Sedimentation of particulate organic matter and silicium during spring and summer in Lindaspollene, Western Norway

Abstract

Sedimentation of organic and inorganic matter was determined at 18, 38, 70 and 85 m between 17 March and 8 October 1982, m the land-locked flord Llndespollene Rates of sedimentation were highest dunng spnng with 2 peaks in sedmentation followmg the first spnng diatom bloonl and a second bloom not dominated by diatoms About half of the biomass (C and N) formed dunng these 2 blooms apparently sedimented out from the euphohc zone Based on the vertical structure of the plankton commumty it is concluded that sedimenting material dunng summer mainly originates from the deeper part of the euphotic zone containing a chlorophyll maxlmum layer Sedimentation of organic matter was correlated with sedimentahon of parhculate shcium both dunng spnng and summer, suggesting that s i n l n g of diatom frustules is a major transport mechanism for vertical flux of organic material Recovery of parhculate sihcium In sediment traps compared to seston content was lower than for organic matenal This indicates rapid dissoluhon of shcium most of which apparently occurred withln the sediment traps Decreasing sedimentahon flux of organic material with depth below the euphohc zone and concomrmtant decrease in the N/C raho and increase in the P/C raho are interpreted to reflect substanhal mineralization and associated microbial growth on the sinking material.