Role of Bacteria in the Carbon and Nitrogen Flow between Water-Column and Sediment in a Shallow Marine Bay (Bay of Piran, Northern Adriatic Sea) |
| |
Authors: | G J Herndl J Faganeli N Fanuko P Peduzzi V Turk |
| |
Institution: | Institute of Zoology, University of Vienna, Althanstr. 14, A-1090 Vienna, Austria.;Marine Biology Station Piran, Cesta JLA 65, YU-66330 Piran, Yugoslavia. |
| |
Abstract: | Abstract. The interdependences between phytoplankton standing crop, bacterial biomass and the dissolved organic matter (DOM) pool in the water column were investigated and related to sediment parameters in a shallow marine bay (Bay of Piran, Northern Adriatic Sea) over an annual cycle. Bacterioplankton density varied between 1–10 × 105 cells ml-1, with lowest density observed in March corresponding to the low Chi a concentrations during this period. Generation times as determined by dialysis incubations ranged between 4h (June) and 82 h (March). Mean bacterial secondary production rates during summer were about 40 mg C m-1 d-1 and 5mg C m-3.d-1 during winter. With a short time lag, DOM concentrations followed the fluctuation in Chi a. Sediment oxygen demand measurements revealed a mean mineralization rate of about 260 mg C m-2 d-1 during summer and 100–200 mg C m-2 d-1 in winter. Sediment bacterial density varied between 108 - 109 cells g (sediment dry wt)-1 in the top 5 cm sediment layer or, in terms of biomass, 4.3 g C m-l during summer and 0.6 g C m-2 during winter. Highest concentrations of DOM in pore waters were measured in September, coinciding with high rates of sediment oxygen demand. |
| |
Keywords: | Phytoplankton dissolved organic matter porewater microheterotrophic utilization bacterial production sediment oxygen demand |
|
|