Abstract-The majority of insecticides currently in use are organophosphorus, carbamate, and synthetic pyrethroid compounds. Organophosphorus insecticides (OPs) produce toxicity by inhibiting the cholinesterase enzymes in the nervous system. Monitoring of acetylcholinesterase (AChE) inhibition has been widely used in terrestrial and freshwater aquatic systems as an indicator of OP exposure and effects. This review describes the use of AChE inhibition as a biomarker in the estuarine environment, discusses the relationship between AChE inhibition and other manifestations of OP toxicity, and highlights areas where additional research is needed. A variety of studies with estuarine fish have suggested that brain AChE inhibition levels of Ͼ70% are associated with mortality in most species. Selected species, however, appear capable of tolerating much higher levels (Ͼ90%) of brain inhibition. Sublethal effects on stamina have been reported for some estuarine fish in association with brain AChE inhibition levels as low as 50%. Most studies suggest, however, that these effects are observed only when brain AChE inhibition is at near-lethal levels. A number of field studies have successfully used AChE inhibition in fish as a biomarker in the estuarine environment. The use of AChE inhibition as a biomarker in estuarine invertebrates has been less well studied. Although AChE inhibition has been measured in the tissues of a variety of invertebrate species following OP exposure, the relationship between AChE inhibition and lethality is less distinct. Additional work is needed in both fish and invertebrates to better explain species-specific differences in the relationship between AChE inhibition and mortality and to investigate other physiological perturbations associated with AChE inhibition.

Within the next five years the manufacture of large quantities of nanomaterials may lead to unintended contamination of terrestrial and aquatic ecosystems 1 . The unique physical, chemical and electronic properties of nanomaterials allow new modes of interaction with environmental systems that can have unexpected impacts 2,3 . Here, we show that gold nanorods can readily pass from the water column to the marine food web in three laboratory-constructed estuarine mesocosms containing sea water, sediment, sea grass, microbes, biofilms, snails, clams, shrimp and fish. A single dose of gold nanorods (65 nm length 3 15 nm diameter) was added to each mesocosm and their distribution in the aqueous and sediment phases monitored over 12 days. Nanorods partitioned between biofilms, sediments, plants, animals and sea water with a recovery of 84.4%. Clams and biofilms accumulated the most nanoparticles on a per mass basis, suggesting that gold nanorods can readily pass from the water column to the marine food web.The transport of contaminants to oceans through estuaries is often mediated by chemical and physical processes associated with mixing fresh water with sea water. As this region is also the habitat for many commercially and ecologically important shellfish and finfish, it could also be a critical point of nanomaterial contaminant entry into the marine food web. For example, salinity gradients, such as those found in tidal mixing zones, typically promote the flocculation and precipitation of organic matter and naturally occurring particulates 4,5 . Organic matter and particulates can be consumed by detritivores or shellfish, and they can also be a sink for anthropogenic material through burial in sediments 6 . At present little is known about the physicochemical behaviour of nanomaterial in the mixing zone, precluding prediction of their eventual environmental distribution. Measurement of nanomaterial distributions in model estuarine systems is a necessary first step towards the evaluation of the effects of nanoparticles on the environment.This study used a series of three replicate estuarine mesocosms as laboratories for measuring the behaviour of nanoparticles in complex environments. These systems are representative of Spartina (cordgrass) dominated estuaries and have been successfully used for estimating the coastal impact of several other contaminants, including atrazine, fipronil, endosulfan and nutrients (Fig. 1) [7][8][9][10] . In this study, three replicates of a complex ecosystem were constructed to model the edge of a tidal marsh creek. The systems were made up from natural, unfiltered sea water from Cherry Point Boat Landing on Wadmalaw Island, South Carolina, USA (salinity determined by conductivity and adjusted to 20‰ by the addition of deionized water) and contained a periodically submerged sediment tray in the primary tank and an attached reservoir for water storage (isolated with a screen) to simulate a tidal cycle [9][10][11] . Sediments were planted with Spartina alterniflora, 100 juvenile Mercenari...

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During Triassic deposition in the Central North Sea, synforms developed on the surface of the extending Zechstein salt. In the ensuing continental environment, coarse-grained clastic sediments were deposited in such depressions. These were later preserved as sediment ‘pods’. A progressive increase in coarse clastic input to the Central North Sea Basin during the Triassic was concurrent with continued salt movement and pod subsidence. During Late Triassic times the best initial reservoir quality sands were developed in the axes of TR30 sediment pods (e.g. Marnock facies). Early Fe-rich chloritization of these high-quality reservoir facies, combined with overpressure development, has resulted in the subsequent, relatively local, preservation of high-quality Triassic reservoirs, often at substantial depths.Understanding the basin-scale halokinetic controls on Triassic sequence and facies development, as well as the subsequent diagenetic effects, is crucial to establishing a framework for Triassic reservoir prediction.We have combined the re-interpretation of newly acquired and reprocessed seismic data with sedimentological and diagenetic studies of available core material. This has enabled the generation of a model for evaluating the distribution of Triassic reservoir and hence exploration potential in the Central North Sea.