Use of chemical tracers in assessing the diet and foraging regions of eastern North Pacific killer whales

Top predators in the marine environment integrate chemical signals acquired from their prey that reflect both the species consumed and the regions from which the prey were taken. These chemical tracers-stable isotope ratios of carbon and nitrogen; persistent organic pollutant (POP) concentrations, patterns and ratios; and fatty acid profiles-were measured in blubber biopsy samples from North Pacific killer whales (Orcinus orca) (n=84) and were used to provide further insight into their diet, particularly for the offshore group, about which little dietary information is available. The offshore killer whales were shown to consume prey species that were distinctly different from those of sympatric resident and transient killer whales. In addition, it was confirmed that the offshores forage as far south as California. Thus, these results provide evidence that the offshores belong to a third killer whale ecotype. Resident killer whale populations showed a gradient in stable isotope profiles from west (central Aleutians) to east (Gulf of Alaska) that, in part, can be attributed to a shift from off-shelf to continental shelf-based prey. Finally, stable isotope ratio results, supported by field observations, showed that the diet in spring and summer of eastern Aleutian Island transient killer whales is apparently not composed exclusively of Steller sea lions.     

Phosphorus distribution in sinking oceanic particulate matter

Despite the recognition of the importance of phosphorus (P) in regulating marine productivity in some modern oceanic systems and over long timescales, the nature of particulate P within the ocean is not well understood. We analyzed P concentration in particulate matter from sediment traps and selected core tops from a wide range of oceanic regimes: open ocean environments (Equatorial Pacific, North Central Pacific), polar environments (Ross Sea, Palmer Deep), and coastal environments (Northern California Coast, Monterey Bay, Point Conception). These sites represent a range of productivity levels, temporal (seasonal to annual) distributions, and trap depths (200–4400 m). P associations were identified using an operationally defined sequential extraction procedure. We found that P in the sediment traps is typically composed of reactive P components including acid-insoluble organic P ( 40%), authigenic P ( 25%), and oxide associated and/or labile P ( 21%), with lesser proportions of non-reactive detrital P depending on location ( 13%). The concentrations and fluxes of all particulate P components except detrital P decrease or remain constant with depth between the shallowest and the deepest sediment traps, indicating some regeneration of reactive P components. Transformation from more labile forms of P to authigenic P is evident between the deepest traps and core top sediments. Although for most sites the magnitudes of reactive P fluxes are seasonally variable and productivity dependent, the fractional associations of reactive P are independent of season. We conclude that P is transported from the upper water column to the sediments in various forms previously considered unimportant. Thus, acid-insoluble organic P measurements (typically reported as particulate organic P) likely underestimate biologically related particulate P, because they do not include the labile, oxide-associated, or authigenic P fractions that often are or recently were biologically related. Organic C to reactive P ratios are typically higher than Redfield Ratio and are relatively constant with depth below 300 m suggesting that preferential regeneration of P relative to C occurs predominantly at shallow depths in the water column, but not deeper in the water column (> 300 m). The view of P cycling in the oceans should be revised (1) to include P fractions other than acid-soluble organic P as important carriers of reactive P in rapidly sinking particles, (2) to include the efficient transformation of labile forms of P to authigenic P in the water column as well as in sediments, and (3) to consider the occurrence of preferential P regeneration at very shallow depths.     

Environmental and Physical Controls on the Formation and Transport of Blooms of the Dinoflagellate <Emphasis Type="Italic">Cochlodinium polykrikoides</Emphasis> Margalef in the Lower Chesapeake Bay and Its Tributaries

Massive blooms of the harmful alga Cochlodinium polykrikoides Margalef occurred in the lower Chesapeake Bay and its tributaries during the summers of 2007 and 2008. The Lafayette and Elizabeth Rivers appeared to act as initiation grounds for these blooms during both years. However, in 2008 there were also localized sites of initiation and growth of populations within the mesohaline portion of the James River. Bloom initiation appeared to be correlated with intense, highly localized rainfall events during neap tides. Subsequent spring tides increased tidal flushing and transport of C. polykrikoides from the Lafayette and Elizabeth Rivers into the lower James River where it was transported upriver by local estuarine circulation. Blooms dissipated in response to increased wind-driven mixing associated with frontal systems moving through the region. A combination of physical factors including, seasonal rainfall patterns, increased stratification, nutrient loading, spring-neap tidal modulation, and complex estuarine mixing and circulation allowed C. polykrikoides to spread and form massive blooms over large portions of the tidal James River and the lower Chesapeake Bay.     

An investigation into the removal of oil from rock utilising magnetic particle technology

The application of magnetic particle technology to environmental remediation has tended to focus, up to now, upon the removal of oil contamination from plumage and fur. The present research demonstrates the potential of this technology to remove oil contamination from the surface of rock. Specifically, a single treatment has been demonstrated to remove more than 80% by weight of heavy bunker oil from the surface of a common foreshore rock type. A further three treatments have been shown to result in an optimum removal of up to 94% by weight. The results are highly reproducible and offer the possibility of achieving up to 100% removal with the appropriate use of pre-conditioners.     

