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Abstract The discovery of stimuli-responsive high affinity host–guest pairs with potential applications under biologically relevant conditions is a challenging goal. This work reports a high-affini...

This data set displays a refined age scale for the U1361A marine sediment core (64.41°S, 143.89°E, 3,454 m water depth), recovered from the continental rise offshore of the Wilkes Subglacial Basin, during the Integrated Ocean Drilling Program (IODP) Expedition (Escutia et al. 2011). This age scale is a refined version of the age scale published in Wilson et al. 2018. Here we use the AICC2012 ice core chronology as a reference curve in order to compare the late Pleistocene sediment core data from U1361A to the TALDICE ice core record. Specifically, we refine the existing U1361A age model through the alignment of barium/aluminium (Ba/Al) ratios from XRF-scanning7 with the EDC δD record on the AICC2012 age scale. We apply a conservative tuning strategy to align the two records, using tie points (derived by visual matching) only at the mid-points of the major glacial terminations I-V. Over the interval of interest for the present study (i.e. ~100-350 ka), the new age model for core U1361 differs by only 0 to 6 ka compared to the previous age model in which the sedimentation rate was assumed to be constant. The Nd and IBRD (ice rafted debris) and 143 Nd/144 Nd records for the U1361A published in Wilson et al. (2018) are drawn on the refined age scale. IBRD was measured by weighing after wet-sievingIBRD (ire rafted debris) and 143Nd/144Nd records of the U1361A sediment core (Wilson et al. 2018) drawn of the refined age scale tuned on the AICC2012 chronology for EDC (Bazin et al. 2013)

This data set displays a refined age scale for the U1361A marine sediment core (64.41°S, 143.89°E, 3,454 m water depth), recovered from the continental rise offshore of the Wilkes Subglacial Basin, during the Integrated Ocean Drilling Program (IODP) Expedition (Escutia et al. 2011). This age scale is a refined version of the age scale published in Wilson et al. 2018. Here we use the AICC2012 ice core chronology as a reference curve in order to compare the late Pleistocene sediment core data from U1361A to the TALDICE ice core record. Specifically, we refine the existing U1361A age model through the alignment of barium/aluminium (Ba/Al) ratios from XRF-scanning7 with the EDC δD record on the AICC2012 age scale. We apply a conservative tuning strategy to align the two records, using tie points (derived by visual matching) only at the mid-points of the major glacial terminations I-V. Over the interval of interest for the present study (i.e. ~100-350 ka), the new age model for core U1361 differs by only 0 to 6 ka compared to the previous age model in which the sedimentation rate was assumed to be constant. The Nd and IBRD (ice rafted debris) and 143 Nd/144 Nd records for the U1361A published in Wilson et al. (2018) are drawn on the refined age scale. 2 s.e. = internal precision (2s level) on sample measurement 2 s.d. = external reproducibility estimated from the within-session standard deviation (2s.d.) on JNdi-1 standards Over the course of the analyses, measurements of rock standard BCR-2 gave 143Nd/144Nd = 0.512640 ± 0.000016 (n=31)IBRD (ire rafted debris) and 143Nd/144Nd records of the U1361A sediment core (Wilson et al. 2018) drawn of the refined age scale tuned on the AICC2012 chronology for EDC (Bazin et al. 2013)

As part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP), several climate modeling centers performed a coordinated pre-study experiment with interactive stratospheric aerosol models simulating the volcanic aerosol cloud from an eruption resembling the 1815 Mt. Tambora eruption (VolMIP-Tambora ISA ensemble). The pre-study provided the ancillary ability to assess intermodel diversity in the radiative forcing for a large stratospheric-injecting equatorial eruption when the volcanic aerosol cloud is simulated interactively. An initial analysis of the VolMIP-Tambora ISA ensemble showed large disparities between models in the stratospheric global mean aerosol optical depth (AOD). In this study, we now show that stratospheric global mean AOD differences among the participating models are primarily due to differences in aerosol size, which we track here by effective radius. We identify specific physical and chemical processes that are missing in some models and/or parameterized differently between models, which are together causing the differences in effective radius. In particular, our analysis indicates that interactively tracking hydroxyl radical (OH) chemistry following a large volcanic injection of sulfur dioxide (SO2) is an important factor in allowing for the timescale for sulfate formation to be properly simulated. In addition, depending on the timescale of sulfate formation, there can be a large difference in effective radius and subsequently AOD that results from whether the SO2 is injected in a single model grid cell near the location of the volcanic eruption, or whether it is injected as a longitudinally averaged band around the Earth.

