Seasonal and regional changes in carbon dynamics in the Wadden Sea, the world's largest intertidal sand and mud flats system, were analysed to quantify the influence of biogeochemical processes on the carbonate system at the land-sea interface. With a focus on the East Frisian Wadden Sea (EFWS), we successfully used the difference between total alkalinity (TA) and dissolved inorganic carbon (DIC) ([TA-DIC]), Delta TA(excess), Delta DICexcess (deviations beyond conservative mixing) and Delta TA(P) (alkalinity production due to primary production) to quantify local biogeochemical influences on carbonate system dynamics. In spring, a phytoplankton bloom with high biological activity, indicated by (a) supersaturated oxygen (up to 180 in % saturation), (b) elevated chlorophyll a (up to 151.7 mu g L-1) and (c) low pCO(2) (as low as 141.3 mu atm), resulted in decrease in nitrate (NO3-, 19.29 +/- 18.11 mu mol kg(-1)) and DIC (159.4 +/- 125.4 mu mol kg(-1)), and a slight increase in TA (9.1 +/- 29.2 mu mol kg(-1)). The regression analysis of the differences between March and May 2022 in NO3- concentrations (Delta NO3-) against the differences in DIC (Delta DIC) yielded a slope of 6.90, matching the Redfield C:N ratio, and suggesting that uptake of nitrate by primary producers increased total alkalinity during the spring bloom. In summer, we assume that organic matter remineralization, along with CaCO3 dissolution in sediments, enhances TA production in the coastal and nearshore regions of the Western EFWS (concentrations up to 2400 mu mol kg(-1)). In the Eastern EFWS, enhanced CaCO3 formation may consume TA ([TA-DIC]<200 mol kg(-1)), but the region still acts as a net source of TA, likely due to sedimentary processes such as organic matter decomposition, which follow the time of increased biological activity during the spring bloom. The increase of TA enhances the coastal ocean's ability to absorb and store CO2 through buffering and suggests that the EFWS can be a source of TA to the coastal regions during the warm productive seasons. This study highlights the complex relationships between these factors, emphasizing the need for a comprehensive understanding of regional and seasonal variations to better assess the role of coastal systems in carbon cycling and storage, as well as climate regulation.

Habitat quality such as food availability and physical structures impacts the abundance of bird species. During 1987–2019, we studied long-term changes in the quality of the habitat of 13 waterbird species in the Wadden Sea, an important stop-over site on the East Atlantic Flyway between arctic breeding areas and wintering grounds in Western Europe and Africa. Monitoring of waterbirds revealed that several species increased or remained stable in the northern and southern sections of the Wadden Sea, while their abundance mainly decreased in more central areas. The Wadden Sea is influenced by freshwater discharge from rivers draining a large part of central Europe, by geomorphological dynamics driven by the tidal cycle and by sea level rise and climate. We hypothesized that the abundance of waterbirds that are dependent on intertidal flats for feeding is influenced by (a) regime shifts in the southern North Sea, (b) climate affecting riverine discharge (the amount of nutrients) from rivers in the Wadden Sea area, (c) climate affecting breeding conditions at arctic and boreal breeding grounds, (d) changes in geomorphology, (e) sea level rise and (f) biomass of macrozoobenthos. The results reveal that the abundance of staging waterbirds in the Wadden Sea is affected by (i) regime shifts and the North Atlantic Oscillation index (NAO), (ii) annual discharge of nutrients (total N and total P have both positive and negative effects) and (iii) biomass of macrozoobenthos. Accretion or erosion of intertidal flats and sea level rise caused local displacements of waterbirds. In a broader context, we found that waterbirds in the Wadden Sea are influenced by a complex array of variables including de-eutrophication due to improved wastewater treatment and a reduced use of fertilizer in central Europe, regime shifts in the southern North Sea including the Wadden Sea (partly driven by the Gulf Stream) and changes in climate conditions, which may affect the breeding conditions of waterbirds in Northern Europe as well as precipitation in Central Europe.

The pollution state in the German Bight was investigated by determination of pollutant concentrations of sediment samples using equilibrium passive sampling. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAH) were determined in the pore water of North Sea sediment. The freely dissolved pore water concentration (Cfree) was measured applying Solid Phase Microextraction (SPME) by using PDMS-coated glass fibers. The obtained results show that the North Sea contamination level with the investigated pollutants is relatively low. However, the stations close to the sediment-dumping site were higher contaminated. A macrofauna analysis showed that bioturbation activities were mostly present in the upper sediment layers, but a direct bioturbation influence on the sediment concentration distribution could not be shown. Overall, the contamination load was below baseline toxicity, but considering that several other priority pollutants will also make a contribution to the baseline toxicity, it can be counted as relatively high.

