Vertical microalga flux in the northern Laptev Sea (from the data collected by the yearlong sediment trap)

First studies of the microalga flux over the Lomonosov Ridge in the norther n Laptev Sea were carried out with a sediment trap at the yearlong mooring station LOMO-2, installed at a 150-m depth (81 degrees 04.3' N; 138 degrees 55.2' E, sea depth 1703 m) from September 15, 1995 to August 16, 1996. The se studies demonstrated essential seasonal variation of the vertical microa lga flux. It was shown that, in summer, a diverse flora (composed mainly of cryophylic diatoms) grows intensively beneath the permanent ice cover. Str ongly pronounced seasonal variations of the microalga growth correlate clos ely with the solar radiation. Exactly during the maximum insolation period, from the middle of July until the end of September, the microalga flux is hundreds of times higher than that in the rest of the year. The summer valu es of the microalga flux over the Lomonosov Ridge in the northern Laptev Se a are similar to those in the Weddell Sea in the Antarctic and exceed the s ummer flux values in the Norwegian and Greenland Seas and in the St. Anna T rough (the northwestern Kara Sea).