Extreme pCO2 Variability in a Macrotidal Eelgrass Meadow Mediated by Tidal and Diurnal Cycles

• Main Authors: Love, Brooke, O'Brien, Colleen, Bulthuis, Douglas A.
• Format: Text
• Language: English
• Published: Western CEDAR 2014
• Subjects: Terrestrial and Aquatic Ecology; Ocean acidification
• Online Access: https://cedar.wwu.edu/ssec/2014ssec/Day2/114; https://cedar.wwu.edu/cgi/viewcontent.cgi?article=1240&context=ssec

It has been suggested that photosynthetic activity of macrophytes in coastal areas can decrease pCO2 and may provide areas of refuge for organisms sensitive to ocean acidification. To assess the effect of a large eel grass meadow on water chemistry, discreet samples were collected hourly over several 24 hour cycles in Padilla Bay, WA. Calculated pCO2 ranged from less than 100 ppm to greater than 700 ppm, often over the course of only a few hours. Aragonite saturation, DIC and pH were also highly variable. These data, weather station data and in-situ sensors(Padilla Bay National Estuarine Research Reserve) were used to develop a model that estimates pCO2 for the summer season. Tidal height and photosynthetically active radiation were the most significant predictors of pH and pCO2, with Salinity and DO. Model estimates suggest that an even wider range of pCO2 values are common in this estuary, especially in the early summer. Data from a mooring in 20 meters of water over a kilometer from the intertidal eel grass environment, provide some hints of the spatial extent of influence.