Uptake of palytoxin‐like compounds by shellfish fed Ostreopsis siamensis (Dinophyceae)

Abstract

Greenshell? mussels (Perna canaliculus Gmelin), scallops (Pecten novaezealandiae Reeve), and Pacific oysters (Crassostrea gigas Thunberg) were fed with a New Zealand strain of mass cultured Ostreopsis siamensis Schmidt (for 27 and 84 h and with 1.5 × 10⁶ or 8.6 × 10⁶ cells, respectively) under laboratory conditions. The microalgal cells contained 0.3 pg palytoxin equivalents cell^–1 (as determined by the haemolysis neutralisation assay (HNA) of Bignami (1993)) and extracts of these cells were toxic to mice after intraperitoneal injection. No palytoxin‐like material was detected either in the hepatopancreas or the muscle and roe of mussels fed O. siamensis. Oysters contained detectable amounts of toxin in hepatopancreas muscle, and roe while higher concentrations were present in the hepatopancreas of scallops. Extracts of control shellfish (tested biotoxin free and not fed O. siamensis) were toxic to mice, and there was no definitive evidence that feeding shellfish with O. siamensis at the levels employed in the present experiment increased the toxicity of shellfish tissue extracts to mice.     

The surface archaeological record in arid Australia: Geomorphic controls on preservation,exposure, and visibility

The conventional approach to assessing the archaeological record in most parts of the world involves a combination of excavation of stratified deposits and extensive survey of surface deposits. Although widely applied in Australia, in both research‐based and management archaeology, the method does not conform well to the nature of the surface archaeological record here. Over much of semi‐arid and arid Australia, archaeological “sites” are, in fact, accretion phenomena that are not easily interpreted as the outcome of short‐term behavioral events. Using results from twelve years of geoarchaeological research in western New South Wales, we demonstrate that there is considerable variability in landsurface age, and hence the “availability” of archaeological surfaces, over relatively short distances. Therefore, it cannot be assumed that stone artifact deposits, for example, that appear to be similar in character are of similar age. Data are also presented that demonstrate that the presence of artifacts on the surface, their apparent absence in sediments buried beneath the surface, and the apparent recent ubiquity of the archaeological record are all a function of geomorphic processes that, at the same time, expose some artifact deposits at the surface and erode and bury others amid large volumes of sediment. Interpreting the surface artifact record within a spatial and temporal geomorphic framework is crucial to understanding the past human behavior that the artifact deposits represent. © 2009 Wiley Periodicals, Inc.     

Vertical distribution of living mangrove foraminifera from KwaZulu-Natal,South Africa

Modern foraminiferal assemblage zones can be used to reconstruct palaeo sea levels when applied to fossil foraminifera down a sediment core. Previous intertidal foraminiferal studies have predominantly focused on assemblages in surface sediments (0–1 cm), with the rationale that surface assemblages reflect the modern-day environment. Foraminifera live infaunally and therefore there is a need to document the infaunal vertical distribution of living foraminifera to fully capture the modern environment. Infaunal foraminiferal populations may compositionally differ from or be similar to those in the uppermost 1 cm of a core sample, but abundance is variable vertically, making it very complex to reconstruct and interpret past sea levels. This can have implications for the choice of assemblages to use as modern analogues for past sea-level reconstructions. This study documents the vertical infaunal distribution of living foraminifera, to allow for more informed interpretations of palaeo-reconstructions in mangrove environments. The down-core vertical distribution and abundance of living foraminifera, along with grain size and organic content, were documented using sediment cores along an elevational transect. Nine taxa were recorded as living at the time of collection, six of which were restricted to the top 4 cm. The majority of these were calcareous and found in the cores situated closer to the intertidal channel. Therefore, we argue that the diversity of living calcareous and agglutinated foraminifera could be restricted by grain size, with coarser grain sizes associated with lower species diversity. The findings suggest that foraminiferal species inhabiting the top 4 cm represent deeper living foraminiferal populations. Therefore, the top 4-cm interval can be used to establish a modern training set upon which reconstructions can be based. The findings from this study will provide guidance on the use of South African mangrove environments for future sea-level reconstructions.     

OSL dating of southeast Australian quartz: A preliminary assessment of luminescence characteristics and behaviour

Australian quartz has been widely considered particularly suitable for OSL dating of sediments. We present the results of a preliminary investigation into the luminescence characteristics and behaviour of quartz from various regions and depositional contexts across southeastern Australia. In doing so, we find that quartz from this region is generally well suited to the SAR protocol, although individual sample behaviour should nevertheless be assessed to confirm this. Furthermore, luminescence sensitivity appears to relate to depositional context, with aeolian samples exhibiting the highest sensitivity values, and lacustrine and periglacial sediments the lowest. The extent of a sample's sedimentary history, which in many cases is characteristic of the region from which it is derived, may also influence quartz sensitisation through repeated cycles of burial and reworking.     

Salt Spray Induces Osmotic Adjustment and Tissue Rigidity in Smooth Cordgrass, <Emphasis Type="Italic">Spartina alterniflora</Emphasis> (Loisel.)

