Richard Owen

Application of biomarkers for improving risk assessments of chemicals under the Water Framework Directive : A case study

To answer the requirement of the European Commissions Water Framework Directive (WFD) for biological-effects endpoints to classify the ecological health of aquatic ecosystems, we propose the biomarker response index (BRI). The BRI, based on a suite of biomarkers at different levels of biological response at the individual level, provides an integrated relative measure of the general health status of coastal invertebrates. Using the BRI, the health of mussels (Mytilus edulis) from 10 estuaries classified by the Environment Agency of England and Wales under the WFD was compared. Eight sites were healthier than predicted and two showed a similar health status to that of the predicted point-source pollution risk classification. Results indicate that the BRI offers a potential measure of organism health that can be used in monitoring under the WFD as an additional aid to reduce uncertainty in defining risk classification and to provide better evidence of existing impact.

Inhibition of coral photosynthesis by the antifouling herbicide Irgarol 1051

International regulation of organotin compounds for use in antifouling paints has led to the development and increased use of replacement compounds, notably the s-triazine herbicide Irgarol 1051. Little is known about the distribution of Irgarol 1051 in tropical waters. Nor has the potential impact of this triazine upon photosynthesis of endosymbiotic microalgae (zooxanthellae) in corals been assessed. In this study Irgarol 1051 was detected in marinas, harbours and coastal waters of the Florida Keys, Bermuda and St. Croix, with concentrations ranging between 3 and 294 ng 1(-1). 14C incubation experiments with isolated zooxanthellae from the common inshore coral Madracis mirabilis showed no incorporation of H14CO3- from the sea water medium after 4-8 h exposure to Irgarol 1051 concentrations as low as 63 ng 1(-1). Reduction in net photosynthesis of intact corals was found at concentrations of l00 ng 1(-1) with little or no photosynthesis at concentrations exceeding 1000 ng 1(-1) after 2-8 h exposure at all irradiances. The data suggest Irgarol 1051 to be both prevalent in tropical marine ecosystems and a potent inhibitor of coral photosynthesis at environmentally relevant concentrations.

Isotopic partitioning between scallop shell calcite and seawater: Effect of shell growth rate

Abstract The relationship between molluscan shell growth rate and skeletal δ18O and δ13C was investigated in a detailed field study for the scallop, Pecten maximus. Seasonal variation in shell growth rate was found to be a governing factor influencing shell δ18O and δ13C. At low shell growth rates, shell δ18O were more positive (of the order +0.4‰) and δ13C more negative (up to −2‰) as compared with predicted values for precipitation of inorganic calcite in isotopic equilibrium with seawater. The deviations in δ18O were hypothesized as reflecting possible differences in solution carbonate chemistry at the site of mineralization in the extrapallial fluid as compared with that of the external seawater medium. The deviations in shell δ13C were consistent with incorporation of isotopically depleted respiratory 13C (i.e., a metabolic effect). A trend toward more depleted shell δ18O and δ13C values occurred at higher shell growth rates, with negative δ18O values as compared with predicted equilibrium at shell growth rates above 0.13 mm per day. These simultaneous negative deviations in skeletal δ18O and δ13C were interpreted as resulting from a kinetic effect. The implications for environmental reconstruction from molluscan isotopic records are discussed in light of a model of isotopic behavior based on the findings of the study.

Experimental investigation into partitioning of stable isotopes between scallop (Pecten maximus) shell calcite and sea water

Stable isotopic compositions of bivalve shells have often been used for the reconstruction of high-resolution records of palaeotemperature and palaeoproductivity cycles. A major assumption in such studies is that isotopic equilibrium between shell carbonate and sea water is maintained at the time of precipitation. This assumption was tested in the laboratory for scallops, Pecten maximus, cultured over the temperature range 10–17°C. At the low shell growth rates exhibited (<0.1 mm day−1), deviations of shell δ18O from equilibrium were +0.6‰ over the experimental temperature range, a temperature equivalency of approximately −3°C. This is hypothesised as reflecting possible differences in the solution carbonate chemistry at the site of mineralisation in the extrapallial fluid (EPF) as compared to that of the external sea water medium, from which the EPF is isolated. Measured depletions of shell δ13C (of the order of −2.0‰) are interpreted as resulting from introduction of 13C-depleted respiratory CO2 into the EPF and subsequent incorporation into the shell.

