Despite a long-documented history of severe harmful algal blooms (HABs) in New England coastal waters, corresponding HAB-associated marine mammal mortality events in this region are far less frequent or severe relative to other regions where HABs are common. This long-term survey of the HAB toxins saxitoxin (STX) and domoic acid (DA) demonstrates significant and widespread exposure of these toxins in New England marine mammals, across multiple geographic, temporal and taxonomic groups. Overall, 19% of the 458 animals tested positive for one or more toxins, with 15% and 7% testing positive for STX and DA, respectively. 74% of the 23 different species analyzed demonstrated evidence of toxin exposure. STX was most prevalent in Maine coastal waters, most frequently detected in common dolphins (Delphinus delphis), and most often detected during July and October. DA was most prevalent in animals sampled in offshore locations and in bycaught animals, and most frequently detected in mysticetes, with humpback whales (Megaptera novaeangliae) testing positive at the highest rates. Feces and urine appeared to be the sample matrices most useful for determining the presence of toxins in an exposed animal, with feces samples having the highest concentrations of STX or DA. No relationship was found between the bloom season of toxin-producing phytoplankton and toxin detection rates, however STX was more likely to be present in July and October. No relationship between marine mammal dietary preference and frequency of toxin detection was observed. These findings are an important part of a framework for assessing future marine mammal morbidity and mortality events, as well as monitoring ecosystem health using marine mammals as sentinel organisms for predicting coastal ocean changes.
Pollution and Marine Debris
Chemical pollution impinges on the quality of water systems and the ecosystem services (ESs) they provide. Expression of ESs in monetary units has become an essential tool for sustainable ecosystem management. However, the impact of chemical pollution on ESs is rarely quantified, and ES valuation often focuses on individual services without considering the total services provided by the ecosystem. The purpose of the study was to develop a stepwise approach to quantify the impact of sediment pollution on the total ES value provided by water systems. Thereby, we calculated the total ES value loss as a function of the multi-substance potentially affected fraction of species at the HC50 level (msPAF(HC50)). The function is a combination of relationships between, subsequently: the msPAF(HC50), diversity, productivity and total ES value. Regardless of the inherent differences between terrestrial and aquatic ecosystems, an increase of diversity generally corresponded to an increase in productivity with curvilinear or linear effects. A positive correlation between productivity and total values of ESs of biomes was observed. The combined relationships showed that 1% msPAF(HC50) corresponded to on average 0.5% (0.05–1.40%) of total ES value loss. The ES loss due to polluted sediments in the Waal-Meuse river estuary (the Netherlands) and Flemish waterways (Belgium) was estimated to be 0.3–5 and 0.6–10 thousand 2007$/ha/yr, respectively. Our study presents a novel methodology to assess the impact of chemical exposure on diversity, productivity, and total value that ecosystems provide. With sufficient monitoring data, our generic methodology can be applied for any chemical and region of interest and help water managers make informed decisions on cost-effective measures to remedy pollution. Acknowledging that the ES loss estimates as a function of PAF(HC50) are crude, we explicitly discuss the uncertainties in each step for further development and application of the methodology.
As filter-feeders, freshwater mussels provide the ecosystem service (ES) of biofiltration. Chemical pollution may impinge on the provisioning of mussels' filtration services. However, few attempts have been made to estimate the impacts of chemical mixtures on mussels' filtration capacities in the field, nor to assess the economic benefits of mussel-provided filtration services for humans. The aim of the study was to derive and to apply a methodology for quantifying the economic benefits of mussel filtration services in relation to chemical mixture exposure. To this end, we first applied the bootstrapping approach to quantify the filtration capacity of dreissenid mussels when exposed to metal mixtures in the Rhine and Meuse Rivers in the Netherlands. Subsequently, we applied the value transfer method to quantify the economic benefits of mussel filtration services to surface water-dependent drinking water companies. The average mixture filtration inhibition (filtration rate reduction due to exposure to metal mixtures) to dreissenids was estimated to be <1% in the Rhine and Meuse Rivers based on the measured metal concentrations from 1999 to 2017. On average, dreissenids on groynes were estimated to filter the highest percentage of river discharge in the Nederrijn-Lek River (9.1%) and the lowest in the Waal River (0.1%). We estimated that dreissenid filtration services would save 110–12,000 euros/million m3 for drinking water production when abstracting raw water at the end of respective rivers. Economic benefits increased over time due to metal emission reduction. This study presents a novel methodology for quantifying the economic benefits of mussel filtration services associated with chemical pollution, which is understandable to policymakers. The derived approach could potentially serve as a blueprint for developing methods in examining the economic value of other filter-feeders exposed to other chemicals and environmental stressors. We explicitly discuss the uncertainties for further development and application of the method.
