hrvatski

Planktonska primarna produkcija u Dunavu kraj Dalja

Primary plankton production in the Danube at Dalj was measured from 12 March until 14 August 1982 in surface water and at depths of 0.5 and 1.0 m. Light and dark bottles were used for the measurements (Knöpp, 1960). Mean values of dissolved oxygen in initial samples and the dissolved oxygen in light and dark bottles at different depths showed that the primary plankton production of oxygen was constantly thehighest (4.0-1.6 g O2 m-3 /4h) in surface water and the lowest (1.6-0.2 g O2 m-3 /4h) at the depth of 1.0 m. The required content of oxygen showed the same value at all three depths in profile I (1.2 g O2 m-3 /4h in May, 0.4 g O2 m-3 /4h in August) and in profile II (1.2 g O2 m-3 /4h in March). In other months, the values either increased or decreased with depth. Both profiles showed an excess of oxygen (7.85-79.39%) at all times, but the excess of oxygen in profile II was always higher than that in profile I (7.85-59.43%). The comparison of these data with the simultaneusly measured primary plankton production in the eutrophic Kopačko lake shows that the primary plankton procuction in the Danube at Dalj is 5.22 times lower.

planktonska primarna produkcija; Dunav

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