Metals in the shell of Bathymodiolus azoricus from a hydrothermal vent site on the Mid-Atlantic Ridge

Specimens of the mussel Bathymodiolus azoricus were collected from Menez Gwen, a relatively shallow (850 m) hydrothermal vent field on the Mid-Atlantic Ridge. Each bivalve shell (n = 21) was individually cleaned by selective chemical. The residual crystal matrix of each shell was individually analysed for the concentrations of the minor elements magnesium and strontium and the trace elements iron, manganese, copper and zinc. The chemical composition of the crystal matrix is unusual. B. azoricus is identified as a species having one of the most strontium impoverished shells amongst the marine molluscs. For a bimineral species the magnesium concentration is also extraordinary low. Despite originating from a trace metal rich environment; the metal concentrations in the shells were exceptionally low. Mean concentrations of iron, manganese, copper and zinc were 20.6, 3.7, 0.6 and 9.4 microg g(-1) respectively. Minor and trace element concentrations exhibited a marked intra-population variability. Copper concentrations increased and iron and zinc concentrations decreased with increasing shell weight. Due to its insensitivity to the high environmental levels of trace elements and the variability in intra-population concentrations induced by shell weight the crystal matrix of the shell of B. azoricus has little potential for use in environmental trace metal monitoring in areas contiguous to deep-sea hydrothermal vents.     

Evidence for Ph Insensitivity in Some Insects Inhabiting Peat Pools in the Loch Fleet Catchment

The impact of liming on the insects associated with peat pools was studied in the Loch Fleet catchment in 1991 and 1992. Fifty-six taxa were identified from 121 timed samples. Despite the raised pH associated with liming in 1986, the population densities of Odonata, Hemiptera and Coleoptera appeared to be unaffected when compared with those of untreated peat pools in the same area. the study demonstrated the existence of two main types of community, that of the steep-sided edges of pools, dominated by odonate nymphs and large species of beetles, and that of the shallower pools, dominated by Hydroporus species (Col., Dytiscidae).     

Shifts in coral community structures following cyclone and red tide disturbances within the Gulf of Oman (United Arab Emirates)

This study documents the effects of two consecutive disturbances on coral community structures in the Gulf of Oman (United Arab Emirates); Cyclone Gonu in June 2007 and the Cochlodinium polykrikoides harmful algal bloom (HAB) that persisted from August 2008 until May 2009. Coral cover, colony densities, size class frequency distributions, and geometric growth rates derived from size class transition probability matrices were used to assess the post-Gonu and post-HAB recovery trajectories at four sites. The net effects of these disturbances were fourfold: (i) storm damage caused >50% losses of live branching and tabular coral cover by fragmentation and dislodgment of pocilloporid and acroporid colonies; (ii) Pocillopora damicornis colonies that survived the cyclone experienced mass mortality during the first 3?months of the HAB, resulting in localized extirpation of this species; (iii) variable Acropora mortality during the HAB indicated individual colony, rather than taxa-wide, susceptibility; and (iv) massive colony coral taxa were resistant to both disturbances.     

Influence of pine wood shavings on the pyrolysis of poultry litter

Poultry litter from broilers and turkeys are a mixture of manure, feathers, feed and wood shavings, thus pyrolysis oils produced from this material are influenced by the individual components. In order to determine the influence of wood shavings that are used as bedding material, we investigated the pyrolysis of pine wood shavings and poultry manure. Because manure from layer chickens are usually not contaminated with wood shavings, we made mixtures of layer manure and pine wood shavings in the following manure to wood ratios, 100:0, 75:25, 50:50, 25:75, and 0:100 w/w and pyrolyzed them in a fluidized bed reactor at 450 °C. The total liquid yield ranged from 43.3 to 62.7 wt.%. The layer manure oil had a HHV of 29.7 MJ/kg and pH of 5.89 compared to pine wood oil which had HHV of 25.6 MJ/kg and pH of 3.04. The addition of wood shavings to manure clearly influenced the physical properties of the oil, resulting in a decrease in pH and HHV and an increase in density. The oils had relatively high nitrogen content ranging from 1.36 to 5.88 wt.%. The ash (<0.07 wt.%) and sulfur (<0.28 wt.%) contents were very low. FTIR, ¹³C NMR and ¹H NMR spectrometric analysis of the oils showed that manure oil was rich in hydrocarbons and nitrogenous compounds such as primary, secondary amides, aromatic amines and N-heterocyclic. The properties of the oils were strongly influenced by the amount of wood in the mixture.     