Coastal regions are highly variable ecosystems and play a crucial role in the global carbon cycle. In the North Sea, the CARBOSTORE project aims to investigate some of the benthic and pelagic reservoirs of carbon. This study focuses on the seasonal and inter-annual changes in the Southern North Sea and the North Frisian Islands in the Wadden Sea. Large regional and seasonal variability has been documented in previous studies of total alkalinity and carbon in these regions, but the driving factors are still being investigated. Since the start of the CARBOSTORE project in spring 2021, two seasonal cruises were completed in July and October 2021. The dissolved inorganic carbon (DIC) and total alkalinity (TA) in the southern North Sea and intertidal regions around the North Frisian Islands were measured, along with several other biogeochemical parameters measured using a Ferry Box. These surveys allow insights into the regional distribution and the seasonal cycle of TA and DIC and will help elucidate the potential sources of carbon. In addition, a close collaboration to colleagues investigating the benthic processes in this project will allow for coupling the benthic and pelagic dynamics. Preliminary results show a gradient in TA and DIC from land to sea, as well as regional variability. In the intertidal zones, TA and DIC values are higher overall than in the southern North Sea. Higher TA and DIC values were measured in July compared to October. What is more, the intertidal regions near the Ems River show some of the highest TA and DIC values, suggesting a potential influence from riverine inputs.

Climate change affects the marine environment on many levels with profound consequences for numerous biological, chemical, and physical processes. Benthic bioturbation is one of the most relevant and significant processes for benthic-pelagic coupling and biogeochemical fluxes in marine sediments, such as the uptake, transport, and remineralisation of organic carbon. However, only little is known about how climate change affects the distribution and intensity of benthic bioturbation of a shallow temperate shelf sea system such as the southern North Sea. In this study, we modelled and projected changes in bioturbation potential (BPp) under a continuous global warming scenario for seven southern North Sea key bioturbators: Abra alba, Amphiura filiformis, Callianassa subterranea, Echinocardium cordatum, Goniada maculata, Nephtys hombergii, and Nucula nitidosa. Spatial changes in species bioturbation intensity are simulated for the years 2050 and 2099 based on one species distribution model per species driven by bottom temperature and salinity changes using the IPCC SRES scenario A1B. Local mean bottom temperature was projected to increase between 0.15 and 5.4 °C, while mean bottom salinity was projected to moderately decrease by 1.7. Our results show that the considered benthic species are strongly influenced by the temperature increase. Although the total BP remained rather constant in the southern North Sea, the BPp for four out of seven species was projected to increase, mainly due to a simultaneous northward range expansion, while the BPp in the core area of the southern North Sea declined for the same species. Bioturbation of the most important species, Amphiura filiformis and Echinocardium cordatum, showed no substantial change in the spatial distribution, but over time. The BPp of E. cordatum remained almost constant until 2099, while the BPp of A. filiformis decreased by 41%. The northward expansion of some species and the decline of most species in the south led to a change of relative contribution to bioturbation in the southern North Sea. These results indicate that some of the selected key bioturbators in the southern North Sea might partly compensate the decrease in bioturbation by others. But especially in the depositional areas where bioturbation plays a specifically important role for ecosystem functioning, bioturbation potential declined until 2099, which might affect the biochemical cycling in sediments of some areas of the southern North Sea.

The contribution of sediments to nutrient cycling of the coastal North Sea is strongly controlled by the intensity of fluxes across the sediment water interface. Pore‐water advection is one major exchange mechanism that is well described by models, as it is determined by physical parameters. In contrast, biotransport (i.e., bioirrigation, bioturbation) as the other major transport mechanism is much more complex. Observational data reflecting biotransport, from the German Bight for example, is scarce. We sampled the major sediment provinces of the German Bight repeatedly over the years from 2013 to 2019. By employing ex situ whole core incubations, we established the seasonal and spatial variability of macrofauna‐sustained benthic fluxes of oxygen and nutrients. A multivariate, partial least squares analysis identified faunal activity, in specifically bioturbation and bioirrigation, alongside temperature, as the most important drivers of oxygen and nutrient fluxes. Their combined effect explained 63% of the observed variability in oxygen fluxes, and 36–48% of variability in nutrient fluxes. Additional 10% of the observed variability of fluxes were explained by sediment type and the availability of plankton biomass. Based on our extrapolation by sediment provinces, we conclude that pore‐water advection and macrofaunal activity contributed equally to the total benthic oxygen uptake in the German Bight.

