Several oceanographers have concluded that Pacific deep water enters the North Pacific from the southern hemisphere and is warmed along its northerly path of flow. The deep water near the Aleutian Trench, however, is noticeably colder than the water lying between it and 30°N in the region east of 170°E. Knauss (1962) attributed this condition to the rising of colder water from below; Gordon and Gerard (1970) were unable to find a path of flow into the northern region....
Reed, R. K.. 1970. "On the anomalous deep water south of the Aleutian Islands." Journal of Marine Research 28, (3). https://elischolar.library.yale.edu/journal_of_marine_research/1196