Individual growth and size-selective mortality of larval turbot (Scophthalmus maximus) reared in enclosures

Larval turbot (Scophthalmus maximus) were reared in a large marine enclosure and in plastic bags in southern Norway. Samples of larvae in the enclosure were taken during the first 12 d of life to estimate individual body growth based on back calculations from daily growth rings on their otoliths. Size selective mortality was documented for these larvae in the predator-free enclosure. Starvation in the laboratory occurred on the seventh day. In the enclosure, a mortality rate of 18.1% d^-1 prevailed. Our data indicates that the survivors beyond the starvation period are larger by 0.18 mm on average. This result is important with regard to the question of whether starvation is an important mechanism for larval mortality in the sea. A possible means of estimating the relative effects of starvation versus predation based on these results and the backcalculation technique is suggested.     

Growth increments in the shell of the living brachiopod Terebratalia transversa

Scanning electron micrographs revealed growth increments in the primary shell layer of the extant terebratulid brachiopod Terebratalia transversa collected from Anacortes, Washington, USA, during the summers of 1982–1984. The increments extend into the secondary shell layer, but only as poorly-defined continuations. Growth increments narrow and widen cyclically, producing patterns similar to tidally-induced, fortnightly growth patterns in bivalve molluscs. Asymmetric increments or doublets that consist of paired wide and narrow bands present additional evidence that the growth pattern is produced by the interference of tidal (24 h 50 min) and solar (24 h) daily environmental influences on growth, as is the case in bivalves. Growth increments are relatively well-defined in specimens from tidal habitats and are poorly-defined in subtidal specimens. Specimens grown in laboratory aquaria and subjected to simulated tidal emersions and submersions had well-defined increments, whereas those that were continuously submerged in aquaria had poorly-defined increments, paralleling the distinctness in growth increments produced at various depths in the natural habitat. Production of growth increments in T. transversa may be related to valve movement and changes in mantle-cavity pH. When the valves are closed, pH drops and, when they are open, pH rises. Highperformance liquid chromatography (HPLC) of mantle tissue and fluid failed to detect any single organic acid that could have been responsible for the pH changes, confirming that intermediate metabolism in T. transversa is very low compared to that of bivalve molluscs. Calculations indicate that cycles in intermediate metabolism may nevertheless be responsible for cycles in growth-increment production and shell dissolution.Please address all correspondence to Dr. G.D. Rosenberg in Indianapolis     

Fate of ϵ-caprolactam in the aquatic environment

The rate and extent of ?-caprolactam degradation in aquatic systems are dependent on the nutrient availability, indigenous microbial population and activity, chemical concentration, and water temperature. The labeled chemical evolved ¹⁴CO₂ indicating ring cleavage with between 35 and 80% of the radioactivity evolved as ¹⁴CO₂ after 21 days in yeast extract-supplemented waters. The percent of caprolactam degraded was indirectly related to the chemical's concentration in the water, suggesting microbial inhibition at high caprolactam concentrations.     

Alarm signal response in the brittle star Amphiura filiformis

 Flat fishes, such as the dab Limanda limanda, commonly prey on arms of Amphiura filiformis. We demonstrate in flume experiments that A. filiformis showed a more or less simultaneous response to an up-stream predation by dab on conspecifics: the arms, which are stretched up into the water column when filter feeding, responded by bending down to the sediment surface, and some arms submerged, at least partly, into the sediment. We interpret this as an alarm response. A similar, but significantly weaker response in A. filiformis was also recorded when dab ate Amphiura chiajei. Homogenates of the two Amphiura species and arm pinching – to simulate partial predation – elicited a similar response in A. filiformis, the arms bent to the sediment surface. In contrast, however, the behavioural response of the arms to the homogenates was to protrude further out of the sediment and sweep the surface vigorously. We interpret this as a feeding behaviour. Response to arm pinching was less clear. The ecological consequences and origin of alarm signal response in A. filiformis are discussed. Received: 8 February 1999 / Accepted: 16 July 1999     

Importance of insects in environmental impact assessment

Insects are particularly suited for use in environmental impact assessment (e.i.a.) because of their high species diversity, ubiquitous occurrence, and importance in the functioning of natural ecosystems. Examples are given of the use of insects in the predictive phase of e.i.a., in the monitoring and assessment phase, and in the much rarer instance of an e.i.a. that includes both of these phases. The importance of working at the species level to understanding the results of e.i.a. is emphasized.     

SIMULATED IMPACTS OF EL NINO/SOUTHERN OSCILLATION ON UNITED STATES WATER RESOURCES1

ABSTRACT: The El Nino/Southern Oscillation (ENSO) phenomena alter global weather patterns with consequences for fresh water supply. ENSO events impact regions and their natural resource sectors around the globe. For example, in 1997 and 1998, a strong El Nino brought warm ocean temperatures, flooding, and record snowfall to the west coast of the United States. Research on ENSO events has improved long range climate predictions, affording the potential to reduce the damage and economic cost of these weather patterns. Here, using the Hydrologic Unit Model for the United States (HUMUS), we simulate the impacts of four types of ENSO states (Neutral, El Niño, La Niña, and strong El Niño) on water resources in the conterminous United States. The simulations show that La Niña conditions increase water yield across much of the country. We find that water yield increases during El Niño years across the south while declining in much of the rest of the country. However, under strong El Niño conditions, regional water yields are much higher than Neutral, especially along the West Coast. Strong El Niño is not simply an amplification of El Niño; it leads to strikingly different patterns of water resource response.     

Local participation, international politics, and the environment: the World Bank and the Grenada Dove

The process of locating waste disposal sites in the Eastern Caribbean country of Grenada illustrates important lessons in the implementation of new international mandates to invite stakeholder participation in projects with environmental and social impacts. This case study analyzes the participatory methods and results of the World Bank-funded project in Grenada, including an unexpected shift in the policy agenda toward habitat protection for the elusive Grenada Dove, the national bird of Grenada. We conclude that the impact of new requirements for stakeholder inclusion by funding agencies such as the World Bank and Global Environmental Facility has been palpable, but mixed. As the catalysts of more participatory methods, funding agencies still must give more careful consideration to the methods by which their participatory requirements are implemented. In particular they must develop more effective knowledge of and relationships with a broader range of stakeholders than are routinely considered by existing methods, allow for and learn from unexpected contingencies, and be flexible as to project goals and methods.     

Sorption of SO2 on Ground Nahcolite Ore

Large quantities of nahcolite ore, a naturally occurring mineral containing between 70 and 90% sodium bicarbonate are known to occur in the Green River Formation of the Piceance Creek Basin of northwestern Colorado.¹ Deposits occur in two major forms, as either bedded or disseminated ore. In the latter case, the host rock is oil shale, a dolomitic marlstone containing kerogen material. Bench and pilot scale studies have shown finely divided nahcolite ore to be an effective SO₂ sorbent in baghouse filters.² These studies form the basis of the nahcolite ore injection process as a means for controlling SO₂ emissions to the environment.³ Although there have been published investigations of reactions of SO₂ with Na₂CO₃and NaHCO_3, ⁴ no reference could be found to a systematic study of nahcolite ore reacting with SO₂.