News

Published on March 15, 2016

Harmful algal blooms, produced by cyanobacteria, not only impact water quality, but they also have the potential to produce toxins that can harm humans, pets and wildlife. The blooms are caused by a combination of factors, one major factor being warmer temperatures. 2015 was the warmest year on record. Before that it was 2014. The long-term trend of rising temperatures is likely to further promote the global expansion of cyanobacteria. As copper is commonly used as an algaecide to eradicate cyanobacterial blooms, we investigated the combined effects of copper and the toxic cyanobacterium Microcystis aeruginosa and how these were affected by temperature and food concentration. Our study shows that the interactive effects between copper and harmful algae blooms are not overly dependent on temperature and food concentration. Nevertheless the present study warns against the use of copper-based algaecides and suggests that environmental risk assessment of copper should consider specific situations where harmful M. aeruginosa blooms can co-occur.

Published on February 18, 2016

Mostly, metal contamination comes as a mixture of different metals. These multi-component mixtures can produce significant mixture effects. In this study, metal mixture toxicity on barley root elongation was investigated. Mixture effects of four metals (Cu, Cd, Ni and Zn) were investigated when each metal was present in the mixture at a low effect concentration, i.e. individually only causing a small effect. Two commonly used ‘reference’ models (concentration addition and independent action) were used to test if it is possible to predict toxicity in these mixtures. In this study, it was shown that the toxicity of a mixture of metals was almost always larger than the effect of the most toxic metal in that mixture. In addition, it was found that a mixture of four metals, each causing individually < 10% effect, produced mixture effects up to 50%. This highlights the need to incorporate mixture toxicity in risk-assessment frameworks.

Published on February 1, 2016

Previous studies have suggested that phosphorus (P) deficiency can increase the sensitivity of microalgae to toxic trace metals, potentially due to reduced metal detoxification at low cell P quota. The existing evidence is, however, inconsistent. This study was set up to determine the combined effects of zinc (Zn) and P supplies on Zn and P bioaccumulation and growth of the green microalgae Pseudokirchneriella subcapitata. Zinc toxicity was investigated in (i) a 24 h growth rate assay with cells varying in initial cell P quota with no supplemental P during Zn exposure and in (ii) a 48 h growth assay initiated with cells at the end of a 14-days steady state culture at three P addition rates (RARs) between 0.8 and 1.6 day−1. Our data at two experimental scenarios and the prediction under various relevant scenarios suggest a weaker effect of secondary stress factor (Zn) when nutrient deficiency (first stress factor) is prevailing.

Published on January 27, 2016

For the second year in a row, the Flanders Marine Institute (VLIZ) organized the PlaneetZee@work competition. As a committed partner of VLIZ, GhEnToxLab hosted an interactive day on marine sciences for high school students. On Tuesday 26 January, 30 fourth-year students of the Barnum school of Roeselare visited our lab to learn - hands on - about the effects of different stressors on the marine environment. After an introductory presentation and a guided tour of our facilities, the students participated in five workshops. Each workshop, organized by five of our PhD students, covered current, high profile issues like: harmful algal blooms, ocean acidification and (micro-)plastic pollution. Additionally workshops on innovative environmental DNA monitoring techniques and basic marine toxicity testing provided insights into new and current ecotoxicological methods. We would like to thank the students for their vibrant enthusiasm and wish them all the best with their further research activities leading to the development and presentation of their scientific posters on these topics.

Published on January 11, 2016

We determined whether a realistic mixture of hydrophobic chemicals affects the growth dynamics of a marine diatom and how this effect compares to the effect of temperature, light regime and nutrient conditions. Passive dosing was used to expose a marine diatom to a realistic mixture of hydrophobic compounds accumulated from Belgian coastal waters using passive samplers. Although ∑7PCBs exceeded the environmental quality standards (2 ng L− 1), we did not observe adverse ecotoxicological effects in a 72 h algal growth inhibition test with P. tricornutum. Natural drivers such as nutrients, temperature and light availability, explaining about 85% of the observed variability, are more important drivers of the growth of P. tricornutum than the mixture of organic pollutants present in Belgian coastal waters.

Published on December 15, 2015

As part of the lectures marine ecology of Prof. Janssen, students of several master programs went on a field trip to the Opal coast in France. In the shadow of the fortress of Ambleteuse they experienced the forces of tidal action in terms of ecological zonation on rocky shores, sandy beaches and within the salt marshes of the river Slack.

Next to the field trip to Ambleteuse, the bioscience engineering students boarded the research vessel Simon Stevin. A video compilation of this excursion can be found on the Media menu.

Published on November 12, 2015

On Sunday the 22nd of November, many research institutes in Flanders open their doors to the general audience for Science Day, an event coordinated by the Flemish Government. The Flanders Marine Institute is also opening its doors from 10am to 5pm. GhenToxLab Researchers are also present! They will take visitors on an interactive tour in the Molecular Lab of the Marine Station Ostend and will explain how DNA plays an important role in developing new techniques to assess biodiversity.

Published on November 5, 2015

Between November 2nd and December 7th, our postdoctoral researcher Gert Everaert performs a research stay at the Norwegian Institute for Water Research (NIVA). The Niva is a non-profit research foundation which researches, monitors and assesses freshwater, coastal and marine environments and environmental technology. Gert will collaborate closely with the scientific staff of the section ‘Contaminants in the aquatic environment’. The research stay is supported by a travel grant of the ‘Fonds voor wetenschappelijk onderzoek  (FWO)’.

Published on September 15, 2015

The chronic toxicity of Ni is strongly dependent on the physico-chemistry of freshwater environments. Metal bioavailability models predict metal toxicity in receiving waters by taking into account the effects of pH and the formation of (in)organic ligand on metal bioavailability and the effects of cations, such as Ca & Mg, on metal uptake. Currently, the Environmental Quality Standard (EQS) for Ni in the Water Framework Directive (WFD) is bioavailability based. Although some of the available chronic Ni bioavailability models are only validated for pH up to 8.2, a considerable fraction of the European surface waters has a pH above 8.2. Therefore, we investigated the effect of a change in pH from 8.2 to 8.7 on chronic Ni toxicity to 3 invertebrate and 2 plant species. Next, we investigated whether the existing chronic Ni bioavailability models could be used to predict chronic Ni toxicity above pH 8.2.

Published on September 9, 2015

As the human population continues to expand, scientists and politicians are faced with a simple question: will we be able to feed ourselves in the future? Many of our food sources are at peak productivity and only in a few sectors, such as the aquaculture industry, is significant growth feasible. However, these sectors are also faced with global concerns like climate change. The rise of sea surface temperature will affect marine ecosystems in drastic ways. Among others, pathogens and harmful algae are expected to benefit from a warmer environment. As a result, both wild and cultured bivalves will become more frequently exposed to these stressors.

Pages