Satellite images from the Kara Sea show that, until July, fast-ice extends along the coast and Fills the estuaries of the Ob' and Yenisey rivers. It is separated from offshore drift-ice by a region of open water, comprising a flaw lead/polynya. By August, much of the fast and drift-ice has melted and retreated from the southwestern Kara Sea, leaving behind a persistent patch of sea-ice east of Novaya Zemlya. Because both the OF and Yenisey rivers discharge water throughout the winter, the fast-ice is likely to incorporate river-borne contaminants by bottom adfreezing. During peak river discharge in June, the fast-ice remains in place, and is potentially influenced by the river outflow throughout the length of the estuary. Breakup and melting of the fast-ice in July could release contaminants to the surface waters. By late July and August, when the fast-ice has disappeared, the river discharge is observed primarily along the shore in a zone that extends offshore more than 100 km. In fall, newly-forming ice may incorporate contaminants from the river plume, while in late winter, convection penetrating to the sea floor may allow resuspended sediments to be entrained in ice forming in the flaw lead/polynya. Drift-ice formed in this region could then advect contaminants offshore. The potential for exchange of water, ice and contaminants with the Barents Sea through Karskiye Vorota, south of Novaya Zemlya, is discussed in the context of the temperature and turbidity distribution observed in the satellite images.
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