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1.
The usefulness of benthic multi-metric indices when assessing seafloor integrity across broad environmental gradients should be deliberated, as their lack of transparency might hide important sources of variation and fail to identify environmental change. This study compares the performance of two multi-metric indices; the Benthic Quality Index (BQI) and the Brackish water Benthic Index (BBI) between three sub-basins in the Baltic Sea. Both indices reflect the salinity-driven gradient in macroinvertebrate diversity and composition as well as changes in bottom water oxygen concentrations. The relative contribution of predictor variables for explaining index variation does, however, differ between sub-basins, resulting in the indices representing different aspects of the benthic community along the environmental gradient. This context-dependency is caused by inherent differences in benthic community characteristics between the sub-basins of the Baltic Sea, and how the communities are portrayed by the indices. An increased transparency of the importance of the different predictors for directing index values is needed for coherent classifications over broad environmental gradients, such as those occurring in large estuarine water bodies. Use of a weight of evidence table to combine multiple indicators would preserve transparency and be more likely to provide a robust assessment method that would detect seafloor degradation at an early stage.  相似文献   
2.
In September 2014, a pod of seven sperm whales (Physeter macrocephalus) was stranded along the Adriatic coast of Southern Italy. Concentrations of 20 essential and non-essential trace elements were quantified in the brain, muscle, liver and kidneys of three female sperm whales, which died in this event.The essential elements copper, iron, manganese and zinc showed low ranges of variability, suggesting a homeostatic physiological control, while selenium concentrations were associated with age. Molybdenum, nickel and chromium showed low ranges of concentrations and no evidence of preferential accumulation in selected organs. Very low concentrations of the non-essential elements cadmium, lead, tin and vanadium were detected in all tissues, suggesting a minor impact of these pollutants on the sperm whale populations of the Mediterranean Sea. Aluminum was revealed to have relatively high concentrations, together with a high variability between tissues and individuals, reaching the highest values in the kidneys and muscle of the oldest female, which was pregnant; the rare earth elements – lanthanum and cerium – were also detected in the kidneys of this female, indicating that pregnancy probably influenced metal concentrations in body tissues.  相似文献   
3.
Macroalgae harbour specific microbial communities on their surface that have functions related to host health and defence. In this study, the bacterial biofilm of the marine brown alga Fucus spiralis was investigated using 16S rRNA gene amplicon-based analysis and isolation of bacteria. Rhodobacteraceae (Alphaproteobacteria) were the predominant family constituting 23% of the epibacterial community. At the genus level, Sulfitobacter, Loktanella, Octadecabacter and a previously undescribed cluster were most abundant, and together they comprised 89% of the Rhodobacteraceae. Supported by a specific PCR approach, 23 different Rhodobacteraceae-affiliated strains were isolated from the surface of F. spiralis, which belonged to 12 established and three new genera. For seven strains, closely related sequences were detected in the 16S rRNA gene dataset. Growth experiments with substrates known to be produced by Fucus spp. showed that all of them were consumed by at least three strains, and vitamin B12 was produced by 70% of the isolates. Since growth of F. spiralis depends on B12 supplementation, bacteria may provide the alga with this vitamin. Most strains produced siderophores, which can enhance algal growth under iron-deficient conditions. Inhibiting properties against other bacteria were only observed when F. spiralis material was present in the medium. Thus, the physiological properties of the isolates indicated adaption to an epiphytic lifestyle.  相似文献   
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A series of 1,5-diaryl- and 4,5-diaryl-1,2,3-triazole derivatives of combretastatin A4 were synthesized and evaluated as antimitotic microtubule destabilizing agents using the sea urchin embryo model.Structure–activity relationship studies identified compounds substituted with 3,4,5-trimethoxyphenyl and 3,4-methylenedioxy-5-methoxyphenyl ring A and 4-methoxyphenyl ring B as potent antiproliferative agents with high cytotoxicity against a panel of human cancer cell lines including multi-drug resistant cells. 4,5-Diaryl-1,2,3-triazoles (C–C geometry) were found to be considerably more active than the respective 1,5-diaryl-1,2,3-triazoles (N–C geometry). Compound 10ad′ induced G2/M cell cycle arrest and apoptosis in human T-leukemia Jurkat cells via caspase 2/3/9 activation and downregulation of the antiapoptotic protein XIAP. A mitotic catastrophe has been evaluated as another possible cell death mode.  相似文献   
7.
