A new paper published in the Journal of Geophysical Research finds no evidence of ocean "acidification" in the upper 100 meters of the Santa Monica Bay from bi-weekly observations over the past six years. According to the authors, "No statistically significant linear trends emerge in the [biologically significant] upper 100 meters."
Key points from prior posts on ocean "acidification":
- Doubling of atmospheric levels would only increase dissolved CO2 in the oceans by .48%
- There is no reliable evidence that ocean pH is falling
- Increased CO2 dissolution in the oceans increases calcification of shellfish and coral
- Corals evolved at a time when CO2 levels were 15 times higher than the present
- Laboratory experiments on sea life in which hydrochloric acid is added to the water (not CO2) and without the natural buffers present in the ocean is meaningless to determine effects of increased CO2 levels on sea life
- prior research has failed to consider that organisms can adapt over time to pH changes
- several marine organisms have been shown to be resistant to "acidification"
- prior research has shown the oceans are a net source of CO2 rather than a sink
Variability and trends of ocean acidification in the Southern California Current System: A timeseries from Santa Monica Bay
A. Leinweber, N. Gruber
Abstract: We investigate the temporal variability and trends of pH and of the aragonite saturation state, Ωarag, in the southern California Current System on the basis of a 6 year timeseries from Santa Monica Bay, using bi-weekly observations of dissolved inorganic carbon and combined calculated and measured alkalinity. Median values of pH and Ωarag in the upper 20 m are comparable to observations from the subtropical gyres, but the temporal variability is at least a factor of 5 larger, primarily driven by short-term upwelling events and mesoscale processes. Ωarag and pH decrease rapidly with depth, such that the saturation horizon is reached already at 130 m, on average, but it occasionally shoals to as low as 30 m. No statistically significant linear trends emerge in the upper 100 m, but Ωarag and pH decrease, on average, at rates of -0.009 ± 0.006 yr-1 and -0.004 ± 0.003 yr-1 in the 100 to 250 m depth range. These are somewhat larger, but not statistically different from the expected trends based on the recent increase in atmospheric CO2. About half of the variability in the deseasonalized data can be explained by the El Niño Southern Oscillation (ENSO), with warm phases (El Niño) being associated with above normal pH and Ωarag. The observed variability and trend in Ωarag and pH is well captured by a multiple linear regression model on the basis of a small number of readily observable independent variables. This permits the estimation of these variables for related sites in the region.