An evaluation of hemolymph cholinesterase activities in the tropical scallop, Euvola (Pecten) ziczac, for the rapid assessment of pesticide exposure

The use of sequential measurements of hemolymph cholinesterase activities as a non-invasive biomarker of seasonal organophosphate/carbamate exposure was investigated for the tropical scallop, Euvola (Pecten) ziczac. Overall activities of both acetylcholinesterase and butyrylcholinesterase were relatively high compared to studies with bivalve tissues. Acute in vivo experiments showed inhibition of hemolymph acetylcholinesterase activity at concentrations of the organophosphate insecticide chlorpyrifos of 0.1, 1 and 10 ng l(-1). Monthly sampling of hemolymph from scallops at two sites in Bermuda over a 15 month period showed seasonal acetylcholinesterase and butyrylcholinesterase inhibition. Direct and indirect evidence suggests that this inhibition did not relate to biochemical or physiological changes associated with gonad maturation and spawning, but rather reflected diffuse contamination of the marine environment by cholinesterase inhibitors or increased bioavailability of such inhibitors at these times. Repetitive sampling of scallop hemolymph for cholinesterase activities represents a rapid, sensitive and non-invasive method for assessing seasonal, sublethal pesticide exposure in these commercially important bivalves and suggests a wider use in marine pollution monitoring.

The influence of shell growth rate on striae deposition in the scallop Pecten maximus

The relationship between shell growth rate and striae deposition was investigated in a field study in which groups of juvenile scallops, Pecten maximus , (Pectinidae: Bivalvia) were deployed for monthly periods over a year in the Menai Strait (North Wales). The number of striae deposited per day, inter-striae width (the increment of shell deposited between successive striae) and striae abundance (the number of striae deposited peru2006mm of shell height) all correlated well with measured shell growth rates. During the winter months, when seawater temperatures were minimal (6°C), inter-striae width declined, whilst striae abundance increased, whereas during the summer when seawater temperatures were maximal (18°C), shell growth was rapid with maximum inter-striae width, resulting in a seasonal pattern of narrowly grouped, then widely spaced striae. This seasonal pattern in inter-striae width variation provides an accurate and reliable method for estimating the number of growth cycles and hence the age of P. maximus .

Chapter 5:Scientific Challenges and Policy Needs

A key determinant of the quality and sustainability of the coastal marine environment is the dramatic growth of the human population, in particular along the global coastal zone, over the course of the last century. Burgeoning population growth, often as a result of reduced infant mortality and migration from rural communities, has created unprecedented social and economic demands for food resources, both in fisheries and aquaculture, while poor governance in respect of haphazard urbanisation and industrialisation and poorly regulated waste management have contributed extensively to the degradation of coastal ecosystems. Human health and wellbeing are consequently at risk from the resultant increased burdens of bacterial and viral pathogens from sewage and agricultural faecal run-off, as well as chemical and particulate waste from a variety of sources such as industry, domestic effluent, combustion processes, agricultural run-off of pesticides and nutrients, transport and road run-off. Unless policy formulation recognises that expansion of the human populations is often a key causative factor in the degradation of the coastal marine environment and related human health risks, and develops effective sustainability and mitigation strategies to deal with this, then any other actions will only provide expensive stop-gap solutions that are essentially ‘papering over the cracks’. A recognition of the complex nature of the connectivity of the coastal marine environment with public health is critical for understanding the relationships involved.A holistic systems approach such as Integrated Coastal Zone Management is necessary to address the highly interconnected scientific challenges of increased human population pressure, pollution and over-exploitation of food (and other) resources as drivers of adverse ecological, social and economic impacts, and the urgent and critical requirement for effective public health solutions to be developed through the formulation of politically and environmentally meaningful policies. Since coastal zone environmental problems and related health and socio-economic issues are trans-national in character, the demands on regulation and governance go well beyond the actions of a single government and will require integrated action on a regional and global scale by national governments and stakeholders (e.g. non-governmental organisations), regional organisations (e.g. European Union) and international organisations (e.g. United Nations).