Global climate change has already caused bottom temperatures of coastal marine ecosystems to increase worldwide. These ecosystems face many pressures, of which fishing is one of the most important. While consequences of global warming on commercial species are studied extensively, the importance of the increase in bottom temperature and of variation in fishing effort is more rarely considered together in these exploited ecosystems. Using a 17 year time series from an international bottom trawl survey, we investigated covariations of an entire demersal ecosystem (101 taxa) with the environment in the Celtic Sea. Our results showed that over the past two decades, biotic communities in the Celtic Sea were likely controlled more by environmental variables than fisheries, probably due to its long history of exploitation. At the scale of the entire zone, relations between taxa and the environment remained stable over the years, but at a local scale, in the center of the Celtic Sea, dynamics were probably driven by interannual variation in temperature. Fishing was an important factor structuring species assemblages at the beginning of the time series (2000) but decreased in importance after 2009. This was most likely caused by a change in spatial distribution of fishing effort, following a change in targeted taxa from nephrops to deeper water anglerfish that did not covary with fishing effort. Increasing bottom temperatures could induce additional changes in the coming years, notably in the cold‐water commercial species cod, hake, nephrops, and American plaice. We showed that analyzing covariation is an effective way to screen a large number of taxa and highlight those that may be most susceptible to future simultaneous increases in temperature and changes in exploitation pattern by fisheries. This information can be particularly relevant for ecosystem assessments.  相似文献   
8.
Collagen is an insoluble protein that widely distributes in the extracellular matrix of marine animals. Collagen degradation is an important step in the marine nitrogen cycle. However, the mechanism of marine collagen degradation is still largely unknown. Here, a novel subtilisin-like collagenolytic protease, myroicolsin, which is secreted by the deep sea bacterium Myroides profundi D25, was purified and characterized, and its collagenolytic mechanism was studied. Myroicolsin displays low identity (<30%) to previously characterized subtilisin-like proteases, and it contains a novel domain structure. Protein truncation indicated that the Pro secretion system C-terminal sorting domain in the precursor protein is involved in the cleavage of the N-propeptide, and the linker is required for protein folding during myroicolsin maturation. The C-terminal β-jelly roll domain did not bind insoluble collagen fiber, suggesting that myroicolsin may degrade collagen without the assistance of a collagen-binding domain. Myroicolsin had broad specificity for various collagens, especially fish-insoluble collagen. The favored residue at the P1 site was basic arginine. Scanning electron microscopy and atomic force microscopy, together with biochemical analyses, confirmed that collagen fiber degradation by myroicolsin begins with the hydrolysis of proteoglycans and telopeptides in collagen fibers and fibrils. Myroicolsin showed strikingly different cleavage patterns between native and denatured collagens. A collagen degradation model of myroicolsin was proposed based on our results. Our study provides molecular insight into the collagen degradation mechanism and structural characterization of a subtilisin-like collagenolytic protease secreted by a deep sea bacterium, shedding light on the degradation mechanism of deep sea sedimentary organic nitrogen.  相似文献   
9.
Oxynoemacheilus cemali sp. nov. is described from the Çoruh River drainage in the eastern Black Sea basin. One molecular marker (coI), 25 morphometric and four meristic characters were analysed. Oxynoemacheilus cemali is distinguished from O. kosswigi, O. banarescui, O. samanticus and O. angorae in the Black Sea basin by having a suborbital groove in males, an axillary lobe at the pelvic-fin base, no dorsal adipose crest on the caudal peduncle, a slightly-forked caudal fin and 7–15 dark grey dorsal saddles. Morever, Oxynoemacheilus cemali is distinguished by commonly having 9–15 irregularly-shaped dark-grey bars on the flank posterior to the dorsal-fin origin or, rarely having a mottled pattern or 4–6 irregularly shaped dark-grey bars on the flank posterior to the dorsal-fin origin. Oxynoemacheilus cemali is also distinguished from the closely related species O. araxensis and O. cyri, distributed outside the Black Sea basin, by having 15 and 31 diagnostic nucleotide substitutions in the coI barcode region, respectively.  相似文献   
10.
Much of the Baltic Sea is currently classified as ‘affected by eutrophication’. The causes for this are twofold. First, current levels of nutrient inputs (nitrogen and phosphorus) from human activities exceed the natural processing capacity with an accumulation of nutrients in the Baltic Sea over the last 50–100 years. Secondly, the Baltic Sea is naturally susceptible to nutrient enrichment due to a combination of long retention times and stratification restricting ventilation of deep waters. Here, based on a unique data set collated from research activities and long‐term monitoring programs, we report on the temporal and spatial trends of eutrophication status for the open Baltic Sea over a 112‐year period using the HELCOM Eutrophication Assessment Tool (HEAT 3.0). Further, we analyse variation in the confidence of the eutrophication status assessment based on a systematic quantitative approach using coefficients of variation in the observations. The classifications in our assessment indicate that the first signs of eutrophication emerged in the mid‐1950s and the central parts of the Baltic Sea changed from being unaffected by eutrophication to being affected. We document improvements in eutrophication status that are direct consequences of long‐term efforts to reduce the inputs of nutrients. The reductions in both nitrogen and phosphorus loads have led to large‐scale alleviation of eutrophication and to a healthier Baltic Sea. Reduced confidence in our assessment is seen more recently due to reductions in the scope of monitoring programs. Our study sets a baseline for implementation of the ecosystem‐based management strategies and policies currently in place including the EU Marine Strategy Framework Directives and the HELCOM Baltic Sea Action Plan.  相似文献   
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