An Unusual Chlorophyll a Derivative in Tropical Phytoplankton: Artifact or Real?

近年来，在热带北大西洋和北太平洋地区发现了叶绿素的衍生物。这一发现意义重大，因为该衍生物的浓度等于或高于叶绿素a。该衍生物也具有类似的光学特性，因此这一发现可能会改变我们对叶绿素作为生物量标记物的解释。这种支持将使韦尔内博士能够分离、识别并开始使用多种技术组合对叶绿素a衍生物进行初步表征。这些包括;高效液相色谱，吸收和荧光光谱，高分辨率质谱。与叶绿素衍生物相关的辅助色素将通过色谱和体内荧光光谱进行估计。此外，富含该叶绿素衍生物的浮游生物组分的光合活性将通过体内荧光激发光谱和14C标记的叶绿素来确定。这些方法的结合应该确定海洋浮游植物中这种改变的叶绿素的真实性，以及它对叶绿素a的活性。悬浮在海洋表层的微观植物负责大部分海洋生物生产，这些植物含有吸收阳光的色素，就像它们的陆地对应物一样。长期以来，叶绿素a等色素一直被用于通过对特定水体中叶绿素的直接化学分析来量化海洋浮游植物。韦尔内博士将研究在热带水域发现的一种不寻常的色素，这种色素的化学性质与叶绿素a相似。因为叶绿素a在生物海洋学中被广泛用于估计植物生物量，所以这种最近发现的色素对我们对海洋表面生物的解释的潜在影响是巨大的。通过与该领域公认的专家（Dr. W. Gieskes）联合进行化学和生物学研究，Vernet博士将确定这种不寻常的色素是否也可以用作植物生物量的指标。韦尔内博士非常有资格进行这项研究，这对我们了解海水中的植物色素有很大的好处。

A derivative of chlorophyll has been detected in tropical North Atlantic and North Pacific in recent years. This is significant because the derivative was found in concentrations equal or higher to chlorophyll a. The derivative also has similar optical characteristics and thus this finding may alter our interpretation of chlorophyll as a biomass marker. This support will enable Dr. Vernet to isolate, identify and begin a preliminary characterization of this chlorophyll a derivative by using a combination of techniques. These include; high performance liquid chromatography, absorption and fluorescence spectra, and high resolution mass spectrometry. Accessory pigments associated with the chlorophyll derivative will be estimated by chromatography and in vivo fluorescence spectra. Also, the photosynthetic activity of the plankton fraction rich in this chlorophyll derivative will be determined using in vivo fluorescence excitation spectra and 14C labeled chlorophyll. The combination of these methods should establish the authenticity of this altered chlorophyll in marine phytoplankton and its activity with respect to chlorophyll a. Microscopic plants suspended in the surface layer of the ocean are responsible for most of the ocean's biological production, and these plants contain pigments for absorbing sunlight just as their terrestrial counterparts do. Pigments such as chlorophyll a have long been used to quantify marine phytoplankton through direct chemical analysis of the chlorophyll present in a given body of water. Dr. Vernet will investigate an unusual pigment that has been discovered in tropical water that is chemically similar to chlorophyll a. Because chlorophyll a is used extensively to estimate plant biomass in biological oceanography, the potential impact of this recently discovered pigment on our interpretation of surface ocean biology is substantial. Through chemical and biological studies in association with a recognized expert in the field, (Dr. W. Gieskes), Dr. Vernet will determine if this unusual pigment can also be used as an indicator of plant biomass. Dr. Vernet is very qualified to carry out this study and significant benefit to our understanding of plant pigments in ocean water will result.