Photosynthetic characteristics of phytoplankton in the subarctic North Pacific Ocean during summer 

作成者 Furuya, Ken, Yoshikawa, Takashi, Obata, Hajime, Takeda, Shigenobu
日本十進分類法 (NDC) 468, 450
内容 研究概要:Geographical variability in the relationship between photosynthesis and irradiance in summer phytoplankton populations was examined in the subarctic North Pacific Ocean in July-August 1997 and July 1999. Photosynthesis versus irradiance (P-E) curves were obtained for seawater that were collected by trace metal clean techniques. Most region sampled during this study was characterized by high nutrient (>8. m nitrate) and low chlorophyll (0.2-0.6 μg l^<-1>) except the central western gyre in 1997 where high chlorophyll concentrations of 1.3-3.0 μg l^<-1>. Ambient iron concentration at the surface was consistently subnano molar during both the years (<0.22 nM). Maximum photosynthetic rates (P^B_m) varied between 1.79 and 5.24 mgC (mg chl)^<-1> h^<-1> with no obvious geographical difference between the western and eastern gyres. In contrast however, there were noticeable east-west gradients in the initial slope of the P-E curves (α^B) for surface population during 1997: Station P (50°N, 145°W), located in the eastern gyre had the lowest α^B (0.088±0.041 mgC (mg chl)^<-1> h^<-1> (μmol m^<-2>s^<-1>)^<-1>, n=3) that increased westward. During July 1999, no major east-west gradient in α^B was seen which was observed to range between 0.012 and 0.029 mgC (mg chl)^<-1> h^<-1> (μmol m^<-2>s^<-1>)^<-1>, while a high α^B was observed in the western gyre area. Significant enhancement of both PBm and α^B were observed with 1-2 nM iron enrichment signifying the role of iron in controlling the productivity potential of phytoplankton as well as the regional variability in P-E during summer.
コンテンツの種類 研究報告書 Research Paper
DCMI資源タイプ text
掲載誌情報 Proceedings of the international symposium on Ocean Color Remote Sensing and Carbon Flux page.28-28 (1999)
言語 英語

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