Exposure of mediterranean countries to ocean acidification

This study examines the potential effects of ocean acidification on countries and fisheries of the Mediterranean Sea. The implications for seafood security and supply are evaluated by examining the sensitivity of the Mediterranean to ocean acidification at chemical, biological, and macro-economic levels. The limited information available on impacts of ocean acidification on harvested (industrial, recreational, and artisanal fishing) and cultured species (aquaculture) prevents any biological impact assessment. However, it appears that non-developed nations around the Mediterranean, particularly those for which fisheries are increasing, yet rely heavily on artisanal fleets, are most greatly exposed to socioeconomic consequences from ocean acidification. © 2014 by the authors; licensee MDPI, Basel, Switzerland

Estimation of the solubility parameters of model plant surfaces and agrochemicals: a valuable tool for understanding plant surface interactions

Background Most aerial plant parts are covered with a hydrophobic lipid-rich cuticle, which is the interface between the plant organs and the surrounding environment. Plant surfaces may have a high degree of hydrophobicity because of the combined effects of surface chemistry and roughness. The physical and chemical complexity of the plant cuticle limits the development of models that explain its internal structure and interactions with surface-applied agrochemicals. In this article we introduce a thermodynamic method for estimating the solubilities of model plant surface constituents and relating them to the effects of agrochemicals. Results Following the van Krevelen and Hoftyzer method, we calculated the solubility parameters of three model plant species and eight compounds that differ in hydrophobicity and polarity. In addition, intact tissues were examined by scanning electron microscopy and the surface free energy, polarity, solubility parameter and work of adhesion of each were calculated from contact angle measurements of three liquids with different polarities. By comparing the affinities between plant surface constituents and agrochemicals derived from (a) theoretical calculations and (b) contact angle measurements we were able to distinguish the physical effect of surface roughness from the effect of the chemical nature of the epicuticular waxes. A solubility parameter model for plant surfaces is proposed on the basis of an increasing gradient from the cuticular surface towards the underlying cell wall. Conclusions The procedure enabled us to predict the interactions among agrochemicals, plant surfaces, and cuticular and cell wall components, and promises to be a useful tool for improving our understanding of biological surface interactions

An experimental study of ²²⁶Ra and ⁴⁵Ca accumulation from the aquatic medium by freshwater turtles (fam. Chelidae) under varying Ca and Mg water concentrations

Snapping turtles Elseya dentata (Gray) from Magela Creek, Northern Territory, were exposed under laboratory conditions for up to 30 days to waters resembling the inorganic composition of Magela Creek water during the Wet season, with background and elevated Ca and Mg concentrations, that were labelled with 226Ra and 45Ca. The resulting concentrations of 45Ca in muscle, skin, gut, liver, shell bone and leg bone of E. dentata equilibrated or approached equilibrium by 12-18 days. Among the experiments, the concentrations of 45Ca in all six tissues were inversely related to turtle mass. An increase in the Ca water concentration by a factor of 15 increased the 45Ca concentration in all six tissues. The arithmetic factors of increase in the concentration in each tissue were proportional or more than proportional to the factor of increase in Ca water concentration; this factor was highest for muscle tissue (26.6). An increase in the Mg water concentration by a factor of 48 reduced the 45Ca concentration in all tissues except skin where it increased. The concentration of 226Ra in each tissue (except the gut) was positively related to its 45Ca concentration and inversely related to turtle mass in muscle, skin and liver. With the exception of the skin, the increased Ca water concentration did not reduce the 226Ra in the tissues but increased the 226Ra concentration in bone and muscle. The increased Mg water concentration had an inverse effect on the 226Ra concentrations in all tissues except shell. With the exception of the skin the effects of increased Ca and Mg water concentrations and turtle size on 226Ra concentrations in the tissues of E. dentata were similar to their effects on 45Ca tissue concentrations, indicating the similar metabolic behaviour of 226Ra and 45Ca in E. dentata. Exposures of the species Elseya latisternum (Gray), Emydura signata (Ahl) and Chelodina longicollis (Shaw), which are the same or closely related to species reported to occur in Magela Creek, to 45Ca-labelled Sydney tap water for 7 days demonstrated their ability to also accumulate 45Ca from their aquatic medium. The patterns of 45Ca concentrations in the tissues of these species indicated that they were inversely related to turtle mass, as demonstrated in E. dentata. The concentrations of 45Ca accumulated in the tissues were also comparable to those found in single specimens of E. dentata and E. victoriae (Gray) that were exposed for 7 days to simulated Magela Creek water. The data also indicated the larger long-necked C. longicollis accumulated less 45Ca per gram of tissue than similar-sized, short-necked species E. signata and E. latisternum, suggesting that long-necked turtles from Magela Creek would accumulate less 226Ra from their aquatic medium than similar-sized short-necked species. The capacity of E. dentata to accumulate 226Ra from the aquatic medium is about two orders of magnitude less than that of the tissue of the freshwater mussel Velesunio angasi (Sowerby) exposed under similar experimental conditions. © 1991 Kluwer Academic Publishers

