Multi-level responses of Macoma balthica to recurring hypoxic disturbance

The frequency of seasonal and short-term hypoxia is increasing in coastal seas. How such repeated disturbances affect key species that have important roles for ecosystem processes and functions remains, however, unknown. By performing a field experiment we explored if the bivalve Macoma balthica can cope with short-term, recurring hypoxic stress, and investigated how hypoxia affects the condition of surviving bivalves. By combining data on different levels of biological organization, i.e., on physiology (biomarker response), behaviour and demography, we identified stress responses before the population declined. One pulse of hypoxic disturbance (3 days) resulted in behavioural alterations, as adult M. balthica extended their siphons, emerged towards the sediment surface and expressed decreased reburial rates. However, the demographic structure of the population remained unaltered. Several pulses of recurring hypoxic stress resulted in physiological response with changes in glutathione reductase and acetylcholinesterase enzyme activities. The recurring hypoxic disturbance was observed to affect juvenile bivalves before adults, while pro-longed hypoxia reduced the entire bivalve population. Our results clearly show that hypoxic stress changes the behaviour and physiology of M. balthica before demographic changes occur, which is likely to have severe implications for the contribution of this key species to ecosystem functioning. That a combination of measures at different levels of organization can detect disturbances at an early stage suggests that such an approach would be useful for assessing the effects of disturbances on marine ecosystems that are increasingly affected by anthropogenic change.peerReviewe

Contaminated by war : A brief history of sea-dumping of munitions

Munitions introduced to the sea during military activities, including naval combat and mine warfare represent only a fraction of military material present in seas and oceans. Huge amounts of obsolete conventional munitions and chemical munitions were dumped to the sea until 1975, when London convention put a stop of sea dumping. Such munitions are a threat for maritime workers, but also for environment. Corroding shells release toxic degradation products to sediments and bottom water, and unlike other contaminants, they cannot be reduced by land measures. Only removal of source can reduce the contamination. Much work has been done in the last decade, and mechanisms of toxicity and bioaccumulation are being recognized, as well as transport and spreading mechanisms. The full assessment of the risk associated with munitions now depends on broad application of developed techniques

Developing English language support for the lingua franca learning environments at the master’s level

This paper focuses on the changing landscape of international higher education and the role language plays in the current trend towards internationalization through English-medium Master’s Degree Programmes at the University of Helsinki. We provide an overview of the changing situation, with the increasing number of new English-medium programmes, and discuss the development of language support designed to meet the needs of the students in these programmes. This paper is based on a pilot project for developing language support for these programmes at the University of Helsink

Congestive heart failure : more common as well as an important cardiovascular outcome: reply

Non peer reviewe

Mussel caging and the weight of evidence approach in the assessment of chemical contamination in coastal waters of Finland (Baltic Sea)

Contamination status of coastal areas of Finland (northern Baltic Sea) markedly affected by anthropogenic activities (harbors, shipyards and maritime activity, industry, municipal and agricultural inputs, legacy contamination) was assessed for the first time using the weight of evidence (WOE) approach. The key element of the study was the caging (transplantation) of Baltic mussels (Mytilus trossulus) for the measurement of tissue accumulation of polycyclic aromatic hydrocarbons (PAHs) and applying a suite of biomarkers of biological effects of contaminants. Additional variables included in the assessment were trace metals in seawater, macrozoobenthos, near-bottom oxygen levels and eutrophication indicators. The chemical parameters were supported by passive sampling of PAHs and organotins at the study sites. The integrated approach combining all the line of evidence (LOE) variables into the WOE showed separation of some sites as more affected by hazardous substances than others, with the most contaminated areas found around harbor and ship yard areas. The contaminant levels measured in the different matrices were not alarmingly high at none of the areas compared to many other areas within or outside the Baltic Sea under more heavy anthropogenic impact, rarely exceeding any given threshold values for Good Environmental Status of the EU Marine Strategy Framework Directive. However, significant biological effects were recorded in mussels in the most contaminated sites, signifying that the combined effects caused by the contaminants and other environmental factors are disturbing the health of marine organisms in the area. The results of this successful combined application based on the mussel transplantation method and the WOE approach are highly encouraging for further trials in developing the monitoring of chemical contamination in the Baltic Sea

Biomarker responses and accumulation of polycyclic aromatic hydrocarbons in Mytilus trossulus and Gammarus oceanicus during exposure to crude oil