In this dataset, we present Fe, Na and Ca concentration and fluxes retrieved from the North Greenland Eemian Ice Drilling (NEEM) ice core project, covering the last 108 kyrs. The sampling resolution was 110 cm. To ensure an effective dissolution of Fe particles, samples were acidified to pH 1 using Suprapure nitric acid and stored at room temperature for 1 month before the analysis. The ice samples were analyzed with an Inductively Coupled Plasma Single Quadrupole Mass Spectrometer equipped with a quartz Scott spray chamber. Limits of Detection, calculated as three times the standard deviation of the blanks, were 0.8 µg L-1 for 57Fe, 1 µg L-1 for Ca and 3 µg L-1 for Na. Our results show that Holocene Fe fluxes (0.042 -11.7 kyr b2k, 0.5 mg m-2 yr-1) at the NEEM site were four times lower than the average recorded over the last glacial period (11.7– 108 kyr b2k, 2.0 mg m-2 yr-1), while they were greater during the Last Glacial Maximum (LGM, 14.5 – 26.5 kyr b2k, 3.6 mg m-2 yr-1) and Marine Isotope Stage 4 (MIS 4, 60 - 71 kyr b2k, 5.8 mg m-2 yr-1). We present Fe, Ca and Na concentration and fluxes. Dating (GICC05modelext-NEEM-1) and accumulation data are from Rasmussen et al., 2013.

We present the full dD of water and d18O of water data at 55 cm resolution on the EPICA Dome C ice core from the near surface (6.6 m) to the bottom (3190 m), hence covering the last 800 ka. The EPICA Dome C ice core has been drilled in Antarctica (-75.1°S; 123.395°E; 3233 m elevation) between 1996 and 2004 and measurements performed from 2001 to 2020. Some of the data were already published in previous published studies (Jouzel et al. 2007; Stenni et al. 2001, 2004, 2010) but corrections were performed in the present data file. dD measurements from Jouzel et al. (2007) were obtained using a uranium reduction method. In this new dataset, these results over the last 800 ka are combined with new dD measurements (760 samples) performed over the deepest 418 m using a Picarro L2130-i (cavity ring-down spectroscopy). The d18O measurements presented here were performed using a water-CO2 equilibration method. This dataset goes along with a paper published in Nature Geoscience (Landais et al., 2021).

Startle response behaviours are important in predator avoidance and escape for a wide array of animals. For many marine invertebrates, however, startle response behaviours are understudied, and the effects of global change stressors on these responses are unknown. We exposed two size classes of blue mussels (Mytilus edulis * trossulus) to different combinations of temperature (15 and 19 °C) and pH (8.2 and 7.5 pHT) for 3 months and subsequently measured individual time to open following a tactile predator cue (i.e. startle response time) over a series of four consecutive trials. Time to open was highly repeatable in the short term and decreased linearly across the four trials. Individuals from the larger size class had a shorter time to open than their smaller-sized counterparts. High temperature increased time to open compared to low temperature, while pH had no effect. These results suggest that bivalve time to open is repeatable, related to relative vulnerability to predation and affected by temperature. Given that increased closure times impact feeding and respiration, the effect of temperature on closure duration may play a role in the sensitivity to ocean warming in this species and contribute to ecosystem level effects. In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2021) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2021-03-30.

Coastal systems can act as filters for anthropogenic nutrient input into marine environments. Here, we assess the processes controlling the removal of phosphorus (P) and nitrogen (N) for four sites in the eutrophic Stockholm archipelago. Bottom water concentrations of oxygen (O2) and P are inversely correlated. This is attributed to the seasonal release of P from iron-oxide-bound (Fe-oxide-bound) P in surface sediments and from degrading organic matter. The abundant presence of sulfide in the pore water and its high upward flux towards the sediment surface (∼4 to 8 mmol m−2 d−1), linked to prior deposition of organic-rich sediments in a low-O2 setting (“legacy of hypoxia”), hinder the formation of a larger Fe-oxide-bound P pool in winter. This is most pronounced at sites where water column mixing is naturally relatively low and where low bottom water O2 concentrations prevail in summer. Burial rates of P are high at all sites (0.03–0.3 mol m−2 yr−1), a combined result of high sedimentation rates (0.5 to 3.5 cm yr−1) and high sedimentary P at depth (∼30 to 50 µmol g−1). Sedimentary P is dominated by Fe-bound P and organic P at the sediment surface and by organic P, authigenic Ca-P and detrital P at depth. Apart from one site in the inner archipelago, where a vivianite-type Fe(II)-P mineral is likely present at depth, there is little evidence for sink switching of organic or Fe-oxide-bound P to authigenic P minerals. Denitrification is the major benthic nitrate-reducing process at all sites (0.09 to 1.7 mmol m−2 d−1) with rates decreasing seaward from the inner to outer archipelago. Our results explain how sediments in this eutrophic coastal system can remove P through burial at a relatively high rate, regardless of whether the bottom waters are oxic or (frequently) hypoxic. Our results suggest that benthic N processes undergo annual cycles of removal and recycling in response to hypoxic conditions. Further nutrient load reductions are expected to contribute to the recovery of the eutrophic Stockholm archipelago from hypoxia. Based on the dominant pathways of P and N removal identified in this study, it is expected that the sediments will continue to remove part of the P and N loads.

