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.     

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.     

The stream hydrology response of converting a headwater pasture catchment to Pinus radiata plantation

ABSTRACT

The planting of degraded land with tree plantations may be effective at improving land use sustainability and profitability but it can also have significant effects on stream hydrology. In this paired catchment study, we report the stream hydrological response to partial (62%) afforestation of a steep pastoral catchment in the western Waikato Region, North Island, New Zealand. We comprehensively analyse the hydrological regime changes over a 23-year period (including eight years before pine planting) with reference to a native-forested ‘control’ catchment. Our results show that afforestation has markedly affected stream hydrology. Seven years after planting, the total annual runoff was 380?mm lower than predicted for the catchment in pasture. Two phases of plantation thinning resulted in the difference between measured and predicted runoff reducing to only 129?mm. Peak flows reduced by ～50% while total stormflow reduced by ～30% – which we attribute to canopy interception attenuating and delaying water yield. The impact of plantation establishment on low flows is not so clear, although afforestation appears to have reduced low flows by ～25%. This study provides information on the hydrological impact of afforestation within a hitherto poorly-represented New Zealand environment (i.e. high rainfall, sedimentary lithology-based, North Island hill country).     

Weak ties, immigrant women and neoliberal states: Moving beyond the public/private binary

This paper engages with the vacillations in provincial and federal gender specific service funding in Canada between 2001 and 2007. I connect this state scale analysis to local settlement experiences of Sikh immigrant women living in a small British Columbia community. Using the concept of network analysis, particularly the idea of weak ties, I offer a corrective to the overly positive appraisals of strong ties and institutional completeness. I argue that experiences of settlement, especially in cases where women face various forms of domestic violence, are shaped by the articulation of neoliberalism and patriarchy. This analysis contributes to the ongoing reformulation advanced by feminist geographers with regard to the public/private binary. In its place this case study reveals the multiple public and private intersections and continuums that exist, and how the recognition of these geographies can assist in building effective public resources to tackle the challenges faced by some immigrant women.     

Cryptic Blooms: Are Thin Layers the Missing Connection?

Harmful algal blooms (HABs) are common in Monterey Bay, CA, and have resulted in repeated closures of shellfish fisheries and the poisoning and death of marine mammals. In the majority of instances, HAB events in this region are first detected by the presence of sick or dying animals. The phrase “cryptic blooms” was adopted to denote the appearance of poisoning at higher trophic levels with no prior evidence of a large phytoplankton bloom. We hypothesize that the onset of many HAB events goes undetected because the bloom is initially concentrated in discrete thin subsurface layers in the water column that are easily missed by conventional sampling and monitoring methods. In this paper, we report on the detection and monitoring of a subsurface layer of phytoplankton in northern Monterey Bay, CA, using a high-resolution, autonomous profiler. This ‘thin layer,’ which measured from 10 cm to 3 m in thickness (85% < 2 m; 54% < 1 m), persisted over a 7-day period near the base of the pycnocline. The phytoplankton assemblage in the layer was primarily composed of a multi-species assemblage of Pseudo-nitzschia including the toxin-producing species Pseudo-nitzschia australis. Concentrations of toxic phytoplankton (P. australis), cyanobacteria, and bacteria in the layer were significantly higher than outside the layer (P < 0.05). Counts of total Pseudo-nitzschia spp. showed similar levels of enrichment in the layer compared to outside the layer. Our findings indicate that, when monitoring for HABs, it is critical to sample at scales appropriate to resolve thin layers. Thin layers have been identified as a common recurrent feature in a variety of coastal systems, suggesting that the use of autonomous high-resolution vertical profilers coupled with targeted sampling, could allow more timely detection of HABs in many coastal environments.     

Ecological Impact of the Introduction to New Zealand of Asian Date Mussels and Cordgrass—The Foraminiferal,Ostracod and Molluscan Record

