Dinoflagellate infections of Favella panamensis from two North American estuaries

Favella panamensis Kofoid and Campbell, 1929 is seasonally abundant in meso- to polyhaline waters of Chesapeake Bay and Indian River, Florida, USA, where it reaches densities of 10³ cells l^-1. During the summers of 1986–1992. F. panamensis populations of the two estuaries were commonly infected by the parasitic dinoflagellate Duboscquella aspida Cachon, 1964. The intracellular phase of the parasite reached maturity in 21 h (30 °C) and consumed 35% of the host's biomass. Infections were not typically lethal to F. panamensis, but sometimes forced the host from its lorica. Several D. aspida were found in the cytoplasm of many hosts, and the number of parasites infection^-1 was directly related to infection level. Parasite prevalence averaged 24.0 and 11.5% with mean number of parasites infection^-1 being 1.5 and 1.3 for Chesapeake Bay and Indian River samples, respectively. D. aspida was estimated to remove up to 68% of host standing stock d^-1 with a mean of 10% for all samples. The average impact of parasitism on F. panamensis populations was somewhat less than would be expected from copepod grazing.     

Transthyretin (prealbumin) binding of PCBS, a model for the mechanism of interference with vitamin A and thyroid hormone metabolism

In this study a direct interaction of a metabolite of 3,4,3′,4′-tetrachlorobiphenyl with transthyretin (prealbumin) was observed, leading to reduced plasma levels of retinol, RBP and thyroxin in rats and mice.     

Concentrations of dioxin-like PCB congeners in unweathered Aroclors by HRGC/HRMS using EPA Method 1668A

We have determined the congener compositions of nine commercial Aroclor products of polychlorinated biphenyls (PCBs) to the sub-part-per-million level using high-resolution gas chromatography combined with high-resolution mass spectrometry according to US Environmental Protection Agency (EPA) Method 1668A. These Aroclor composition data should allow improved characterization and risk assessment of PCB contamination at hazardous waste sites, particularly for dioxin-like PCB congeners. By combining the data on the concentrations of each dioxin-like congener with its World Health Organization toxicity equivalency factor, we have established dioxin toxic equivalent concentrations for each pure Aroclor product.     

Meadow management and occurrence of corncrake Crex crex

The aim of this study was to analyse the occurrence of corncrakes in two Swedish meadow sites managed by mowing and grazing, but also with abandoned meadows. Most corncrakes (58%) on meadows were found in unmanaged areas without subsidies to the farmers (i.e. areas with tall vegetation). Several corncrakes (62%) were found in restored areas, managed for less than 10 of the last 40 years, fewer (38%) in areas under continuous management. Vegetation height was negatively associated with number of years of management the last 40 years, and the continuously managed areas were avoided by corncrakes. Sites where corncrake territories occur regularly should be managed to maintain tall vegetation suitable for the species, which requires increased use of mowing. However, the results from our study also suggest that yearly mowing might result in a vegetation structure that is avoided by corncrakes. To achieve a balance between tall grassy vegetation and prevention of succession to scrub a possible management regime would therefore be mowing at intervals of a few years.     

Controls on coarse wood decay in temperate tree species: birth of the LOGLIFE experiment

Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term 'common-garden' experiment to disentangle the effects of species' wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation.     

Controls on Coarse Wood Decay in Temperate Tree Species: Birth of the LOGLIFE Experiment

Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term ‘common-garden’ experiment to disentangle the effects of species’ wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation.