TY - JOUR
T1 - Carbon, nitrogen and phosphorus resource supply and utilisation for coastal planktonic heterotrophic bacteria in a gradient of nutrient loading
AU - Vadstein, Olav
AU - Andersen, Tom
AU - Reinertsen, Helge R.
AU - Olsen, Yngvar
PY - 2012/2/13
Y1 - 2012/2/13
N2 - Data from 7 mesocosms with a gradient in daily nutrient loading rate (LN) and inverse modelling were used to estimate all C, N and P flows in an idealised food web. The gradient in LN created autotrophic production (AP) of 7 to 314 μ g C l -1 d -1 (mean values over 18 d). The production of dissolved organic C (DOC) decreased from 240 to 40% of AP, and was dominated by heterotrophs (80 to 58%), with heterotrophic bacteria (BAC) producing 48 ± 8% (means ± SD) by excretion or lysis. The consumption of DOC by BAC was 133 to 86% of AP, and DOC accumulated when experimental LN = natural LN. C of BAC origin constituted 5.5 to 0.2% of the C consumed by copepods. The production of dissolved N and P was mainly by heterotrophs (92 ± 2% of DN, 92 ± 4% DP), but autotrophs produced 26 ± 7% of dissolved organic N (DON) and 21 ± 8% of dissolved organic P (DOP). For the production of inorganic N and P (DIN and DIP, respectively), BAC predators produced >50% of DIN and >70% of DIP at low or moderate LN (averages 37 ± 16% of DIN and 66 ± 14% of DIP). The contribution by BAC was low for DIN (12 ± 6%) and zero for DIP. For the re-mineralisation of N and P, the significance of BAC was as N and P rich food particles. DOP accumulated more than DOC, despite the high demand for P. Turnover time of dissolved organic matter (DOM) decreased from around 80 to 12 d with increasing LN. These data provide new insights into the role of various functional groups of organisms for the cycling of DOM, and to the differences in C, N and P cycling.
AB - Data from 7 mesocosms with a gradient in daily nutrient loading rate (LN) and inverse modelling were used to estimate all C, N and P flows in an idealised food web. The gradient in LN created autotrophic production (AP) of 7 to 314 μ g C l -1 d -1 (mean values over 18 d). The production of dissolved organic C (DOC) decreased from 240 to 40% of AP, and was dominated by heterotrophs (80 to 58%), with heterotrophic bacteria (BAC) producing 48 ± 8% (means ± SD) by excretion or lysis. The consumption of DOC by BAC was 133 to 86% of AP, and DOC accumulated when experimental LN = natural LN. C of BAC origin constituted 5.5 to 0.2% of the C consumed by copepods. The production of dissolved N and P was mainly by heterotrophs (92 ± 2% of DN, 92 ± 4% DP), but autotrophs produced 26 ± 7% of dissolved organic N (DON) and 21 ± 8% of dissolved organic P (DOP). For the production of inorganic N and P (DIN and DIP, respectively), BAC predators produced >50% of DIN and >70% of DIP at low or moderate LN (averages 37 ± 16% of DIN and 66 ± 14% of DIP). The contribution by BAC was low for DIN (12 ± 6%) and zero for DIP. For the re-mineralisation of N and P, the significance of BAC was as N and P rich food particles. DOP accumulated more than DOC, despite the high demand for P. Turnover time of dissolved organic matter (DOM) decreased from around 80 to 12 d with increasing LN. These data provide new insights into the role of various functional groups of organisms for the cycling of DOM, and to the differences in C, N and P cycling.
KW - Community interactions
KW - DOC accumulation
KW - DOM production
KW - DOM utilisation
KW - Heterotrophic bacteria
KW - Inverse modelling
KW - Re-mineralisation
UR - http://www.scopus.com/inward/record.url?scp=84857352272&partnerID=8YFLogxK
U2 - 10.3354/meps09473
DO - 10.3354/meps09473
M3 - Article
AN - SCOPUS:84857352272
SN - 0171-8630
VL - 447
SP - 55
EP - 75
JO - Marine Ecology Progress Series
JF - Marine Ecology Progress Series
ER -