Salt spray is one of many abiotic factors that can influence plant productivity and species composition in coastal ecosystems. However, little is known about how marsh plants respond physiologically to the accumulation of sea aerosols on foliar tissues. In this study, experimental microcosms maintained in controlled greenhouse conditions were used to evaluate how low- (1.7 mg dm⁻² day⁻¹, weekly averages) and high- (8.6 mg dm⁻² day⁻¹) salt-spray loads would influence plant–water relations in Spartina alterniflora (Loisel.). While no differences in plant performance (e.g., changes in biomass and leaf area) were observed between the treatments and control plants, a number of physiological modifications attributed to salt spray were observed. In general, salt-treated plants underwent significant decreases in water potential (Ψ) and osmotic potential (Ψ _π) and increases in leaf conductance (g) and bulk modulus of elasticity (ε). It is likely that these physiological responses were used to generate lower Ψ while maintaining osmotic and water homeostasis. That is, by decreasing Ψ _π and increasing g and ε, more efficient water flow through the soil–plant–atmosphere continuum can be achieved, thus generating lower Ψ without promoting loss of turgor.     

The close binary system SU Ind

Photometric data on the southern mid‐F type close eclipsing binary system SU Ind from the Carter Observatory (NZ) were examined, together with a light curve obtained from the Hipparcos Epoch Photometry (HEP) database. The system appears detached, although appreciably evolved from the Zero Age Main Sequence. The HEP period must be accurate for its own epoch, but it is significantly different from the reference (Hoffmeister 1956) value. This is difficult to explain, given the uncomplicated nature of the light curve. The apparent discrepancy can be reconciled with a period that has remained almost constant over the 40 year interval between the epochs by assuming some confusion between the almost equal depth minima. The near‐equality of components raises issues of determinacy in light curve analysis, which are reviewed against the presentation of relevant numerical curve‐fitting details. The system is of physical interest, in that it is close to the start of the ‘active’ range of spectral types. Its stars have relatively rapid rotation speeds and probably shallow convective subphotospheric layers. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

内蒙古西拉沐伦成矿带碾子沟钼矿床成矿流体地球化学特征

碾子沟钼矿床是内蒙古西拉沐伦钼多金属成矿带中石英脉型钼矿床的典型代表,矿体以石英大脉形式产于燕山期中粗粒黑云母二长花岗岩内,受断裂构造控制。流体包裹体研究发现包裹体均为气液两相,按照相比不同,可进一步分为WL型(5%～20%)和WV型(20%～50%)。Ⅰ阶段流体为低温(89.3～245.2℃)、中低盐度(2.07%～17.96%NaCleqv)流体;Ⅱ阶段流体具有中低温(134.4～458.8℃,峰值170℃～240℃)、中低盐度(0.53%～19.92%NaCleqv)特征;Ⅲ阶段流体为低温(134.9～202.4℃)、中低盐度(4.96%～14.97%NaCleqv)流体。流体成分均以H2O为主(96.1mol%),含少量挥发份CO2、N2、CH4、C2H6、Ar、H2S,阳离子以Na+为主,阴离子以SO42-、Cl-为主,属NaCl-H2O体系。各阶段成矿热液氢、氧同位素特征为:δ18OH2O介于-5.75‰～-1.90‰、δD介于-128.821‰～-109.234‰,说明成矿流体是岩浆热液与古大气降水混合而成。开放的断裂体系为流体混合创造了条件,流体的混合作用是造成碾子沟辉钼矿沉淀成矿的主要原因。这与斑岩型钼矿床的高盐度流体以及以沸腾为主的矿石沉淀机制具有显著区别。     

The Cawthron Institute Culture Collection of Micro-algae: a significant national collection

The Cawthron Institute Culture Collection of Micro-algae (CICCM) is a unique, nationally and internationally significant collection of 450 strains of approximately 100 micro-algae and 50 cyanobacteria species, both living and cryopreserved. The collection comprises 13 taxonomic classes and underpins research into the ecology and taxonomy of the isolates and the biotoxins they produce and their toxicity. The CICCM expanded significantly in the 1990s after a major harmful algae bloom event in the Hauraki Gulf, New Zealand. Since 2000, it has underpinned development of molecular detection tools and enabled development of new chemical testing methods for biotoxins in seafood. The tropical collection allows research into potential issues for New Zealand as the oceans warm, for example, the risks of ciguatera fish poisoning and palytoxins in seafood. Research results generated from isolates in the cyanobacterial collection have assisted national risk management regarding drinking water and informed the development of the New Zealand guidelines for managing cyanobacteria in recreational fresh waters. The actual living and cryopreserved micro-algae and cyanobacteria collection (without infrastructure) has a current estimated value of NZ$1.6 million.     

Data Infrastructures for Estuarine and Coastal Ecological Syntheses

Holistic understanding of estuarine and coastal environments across interacting domains with high-dimensional complexity can profitably be approached through data-centric synthesis studies. Synthesis has been defined as “the inferential process whereby new models are developed from analysis of multiple data sets to explain observed patterns across a range of time and space scales.” Examples include ecological—across ecosystem components or organization levels, spatial—across spatial scales or multiple ecosystems, and temporal—across temporal scales. Though data quantity and volume are increasingly accessible, infrastructures for data sharing, management, and integration remain fractured. Integrating heterogeneous data sets is difficult yet critical. Technological and cultural obstacles hamper finding, accessing, and integrating data to answer scientific and policy questions. To investigate synthesis within the estuarine and coastal science community, we held a workshop at a coastal and estuarine research federation conference and conducted two case studies involving synthesis science. The workshop indicated that data-centric synthesis approaches are valuable for (1) hypothesis testing, (2) baseline monitoring, (3) historical perspectives, and (4) forecasting. Case studies revealed important weaknesses in current data infrastructures and highlighted opportunities for ecological synthesis science. Here, we list requirements for a coastal and estuarine data infrastructure. We model data needs and suggest directions for moving forward. For example, we propose developing community standards, accommodating and integrating big and small data (e.g., sensor feeds and single data sets), and digitizing ‘dark data’ (inaccessible, non-curated, non-archived data potentially destroyed when researchers leave science).