摘要
首次通过2008年12月-2010年3月在南太平洋副热带环流区(复活节岛外海)投放的一台Bio-Argo浮标的观测数据,分析与研究了该海区叶绿素a垂向分布的季节变化规律。研究表明,作为典型的贫营养水体,南太平洋环流区表层叶绿素a浓度仅为O.02mg m^(-3),次表层叶绿素极大值(SCM)仅为0.15mg m^(-3)左右。SCM出现在180m深处,而次表层生物量极大值(SBM)的深度约50m。此外,SCM的深度存在季节特征,冬浅(150m)夏深(200m),位于真光层之下约30m。虽然SCM的深度在6月达到最浅,但SCM层的厚度和强度在7月才降至最低,这可能是由于混合层在6月时仍然持续加深导致的。通过估算日光合有效辐照度(PAR)的垂向分布发现,SCM大约位于0.2%光强深度处,跟随等光照线(PAR=0.08 mol quanta m^(-2)d^(-1))而发生季节波动,经分析,这主要是由于Chla:C值随光强变化而导致的。
Based on the in situ dataset observed by a Bio-Argo float deployed in the South Pacific subtropical gyre （ off the Easter Island）from Dec. 2008 to Mar. 2010, this study focuses on the seasonal variations of chlorophyll-a vertical distribution. The research results show that, in this typical oligotrophic water, the surface chlorophyll-a concentration was only 0.02 mg m-3, and the subsurface chlorophyll maximum（SCM） reached 0.15 mg m-3. The SCM averagely appeared at the depth of 180 m, while the depth of subsurface biomass maximum（SBM） was around 50m. Besides, SCM depth exhibited obvious seasonality, shallower in winter（150m） and deeper in summer（200m）, always below the euphotic depth about 30 m. It was also found that the SCM depth was shallowest in June,but the thickness and intensity of SCM layer（SCML） reached minimum in July, probably as the mixed layer depth still deepened in June. Through estimated vertical photosynthetically available radiance（PAR） ,the SCM seemed to follow the 0.2% isol- ume or an absolute isolume （ PAR = 0.08 mol quanta m -2 d - 1 ）, which was considered as a result of the seasonal variation of Chla：C and its light-dependence.
出处
《高技术通讯》
CAS
CSCD
北大核心
2013年第10期1038-1047,共10页
Chinese High Technology Letters
基金
国家自然科学基金(41206028)
中国博士后科学基金(2012M511065)
国家自然科学基金创新群体项目(41121064)
海洋公益性行业科研专项(201005030)资助项目
