Plankton respiration is an important part of the carbon cycle and significantly affects the balance of autotrophic assimilation and heterotrophic production in oceanic ecosystems. In the present study, respiration rat...Plankton respiration is an important part of the carbon cycle and significantly affects the balance of autotrophic assimilation and heterotrophic production in oceanic ecosystems. In the present study, respiration rates of the euphotic zone plankton community（CR_（eu））, size fractionated chlorophyll a concentration（Chl a）, bacterial abundance（BAC）, and dissolved oxygen concentration（DO） were investigated during winter and summer in the northern South China Sea（n SCS）. The results show that there were obvious spatial and temporal variations in CR_（eu） in the n SCS（ranging from 0.03 to 1.10 μmol/（L·h））, CR_（eu） in winter（（0.53±0.27） μmol/（L·h）） was two times higher than that in summer（（0.26±0.20） μmol/（L·h））, and decreased gradually from the coastal zone to the open sea. The distribution of CR_（eu） was affected by coupled physical-chemical-biological processes, driven by monsoon events. The results also show that CR_（eu） was positively correlated with Chl a, BAC, and DO, and that BAC contributed the highest CR_（eu） variability. Furthermore, the results of the stepwise multiple linear regression suggest that bacteria and phytoplankton were the dominant factors in determining CR_（eu）（R^2 = 0.82, p〈0.05） in the n SCS. Based on this relationship, we estimated the integrated water column respiration rate（CRint） within 100 m of the investigated area, and found that the relationship between the biomass of the plankton community and respiration may be nonlinear in the water column.展开更多
基金The National Natural Science Foundation of China(NSFC)under contract Nos 90711006,41306162 and 41006101the National Key Research and Development Program of China under contract No.2016YFC1401601the National Programme on Global Change and Air-Sea Interaction under contract No.GASI-0301-03-03
文摘Plankton respiration is an important part of the carbon cycle and significantly affects the balance of autotrophic assimilation and heterotrophic production in oceanic ecosystems. In the present study, respiration rates of the euphotic zone plankton community（CR_（eu））, size fractionated chlorophyll a concentration（Chl a）, bacterial abundance（BAC）, and dissolved oxygen concentration（DO） were investigated during winter and summer in the northern South China Sea（n SCS）. The results show that there were obvious spatial and temporal variations in CR_（eu） in the n SCS（ranging from 0.03 to 1.10 μmol/（L·h））, CR_（eu） in winter（（0.53±0.27） μmol/（L·h）） was two times higher than that in summer（（0.26±0.20） μmol/（L·h））, and decreased gradually from the coastal zone to the open sea. The distribution of CR_（eu） was affected by coupled physical-chemical-biological processes, driven by monsoon events. The results also show that CR_（eu） was positively correlated with Chl a, BAC, and DO, and that BAC contributed the highest CR_（eu） variability. Furthermore, the results of the stepwise multiple linear regression suggest that bacteria and phytoplankton were the dominant factors in determining CR_（eu）（R^2 = 0.82, p〈0.05） in the n SCS. Based on this relationship, we estimated the integrated water column respiration rate（CRint） within 100 m of the investigated area, and found that the relationship between the biomass of the plankton community and respiration may be nonlinear in the water column.