The ecological impact from the establishment of dense intertidal beds of introduced Asian date mussels (Musculista senhousia) and cordgrass (Spartina alterniflora) in five northern New Zealand estuaries and harbours was documented in 2005–2006, using the fossil record of the shells of foraminifera, ostracods and molluscs in paired sediment cores and surface samples taken from inside and outside selected beds. The most significant changes in faunal composition in all, but the most saline sites, generally occurred in both cores in each pair and could be attributed to the impact of decreased salinity and pH as a result of increased freshwater runoff following clearance of the surrounding forest in the 19th century and urban development in the late 20th century. Establishment of Asian date mussel beds had a greatest impact on the composition of ostracod faunas. At near oceanic salinity, the mussels had completely replaced the native infaunal bivalve fauna, but had little impact on the foraminifera. At more brackish sites, the presence of mussel shells appears to have buffered the calcareous foraminifera from the effects of lowered pH, which had dissolved this component outside the beds. Establishment of cordgrass patches had no impact on ostracod faunas, and little on molluscs except at Kaipara, where introduced Pacific oysters had colonised the cordgrass. Cordgrass had the most impact on the foraminifera. At brackish sites, cordgrass patches had been colonised by agglutinated foraminiferal species different from those that dominate outside. In cordgrass at more saline sites, agglutinated foraminifera have invaded and bloomed at the expense of calcareous Ammonia spp., which dominated outside the patches.     

High‐frequency precipitation and stream water quality time series from Plynlimon,Wales: an openly accessible data resource spanning the periodic table

This scientific briefing announces the availability of a new multi‐element high‐frequency water quality data set that is openly accessible to the research community. The data set comprises up to 2 years of 7‐hourly water quality data for two streams and one rainfall site in the Upper Severn catchment at Plynlimon in Mid‐Wales. The measurements cover 50 analytes ranging from H⁺ to U and spanning six orders of magnitude in concentration, including major, minor and trace elements as well as nutrients, and they complement decades of weekly measurements of the same analytes at the Upper Severn. Together, the weekly and 7‐hourly time series provide a unique data set for studying both long‐term trends and short‐term dynamics. The data show complex behaviour over a wide range of timescales, challenging our understanding of catchment processes and informing future modelling efforts. Copyright © 2013 John Wiley & Sons, Ltd.     

Interacting physical,chemical and biological forcing of phytoplankton thin-layer variability in Monterey Bay,California

During the 2005 Layered Organization in the Coastal Ocean (LOCO) field program in Monterey Bay, California, we integrated intensive water column surveys by an autonomous underwater vehicle (AUV) with satellite and mooring data to examine the spatiotemporal scales and processes of phytoplankton thin-layer development. Surveying inner to outer shelf waters repeatedly between August 18 and September 6, the AUV acquired 6841 profiles. By the criteria: [(1) thickness ≤3 m at the full-width half-maximum, (2) peak chlorophyll at least twice the local background concentrations, and (3) a corresponding peak in optical backscattering], thin layers were detected in 3978 (58%) of the profiles. Average layer thickness was 1.4 m, and average intensity was 13.5 μg l^?1 above (3.2x) background. Thin layers were observed at depths between 2.6 and 17.6 m, and their depths showed diurnal vertical migration of the layer phytoplankton populations. Horizontal scales of thin-layer patches ranged from <100 m to>10,000 m. A thin-layer index (TLI), computed from layer frequency, intensity and thinness, was highest in mid-shelf waters, coincident with a frontal zone between bay waters and an intrusion of low-salinity offshore waters. Satellite observations showed locally enhanced chlorophyll concentrations along the front, and in situ observations indicated that phytoplankton may have been affected by locally enhanced nutrient supply in the front and concentration of motile populations in a convergence zone. Minimum TLI was furthest offshore, in the area most affected by the intrusion of offshore, low-chlorophyll waters. Average thin-layer intensity doubled during August 25–29, in parallel with warming at the surface and cooling within and below the thermocline. During this apparent bloom of thin-layer populations, density oscillations in the diurnal frequency band increased by an order of magnitude at the shelfbreak and in near-bottom waters of the inner shelf, indicating the role of internal tidal pumping from Monterey Canyon onto the shelf. This nutrient transport process was mapped by the AUV. Peak TLI was observed on August 29 during a nighttime survey, when phytoplankton were concentrated in the nutricline. Empirical orthogonal function decomposition of the thin-layer particle size distribution data from this survey showed that throughout the inner to outer shelf survey domain, the layers were dominated by phytoplankton having a cross-section of ～50 μm. This is consistent with the size of abundant Akashiwo sanguinea cells observed microscopically in water samples. During a subsequent and stronger intrusion of low-salinity offshore waters, spatially-averaged vertical density stratification decreased by > 50%, and phytoplankton thin layers disappeared almost completely from the AUV survey domain.