Abstract
Polar regions are experiencing some of the most rapid warming due to climate change. The Palmer (PAL) Long-Term Ecological Research (LTER) study area, located along the west Antarctic Peninsula (wAP), is experiencing a shift in the gradient from subpolar to polar ecosystems due to climate change. A shift in the climate gradient impacts sea ice, ocean circulation, ecosystems, and ice-obligate species such as the Adélie penguin. Alongside warming, this region has exhibited increased wind activity, a decrease in the number of sea-ice days, and a decline in the Adélie penguin population. The Adélie penguin is a sentinel of climate change and a key indicator of changes within the ecosystem. It is important to understand how pulse disturbances, in additional to climate shifts, can cause changes in environmental variables. An improved understanding of the influence of storm disturbances is imperative for predictions of species population ecology, habitat changes, and planning for future warming conditions under a changing climate. This study investigates the temporal relationships between storm tracks, sea ice indices, snow, and Adélie penguin chick fledging mass from 1979 to 2021 along the continental shelf of the wAP. Linear regression and linear mixed models are utilized to better understand how storm characteristics relate to variations in sea ice along different subsections of the PAL LTER sampling grid. The sampling area is divided into latitudinal regions (north, south, and far south) as well as into longitudinal zones (coastal, shelf, slope). Differences at the regional and zonal scale in storm and sea ice characteristics occur from 1979 to 2021. Storm frequency showed a statistically significant decrease over time only for the austral winter season. Seasonal sea-ice day of advance shifts later in the season in many areas, especially in coastal zones. Coastal and shelf zones experience a delayed sea-ice advancement when mean storm intensity increases. Increased storm frequency correlates with a later sea-ice retreat day in coastal zones. In addition to these impacts to the Adélie penguin’s environment, direct impacts are exhibited in negative correlations between chick fledging mass and storm frequency, intensity, and duration. Seasonal storm characteristics exhibit differences in correlations with CFM, where spring intensity and frequency correlate to a decrease in CFM; whereas summer storm intensity correlates with higher CFM. Future work will seek to distill the complex seasonal differences in storm influence on the chick fledging mass in order to better inform impacts to the Adélie chick survivability.
