major portion of the dense water required to drive the thermohaline circulation. Mid-sea polynyas are formed when specific atmospheric conditions occur over preconditioned oceanographic areas. Such atmospheric conditions should favor ice drift in opposite directions to open the ice pack. Polar cyclones are a typical atmospheric trigger for the occurrence of mid-sea polynyas as the cyclonic winds push the ice in opposite directions away from the cyclone center. Also, cold fronts, where two opposite flows in direction are found, are ideal for creating a mid-sea polynya. Antarctic Bottom Water (AABW) Antarctic Bottom Water is the dense water with high salinity that exists in the abyssal layer of the Southern Ocean. It plays a major role in the global overturning circulation. Coastal polynyas (latent heat polynyas) are a source of AABW as brine rejection during the formation of sea ice at these polynyas increases the salinity of the seawater, which then sinks down to the ocean bottom as AABW. Antarctic polynyas form when ice masses diverge from the coast and move away in the direction of the wind, creating an exposed area of sea water which subsequently freezes over, with brine rejection, to form another mass of ice. Ecology Some polynyas, such as the North Water Polynya between Canada and Greenland, occur seasonally at the same time and place each year. Because animals can adapt their life strategies to this regularity, these types of polynyas are of special ecological research significance. In winter, marine mammals such as walruses, narwhals, and belugas that do not migrate south remain there. Polar bears are known to be able to swim as far as across open waters of a polynya. Polynya blooms The presence of open water in an otherwise ice-covered area can result in a localized marine algal bloom, also referred to as a polynya bloom. While algal communities are often found under sea ice, as evidenced by ice algae, the rate of phytoplankton growth is substantially higher in the open water of a polynya. The primary drivers of polynya blooms are sunlight and nutrients. Specifically, the lack of sea ice allows light, a necessary component for photosynthesis, to penetrate deeper into the water and enable elevated phytoplankton growth compared to the surrounding ice-covered waters. Furthermore, polynya formation is typically associated with upwelling, a process that transports nutrient-rich water from the ocean bottom towards the surface. This influx of nutrients coupled with increased light