No abstract

Across the European Atlantic Arc (Scotland, Ireland, England, France, Spain, and Portugal) the shellfish aquaculture industry is dominated by the production of mussels, followed by oysters and clams. A range of spatially and temporally variable harmful algal bloom species (HABs) impact the industry through their production of biotoxins that accumulate and concentrate in shellfish flesh, which negatively impact the health of consumers through consumption. Regulatory monitoring of harmful cells in the water column and toxin concentrations within shellfish flesh are currently the main means of warning of elevated toxin events in bivalves, with harvesting being suspended when toxicity is elevated above EU regulatory limits. However, while such an approach is generally successful in safeguarding human health, it does not provide the early warning that is needed to support business planning and harvesting by the aquaculture industry. To address this issue, a proliferation of web portals have been developed to make monitoring data widely accessible. These systems are now transitioning from “nowcasts” to operational Early Warning Systems (EWS) to better mitigate against HAB-generated harmful effects. To achieve this, EWS are incorporating a range of environmental data parameters and developing varied forecasting approaches. For example, EWS are increasingly utilizing satellite data and the results of oceanographic modeling to identify and predict the behavior of HABs. Modeling demonstrates that some HABs can be advected significant distances before impacting aquaculture sites. Traffic light indices are being developed to provide users with an easily interpreted assessment of HAB and biotoxin risk, and expert interpretation of these multiple data streams is being used to assess risk into the future. Proof-of-concept EWS are being developed to combine model information with in situ data, in some cases using machine learning-based approaches. This article: (1) reviews HAB and biotoxin issues relevant to shellfish aquaculture in the European Atlantic Arc (Scotland, Ireland, England, France, Spain, and Portugal; (2) evaluates the current status of HAB events and EWS in the region; and (3) evaluates the potential of further improving these EWS though multi-disciplinary approaches combining heterogeneous sources of information.

The anthropogenic emissions of Pt to the environment have increased significantly over the past decades, especially after the introduction of the catalytic converters in motor vehicles. In order to check whether this is affecting the levels of this trace metal on living organisms, time-series analysis of freeze-dried soft tissue material of wild mussels (Mytilus galloprovincialis) covering the period from 1991 to 2001 and collected at an urban beach in the city of Vigo (NW Iberian Peninsula) was conducted. Concentrations ranged from 0.30 to 0.68 ng g(-1) with an average concentration of 0.47 ± 0.10 ng g(-1) (n=21); these concentrations were higher than those obtained for samples collected at a control location away from anthropogenic pressure (0.31 ± 0.10 ng g(-1); n=5). Platinum concentrations followed a statistically significant temporal trend (at the 0.020 level), and the excess of Pt in mussels over the 1991-2011 period compared to the control location were correlated with the European Pt autocatalyst demand (p=0.0006) and, especially, the car sales in Spain (p=0.0001). A bioaccumulation factor of ~5·10(3) was derived, which is greater than those previously calculated for Pt from exposure experiments, but 1-2 orders of magnitude lower than other trace elements (e.g. Zn, Cu, Pb, Cd).

Platinum Group Metals (PGM) are modern, technologically relevant elements for which (i) the anthropogenic cycle has outcompeted the natural cycles and (ii) environmental behavior, fate and impact are still widely unknown. Stripping voltammetry was used for accurate determinations of platinum (Pt) in historical records of river sediments and estuarine oysters from the Gironde fluvial-estuarine continuum (SW France) comprising the Lot River. Sediment cores from the Lot River, dated from 1952 to 2001, showed past Pt contamination due to former industrial (smelter) activities in the Lot River watershed. These samples revealed the phasing-out of a historical Pt contamination with Pt/Th (Thorium) values of 11 × 10− 5 ± 0.79 × 10− 5 for the deepest part of the core which is clearly greater than the regional geochemical background value (Pt/Th ~ 2.2 × 10− 5 ± 0.68 × 10− 5). Wild oyster samples from the mouth of the Gironde Estuary collected from 1981 to 2013 showed Pt concentrations ranging from 0.80 ± 0.01 pmol.g− 1 to 3.10 ± 0.14 pmol.g− 1. Oyster samples have recorded the phasing-out of the smelter-related historical industrial Pt contamination and empirical modelling suggests the recent rise of a new source of Pt to the system. Temporal variations of Pt in oysters attributed to this recent source reflect the exponential increase of Pt demand for car catalytic converters, pointing towards the increasing importance of this emerging source to the aquatic system. Estuarine oysters prove to be suitable bioindicators for Pt contamination providing sensitive monitoring of emission variations over time. Furthermore, oysters may bioconcentrate Pt (Bioconcentration Factor, BCF ~ 103) and transfer this metal contamination to the higher food chain. These findings highlight the need for a deeper understanding of environmental Pt contamination, processes and possible adverse effects to biota. Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.

Rare earth elements (REEs) or lanthanides are often found together in nature, and they are used in multiple anthropogenic activities from green energy and medical technologies to telecommunications and defense systems. However, the current understanding on the concentration and behavior of REEs in oceans and marine organisms is limited, and no regulatory information or limits have been settled. Here, we present a review of the concentrations of lanthanides in marine waters and biota. REEs reach aquatic ecosystems mainly by continental contributions, and the maximum reported concentrations of REEs are found on the platform surface near the coast due to their continental origin. For coastal waters, we find maximum REE levels in the surface water that decrease with depth until a certain stability. Their concentrations diminish as they move toward the open ocean, where concentrations tend to increase vertically with depth in the water column. Only cerium (Ce) showed different patterns from other REEs caused by Ce different redox states: III and IV, reflecting the oxidation of dissolved Ce (III) to particulate Ce (IV) when reacting with the O2 to form CeO2. In seawater, heavy REEs tend to remain in solution forming complexes usually unavailable for organisms, while light REEs are most likely to be assimilated by them, posing potential biological implications. Bioaccumulation of REEs decreases as marine trophic level increases, showing a trophic dilution pattern. Generally, higher concentrations are found in organisms such as phytoplankton, zooplankton, and algae species, while the lowest concentrations are found in mollusks, corals, and fish species. According to the current trend in the REE industry, the increasing anthropogenic emissions are a fact; therefore, more studies will be needed regarding their fractionation, the transformation processes with which they become bioavailable, and their pathways in marine systems.