Effects of scrubber washwater discharge on microplankton in the Baltic Sea

• Published in: Marine pollution bulletin Vol. 145; pp. 316 - 324
• Main Authors: Ytreberg, Erik, Hassellöv, Ida-Maja, Nylund, Amanda T., Hedblom, Mikael, Al-Handal, Adil Y., Wulff, Angela
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2019; Elsevier BV
• Subjects: Acidic water; Baltic States; blooms; Chemical analysis; Chlorophyll; Chlorophyll a; Chlorophyll A - analysis; Communities; Contaminants; copper; Cyanobacteria; Cyanobacteria - drug effects; Diatoms; Discharge; Ecology; Ekologi; emissions; Environmental Sciences & Ecology; Exhaust emissions; Exhausts; Marine & Freshwater Biology; Marine environment; Marine pollution; Nitrogen; Nitrogen - analysis; Nodularia - drug effects; Nodularia spumigena; Nutrients; Organic phosphorus; Particulate organic carbon; Particulate organic phosphorus; Phosphorus; Phosphorus - analysis; Photosynthesis; Photosynthesis - drug effects; Plankton - drug effects; Primary production; Scrubbers; Seawater; Seawater - microbiology; Ships; speciation; Sulfur; Sulfur - toxicity; Sulphur; Vehicle Emissions - prevention & control; Vehicle Emissions - toxicity; Water analysis; Water pollution; Water Pollution - prevention & control; Baltic States; Baltic Sea
• ISSN: 0025-326X; 1879-3363; 1879-3363
• DOI: 10.1016/j.marpolbul.2019.05.023

In 2020, the global cap of maximum allowable sulphur content in marine fuel will be reduced from the current 3.5% to 0.5%. Another way to reduce the sulphur emissions is to install a seawater scrubber that cleans exhausts but instead release acidic water containing nutrients and contaminants back to the marine environment. In the current study, scrubber washwater was tested on a Baltic Sea microplankton community. A significant increase in chlorophyll a, particulate organic phosphorus (POP), carbon (POC) and nitrogen (PON) were observed when the community was exposed to 10% scrubber washwater for 13 days as compared to the control. A laboratory experiment with the filamentous cyanobacteria Nodularia spumigena and the chain-forming diatom Melosira cf. arctica showed negative responses in photosynthetic activity (EC10 = 8.6% for N. spumigena) and increased primary productivity (EC10 = 5.5% for M. cf. arctica), implying species-specific responses to scrubber washwater discharge. •Open-loop scrubbers on ships produce acidic washwater containing contaminants.•A Baltic microplankton community was significantly affected when exposed to 10% washwater.•Laboratory experiments showed species-specific responses to scrubber washwater.•Discharged scrubber washwater may impact water quality in the Baltic Sea.