Controls on planktonic metabolism in the Bay of Blanes, northwestern Mediterranean littoral

被引:45
作者
Duarte, CM [1 ]
Agustí, S [1 ]
Vaqué, D [1 ]
机构
[1] UIB, CSIC, IMEDEA, Inst Mediterraneo Estudios Avanzados,Grp Oceanog, E-08003 Barcelona, Spain
关键词
D O I
10.4319/lo.2004.49.6.2162
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
Long-term and experimental approaches were used to examine the metabolic balance of the planktonic community in the Bay of Blanes (Spanish Mediterranean). Incubation measurements at weekly intervals for 6 yr revealed that community respiration, R, was consistently larger than gross primary production (GPP) by a factor of 2. The plankton community was net heterotrophic for 2/3 of the study period, with a median P/R ratio of 0.65. The biomass of autotrophs comprised, on average, 41% +/- 3% of the planktonic biomass, and the total microplankton biomass was about 2.5-fold greater than that of the primary producers. The monthly average GPP and R were positively correlated with day length, and the planktonic respiration and gross production per unit microplankton biomass increased with increasing water temperature. Experimental nutrient additions had a greater effect on GPP than respiration rates; the increase in R along the nutrient gradient was 7.8% (+/- 0.4%) of the increase in GPP As a result, net community production increased in parallel with GPP, shifting from net heterotrophic at low GPP to net autotrophic when GPP increased because of nutrient additions. Our results show that the R that would be supported by allocthonous inputs was 3.83 +/- 0.67 mumol O-2 L-1 d(-1), and the average GPP required to shift the community from net heterotrophic to net autotrophic was about 4 mumol O-2 L-1 d(-1). This is well above the average GPP recorded in the Bay of Blanes along this study (2.56 +/- 0.13 mumol O-2 L-1 d(-1)), explaining the net heterotrophic nature of the community.
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收藏
页码:2162 / 2170
页数:9
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