In the brackish water Baltic Sea, oil pollution is an ever-present and significant environmental threat mainly due to the continuously increasing volume of oil transport in the area. In this study, effects of exposure to crude oil on two common Baltic Sea species, the mussel Mytilus trossulus and the amphipod Gammarus oceanicus, were investigated. The species were exposed for various time periods (M. trossulus 4, 7, and 14 days, G. oceanicus 4 and 11 days) to three oil concentrations (0.003, 0.04, and 0.30 mg L−1 based on water measurements, nominally aimed at 0.015, 0.120, and 0.750 mg L−1) obtained by mechanical dispersion (oil droplets). Biological effects of oil exposure were examined using a battery of biomarkers consisting of enzymes of the antioxidant defense system (ADS), lipid peroxidation, phase II detoxification (glutathione S-transferase), neurotoxicity (acetylcholinesterase inhibition), and geno- and cytotoxicity (micronuclei and other nuclear deformities). In mussels, the results on biomarker responses were examined in connection with data on the tissue accumulation of polycyclic aromatic hydrocarbons (PAH). In M. trossulus, during the first 4 days of exposure the accumulation of all PAHs in the two highest exposure concentrations was high and was thereafter reduced significantly. Significant increase in ADS responses was observed in M. trossulus at 4 and 7 days of exposure. At day 14, significantly elevated levels of geno- and cytotoxicity were detected in mussels. In G. oceanicus, the ADS responses followed a similar pattern to those recorded in M. trossulus at day 4; however, in G. oceanicus, the elevated ADS response was still maintained at day 11. Conclusively, the results obtained show marked biomarker responses in both study species under conceivable, environmentally realistic oil-in-seawater concentrations during an oil spill, and in mussels, they are related to the observed tissue accumulation of oil-derived compounds

Field-realistic acute exposure to glyphosate-based herbicide impairs fine-color discrimination in bumblebees

Pollinator decline is a grave challenge worldwide. One of the main culprits for this decline is the widespread use of, and pollinators' chronic exposure to, agrochemicals. Here, we examined the effect of a field-realistic dose of the world's most commonly used pesticide, glyphosate-based herbicide (GBH), on bumblebee cognition. We experimentally tested bumblebee (Bombus terrestris) color and scent discrimination using acute GBH exposure, approximating a field-realistic dose from a day's foraging in a patch recently sprayed with GBH. In a 10-color discrimination experiment with five learning bouts, GBH treated bumblebees' learning rate fell to zero by third learning bout, whereas the control bees increased their performance in the last two bouts. In the memory test, the GBH treated bumblebees performed to near chance level, indicating that they had lost everything they had learned during the learning bouts, while the control bees were performing close to the level in their last learning bout. However, GBH did not affect bees' learning in a 2-color or 10-odor discrimination experiment, which suggests that the impact is limited to fine color learning and does not necessarily generalize to less specific tasks or other modalities. These results indicate that the widely used pesticide damages bumblebees' fine-color discrimination, which is essential to the pollinator's individual success and to colony fitness in complex foraging environments. Hence, our study suggests that acute sublethal exposure to GBH poses a greater threat to pollination-based ecosystem services than previously thought, and that tests for learning and memory should be integrated into pesticide risk assessment

Exposure to dissolved TNT causes multilevel biological effects in Baltic mussels (Mytilus spp.)

Highlights • Shell closing as simple defence against acute toxicity of TNT. • Mussels appear to be able to metabolize TNT to 2- and 4-ADNT.Biomarker responses occurred already at the lowest TNT exposure concentrations. • Biomarker responses occurred already at the lowest TNT exposure concentrations.Baltic mussels (Mytilus spp.) were exposed to the explosive trinitrotoluene (TNT) for 96 h (0.31–10.0 mg/L) and 21 d (0.31–2.5 mg/L). Bioaccumulation of TNT and its degradation products (2- and 4-ADNT) as well as biological effects ranging from the gene and cellular levels to behaviour were investigated. Although no mortality occurred in the concentration range tested, uptake and metabolism of TNT and responses in antioxidant enzymes and histochemical biomarkers were observed already at the lowest concentrations. The characteristic shell closure behaviour of bivalves at trigger concentrations led to complex exposure patterns and non-linear responses to the exposure concentrations. Conclusively, exposure to TNT exerts biomarker reponses in mussels already at 0.31 mg/L while effects are recorded also after a prolonged exposure although no mortality occurs. Finally, more attention should be paid on shell closure of bivalves in exposure studies since it plays a marked role in definining toxicity threshold levels