to study both the direct and indirect impact of offshore operations.

We used the isotopic signal of fin whale baleens to determine the precedence of thestranded whales and their possible encounter with ships along the way to the port offinding (Rotterdam). Additionally we used the amino acid δ15N of the baleens to track themigration of these species which potentially could travel between isotopically differentregions.

ARAMACC(Annually-Resolved Archives of MArine Climate Change) is a multi partner Marie Curie Initial Training Network consisting of six Full Participants, three Associated Partners and one Visiting Researcher. ARAMACC will provide three years of training to ten Early Stage Researchers, and two years of employment to an Experienced Researcher whose remit will be to network between the research and commercial sectors. ARAMACC science will be based around four work packages, which will address (1) the construction of a network of shell-based chronologies for the climatically important NE Atlantic region ; (2) the use of data from these and other existing chronologies in numerical climate models ; (3) the environmental drivers of shell growth ; and (4) novel applications of the shell material, including the production of baseline environmental data for commercial and regulatory organizations. ARAMACC training will be delivered at seven network-wide training events, to include five generic skills modules and seven sclerochronology-specific scientific skills modules (including cruises to NW Scotland and the Faroe Islands which will combine sample collection with training in techniques associated with seagoing research. Here we present an overview of ARAMACC, concentrating particularly on 1) the potential of this project for the advancement of the science of sclerochronology ; 2) the opportunities it will provide to our best students ; and 3) the emphasis it gives to the use of sclerochronology in the commercial and regulatory sectors.

Within the North Sea the southernmost distribution limit of Arctica follows the 30 m depth contour. This border is most likely set by the maximum bottom water temperature of 16 graden. Densities of 16 individuals/m2 were found in the northern North Sea. In the south-eastern North Sea the maximum density of 0.1 ind./m2 is low, especially compared to those around Iceland or the western Atlantic. In the south-eastern North Sea the densities decreased between the 1970s and the early 1990s. Both the percentage of sampling stations and the corresponding densities decreased. The mortality rate in the south-eastern North Sea is twice as high as that in the northern North Sea. ... Zie: Summary