Experimental comparison of the bioaccumulation of anthropogenic radionuclides by egg and juvenile life stages of a small shark

© 2017 Elsevier Ltd This study compared the bioaccumulation of anthropogenic nuclides (65Zn, 134Cs, 60Co and 241Am) between the egg and juvenile life stages of a small shark (Scyliorhinus canicula), based on previously published experimental data. Rates of accumulation over 15 days were derived and summed for the transfer pathways which were specific to these two life stages. Radionuclide transfers to the egg and its embryo & yolk were quantified for i) the maternal pathway following her uptake of radionuclides via food and seawater and ii) from seawater following its oviposition. For the juvenile, the transfer of radionuclides were measured for aqueous & dietary pathways. The results show that, compared to juveniles, eggs have equivalent rates of accumulation of 65Zn and 134Cs but enhanced accumulation of 241Am by a factor of five and of 60Co by two orders of magnitude. The radiological exposure of the embryo due to radionuclides maternally transferred to the embryo & yolk is also enhanced for the alpha-emitting 241Am. This enhanced accumulation of 241Am and 60Co, as well as the equivalent accumulation of 65Zn and 134Cs, suggest greater likely vulnerability to radiation damage in eggs as compared to juveniles. Radiological dose assessment confirmed highest doses to the egg which is predominantly due to accumulated 241Am

Mining pollution and the diet of the purple-striped gudgeon Mogurnda mogurnda Richardson (Eleotridae) in the Finniss River, Northern Territory, Australia

During the dry season of 1974, collections of the purple-striped gudgeon Mogurnda mogurnda were taken from the Finniss River of the Northern Territory; during the wet season, this river receives acidic and metallic pollutants from the formerly mined area of Rum Jungle. The fish consumed a great variety of foods, with high abundances of Dytiscidae, Chironomidae, Ceratopogonidae, Trichoptera, Odonata, Copepoda, Decapoda, and Pisces. Within polluted and unpolluted zones of the river, the dietary abundances of some foods varied with the size of the consuming fish and with habitat descriptors. For no food was there a significant regression against habitat descriptors in both of the zones; this emphasizes that pollution effects are more complex than simply depressing or raising the abundances of the dietary species. Five foods were more abundant in the diets of the polluted zone, and three in those of the unpolluted zone. The dietary abundances of two foods, both crustacean, increased in the polluted zone, compared to the unpolluted zone, through the dry season. Two categories of foods: (1) those obtaining oxygen directly from the atmosphere or via a film or bubble of air; and (2) the converse set (aquatic respirers), were contrasted for their usefulness in distinguishing between the zones, by both hierarchical agglomerative and discriminant function analyses. Aquatic respirers were the more effective. The polluted collections were more heterogeneous than the unpolluted ones in both the hierarchical and the discriminant analyses. One collection from the polluted zone was reclassified as unpolluted on the basis of its grouping behavior. The relevance for pollution studies of dietary analysis of euryphagous fish, rather than sampling aquatic fauna directly, is discussed in terms of food substitution, switching, strategies for abundance and recovery by the fauna, and possible effects of the pollutants on the fish as an intervening collector. Downstream patterns of abundance of the invertebrate fauna in this study are broadly similar to those of other studies in which such chemically diverse metals as Pb, Zn, and Cu are the pollutants, but there are differences for some faunal components. Difficulties in the comparison and causal interpretation of results of pollution studies in the field stem from a lack of experimental data on tolerances to pollutants and causes of abundance of stream invertebrates. However, because of the great detail required in such data, more profit for purposes of prediction may derive from experimental multivariate studies on faunal assemblages

