Carbonate chemistry and calcifying plankton in Scottish coastal waters (text & video)

OA Week 2021, Northeast Atlantic Hub Session

Dr. Pablo León Díaz, Marine Scotland Science, UK


Ocean acidification (OA) is likely to have a significant impact on calcifying plankton. This group plays a key role in the ocean food webs and global biogeochemical cycles and includes larvae of species of commercial importance for aquaculture and fishery industries (e.g. bivalves). However field studies on carbonate chemistry and calcifying plankton are scarce.

Operated by Marine Scotland Science, the Scottish Coastal Observatory (SCObs; monitoring site at Stonehaven is providing baseline information about the seasonality and interannual variability of carbonate chemistry as well as the plankton community in Scottish waters. Three years of monthly samples were analysed using Scanning Electron Microscopy (SEM) to investigate the relationship between carbonate chemistry parameters and calcifying groups at Stonehaven, including coccolithophores, pelagic gastropods and the planktonic larvae of benthic bivalve species. SEM analyses revealed evidence of shell dissolution in all analysed species during the study period despite the seawater being supersaturated with respect to aragonite, with the most severe damaged observed during periods of decreasing aragonite saturation. These results suggest that seasonal and short-term changes in carbonate chemistry might affect the shell integrity of plankton calcifiers, also indicating that dissolution may appear under higher saturation values than previously assumed. This work also highlights the value of sustained observations to distinguish OA changes from natural variability and to assess the potential impacts of OA on marine ecosystems.

Ocean Acidification Week 2021 was sponsored by the following organizations:

(1) GOA-ON, the Global Ocean Acidification Observing Network,

(2) NOAA, the United States National Oceanic & Atmospheric Administration,

(3) IAEA OA-ICC, the International Atomic Energy Agency – Ocean Acidification International Coordination Centre, and

(4) IOC-UNESCO – the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization

For more information, please visit

GOA-ON, YouTube, 24 September 2021. Text and video.

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