The cockle Cerastoderma edule is one of the most common macrofauna species in the Wadden Sea areas of the North Sea. Cockle population dynamics are influenced by various abiotic and biotic factors such as temperature, food availability, and inter- and intraspecific competition. Cockles play an important role in the food web of the Wadden Sea, for instance, large shellfish-eating birds, such as oystercatchers and common eiders, use the cockle C. edule and the blue mussel Mytilus edulis as a main diet component. However, the populations of shellfish-eating bird species have been declining dramatically across the Wadden Sea since the beginning of the 21st century. While there are detailed monitoring programs in blue mussels due to commercial interests, little information is known about the stocks and long-term dynamics of cockles in the German Wadden Sea. To fill this gap, in 2005 a local conservation society (“Der Mellumrat e.V.”) initiated a study to sample cockles at one transect per year south of the island of Mellum, which was extended by 5 more transects in 2011. In addition to the spatial analysis, we analyzed the long-term variability in cockle population dynamics. Min/max autocorrelation factor analysis (MAFA) revealed a decline in cockle abundance, while no clear length trends were found. Canonical and spearman correlation analyses exposed significant correlations between cockle abundance and length and chlorophyll a, mussel bank area as well as oystercatcher and common eider populations. This study clearly shows that there is an urgent need for comprehensive time series of cockle data to analyze and explain ecological long-term changes in cockle population dynamics in relation to environmental changes and to point out how parts of the Wadden Sea food web, such as shellfish-eating birds are affected by these changes.

Coastal sediments play an important role in the nutrient cycling, and the intensities of exchange processes between bottom water and pore water control the balance between sequestration and recycling of nutrients. Pore water advection as one major exchange mechanism is determined by physical parameters and thus well describable with models. By contrast, biotransport (bioirrigation, bioturbation) as the other major transport mechanism is much more complex and observational data are often scarce to quantify these processes. We present ex-situ observations of oxygen and nutrient fluxes, sediment characteristics, and fauna composition over the past six years from all benthic provinces of the German Bight, which enable us to describe the spatial and seasonal variability of the benthic- pelagic coupling. We employ this dataset to detect environmental drivers of the observed variability and to test several proxies of faunal activity. Our results show that abiotic parameters (sediment type, local primary production) explain the spatial variability while the dynamics of temperature and faunal activity explain the temporal variability. Effects of the complex benthic communities on benthic exchange rates can be parameterized by surprisingly simple proxies, which may help to improve benthic exchange models. By comparing in-situ measurements of pore water advection with ex situ observations, we conclude that biotransport approximately doubles the benthic- pelagic exchange rates in the German Bight.

Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15–91 years) collected across Europe, using a comprehensive dataset comprising ~6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions. Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe.

The importance of macrobenthos in benthic‐pelagic coupling and early diagenesis of organic carbon has long been recognized but has not been quantified at a regional scale. By using the southern North Sea as an exemplary area we present a modeling attempt to quantify the budget of total organic carbon (TOC) reworked by macrobenthos in seafloor surface sediments. Vertical profiles in sediments collected in the field indicate a significant but nonlinear correlation between TOC and macrobenthic biomass. A mechanistic model is used to resolve the bidirectional interaction between TOC and macrobenthos. A novelty of this model is that bioturbation is resolved dynamically depending on variations in local food resource and macrobenthic biomass. The model is coupled to 3‐D hydrodynamic‐biogeochemical simulations to hindcast the mutual dependence between sedimentary TOC and macrobenthos from 1948 to 2015. Agreement with field data reveals a satisfactory model performance. Our simulations show that the preservation of TOC in the North Sea sediments is determined not only by pelagic conditions (hydrodynamic regime and primary production) but also by the vertical distribution of TOC, bioturbation intensity, and the vertical positioning of macrobenthos. Macrobenthos annually ingest 20–35% and in addition vertically diffuse 11–22% of the total budget of TOC in the uppermost 30‐cm sediments in the southern North Sea. This result indicates a central role of benthic animals in modulating the organic carbon cycling at the sediment‐water interface of continental margins.