In this study, the wave-induced distribution of 13 microplastic (MP) samples of different size, shape, and density was investigated in a wave flume with a sandy mobile beach bed profile. The particle parameter were chosen based on an occurrence probability investigated from the field. MP abundances were analyzed in cross-shore and vertical direction of the test area after over 40,000 regular waves. It was found, that MP particles accumulated in more shallow waters with increasing size and density. Particles with high density (ρs>1.25 g/cm3ρs>1.25 g/cm3) have been partly confined into deeper layers of the sloping beach during the formation of the bed profile. Particles with a density lower than that of water used in the experiments floated constantly in the surf zone or deposited on the beach caused by wave run-up. A correlation was found between the settling velocity of the MP particles and the flow velocity at the accumulation point and a power function equation developed. The obtained results were critically discussed with findings from the field and further laboratory studies.
Assessment of chemical exposures in the marine environment is frequently undertaken in sedentary organisms inhabiting coastal environments. However, predatory pelagic fish should be considered sentinel species, as they play an important role in the sustainability of the ecosystems due to their high position in trophic webs. In this study, carboxylesterase (CE) activities were analysed in four predatory tuna species of commercial interest along the western Mediterranean Sea: little tunny (Euthynnus alletteratus), Atlantic bonito (Sarda sarda), bullet tuna (Auxis rochei) and albacore tuna (Thunnus alalunga). CEs are potential biomarkers of chemical exposure, as they are an important family of enzymes involved in the metabolism of xenobiotic and endogenous compounds. CE measures were taken from the liver of these tuna species using five commercial substrates: 4-nitrophenyl acetate (4NPA), 4-nitrophenyl butyrate (4NPB), 1-naphthyl acetate (1NA), 1-naphthyl butyrate (1NB), and 2-naphthyl acetate (2NA). Butyrate substrates (1NB and 4NPB) yielded the highest hydrolysis rates, and were thus the best substrates for these measures. CE activities differed between species. The larger differences were attained with 1NB-CE, with higher activities seen in bullet tuna, followed by little tunny, Atlantic bonito and albacore tuna. Individual size was identified as one of the main factors modulating CE activities, while there was no evidence for a role for trophic level (measured as δ15N). Using little tunny as sentinel, no geographical differences but inter-annual variation in CE activity was observed. The kinetic parameters and in vitro exposure to the pesticide dichlorvos provided complementary information on the sensitivity of tuna CEs to this model pesticide. Our results propose that the little tunny could be considered a potential bioindicator species in the pelagic realm.
Microplastics (MPs) are ubiquitous in the aquatic environment due to plastic waste proliferation in diverse sectors. The recent years have witnessed exponential growth in the number of studies focusing on their occurrence, distribution and toxicity in several parts of India. The overarching aim of this article is to evaluate the sources, abundance, and characteristics of MPs reported in the sediments, water, and biota of the aquatic ecosystems in India. The review revealed that while the MPs from land-based sources such as littering, domestic sewage, and industrial runoff were carried by rivers and streams, MPs from other sources including marine litter and accidental spillages during shipping directly enter the aquatic environment. The unique hydrodynamic conditions during the southwest and northeast monsoons were found to influence the abundance and distribution of MPs in the Indian aquatic ecosystems. Although the seaward flushing and monsoonal flux were reported to increase the abundance of MPs, the reversal of the winds and currents during the NE monsoon was observed to oppose the drift of MPs towards the Goa coast. The reported higher concentrations of MPs in the beach sediments collected from the high tide line (1323 ± 1228 mg/m2) as compared to that of low tide line (178 ± 261 mg/m2) along the southeast coast of India also emphasize the tidal influence. While the shape and type of MPs can help in determining their sources, their size and colour might influence their ingestion in aquatic biota and also indicate the amount of degradation. The variability in the characteristics of MPs observed between different studies could also be a factor of difference in the sampling and analysis techniques adopted. Although the general practice of degutting before consumption could lower the risk of MPs transfer from fish, popular delicacies of dried fish and shrimps could be potential sources of human ingestion. Since the research was mostly confined to the southern coasts of India and some urban recreational beaches, the MP pollution on other coastal regions of India remains largely unexplored. Moreover, with very few studies reporting on the MP pollution in the freshwater ecosystems, the wide network of rivers and enclosed water bodies could also be the major focus of future research.
