Award: OPP-1443604

The INSPIRE project investigated an important region of the coastal Antarctic (the Amundsen Sea Polynya, ASP) characterized by fast-melting glaciers nearby and a very high summertime production of microscopic algae, or phytoplankton. The Amundsen Sea is about as far from human habitation as one can get on Earth, and yet satellites tell us that its polynya (an area of open water surrounded by ice) is the greenest ocean in all of Antarctica. The INSPIRE project helped to uncover the inner workings of this region and to progressively reveal the secrets behind its lushness and abundance. One of the most important outcomes of INSPIRE relates to the circulation of the water in the region. The meltwater from the glaciers was found to act like warm air in a shower, rising toward the top while pulling in water at the bottom. This 'meltwater pump' is amplified by the increasing glacier melt rates of the West Antarctic Ice Sheet and can influence the ocean circulation a hundred miles away from the glaciers. The key effect of this pump is that it pulls along bottom water that is rich in the fertilizer iron, transports it upward, and then releases it close to the surface where the phytoplankton live. Computer simulations (akin to those used for weather forecasts) further revealed that the water that is pumped up will accumulate over several years in the ASP. The accumulation of water that is rich in iron has important implications for marine life and the rates of carbon dioxide (CO2) uptake by the ocean. Single-celled algae, the backbone of the marine food web, are often deficient in iron in this region of the world ocean, which can limit their growth rate and therefore the annual 'yield' of the region. The meltwater pump partly alleviates this situation in the ASP and contributes to the region?s lushness. This productivity is limited by another factor; the availability of sunlight. Computer simulations reveal that once the seasonal sea ice cover declines and sunlight penetrates the surface ocean, the fertilized algae become so abundant in the ASP that they partially block the incident sunlight. This so-called ?self-shading? slows down the bloom. Ultimately, it is the limited availability of both light and iron that determines the decline of the algae production and its sinking to depth at the end of the season. With this additional insight on the productivity of the ASP, the project also illustrated the sequestration in the deep waters of some of the ?leaf litter? or detritus carbon produced during the summer bloom. This investigation was innovative because it used a state-of-the-art computer simulation representing simultaneously the melt of the glaciers, the circulation of the water and the biological interactions. The simulation revealed that detritus carbon is transported by the ocean circulation over a distance of a hundred miles before reaching the sea floor or being recycled. This result expands our understanding of the fate of carbon in the ASP and represents valuable insight for future field efforts. The INSPIRE project had multiple beneficial impacts for society at large. INSPIRE contributed to our understanding of how the ocean, like forests on land, can potentially slow down the increase in atmospheric CO2 concentrations. Increasing atmospheric CO2 affects the environment through global warming and ocean acidification. Our project also potentially contributed to an improved understanding of sea level rise. The computer simulations developed during INSPIRE were shared with other research groups, notably glaciologists studying the contribution of Antarctic glacial melting to the global sea level rise affecting coastal communities around the world. The results of INSPIRE were also integrated into educational activities by a STEM specialist. The activities introduced the students to important physical/biological concepts of marine life and to STEM-related careers in environmental sciences. The goals and outcomes of INSPIRE were communicated in a variety of formats including a website (http://www.nordet.net/inspire.html),a magazine article targeting the general public (https://researchfeatures.com/wp-content/uploads/2017/12/Professor-Patricia-Yager-University-of-Georgia-Climate-Change.pdf), multiple open-access per-reviewed publications (https://doi.org/10.1002/2017JC013162; https://doi.org/10.1029/2018JC014773; https://doi.org/10.1029/2018GB006168), and presentations for the scientific community, including invited public lectures at the University of Rhode Island, the University of Virginia, the University of Southern Mississippi, the University of Manitoba, and the Rutgers Climate Institute. Results were also presented at the American Geophysical Union annual meeting, the Ocean Sciences Meeting, several West Antarctic Ice Sheet workshops, and Gordon Research Conferences. Datasets and model code used by or produced during INSPIRE are publicly available at BCO-DMO or Scholar Works (links are on the website listed above). Field data used for the models are located at: https://www.bco-dmo.org/dataset/765081. Last Modified: 04/24/2019 Submitted by: Patricia L Yager