Bioturbation is one of the most important processes for benthic-pelagic coupling and biogeochemical fluxes in marine sediments, such as the intake, transport, and preservation of organic carbon. However, only little is known about the large-scale and long-term variability of community bioturbation potential (BPc) and trait diversity of south-eastern North Sea (NS) macrofauna communities in relation to anthropogenic and environmental parameters. Here we pooled macrofauna species with similar life traits into functional groups, revealing the main functionality of a benthic ecosystem. The BPc and trait diversity of south-eastern NS macrofauna communities, derived from the NS Benthos Survey in 1986, the NS Benthos Project in 2000, and a more recent study from 2010-2015, were analyzed and compared. Significant changes in spatial variability of BPc were found, simultaneously to regionally decreasing BPc, e.g. in the central parts of the Oysterground, while BPc increased in other areas, e.g. along the North Frisian coast. Contrastingly, the spatial variability of trait diversity has remained stable since 1986. Overall, the study area was dominated by the functional group 'biodiffusors with slow free movement.' During the 1986 study period, we identified 3 basically different trait-based communities, i.e. the Dogger Bank, Oysterground, and coast community. Long-term analyses based on these 3 trait-based communities revealed changes in dominance of functional groups within each of the communities up to 2010-2015, which were related to anthropogenic pressures such as fishery and seabed degradation, synergistic to increasing sea surface temperature, food limitation, and de-eutrophication.

Current research revealed distinct changes in ecosystem functions, and thus in ecosystem stability and resilience, caused by changes in community structure and diversity loss. Benthic species play an important role in benthic-pelagic coupling, such as through the remineralization of deposited organic material, and changes to benthic community structure and diversity have associated with changes in ecosystem functioning, ecosystem stability and resilience. However, the long-term variability of traits and functions in benthic communities is largely unknown. By using abundance and bioturbation potential of macrofauna samples, taken along a transect from the German Bight towards the Dogger Bank in May 1990 and annually from 1995 to 2017, we analysed the taxonomic and trait-based macrofauna long-term community variability and diversity. Taxonomic and trait-based diversity remained stable over time, while three different regimes were found, characterised by changes in taxonomic and trait-based community structure. Min/max autocorrelation factor analysis revealed the climatic variables sea surface temperature (SST) and North Atlantic Oscillation Index (NAOI), nitrite, and epibenthic abundance as most important environmental drivers for taxonomic and trait-based community changes.

Since the second half of the 20th century drastic changes were found within the marine environment, mostly driven by anthropogenic and climatic pressures. Within this study, the long-term variability of south-eastern North Sea macrofauna community structure was analysed on a large spatial extent, to examine effects of increasing sea surface temperature, decreasing pelagic and benthic primary production and phytoplankton biomass, together with de-eutrophication effects since the late 1980s. Macrofauna data from the 1986 North Sea Benthos Survey and the 2000 North Sea Benthos Project were reanalysed and compared with present data from 2010 to 2015. A stable spatial distribution of four main macrofauna communities was found, based on the environmental parameters depth, sediment composition, and tidal parameters. Diversity and taxa numbers remained stable since 1986. However, in 2010–2015, mean abundance and biomass of offshore waters had decreased slightly, while at the coastal nearshore areas and parts of the Oysterground a significant increase was found. Simultaneously, a spatial shift in maximum mean abundance and biomass from the Dogger Bank and Oysterground in 1986 towards the North Frisian coast in 2000 and 2010–2015 was found. Changes were probably driven by de-eutrophication effects in line with food limitation caused by decreasing phytoplankton biomass and pelagic and benthic primary production that strengthen the dominance of opportunistic tube-living taxa such as Phoronis spp. and Spiophanes bombyx. Synergistic effects of increasing sea surface temperature, ongoing seabed degradation, and predation by small non-target fish species caused distinct regionally different changes in characteristic species and dominance structure.