The Finniss River: a natural laboratory of mining impact- past present and future.

The Rum Jungle uranium-copper mine in tropical northern Australia has been a source of acid rock drainage contaminants since the 1950s which have had adverse impacts on the receiving waters of the Finniss River. Mine site remediation began in 1982 followed by long-term monitoring of water quality and flow based on daily measurements within the Finniss River system. A decade or more after the initiation of these remedial activities a set of investigations have been completed that have measured the post-remedial ecological status of the Finniss River system relative to this environmental benchmark. These studies have also been complemented by studies on various other ecological endpoints. Moreover the Finniss River system has provided unique opportunities for broader scientific goals to be pursued. Because it has been so well-monitored it can be viewed as a natural laboratory to investigate the impacts of acid rock drainage on tropical freshwater biodiversity. The scientific papers presented at this symposium address a broad spectrum of issues that are directly related to environmental sustainability and mining. The topics range across future contaminant scenarios and their predicted ecological impacts the various metrics used to assess ecological detriment to biodiversity the abilities of laminated biological structures to act as archives of pollution history and also spin-off applications in environmental and wildlife management. Furthermore the participation of many stakeholders in open discussion during the symposium provided an important set of views and opinions on the needs for future studies in the Finniss River system

Accumulation of Radiocalcium From the Aquatic Medium Via the Cloaca and Bucco-Pharynx of Australian Fresh-Water Turtles (chelidae)

1. The cloacal and bucco-pharyngeal regions of three species of Australian freshwater turtles were experimentally compared for their ability to take up radiocalcium directly from the aquatic medium

Marine radionuclide transfer factors in chordates and a phylogenetic hypothesis

Previous radiotracer experiments that compared multi-elemental whole organism: water transfer factors among chondrichthyan and teleost fishes, including an ICRP reference flatfish Psetta maxima, demonstrated distinctive contrasts in their bioaccumulation characteristics, with generally elevated bioaccumulation in chondrichthyans. These results supported a hypothesis that phylogenetic divergence may influence marine radionuclide transfer factors. This notion has been further evaluated in an amphioxus species Branchiostoma lanceolatum, sub-phylum Cephalochordata. This taxon diverged about 800 MYBP from a common ancestor of the teleosts and the chondrichthyans, which in turn diverged from each other around 500 MYBP. Our experimental results indicate that amphioxus is indeed more divergent in its multi-elemental bioaccumulation patterns from teleosts and chondrichthyans than they are from each other, consistent with our hypothesis. The experimental comparisons with the ICRP reference flatfish P.maxima also revealed an unexpectedly enhanced capacity in amphioxus to accumulate all eight tested trace elements from seawater, and for some by more than two orders of magnitude. These results have practical applications for the strategic selection of marine biota for further radioecological investigations to better guarantee the radiological protection of marine biodiversity. Such seemingly anomalous results for understudied biota like amphioxus and chondrichthyans suggest that more effort in marine radioecology be directed to assessing the bioaccumulatory capacities of other phylogenetic groups that have received less attention so far, particularly those that are phylogenetically more remote from commonly investigated taxa and those nominated as ICRP marine reference organisms. © 2012 Elsevier Ltd