The combined effects of climate change and ocean acidification are altering the habitat of commercially important species in the Gulf of Alaska. Climate induced enhancement of glacial melting may impact the progression of ocean acidification in the Gulf of Alaska. However, due to a limited number of measurements in the Gulf of Alaska, little is known about the current state and rate of change of the chemical habitat of key species. We have developed a model of the ocean circulation, chemistry and biology for this region to get a better idea of how the system may have already changed, potentially find regional hotspots, and identify environmental controls that either enhance or mitigate ocean acidification in the Gulf of Alaska. The model was run from 1980 through 2013 and is capable of reproducing recently observed features, such as the seasonal manifestation of on shelf aragonite undersaturation in subsurface waters.
With the Gulf of Alaska Interactive Model Tool you can create maps, timeseries, and statistics of over 100 oceanographic variables, including ocean acidification and climate change related parameters like temperature, salinity, pH, aragonite saturation state and carbon dioxide in the water from the above described simulation. Both, monthly and daily output is available.
This simulation into the past proposes that certain areas on the shelf have already been undersaturated with regard to aragonite 40 years ago, however, at present, aragonite undersaturation on the shelf is more widespread and lasts longer. Preliminary results also suggest that aragonite saturation state is decreasing by about 0.06 per decade and some of it is driven by increased freshwater input in near-shore areas. We are currently looking into different modes of variability, from daily, seasonal, interannual to decadal variability to better distinguish between natural and human-made changes. In collaboration with marine biologists, the simulation will be used to study how these environmental changes may have already shaped the distribution of organisms in the Gulf of Alaska
For more details on the model and first results, please refer to our recent publication in Biogeosciences.