Metal accumulation by wood-decaying fungi

Metal concentrations (Na, K, Rb, Mg, Ca, Sr, Mn, Fe, Cu, Zn, Cd, Al, and Pb) in the sporophores of ten wood-decaying macromycete species were related to concentrations in the wood substrates. Manganese, Sr, Ca, and Pb were usually excluded by the fungi, K, Rb, and, to a lower degree, Cd, Fe, Zn, Cu, Mg and Na, were accumulated. Accumulation ratios are compared with similar ratios for soil and litter inhabiting species previously studied.     

A field study of the generation of nitrate in a hill cap cloud

A field experiment to investigate the formation of nitrate as an airstream passes through a hill cap cloud has been performed at the UMIST field station on Great Dun Fell. It has been shown that the aerosol nitrate concentration increased by about 0.5 microg m(-3) as the airstream passed through the cloud during the night. At sunrise the nitrate production disappeared. It is suggested that the most likely mechanism for this nitrate production was due to the solution of N2O5 and NO3 formed from the reaction of NO2 with O3. These higher oxides build up overnight in the absence of short wave radiation to photolyse them. Other possible mechanisms of nitrate production are also discussed.     

Reproductive strategies and diet in deep-sea nuculanid protobranchs (Bivalvia: Nuculoidea) from the Rockall Trough

Although the taxonomy of deep-sea protobranch bivalves is becoming better known, relatively little information is available on their reproductive biology and whether or not populations show reproductive periodicities. We have examined the reproductive biology of three common sympatric species as part of a long-term time-series of samples taken from 2900 m in the Rockall Trough from 1973 to 1983. Malletia cuneata Jeffreys, 1876 produces a maximum of 30 oocytes at any one time and these grow to a maximum size of 240 m. Maximum fecundity of Ledella pustulosa (Jeffreys, 1876) and Yoldiella jeffreysi (Hidalgo, 1877) is 174 and 360, respectively, and both species produce an egg of 120 m in diameter. These data indicate lecithotrophic early development in L. pustulosa and Y. jeffreysi, but direct development in M. cuneata; however, evidence from the prodissoconch length of M. cuneata suggests lecithotrophic development. L. pustulosa and Y. jeffreysi also differ from M. cuneata in having a distinct reproductive cycle with spawnout in the winter months. Both the continuously breeding M. cuneata and the seasonally breeding L. pustulosa ingest diatoms, coccoliths and foraminiferans, but whereas the diet of M. cuneata appears to be constant throughout the year there is an apparent reduction in the feeding activity of L. pustulosa concomitant with the deposition of phytodetritus on the deep-sea bed.     

Egg mass and shell thickness in dippers Cinclus cinclus in relation to stream acidity in Wales and Scotland

The shell thickness and mass of eggs of the dipper (Cinclus cinclus) collected on streams of different pH in Wales and Scotland were measured. The aluminium, phosphorus and calcium content of their invertebrate prey were also measured. In a regression analysis, significant at p<0.05, stream pH accounted for up to 7% of the variance in shell thickness, with shells decreasing by 2.5% of the overall mean with each unit of pH decline. In the Welsh sample, differences in shell thickness due to pH were small compared with differences between years across all sites. In data pooled between Scotland and Wales, pH accounted for 17% of the variance in egg mass, but a greater proportion (25%) in Scottish eggs alone. Aluminium concentrations in invertebrates showed no relationship with stream pH, but calcium levels in two insect orders increased significantly with pH. Calcium rich prey, such as Gammarus, were found only in circumneutral streams. The importance of calcium in the diet of dippers before and during egg formation is discussed. No evidence that aluminium in prey adversely affected dipper eggs was found.     

An ecologically oriented database to guide remediation and reuse of contaminated sites

This article presents a database developed to determine the potential reuse of contaminated sites for primarily ecologically and culturally based activities. The database consists of 172 quantitative and qualitative measures of on‐site land suitability, ecological, cultural, and recreational value, and off‐site suitability, economic, and demographic information. Using sites owned by the U.S. Department of Energy (DOE) as a case study, the article evaluates the quality of available data and suggests ways of using it for planning ecologically sensitive remediation activities and future land use. This type of database can be developed and used by anyone who needs to select, review, or evaluate site remediation and future land use options. Also discussed are the challenges associated with compiling and using data that has been generated by many sources over several years. © 2003 Wiley Periodicals, Inc.     

Very slow development in two Antarctic bivalve molluscs,the infaunal clam <Emphasis Type="Italic">Laternula elliptica</Emphasis> and the scallop <Emphasis Type="Italic">Adamussium colbecki</Emphasis>

Embryos of the large infaunal clam Laternula elliptica and the scallop Adamussium colbecki, from Antarctica, were cultured over an 18-month period. Their development rates were extremely slow, taking 240 and 177 h, respectively, to reach the trochophore stage. This is ×4 to ×18 slower than related clams and scallops from temperate latitudes. The relationship between temperature and development rate for bivalve molluscs shows the expected slowing with reduced temperature (Q ₁₀ in the range 2–4) for temperate and tropical species. However, the slowing at polar latitudes is much stronger than at warmer waters, and all of the limited data for Antarctic species are well above the Arrhenius plot for the overall bivalve data, and the Q ₁₀ value for Antarctic to cool temperate species is 11.8, well outside the expected range for biological systems. Either the relationships describing the effects of temperature on the kinetics of biological systems do not apply to Antarctic bivalve molluscs, or some other factor that cannot be compensated for becomes important at low temperature. In the laboratory, L. elliptica embryos stayed viable in very sticky egg capsules for up to 18 months without hatching. However, even the disturbance of removing eggs using a pipette ruptured some egg capsules allowing embryo release. Gametogenesis in Antarctic marine invertebrates is almost universally slowed compared to temperate species, with nearly all cases documented requiring more than 1 year to complete oogenesis. The only exception so far appears to be A. colbecki, which has a 1-year gametogenic cycle. The data here indicate that it has been unable to adapt embryonic development in a similar way, and we are not aware of any exceptions to the markedly slowed development at low temperature rule.     

