Role of protein in larval swimming and metamorphosis of Bugula neritina (Bryozoa: Cheilostomatida)

Larvae of the marine cheilostomatid bryozoan Bugula neritina (L.) were prevented from settling for 1, 4 and 8 h by mechanical agitation, following which settlement and metamorphosis success were examined. Settlement rates were significantly affected by swimming time, which decreased from 100% after 2 h to 93.7 ± 4.3% after 8 h. Similarly, metamorphosis to the feeding ancestrula was significantly impaired following a swimming time of 8 h, declining from 93.7 ± 4.3% after 1 h to 65.9 ± 7.0% after 8 h. The resultant colonies grew well for the first 3 wk, following which time, growth patterns became erratic. Growth rate was in all cases highly variable, and did not correlate with enforced swimming times. Larval protein composition was examined after 1, 4 and 8 h swimming time, and post-larval composition 1, 2, 5, 24 and 48 h after settlement using sodium-dodecyl-sulphate polyacrylamide-gel electrophoresis (SDS-PAGE). Individual protein content was measured using a densitometer. Larvae did not consume protein during swimming, however a protein measuring 170 kdaltons was consumed during metamorphosis. These results are discussed in the context of larval settlement and energetics. Received: 19 July 1998 / Accepted: 3 December 1998     

Multiple lineages and absence of panmixia in the “circumpolar” crinoid <Emphasis Type="Italic">Promachocrinus kerguelensis</Emphasis> from the Atlantic sector of Antarctica

Despite considerable interest in physiology, evolution and life history of Antarctic marine invertebrates, only a limited number of studies have examined the genetic variability and diversity patterns of these organisms. Moreover, understanding and characterizing patterns of Antarctic biodiversity has taken on a degree of urgency because of potential impacts of global warming. To expand an understanding of the evolutionary history of Antarctic marine invertebrates, the genetic diversity of the crinoid Promachocrinuskerguelensis Carpenter, 1888 was investigated, which is documented to have a circumpolar distribution extending to subantarctic islands. Specimens of P. kerguelensis were collected from the western side of the Antarctic Peninsula, and the subantarctic islands South Georgia, South Sandwich and Bouvetøya Island from 2001 to 2004. P. kerguelensis was previously subject to morphological review that confirmed the taxonomic recognition of only one species. The wide distribution and reported high dispersal capability for P. kerguelensis predicts one large panmictic population. In contrast, nucleotide sequence data from mitochondrial cytochrome oxidase subunit I and cytochrome b genes, collected herein, reveal distinct genetic structure and cryptic speciation within P.kerguelensis. In the Antarctic Atlantic sector alone, there were at least five “species-level” clades. Some of these clades are geographically limited, and most exist in sympatry. The largest and most widespread of these clades was examined to help elucidate connectivity along the subantarctic islands of the Scotia Arc and the Antarctic Peninsula. Within this clade, most genetic diversity was contained within populations, but significant differences were present between regions (Antarctic Peninsula, South Sandwich Is., South Georgia, Bouvetøya Is.), suggesting a corresponding lack of gene flow. Given that P. “kerguelensis” is a well-studied taxon, the finding of considerable genetic diversity within the Atlantic sector alone suggests that the recognized diversity of Antarctica’s benthic marine life may be underestimated, and will rise dramatically with phylogeographic analyses of putative widespread species.     

Injection of innocuous oils to create reactive barriers for bioremediation: laboratory studies

In situ groundwater remediation may be achieved using stationary permeable barriers created by the injection of a substrate, such as innocuous vegetable oil, into the contaminated aquifer. The oil provides the electron donor stimulating microorganisms to degrade or sequester many contaminants. At present, little is known about the best procedures to use when injecting oil into an aquifer. In this investigation, laboratory column and sand tank studies were used as model systems to explore the effect of different injection parameters on the distribution of oil emulsions into water-saturated sand. The parameters investigated included injection pressures of 70, 1400 and 18,000 KPa; injection times of 15, 30, 60 or 120 s; and the influence of an emulsifier, polyoxyethylenesorbitan monooleate (Tween 80), upon the distribution of the injected oil. The longest injection patterns were achieved at 18,000 KPa. A pattern that was 46+/-1.8 cm long was produced with an 18,000 KPa injection for 60 s. Increasing the injection time to 120 s increased the length of the pattern by only 6.5%. Tween 80 at concentrations of 0.05% increased the width of the injection patterns but did not increase the length of the pattern. A multi-ported injection probe might be used to create in situ permeable barriers approximately 1 m wide.     

Results of the European Commission MARINA II study: part I--general information and effects of discharges by the nuclear industry

From the collated data relevant to discharges by the nuclear industry, it results that the input of beta activity (excluding Chernobyl fallout and tritium) into the OSPAR region decreased by a factor of 4 from 1986 to 1991, reaching by this date the same level as in the early 1950s. Over the same period the discharges of the alpha activity into the OSPAR region also decreased by a factor 3, the same trend has been seen also for tritium. Since 1986 the effective dose to members of the critical group in the vicinity of Sellafield and Cap de La Hague was consistently below the ICRP and EU limit of 1 mSv per year to members of the general public. The overall radiological impact from nuclear industry on the population of the European Union from the OSPAR area has decreased from 280 manSv y(-1) in 1978 to 14 manSv y(-1) in 2000.     

Use of vegetable oil in a pilot-scale denitrifying barrier

Nitrate in drinking water is a hazard to both humans and animals. Contaminated water can cause methemoglobinemia and may pose a cancer risk. Permeable barriers containing innocuous oils, which stimulate denitrification, can remove nitrate from flowing groundwater. For this study, a sand tank (1.1 x 2.0 x 0.085 m in size) containing sand was used as a one-dimensional open-top scale model of an aquifer. A meter-long area near the center of the tank contained sand coated with soybean oil. This region served as a permeable denitrifying barrier. Water containing 20 mg l(-1) nitrate-N was pumped through the barrier at a high flow rate, 1112 l week(-1), for 30 weeks. During the 30-week study, the barrier removed 39% of the total nitrate-N present in the water. The barrier was most efficient during the first 10 weeks of the study when almost all of the nitrate and nitrogen was removed. Efficiency declined with time so that by week 30 almost no nitrate was removed by the system. Nitrite levels in the effluent water remained low throughout the study. Barriers could be used to protect groundwater from nitrate contamination or for the in situ treatment of contaminated water. At the low flow rates that exist in most aquifers, such barriers should be effective at removing nitrate from groundwater for a much longer period of time.     

Larvicidal and repellent activity of N-methyl-1-adamantylamine and oleic acid a major derivative of bael tree ethanol leaf extracts against dengue mosquito vector and their biosafety on natural predator

Environmental Science and Pollution Research - Aegle marmelos (L.) Correa belongs to the family Rutaceae is generally known as “bael fruit tree” occuring across the south Asian...