Identifying and Preventing Biopiracy in Australia: patent landscapes and legal geographies for plants with Indigenous Australian uses

There are legal and moral imperatives to protect biological resources and the ‘traditional knowledge’ associated with them. These imperatives derive from complex legal geographies: international law (such as the Convention on Biological Diversity and the Nagoya Protocol), State and federal laws, Indigenous customary law, codes of ethics and research protocols. This paper reports on a ‘patent landscape’ analysis of patents that refer to Australian plant species for which there is Indigenous Australian knowledge. We have identified several patents of potential new biopiracy concern. The paper highlights the way in which actors can gain private property monopolies over biological resources and associated traditional knowledge, even though there are overlapping sovereign rights and Indigenous rights claims. Regulatory gaps need to be closed nationally to fully govern the diverse human–plant bio-geographies in Australia. Further, Indigenous laws and governance have largely been ignored by these actors. We suggest that the introduction of ‘disclosure of origin’ requirements in patent applications, sui generis Indigenous knowledge protections, the development of biocultural protocols, and a more nationally consistent system for ‘access and benefit-sharing’ are required to ensure more ‘fair and equitable’ use of plants and Indigenous knowledge in/from Australia, and to ensure the recognition of Indigenous rights to knowledge.     

Water quality along a river continuum subject to point and diffuse sources

The water quality along the River Kennet, in the Thames basin of southern England, was examined in terms of the influence of point- and diffuse-nutrient inputs. The river is supplied mainly from a Cretaceous Chalk aquifer and hence the waters are of a calcium bicarbonate type. The nitrate largely comes from agricultural sources, with concentrations decreasing downstream due to plant uptake and probable denitrification. In contrast, soluble reactive phosphorus (SRP) is largely associated with sewage inputs and concentrations increase downstream in line with effluents from major towns such as Newbury and Reading. Adjacent to the river in the lower half of the catchment is the Kennet and Avon Canal and the two are in places hydrologically connected. The canal inputs may influence calcium carbonate (calcite) precipitation and increase suspended sediment and particulate phosphorus concentrations in the river. Monitoring upstream and downstream of Marlborough sewage treatment works (STW) showed that SRP concentrations in the effluent were highly variable due to variable efficiency of P stripping and still sufficiently concentrated to dominate downstream river SRP with potential impacts on stream ecology. Biological recovery in this river following P stripping at STWs is complex and controlling those spikes in SRP that are above a threshold of 100 μg l⁻¹ may be a critical requirement. More stringent effluent targets than are currently recommended may be needed (less than 800 μg RP l⁻¹) to achieve good ecological status in this river depending on SRP concentrations upstream.     

Individual variation in patterns of benzo[a]pyrene metabolism in the marine fish scup (Stenotomus chrysops)

The metabolism at specific sites on carcinogenic hydrocarbons such as benzo[a]pyrene (BP) is responsible for activation to the ultimate mutagens and carcinogens, and patterns of metabolism can thus influence the biological effect of such compounds. Marine fish are known to efficiently metabolize BP at the benzo-ring, forming high percentages of the 9,10-dihydrodiol (DHD) and 7,8-DHD, the latter including the penultimate carcinogen.^1,2 Hydrocarbon-induced cytochrome P-450 in fish is responsible for initiating metabolism on the benzo-ring, but epoxide hydrolase (EH) activity is required for DHD formation.^3,4 Both factors could influence formation of the DHD leading to the ultimate carcinogenic diol-epoxide. In the present study, patterns of BP metabolism were evaluated in a number of individual scup Stenotomus chrysops sampled from local Woods Hole waters, and a correlation is described between variation in the DHD formation and EH activity in these feral fish.     

Characterisation of choline esterases and their tissue and subcellular distribution in mussel (Mytilus edulis)

Acetylcholinesterase in mussel is potentially a useful biomarker of exposure to organophosphates (OP) in the marine environment. This study looked at cholinesterase activity in subcellular fractions of various tissues from the common mussel, Mytilus edulis. Measurement of enzyme rates demonstrated that although highest specific activity was found in foot 'mitochondrial' fraction, recovery of activity was very low. Gill 'microsomal' fraction had the second highest specific activity with a useful level of recovery and therefore was the most suitable tissue fraction for biomarker applications. Comparative studies of alternative alkylthiocholine substrates and competitive inhibitors suggest there is a single cholinesterase enzyme type present in this fraction. Inhibition of alkylcholine hydrolysis by BW284C51, specific to acetylcholinesterase in vertebrates, showed that cholinesterase activity in gill 'microsomal' fraction is inhibited by this compound but to a lesser extent than in vertebrate AChE. Inhibition of cholinesterase activity by azamethiphos in gill 'microsomal' fraction gave an IC50 of approximately 100 microM and showed both time and concentration dependence. However this indicates a lower potency compared to other animals and it is debatable whether mussel cholinesterase activity is useful as a biomarker of exposure in the field.