Toxic algal bloom induced by ocean acidification disrupts the pelagic food web

• Published in: Nature climate change Vol. 8; no. 12; pp. 1082 - 1086
• Main Authors: Riebesell, Ulf, Aberle-Malzahn, Nicole, Achterberg, Eric P., Algueró-Muñiz, María, Alvarez-Fernandez, Santiago, Arístegui, Javier, Bach, Lennart T., Boersma, Maarten, Boxhammer, Tim, Guan, Wanchun, Haunost, Mathias, Horn, Henriette G., Löscher, Carolin R., Ludwig, Andrea, Spisla, Carsten, Sswat, Michael, Stange, Paul, Taucher, Jan
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2018; Nature Publishing Group
• Subjects: 631/158/2165; 631/158/853; 704/106/829/827; 704/829/826; Abundance; Acidification; Algal blooms; Anthropogenic factors; Aquaculture; Carbon dioxide; Carbon dioxide emissions; Carbonates; Climate Change; Climate Change/Climate Change Impacts; Community composition; Disruption; Earth and Environmental Science; Ecological succession; Ecosystems; Environment; Environmental Law/Policy/Ecojustice; Fish; Fisheries; Food chains; Food webs; Geographical distribution; Human influences; Interactions; Keystone species; Letter; Marine ecosystems; Marine organisms; Ocean acidification; Oceans; Organic chemistry; Organic matter; Particulate emissions; Particulate matter; Plankton; Proliferation; Seawater; Suspended particulate matter; Trophic relationships; Uptake; Water column; Water quality; Zooplankton
• ISSN: 1758-678X; 1758-6798
• DOI: 10.1038/s41558-018-0344-1

Ocean acidification, the change in seawater carbonate chemistry due to the uptake of anthropogenic CO 2 , affects the physiology of marine organisms in multiple ways 1 . Diverse competitive and trophic interactions transform the metabolic responses to changes in community composition, seasonal succession and potentially geographical distribution of species. The health of ocean ecosystems depends on whether basic biotic functions are maintained, ecosystem engineers and keystone species are retained, and the spread of nuisance species is avoided 2 . Here, we show in a field experiment that the toxic microalga Vicicitus globosus has a selective advantage under ocean acidification, increasing its abundance in natural plankton communities at CO 2 levels higher than 600 µatm and developing blooms above 800 µatm CO 2 . The mass development of V. globosus has had a dramatic impact on the plankton community, preventing the development of the micro- and mesozooplankton communities, thereby disrupting trophic transfer of primary produced organic matter. This has prolonged the residence of particulate matter in the water column and caused a strong decline in export flux. Considering its wide geographical distribution and confirmed role in fish kills 3 , the proliferation of V. globosus under the IPCC 4 CO 2 emission representative concentration pathway (RCP4.5 to RCP8.5) scenarios may pose an emergent threat to coastal communities, aquaculture and fisheries. Ocean acidification will result in biological winners and losers. A mesocosm experiment shows that a toxic algal species is a winner under ocean acidification, with implications for the marine food web and, more generally, ecosystem services.