| dc.description.abstract | To meet the new environmental requirements of reduced sulfur emissions from ships, many
shipowners have installed an open-loop scrubber to clean the exhaust. In this scrubbing
process, seawater is pumped from the ocean and combined with the emission gas, creating an
acidic and toxic effluent that is directly discharged into the ocean, potentially damaging the
marine environment. This study aims to understand the effects of different concentrations of
scrubber effluent (toxicant mixtures, pH and alkalinity decrease) on green sea urchin larvae
(Strongylocentrotus droebachiensis). The central hypothesis was that the combination of
toxins and low pH/alkalinity in scrubber effluent would negatively impact survival, growth,
and morphology of sea urchin larvae. Moreover, it was hypothesized that part of the negative
effect driven by low pH and low alkalinity could be minimized by correcting these parameters
using a strong base. However, some negative effects would still be observed due to the toxins
present in the scrubber effluent. The experiment was conducted at the Kristineberg Marine
Research Station. Larvae were cultured for 14 days in different concentrations of scrubber
effluent in filtered seawater. In the treatments with highest concentrations, pH and alkalinity
were corrected to a similar level as filtered seawater to only evaluate the effect of the mixture
of toxicants. We found severe effects on body length growth rate and development caused by
the scrubber effluent in the treatment with the highest concentration (10% ~ pH 7.3). When
corrected for pH and alkalinity (10%AT ~ pH 7.9), we observed a decrease of the harmful
effects enabling the larvae to develop and grow. However, toxins hindered the larvae from
reaching the same growth rate as the larvae in the water without scrubber effluent. In
conclusion, the scrubber effluent harms the green sea urchin larvae development and growth.
While this effect can be reduced by treating the effluent for its increased acidity, sea urchin
larvae still suffer from toxicity of the chemical cocktail. | en |
