Diel cycles in surface ocean oxygen and carbon – A path to accurate, global photosynthetic rates?
Photosynthesis is the ultimate source of energy for the vast majority of living organisms, both on land and in the oceans. Good estimates of photosynthetic rates are therefore fundamental to our understanding of ocean ecosystems. Traditional measurements of photosynthetic rates can cover only a tiny fraction of the ocean. Satellite chlorophyll-based models provide nearly global coverage, but accuracy remains a challenge, especially where validation data are sparse. Each day, the day/night cycle produces provides a natural “light-dark” experiment across most of the world’s ocean, in principle permitting another, more direct measurement of photosynthesis at global scale. In this talk, I will explore the potential for making accurate, global-scale photosynthetic rate estimates using autonomous platforms capable of resolving the diel cycle in dissolved oxygen (and particulate carbon). I will also present the results of a validation exercise using autonomous float and glider data from the Iceland Basin.