This brief summarizes the paper “Climate change and Wind Intensification in Coastal Upwelling Ecosystems” by Sydeman et al., which was published in Science magazine.
https://www.sciencemag.org/content/345/6192/77
What is upwelling and how do wind patterns relate to it?
Upwelling refers to the process by which equator-ward, alongshore wind currents over ocean regions drive nutrient-drained water away from the shoreline, replacing it with cold, nutrient-rich water from the bottom of the ocean. This helps to maintain ecosystem productivity and thus overall health.
What is the importance of eastern boundary upwelling systems?
Eastern boundary current systems (EBCSs) are areas in the ocean along the eastern margins of ocean basins. In these regions, wind-driven currents and coastal formations (i.e. headlands) create a prime environment for upwelling, leading to extraordinary productivity and range of species. The California (California, Oregon, and Washington), Humboldt (Peru and Chile), Benguela (South Africa and Namibia), and Canary (northern Africa to Spain) regions comprise the world’s EBCSs, and thus are the focus of this study’s analysis. These essential upwelling systems are among the most heavily impacted in the world; mankind is exhausting fish populations, changing food web dynamics, and altering habitats to the detriment of naturally stable cycles. The scientific framework for an all-encompassing approach to ecosystem management is still in the process of being developed. Ecosystem-based management will be enhanced by understanding changes to upwelling since it is fundamental to the health and productivity of these ecosystems.
What did Andrew Bakun propose in 1990? How is this paper related to Bakun’s hypothesis?
In 1990, Andrew Bakun proposed that the increase in greenhouse gases provoked by humans would lead to intensification of upwelling in the world’s EBCSs. He proposed that a strengthening of upwelling-favorable winds in key regions would cause this intensification. Since there is significant debate within the scientific community as to whether current wind patterns corroborate his hypothesis, scientists at the Farallon Institute and their collaborators created a combined analysis of 22 different studies, published between 1990 and 2012, that tested Bakun’s theory in order to get a more accurate view of global upwelling patterns.
What were our results and what do they mean for ecosystem productivity?
The results of the combined analysis find that the existing body of research generally supports Bakun’s hypothesis, with evidence of wind intensification in the California, Humboldt, and Benguela systems. We also found that at greater latitudes, the degree of wind intensification was more pronounced, which is in line with warming patterns observed with the onset of climate change. While it may sound as if wind intensification could benefit ecosystems due increased upwelling, large changes in wind patterns could, in fact, harm ecosystems by throwing off the balance of organism interactions and by changing ocean chemistry. The complex nature of natural systems, though, makes it extremely difficult to predict the ecological effects of wind intensification in these ecosystems.