Spring development in the hydrolittoral zone was investigated at five wave-sheltered and five wave-exposed sites on four occasions from late March to late May (every third week). The number of species was higher at the sheltered locations and increased significantly over time. The difference in community structure was significant: over 95% of the Bray-Curtis dissimilarities were due to the biomass of only eleven taxa, and the total Bray-Curtis dissimilarity between exposed and sheltered sites was 75%. Macroalgae made up 70-80% of the total biomass and was dominated by filamentous species. In contrast to previous studies, macroalgal biomass was higher at the exposed sites, which may be due to the fact that this was a spring study, unlike previous studies, which were conducted during summer.

Multimedia mass balance models of chemical fate in the environment have been used for over 3 decades in a regulatory context to assist decision making. As these models become more comprehensive, reliable, and accepted, there is a need to recognize and adopt principles of Good Modeling Practice (GMP) to ensure that multimedia models are applied with transparency and adherence to accepted scientific principles. We propose and discuss 6 principles of GMP for applying existing multimedia models in a decision-making context, namely 1) specification of the goals of the model assessment, 2) specification of the model used, 3) specification of the input data, 4) specification of the output data, 5) conduct of a sensitivity and possibly also uncertainty analysis, and finally 6) specification of the limitations and limits of applicability of the analysis. These principles are justified and discussed with a view to enhancing the transparency and quality of model-based assessments.

α-, β, γ-, and δ-Hexachlorocyclohexane (HCH), the four major isomers of technical HCH, are susceptible to biotic transformations, whereby only α- and γ-HCH undergo complete mineralization. Nevertheless, LinA and LinB catalyzing HCl elimination and hydrolytic dehalogenations, respectively, as initial steps in the mineralization also convert β- and δ-HCH to a variety of mainly hydroxylated metabolites. In this study, we describe the isolation of two minor components of technical HCH, ε-HCH, and heptachlorocyclohexane (HeCH), and we present data on enzymatic transformations of both compounds by two dehydrochlorinases (LinA1 and LinA2) and a haloalkane dehalogenase (LinB) from Sphingobium indicum B90A. In contrast to reactions with α-, γ-, and δ-HCH, both LinA enzymes converted ε-HCH to a mixture of 1,2,4-, 1,2,3-, and 1,3,5-trichlorobenzenes without the accumulation of pentachlorocyclohexene as intermediate. Furthermore, both LinA enzymes were able to convert HeCH to a mixture of 1,2,3,4- and 1,2,3,5-tetrachlorobenzene. LinB hydroxylated ε-HCH to pentachlorocyclohexanol and tetrachlorocyclohexane-1,4-diol, whereas hexachlorocyclohexanol was the sole product when HeCH was incubated with LinB. The data clearly indicate that various metabolites are formed from minor components of technical HCH mixtures. Such metabolites will contribute to the overall toxic potential of HCH contaminations and may constitute serious, yet unknown environmental risks and must not be neglected in proper risk assessments.

Thiamine deficiency has recently been demonstrated in several species of wild birds, both adults and newly hatched young, in connection with extensive mortality in a paralytic disease in the Baltic Sea. This thiamine deficiency may be the dominating cause of the observed population declines in many bird species during the last three decades. Accordingly, the need for an understanding of this problem is urgent. Our research team has found reduced thiamine concentrations in the egg-yolk, liver, and brain, as well as reduced activities of the thiamine-dependent enzymes transketolase and alpha-ketoglutarate dehydrogenase in the liver and brain. In these organs, there were also very high proportions of apoenzyme of these enzymes. The thiamine status of females in the field was critical for the degree of breeding failure. The many observations of advanced thiamine deficiency in adult birds strongly suggest that also varying degree of moderate thiamine deficiency occurs among the affected species. One effect of moderate thiamine deficiency is altered behaviour. We have made plenty of observations of reduced aggressiveness and low noise level in bird colonies, as well as incomplete nest building and egg laying in nests of other species. The observed degree of thiamine deficiency suggests that the birds also suffer from weakening of the blood-brain barrier and immune suppression. This is not only an obvious threat to ecosystem sustainability. For example, infectious diseases may be more easily spread to humans by immunosuppressed birds. The thiamine deficiency may be induced either by a causative agent(s) acting directly on the affected individual, and/or by insufficient transfer of thiamine between the trophic levels in the food web.