Effects of seasonality on the reproductive cycle of <Emphasis Type="Italic">Diadema</Emphasis> aff. <Emphasis Type="Italic">antillarum</Emphasis> in two contrasting habitats: implications for the establishment of a sea urchin fishery

Reproduction of Diadema aff. antillarum was examined between 2002 and 2005 at subtidal rocky bottoms around the Canary Islands. Two contrasting habitats (urchin barrens and grazing fronts) characterized by different levels of food availability were chosen, and factors thought to influence reproductive periodicity were monitored, including temperature, photoperiod, phytoplankton abundance and benthic food availability. Histological analyses showed that D. aff. antillarum had an annual reproductive cycle that was relatively synchronous across the studied sites and habitats. Photoperiod was the most significant factor that correlated with gonad periodicity; benthic food availability of 2 month lag was also correlated. However, some differences were detected between males and females in the timing of the onset of gametogenesis. Spawning was synchronized between both sexes from June to August. Results suggest that the optimum time of year to harvest urchin gonads would be between May and June when gonads were maximal in size but not full of gametes. This species may not provide optimal conditions for an industrial scale fishery, as sea urchins occurring in high density had small gonads and those producing larger volume or more marketable gonad tissue occurred in low densities where harvesting costs would exceed profit.     

Allozyme heterozygosity and escape response performance of the scallops, <Emphasis Type="Italic">Argopecten purpuratus</Emphasis> and <Emphasis Type="Italic">Placopecten magellanicus</Emphasis>

Multilocus allozyme heterozygosity (MLH) has been positively correlated with growth in some marine bivalves and was suggested to facilitate swimming activity in pectinids. Using two highly mobile scallops, Placopecten magellanicus and Argopecten purpuratus, we examined escape response performance and morphometric characteristics as a function of allelic variability at metabolic loci. Ten allozyme systems were used for A. purpuratus and 7 for P. magellanicus. In each species, the morphometric characteristics and escape response parameters were analyzed separately using principal components analysis (PCA) and the scores of the major principal components were related to allozyme heterozygosity. In both P. magellanicus and A. purpuratus, positive correlations were found between MLH and morphometric parameters, but escape response parameters were only positively linked to MLH in P. magellanicus, and then weakly. The hypothesis that MLH improves fitness of pectinids by increasing the capacity to escape predators is not supported.     

Assessment of risk from lead intake in mining areas: proposal of indicators

Environmental Geochemistry and Health - This study discusses an estimate of the risk associated with the intake of soil contaminated by lead, based on the nature of the source, through a detailed...     

Long-term effects of amendment with liquid swine manure on proton binding behavior of soil humic substances

The acid-base properties of humic acids (HAs) and fulvic acids (FAs) isolated from liquid swine manure (LSM), soils amended with either 90 or 150 m(3)ha(-1)year(-1) of LSM for 7 years, and the corresponding unamended control soil were investigated by a current potentiometric titration method. The non-ideal competitive adsorption (NICA)-Donnan model for proton binding by two classes of binding sites (i.e., carboxylic- and phenolic-type groups) was fit to titration data, and a set of fitting parameters was obtained for each HA and FA sample. The NICA-Donnan model was shown to describe with a great degree of accuracy the behavior of experimental titration datasets, and highlighted important differences in the acid-base properties of the HAs and FAs examined. When compared to the unamended soil HA and FA, LSM-HA and LSM-FA, had smaller acidic functional group contents, larger proton binding affinities of both carboxylic- and phenolic-type groups, smaller heterogeneity of carboxylic-type groups, and smaller, in the case of HA, or similar, in the case of FA, heterogeneity of phenolic-type groups. Amendment with LSM caused a decrease of acidic functional group contents and a slight increase of proton binding affinities of carboxylic- and phenolic-type groups of soil HAs and FAs. Further, LSM application induced a decrease of the heterogeneity of carboxylic-type groups, whereas appeared not to affect substantially the heterogeneity of phenolic-type groups of LSM-amended soil HAs and FAs. These effects were more evident for HAs than for FAs and tended to slightly increase with increasing LSM amendment rate.     

Detection of copper(II) and zinc(II) binding to humic acids from pig slurry and amended soils by fluorescence spectroscopy

The effect of the consecutive annual additions of pig slurry at rates of 0 (control), 90 and 150 m3 ha(-1) yr(-1) after a 7-year period on the Cu(II) and Zn(II) binding behavior of soil HAs was investigated in a field experiment. A fluorescence titration method and a single site model were used for determining metal ion complexing capacities and stability constants of metal ion complexes of HAs isolated from pig slurry and unamended and amended soils. With respect to control soil HA, pig-slurry HA featured much smaller Cu(II) and Zn(II) binding capacities and stability constants. Pig-slurry application to soil decreased Cu(II) and Zn(II) complexing capacities and binding affinities of soil HA. These effects increased with increasing the rate per year of PS application to soil, and are expected to have a large impact on bioavailability, mobilization, and transport of Cu(II) and Zn(II) ions in pig slurry-amended soils.     

Organochlorine and heavy metal residues in the water/sediment system of the Southeast Regional Park in Madrid, Spain

A study into levels of contamination by organochlorine compounds (insecticides and PCBs) and heavy metals (Cd and Pb) in the water/sediment system of the Southeast Regional Park (SERP) in Madrid, Spain, has been carried out. Residue levels of xenobiotics were determined in surface and underground waters and sediments from selected sites throughout the protected area. The results showed these contaminants to be widespread throughout the studied area. p,p'-DDT concentration levels were consistently higher than its metabolite p,p'-DDE, indicating a recent use of this organochlorine insecticide in the area. PCB levels exceeded, in the majority of the cases, the levels taken as the maximum (100 ng/microl) for highly polluted waters. Cd and Pb levels found in water samples were under the detection limits of the methodology used. Pb levels found in sediment samples were higher than Cd.     

Occurrence,impact, and elimination of contaminants of emerging concern (CECs) in soil,water, and air streams: advances and challenges in Ibero-American countries

Environmental Science and Pollution Research -