Reproductive isolation among morphotypes of the Atlantic seastar species<Emphasis Type="Italic"> Zoroaster fulgens</Emphasis> (Asteroidea: Echinodermata)

Zoroaster fulgens is a slope-dwelling seastar species that is distributed throughout the Atlantic Ocean. Studies into the population structure and systematics of marine animals have increasingly found that species with a reported cosmopolitan distribution are, in fact, collections of closely related cryptic or sibling species. In the Porcupine Seabight, three morphotypes of Z. fulgens can be found that have a distribution that is stratified by depth. This study investigates the genetic divergence between these morphotypes using sections of the cytochrome oxidase 1 (COI) and 16S regions of the mitochondrial genome. Bathymetrically separated morphotypes of Z. fulgens are reproductively isolated over distances of approximately 1 km while gene flow occurs among morphotypes, along isobaths, over distances of approximately 900 km. Reproductive isolation on the continental slope may have occurred as a result of selection exerted by gradients of depth-correlated physical factors, such as pressure and temperature. However, allopatric speciation with subsequent range expansion may also explain the observed patterns of genetic divergence. Further investigation of radiation within this group may provide important information on the evolution of slope species. Taxonomic revision of the genus is required.Communicated by J.P. Thorpe, Port Erin     

Nitrogen inputs promote the spread of an invasive marsh grass.

Excess nutrient loading and large-scale invasion by nonnatives are two of the most pervasive and damaging threats to the biotic and economic integrity of our estuaries. Individually, these are potent forces, but it is important to consider their interactive impacts as well. In this study we investigated the potential limitation of a nonnative intertidal grass, Spartina alterniflora, by nitrogen (N) in estuaries of the western United States. Nitrogen fertilization experiments were conducted in three mud-flat habitats invaded by S. alterniflora in Willapa Bay, Washington, USA, that differed in sediment N. We carried out parallel experiments in San Francisco Bay, California, USA, in three habitats invaded by hybrid Spartina (S. alterniflora x S. foliosa), in previously unvegetated mud flat, and in native S. foliosa or Salicornia virginica marshes. We found similar aboveground biomass and growth rates between habitats and estuaries, but end-of-season belowground biomass was nearly five times greater in San Francisco Bay than in Willapa Bay. In Willapa Bay, aboveground biomass was significantly correlated with sediment N content. Addition of N significantly increased aboveground biomass, stem density, and the rate of spread into uninvaded habitat (as new stems per day) in virtually all habitats in both estuaries. Belowground biomass increased in Willapa Bay only, suggesting that belowground biomass is not N limited in San Francisco Bay due to species differences, N availability, or a latitudinal difference in the response of Spartina to N additions. The relative impact of added N was greater in Willapa Bay, the estuary with lower N inputs from the watershed, than in San Francisco Bay, a highly eutrophic estuary. Nitrogen fertilization also altered the competitive interaction between hybrid Spartina and Salicornia virginica in San Francisco Bay by increasing the density and biomass of the invader and decreasing the density of the native. There was no significant effect of N on the native, Spartina foliosa. Our results indicate that excess N loading to these ecosystems enhances the vulnerability of intertidal habitats to rapid invasion by nonnative Spartina sp.     

Post-larval development of the common north-west European brittle stars Ophiura ophiura,O. albida and Acrocnida brachiata (Echinodermata: Ophiuroidea)

The post-larval skeletal plate ontogeny of the ophiuroids Ophiura ophiura (Linnaeus) and Acrocnida brachiata (Montagu) from the recently metamorphosed 0.3 mm disc diameter size to a juvenile size of 2.0 mm disc diameter has been examined using scanning electron microscopy. Post-larval development of O. albida Forbes is briefly described for sizes between 1.0 and 2.0 mm disc diameter. Early post-larval development in the 0.2 to 1.0 mm discsize range involves considerable morphogenetic change and necessitates the use of a developmental series in the identification of newly settled ophiuroids. Comparison of these ophiuroids with other closely related species reveals that the post-larvae are readily distinguishable at even the smallest sizes by their transient post-larval morphologies. Abbreviated larval development in A. brachiata is suggested from the egg size and post-larval form. The ophiuroid post-larvae were collected from the shallow sublittoral of Oxwich Bay, Bristol Channel, UK, during the years 1980 to 1982.     

The feeding habits of three species of lanternfishes (family myctophidae) off oregon,USA

The common myctophids Stenobrachius leucopsarus, Diaphus theta and Tarletonbeania crenularis were found to feed primarily on the euphausiid Euphausia pacifica, the copepods Metridia lucens and Calanus spp., and the amphipod Parathemisto pacifica. The diets of these species of fishes were diverse and overlapped broadly, suggesting that they are feeding generalists. Most stomachs contained either all copepods or all euphausiids. Euphausiids were the most important prey on the basis of biomass. They comprised over one-half the weight of the stomach contents in over 40% of individuals of each of the three fishes. Stomach fullness and state of digestion of stomach contents differed over the diel period, but not enough to indicate feeding only during the nighttime. Average stomach fullness was greatest during the morning and night and well-digested material, which predominated in most stomachs, was most prevalent in the morning and afternoon. Either some feeding occurs throughout the day or digestion rates are slow.