Polychlorinated biphenyls (PCBs) tend to accumulate in adipose tissue and induce toxicity due to their high lipophilicity and persistence. Tuna play an important role in the ocean food web and human diet. PCBs can damage the growth of tuna directly and have some adverse effects on human indirectly. This review aims to provide geographic variations, bioaccumulation factors and the toxic effects of PCBs in tuna. PCB levels found were varied significantly among the different regions and it showed a trend of offshore greater than pelagic, with the northern hemisphere higher than the southern hemisphere. The highest PCB concentration of tuna was in FAO area 37. Nearly all of the specimens presented similar domain configuration, while their concentrations varied significantly. PCB congeners and concentrations in tuna were affected by a vast of factors, such as geographical distribution, tissue types, trophic level and growth stage, gender, tuna species and physical and chemical properties of PCBs. They can damage reproductive, neurologic and development systems. This review gives a systematic insight into PCBs in tuna and highlights the more attention should be paid to the long-term changes of PCBs in tuna and oceans. There is also a need to strengthen the assessment of PCB impacts on tuna ecology.
Water quality standards are essential for regulation of contaminants in marine environment. Seawater quality criteria (SWQC) for arsenic (As), cadmium (Cd) and lead (Pb) have not been developed for India. The aim of this study is to derive the SWQC for the metals based on Species Sensitivity Distribution (SSD). Eight species of sensitive marine organisms belonging to five phyla were assessed for their sensitivity to toxicity of As, Cd and Pb. Median effective concentrations (EC50) and Median Lethal Concentrations (LC50) were derived from the acute toxicity bio-assays. No Observed Effect Concentrations (NOEC), Lowest Observed Effect Concentrations (LOEC) and chronic values were derived from chronic toxicity bio-assays. Diatoms were more sensitive to As with 96 h EC50 of 0.1 mg/l and copepods were more sensitive to Cd and Pb with 96 h EC50 of 0.019 mg/l and 0.05 mg/l respectively. Estimated NOECs ranged from 4.87 to 21.55 µg/l of As, 1.0 to 120 µg/l of Cd and 5.67 to 91.67 µg/l of Pb. Similarly, chronic values (µg/l) were in the range of 6.71–26.1, 1.38–170, and 7.67–91.67 of As, Cd and Pb respectively. The Criterion Maximum Concentration (CMC), Criterion Continuous Concentration (CCC) and Predicted No Effect Concentration (PNEC) values were prescribed as SWQC. The CMC (µg/l) of 19, 1.7 and 17 for As, Cd, and Pb were derived respectively for acute exposure during accidental marine outfalls. The CCC (µg/l) for As was 4.6, 1.1 for Cd and 5.9 for Pb are recommended as SWQC for protection of 95% of marine organisms. PNEC (µg/l) of 3.8 for As, 0.92 for Cd and 4.3 for Pb are suggested for highly disturbed ecosystems, shell fishing and mariculture uses of water bodies. These values are recommended as a baseline for site specific water quality criteria for the coastal waters of the country.
To evaluate the current microplastics (MPs) contamination on the NW coast of Portugal, opportunistic samples from coastal areas with different levels of anthropogenic impacts were analyzed. Water samples were collected from a coastal marine protected area, an urban estuary, a submarine wreck, and a recreational marina. An optimized protocol for the quantification of MPs, followed by visual identification and FTIR spectroscopy analysis was used to characterize MPs (polymer, type, size, color). MPs were found in all the case studies. A total of 2456 MPs particles were identified and classified as fibers (39%), film (39%), and fragments (22%). Up to 54% of MPs had a size range between 1 and 3 mm. Transparent was the dominant color (56%), followed by white (19%). Polyethylene and polypropylene were the main MPs polymers detected. Higher MPs concentration were found in areas associated with high intense fishing and shipping activities. This study showed that different types of MPs were present in all the aquatic environments surveyed, mainly in areas with more anthropogenic activities, emphasizing the need for measures to properly manage plastic litter and mitigate marine plastic pollution.
CircularSeas European Project, as part of the European Union Circular Economy , aims at promoting the Green Economy by encouraging the development of green products, parts and components by Maritime Industries. The strategy is a combination of Circular Economy principles, with the use of ocean plastic waste for developing new greener materials, and the uptake of advanced manufacturing technology, 3D printing, flexible enough to adapt to the manufacturing conditions for new eco-innovative small and medium parts and components. The paper presents the ongoing research in the project about strategies to introduce Circular Economy in the maritime sector from plastic wastes. This first prospective phase is focused on a series of interviews with each node stakeholders. The paper presents the survey results, together with the challenges to be faced for the implementation of Circular Economy in that specific scenario, despite the -apriori- short term low-profit disadvantages.