Within this long-term study, the short- and long-term variability of demersal fish and epibenthic species in relation to temperature and climate-driven environmental changes in the inshore tidal bay system of the Jade area was investigated. Semiquantitative sampling took place once per spring and summer period from 1972 to 2014 by using a 2 m beam trawl at one station in the Jade area (German Wadden Seal southern North Sea). Min/max autocorrelation analysis (MAFA) and Mann-Kendall analysis revealed significant increasing trends in total abundance and species number. Homogeneity analysis revealed shifts for abundance in spring and summer in the late 1980s and for species number in the late 1980s in spring and early 2000s in summer. Abundances of the estuarine crustacean species Carcinus maenas and Liocarcinus holsatus and of the estuarine fish species Pomatoschistus spp. showed significant increasing abundances since the late 1980s. The marine juvenile species Pleuronectes platessa and Limanda limanda showed significant decreasing abundances, while abundances of Solea solea showed significant increasing abundances since the early 2000s. Abundances of L. holsatus and C. maenas showed mass occurrences since the early 2000s. Spearman correlation analysis revealed significant correlations of temperature and abundance data of some characteristic species. Statistical downscaling analysis revealed significant correlations between observations and climate indicators such as the North Sea Environmental (NSE) Index for spring. Thus, it appears that climate effects influenced the long-term variability of species number and abundance of epibenthic and demersal fish species in the Jade area, resulting in community shifts in the late 1980s and early 2000s. (C) 2016 Elsevier Ltd. All rights reserved.

Background: The purpose of this article is to review the current situation with regard to sodium intake in the European Union, provide an update on the efforts being made to reduce the sodium content of food products in various industries via food reformulation and identify the factors motivating food reformulation. Methods: A review was conducted of published literature as well as government and nongovernment organization websites and publications. Results: Food reformulation efforts have been made in the bread, meat, dairy and convenience foods industries. The World Health Organization (WHO) recommendation of <5 g/day of dietary salt intake (<2 g/day sodium) provides an internationally accepted baseline for reformulation efforts. Most Europeans continue to consume salt above the recommended limit. About half of the EU member states have legislated change in the form of taxation, mandatory nutrition labeling and regulated nutrition/health claims. Conclusions: These actions have encouraged sodium reductions in existing food products, but food safety, consumer acceptance, cost and complications arising from the use of sodium alternatives remain limitations to food reformulation.

ABSTRACT During productive herpes simplex virus type 1 (HSV-1) infection, a subset of viral delayed-early (DE) and late (L) genes require the immediate-early (IE) protein ICP27 for their expression. However, the cis -acting regulatory sequences in DE and L genes that mediate their specific induction by ICP27 are unknown. One viral L gene that is highly dependent on ICP27 is that encoding glycoprotein C (gC). We previously demonstrated that this gene is posttranscriptionally transactivated by ICP27 in a plasmid cotransfection assay. Based on our past results, we hypothesized that the gC gene possesses a cis -acting inhibitory sequence and that ICP27 overcomes the effects of this sequence to enable efficient gC expression. To test this model, we systematically deleted sequences from the body of the gC gene and tested the resulting constructs for expression. In so doing, we identified a 258-bp “silencing element” (SE) in the 5′ portion of the gC coding region. When present, the SE inhibits gC mRNA accumulation from a transiently transfected gC gene, unless ICP27 is present. Moreover, the SE can be transferred to another HSV-1 gene, where it inhibits mRNA accumulation in the absence of ICP27 and confers high-level expression in the presence of ICP27. Thus, for the first time, an ICP27-responsive sequence has been identified in a physiologically relevant ICP27 target gene. To see if the SE functions during viral infection, we engineered HSV-1 recombinants that lack the SE, either in a wild-type (WT) or ICP27-null genetic background. In an ICP27-null background, deletion of the SE led to ICP27-independent expression of the gC gene, demonstrating that the SE functions during viral infection. Surprisingly, the ICP27-independent gC expression seen with the mutant occurred even in the absence of viral DNA synthesis, indicating that the SE helps to regulate the tight DNA replication-dependent expression of gC.

ArticleTHE EFFECT OF SODIUM AND CHLORIDE SALTS IN PREVENTING THE SHOCKLIKE STATE FOLLOWING VENOUS OCCLUSION OF A LIMB IN THE DOGJulia Meyer, Bessie Lendrum, and Louis N. KatzJulia MeyerFrom the Cardiovascular Department, Michael Reese Hospital, Chicago, Ill., Bessie LendrumFrom the Cardiovascular Department, Michael Reese Hospital, Chicago, Ill., and Louis N. KatzFrom the Cardiovascular Department, Michael Reese Hospital, Chicago, Ill.Published Online:01 Dec 1945https://doi.org/10.1152/ajplegacy.1945.145.2.151MoreSectionsPDF (485 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation More from this issue > Volume 145Issue 2December 1945Pages 151-153 Copyright & PermissionsCopyright © 1945 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1945.145.2.151PubMed21009252History Received 13 August 1945 Published online 1 December 1945 Published in print 1 December 1945 Metrics