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Document Type: Journal Article
Center: NWFSC
Document ID: 4783
Title: Seasonal carbonate chemistry covariation with temperature, oxygen and salinity in a fjord estuary: implications for the design of ocean acidification experiments
Author: Jonathan C. P. Reum, S. R. Alin, Richard A. Freely, Jan Newton, Mark Warner, Paul McElhany
Publication Year: 2014
Journal: PLoS ONE
Volume: 9
Issue: 2
DOI: 10.1371/journal.pone.0089619
Keywords: Puget Sound,Ocean acidification,hypoxia,Multiple stressors,climate change,diel vertical migration

 Carbonate chemistry variability is often poorly characterized in coastal regions and patterns of covariation with other

biologically important variables such as temperature, oxygen concentration, and salinity are rarely evaluated. This absence

of information hampers the design and interpretation of ocean acidification experiments that aim to characterize biological

responses to future pCO2 levels relative to contemporary conditions. Here, we analyzed a large carbonate chemistry data set

from Puget Sound, a fjord estuary on the U.S. west coast, and included measurements from three seasons (winter, summer,

and fall). pCO2 exceeded the 2008–2011 mean atmospheric level (392 matm) at all depths and seasons sampled except for

the near-surface waters (, 10 m) in the summer. Further, undersaturated conditions with respect to the biogenic carbonate

mineral aragonite were widespread (Var,1). We show that pCO2 values were relatively uniform throughout the water

column and across regions in winter, enriched in subsurface waters in summer, and in the fall some values exceeded

2500 matm in near-surface waters. Carbonate chemistry covaried to differing levels with temperature and oxygen

depending primarily on season and secondarily on region. Salinity, which varied little (27 to 31), was weakly correlated with

carbonate chemistry. We illustrate potential high-frequency changes in carbonate chemistry, temperature, and oxygen

conditions experienced simultaneously by organisms in Puget Sound that undergo diel vertical migrations under presentday

conditions. We used simple calculations to estimate future pCO2 and Var values experienced by diel vertical migrators

based on an increase in atmospheric CO2. Given the potential for non-linear interactions between pCO2 and other abiotic

variables on physiological and ecological processes, our results provide a basis for identifying control conditions in ocean

acidification experiments for this region, but also highlight the wide range of carbonate chemistry conditions organisms

may currently experience in this and similar coastal ecosystems.


 We describe carbonate chemistry variability in Puget Sound across multile seasons, locations, and depths.

Theme: Habitats to Support Sustainable Fisheries and Recovered Populations
Official Citation:

Reum JCP, Alin SR, Feely RA, Newton J, Warner M, McElhany P. (2014) Seasonal Carbonate Chemistry Covariation with Temperature, Oxygen, and Salinity in a Fjord Estuary: Implications for the Design of Ocean Acidification Experiments. PLoS ONE 9(2): e89619. doi:10.1371/journal.pone.0089619