A song of wind and ice: increased frequency of marine cold-spells in southwestern Patagonia and their possible effects on giant kelp forests

In contrast to other coastal regions of the world, the giant kelp (Macrocystis pyrifera)  ecosystem in southwestern Patagonia has been persistent in area and associated biodiversity in the last decades. In this ecoregion, Sea Surface Temperature (SST) records have consistently remained below the upper thermal threshold for kelp survival, however no studies have analysed the spatiotemporal variability of SSTs and their anomalies across the geographical diversity of the southwestern Patagonian coastline. We explored the geographical distribution of extreme warm and cold events in this region from latitudes 47° to 56° S in a range of 1,000 km, identifying the dates and spatial distribution of Marine Heatwaves (MHWs) and Marine Cold-Spells (MCSs) from 1982 to 2020. Results show that a peak in the number of MHWs occurred in the great El Nino year of 1998. Additionally, the 2014-2019 period has had more severe and extreme MCSs than the previous decades. We discuss the origin of these events w...