The extracellular concentration of H2O2 in surface aquatic environments is controlled by a balance between photochemical production and the microbial synthesis of catalase and peroxidase enzymes to remove H2O2 from solution. In any kind of incubation experiment, the formation rates and equilibrium concentrations of reactive oxygen species (ROSs) such as H2O2 may be sensitive to both the experiment design, particularly to the regulation of incident light, and the abundance of different microbial groups, as both cellular H2O2 production and catalase–peroxidase enzyme production rates differ between species. Whilst there are extensive measurements of photochemical H2O2 formation rates and the distribution of H2O2 in the marine environment, it is poorly constrained how different microbial groups affect extracellular H2O2 concentrations, how comparable extracellular H2O2 concentrations within large-scale incubation experiments are to those observed in the surface-mixed layer, and to what extent a mismatch with environmentally relevant concentrations of ROS in incubations could influence biological processes differently to what would be observed in nature. Here we show that both experiment design and bacterial abundance consistently exert control on extracellular H2O2 concentrations across a range of incubation experiments in diverse marine environments. During four large-scale (>1000 L) mesocosm experiments (in Gran Canaria, the Mediterranean, Patagonia and Svalbard) most experimental factors appeared to exert only minor, or no, direct effect on H2O2 concentrations. For example, in three of four experiments where pH was manipulated to 0.4–0.5 below ambient pH, no significant change was evident in extracellular H2O2 concentrations relative to controls. An influence was sometimes inferred from zooplankton density, but not consistently between different incubation experiments, and no change in H2O2 was evident in controlled experiments using different densities of the copepod Calanus finmarchicus grazing on the diatom Skeletonema costatum (<1 % change in [H2O2] comparing copepod densities from 1 to 10 L−1). Instead, the changes in H2O2 concentration contrasting high- and low-zooplankton incubations appeared to arise from the resulting changes in bacterial activity. The correlation between bacterial abundance and extracellular H2O2 was stronger in some incubations than others (R2 range 0.09 to 0.55), yet high bacterial densities were consistently associated with low H2O2. Nonetheless, the main control on H2O2 concentrations during incubation experiments relative to those in ambient, unenclosed waters was the regulation of incident light. In an open (lidless) mesocosm experiment in Gran Canaria, H2O2 was persistently elevated (2–6-fold) above ambient concentrations; whereas using closed high-density polyethylene mesocosms in Crete, Svalbard and Patagonia H2O2 within incubations was always reduced (median 10 %–90 %) relative to ambient waters.

The speciation of dissolved iron (DFe) in the ocean is widely assumed to consist almost exclusively of Fe(III)-ligand complexes. Yet in most aqueous environments a poorly defined fraction of DFe also exists as Fe(II), the speciation of which is uncertain. Here we deploy flow injection analysis to measure in situ Fe(II) concentrations during a series of mesocosm/microcosm/multistressor experiments in coastal environments in addition to the decay rate of this Fe(II) when moved into the dark. During five mesocosm/microcosm/multistressor experiments in Svalbard and Patagonia, where dissolved (0.2 µm) Fe and Fe(II) were quantified simultaneously, Fe(II) constituted 24 %–65 % of DFe, suggesting that Fe(II) was a large fraction of the DFe pool. When this Fe(II) was allowed to decay in the dark, the vast majority of measured oxidation rate constants were less than calculated constants derived from ambient temperature, salinity, pH, and dissolved O2. The oxidation rates of Fe(II) spikes added to Atlantic seawater more closely matched calculated rate constants. The difference between observed and theoretical decay rates in Svalbard and Patagonia was most pronounced at Fe(II) concentrations <2 nM, suggesting that the effect may have arisen from organic Fe(II) ligands. This apparent enhancement of Fe(II) stability under post-bloom conditions and the existence of such a high fraction of DFe as Fe(II) challenge the assumption that DFe speciation in coastal seawater is dominated by ligand bound-Fe(III) species.