While acidification of the oceans due to increased atmospheric CO2 is a well-known phenomenon, IT remains an open question as to whether a similar acidification is or will happen in the laurentian…

This Cooperative Agreement award from the National Oceanic and Atmospheric Administration's (NOAA) Ocean Acidification Program (CFDA 11.017) will provide $1,306,441 to Michigan Technological University to conduct research on whether acidification is occurring in the Laurentian Great Lakes. The project will involve installing instrumented moorings in Lakes Superior and Erie to measure atmospheric and dissolved CO2 and pH levels over a two-year period. Ancillary chemical and biological process data will also be collected to understand the factors affecting pH in these large lake ecosystems. A coupled hydrodynamic-biogeochemical model will be implemented and validated using the measured data. The model experiments and statistical analysis will determine whether temperature change, vertical mixing, biological processes, air-water exchange, or changes in dissolved organic/inorganic carbon pools are the primary drivers of pH levels. This research is intended to enable NOAA's Great Lakes Environmental Research Lab to expand similar studies to the other Great Lakes and develop models to predict pH changes under altered climate conditions.

While acidification of the oceans due to increased atmospheric CO2 is a well-known phenomenon, IT remains an open question as to whether a similar acidification is or will happen in the laurentian great lakes or other large lakes of the world. Existing measurements show no evidence of acidification over the past 30-40 years, but the data are sparse, of poor quality, and inadequate to prove whether or not acidification is happening or will in the future. This project will demonstrate how a high-quality set of data can be collected and modelled to determine what factors are regulating PH on a daily scale. Instrumented moorings will be installed in lakes superior and erie in central locations to avoid influence of catchment inputs. Atmospheric and dissolved CO2 and PH will be measured by high precision instruments for two years. Ancillary chemical and biological process data will be collected to gain a fuller understanding of factors affecting PH. A coupled hydrodynamic-biogeochemical model will be implemented and validated with the measured data. Model experiments and statistical analysis of the measurement data will be used to determine whether temperature change, vertical mixing of the water column, biological processes, air-water exchange, or changes in pools of dissolved organic and inorganic carbon are more important in controlling PH. The NOAA great lake environmental research lab (GLERL) will partner with michigan technological university on this project. Experience from this project will enable GLERL to implement similar studies in the other great lakes as well as how to develop models to predict lake PH under an altered climate.