Potential Interference Between a Threatened Endemic Thistle and an Invasive Nonnative Plant

Although the establishment of nonnative plants is recognized as a threat to native ecosystems, there are few documented examples of an invasive species directly influencing a rare native plant. The Eurasian biennial Dipsacus sylvestris (teasel) is invading the central New Mexico habitat of Cirsium vinaceum , an endemic thistle that is federally listed as threatened. We documented changes in teasel distribution and abundance between 1989 and 1993 that suggest the potential for direct interactions with the native thistle. We then compared habitat characteristics, germination behavior, and performance in greenhouse and field competition trials to evaluate the potential outcome of interference between these two species. There were no significant differences in measured habitat characteristics between sites supporting C. vinaceum and those with D. sylvestris. Dipsacus was better able to germinate in low light than the thistle, suggesting that D. sylvestris might invade C. vinaceum populations but that thistle recruitment would be unlikely in dense stands of the nonnative plants. In the greenhouse growth of C. vinaceum rosettes was significantly reduced by the presence of Dipsacus , but the invader was unaffected by the thistle; results of a short-term field experiment were equivocal but suggestive of interference between the two. We suggest criteria for managers to use in determining whether invading species pose problems for specific rare native taxa, and we discuss the constraints on experimental work where protected taxa are involved.     

Metabolic fate and elimination in milk, urine and bile of deoxynivalenol following administration to lactating sheep

Using a combination of radioisotopic counting and chromatographic detection techniques, the kinetics and metabolic fate of deoxynivalenol (DON) in plasma, urine and bile were studied in lactating sheep, as was the transmission of residues to milk. Following intravenous administration, the plasma clearance of 14C-DON-derived radioactivity was rapid and followed a tri-phasic decay curve comprised of a bi-exponential decrease in DON (rapid distribution phase, t1/2 alpha = 16.2 min; slower elimination phase t1/2 beta = 66.5 min) and the formation and elimination (t1/2 beta = 188.0 min) of its major plasma metabolite, DON-glucuronide conjugate, which accounted for 13% of the plasma radioactivity levels. DON was rapidly cleared from the body by metabolism to 7 possible metabolites, which were excreted essentially in the urine (91%) and to a lesser extent in the bile (6%). Most (67%) of the recovered radioactivity was in the form of the glucuronide conjugates of DON (54%) and the de-epoxide metabolite, DOM-1 (13%). Excretion of unmetabolized DON accounted for 11%. The remaining recovered dose (18%) comprised of minor amounts of DOM-1 (6%), DON-sulfate conjugate (2%) and 3 unidentified radioactive components (10%). Studies on the presence of DON-derived residues in milk indicated that, relative to the dose, only trace amounts were transmitted following either oral or iv administration of the toxin.     

Partitioning of trace metals between soft tissues and shells of Patella aspera

This paper describes the partitioning of iron, manganese, zinc, copper, cadmium, cobalt, nickel and lead between the soft tissues and the shells of the gastropod mollusc Patella aspera. Specimens of the limpet P. aspera were collected from a clean coastal marine site (CMS) and from an estuarine contaminated site (ECS) on the south coast of Portugal. Fe and Zn concentrations were significantly lower on both populations and less variable in the shells than in the soft tissues. In contrast Mn concentrations were higher in the shells than in the soft tissues at ECS. The partitioning factor (PF), defined as the ratio between the mean metal concentrations in soft tissues and in the shells, was maximum for iron and minimum for manganese. Between the soft tissues and the shells, only manganese at ECS recorded a significant relationship between metal concentrations, suggesting that the mechanism that controls the accumulation of this essential metal in both tissues was different from the others. From the obtained data, in biomonitoring sewage contamination studies, shells of P. aspera can be considered as a good indicator for Mn while the soft tissues for Zn. As copper, cadmium, nickel and cobalt concentrations were much higher in the soft tissues than in the shells (< 0.1 microg g(-1)), this indicates that the shells were not a good indicator for these metals because they do not reflect the environmental bioavailability as do the soft tissues.