Search

Shelf seas play an important role in the global carbon cycle, absorbing atmospheric carbon dioxide (CO2) and exporting carbon (C) to the open ocean and sediments. The magnitude of these processes is poorly constrained, because observations are typically interpolated over multiple years. Here, we used 298500 observations of CO2 fugacity (fCO2) from a single year (2015), to estimate the net influx of atmospheric CO2 as 26.2 ± 4.7 Tg C yr−1 over the open NW European shelf. CO2 influx from the atmosphere was dominated by influx during winter as a consequence of high winds, despite a smaller, thermally-driven, air-sea fCO2 gradient compared to the larger, biologically-driven summer gradient. In order to understand this climate regulation service, we constructed a carbon-budget supplemented by data from the literature, where the NW European shelf is treated as a box with carbon entering and leaving the box. This budget showed that net C-burial was a small sink of 1.3 ± 3.1 Tg C yr−1, while CO2 efflux from estuaries to the atmosphere, removed the majority of river C-inputs. In contrast, the input from the Baltic Sea likely contributes to net export via the continental shelf pump and advection (34.4 ± 6.0 Tg C yr−1). [ABSTRACT FROM AUTHOR]

An intercomparison study has been carried out on the analysis of inorganic nutrients at sea following the operation of two nutrient analysers simultaneously on the GO-SHIP A02 trans-Atlantic survey in May 2017. Both instruments were Skalar San ++ Continuous Flow Analyzers, one from the Marine Institute, Ireland and the other from Dalhousie University, Canada, each operated by their own laboratory analysts following GO-SHIP guidelines while adopting their existing laboratory methods. There was high comparability between the two data sets and vertical profiles of nutrients also compared well with those collected in 1997 along the same A02 transect by the World Ocean Circulation Experiment. The largest differences between data sets were observed in the low-nutrient surface waters and results highlight the value of using three reference materials (low, middle and high concentration) to cover the full range of expected nutrients and identify bias and non-linearity in the calibrations. The intercomparison also raised some interesting questions on the comparison of nutrients analysed by different systems and a number of recommendations have been suggested that we feel will enhance the existing GO-SHIP guidelines to improve the comparability of global nutrient data sets. A key recommendation is for the specification of clearly defined data quality objectives for oceanic nutrient measurements and a flagging method for reported data that do not meet these criteria. The A02 nutrient data set is currently available at the National Oceanographic Data Centre of Ireland: 10.20393/CE49BC4C-91CC-41B9-A07F-D4E36B18B26F and 10.20393/EAD02A1F-AAB3-4F4E-AD60-6289B9585531. [ABSTRACT FROM AUTHOR]

An inter-comparison study has been carried out on the analysis of inorganic nutrients at sea following the operation of two nutrient analysers simultaneously on the GO-SHIP A02 trans-Atlantic survey in May 2017. Both instruments were Skalar San++ Continuous Flow Analysers, one from the Marine Institute, Ireland and the other from Dalhousie University, Canada, each operated by their own laboratory analysts following GO-SHIP guidelines, while adopting their existing laboratory methods. High quality control of the nutrient analysis was achieved on both instruments and there was high comparability between the two datasets. Vertical profiles of nutrients also compared well with those collected in 1997 along the same A02 transect by the World Ocean Circulation Experiment. The comparison of the two 2017 datasets and individual laboratory methods, did however raise some interesting questions on the comparison of nutrients analysed from different systems, in particular the calibration range of daily standards and its influence on low nutrient samples, and the importance of using certified reference materials of high and low concentrations to identify bias in the data. Based on the results from this inter-comparison, a number of recommendations have been suggested that we feel will enhance the existing GO-SHIP guidelines to improve the comparability of global nutrient datasets. [ABSTRACT FROM AUTHOR]

The article discusses the monitoring of chemical residues in aquaculture conducted by the Marine Institute on behalf of the Department of Agriculture, Food and the Marine (DAFM). Topics cited include the National Residues Control Plan for Aquaculture whose objective is to ensure farmed fishes are fit for human consumption and provide a body of data showing that Irish farmed fish is of high quality and promote good practices in aquaculture.

The article discusses the report "An Assessment of Dangerous Substances in Water Framework Directive Transitional and Coastal Waters: 2007 - 2009" by the Marine Institute for the Environmental Protection Agency. Topics discussed include assessment of hazardous substances in Transitional and Coastal Waters (TCW), monitoring of TCW and classification of the chemical and ecological status of water bodies, and assessment of trends in concentrations in biota and sediment.

The present study reports an in vitro screening method for contaminants in sediment samples utilizing an RTG-2 cell line. This technique integrates cytotoxicity testing with analytical chemistry with the aim of achieving a toxicity evaluation of the sediment sample. The toxic effect of individual organotin (OT) compounds and their presence in the sediment sample is the focus of the present study; however, other contaminants are also discussed. The following OT compounds: tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPT), diphenyltin (DPT), and a sediment solvent extract are exposed to the RTG-2 fish cell line. Both the alamar blue (AB) and neutral red (NR) assays are used to assess cytotoxicity after 24-h and 96-h exposure. Methodology for preparation of a sediment solvent extract suitable for biological testing and analytical determination is also described. With the RTG-2 cells, the AB and NR assays had comparable sensitivity for each individual OT compound exposure after 24 h, with TPT being the most toxic compound tested. The individual OT compound concentrations required to induce a 50% toxic effect on the cells (369 ng ml TBT, 1,905 ng ml DBT) did not equate to the concentrations of these contaminants present in the sediment extract that induced a 50% effect on the cells (294 ng ml TBT, 109 ng ml DBT). The solvent extract therefore exhibited a greater toxicity, and this suggests that the toxic effects observed were not due to OT compounds alone. The presence of other contaminants in the solvent extract is confirmed with chemical analysis, warranting further toxicity testing of contaminant mixtures and exposure to the cell line to further elucidate a complete toxicity evaluation. Environ. Toxicol. Chem. 2011;30:154-161. © 2010 SETAC [ABSTRACT FROM AUTHOR]

Caging studies have been previously reported to be useful for providing valuable information on biological effects of mollusks over short periods of time where resident species are absent. The degree of imposex in caged dog whelk (Nucella lapillus), was measured using the vas deferens sequence index (VSDI) and the Relative Penis Size Index (RPSI) and the extent of shell thickening in caged Pacific oyster (Crassostrea gigas) was investigated at t = 0 and t = 18 weeks. Nucella lapillus, when provided with mussels as a food source at the control site at Omey Island on the west Irish coast, did not demonstrate imposex features, whereas those transplanted to port areas did. Dunmore East exhibited the highest level of imposex (3.25 VDSI and 2.37 RPSI). Shell thickening was evident in C. gigas transplanted to Dunmore East, with low effects evident at the control location, Omey Island, and Dublin Bay at t = 18 weeks. Dry weight whole-body concentrations of organotins were most elevated in all species held at Dunmore East compared with other locations. Greatest δ15N and δ13C enrichment was observed within the tissues of the predatory N. lapillus in all three test sites. Increased assimilation in the Dublin Bay oysters might have been influenced by the presence of more nutrients at this location. Surficial sediment organotin levels were most elevated in the Dunmore East <2-mm fraction (22,707 μg tributyltin/kg dry weight), whereas low organotin levels were determined from Dublin and Omey Island sediments. The valuable application of cost-effective caging techniques to deliver integrated biological effects and chemical measurements in the absence of resident gastropod populations in potential organotin/tributyltin hotspot locations is discussed. [ABSTRACT FROM AUTHOR]