|The effect of ocean acidification on the functioning of coastal marine benthos|
Elsen, J. (2014). The effect of ocean acidification on the functioning of coastal marine benthos. MSc Thesis. Universiteit Antwerpen/Universiteit Gent/VUB: Antwerpen, Gent, Brussel. 13, 33 pp.
The marine environment experiences, at this very moment, the negative effects of two abiotic, anthropogenic processes: ocean acidification and O2 limitation. Yet, even though ample research has been performed on the individual effects of these stressors, research investigating the combined effects of both stressors is largely absent in literature. Additionally, previous research usually covers only lethal effects whilst sub-lethal effects are often left aside, even though they can have as large of an impact on marine ecosystems as lethal effects do. Consequently, our current understanding concerning the impacts we have on the oceans may be biased. As a response, this thesis sets out to investigate the combined sublethal effects of ocean acidification and O2 limitation. Specimens of Abra alba, Macoma balthica, Nephtys hombergii, Ophiura ophiura, Siaglion mathildae, Tellina fabula and different nematode genera have been kept in mesocosm experiments, in which they were to be subjected to an acidification of 0.3 pH units; and the full range of O2 availability (100% O2 saturation – hypoxia). The gathered results show that, even though both stressors have impacted the respiration rates of both macro- and meiofauna, no combined effect of ocean acidification and O2 limitation was found. Simultaneously, as a result of the acidification, significant shifts occurred in the nematode assemblage composition, and a lowered sedimentary pH was observed in the top 0.25 cm sediment layer.