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检测到了一种叶绿素的衍生物。这一点很有意义，因为该衍生物的浓度与叶绿素a相同或更高。该衍生物也具有类似的光学特性，因此这一发现可能改变我们对叶绿素作为生物量标记的解释。这项支持将使Vernet博士能够使用多种技术组合分离、鉴定并开始对这种叶绿素a衍生物进行初步表征。这些技术包括：高效液相色谱、吸收光谱和荧光光谱以及高分辨质谱学。与叶绿素衍生物相关的辅助色素将通过层析和体内荧光光谱进行评估。此外，还将利用体内荧光激发光谱和14C标记的叶绿素来测定富含该叶绿素衍生物的浮游生物部分的光合作用活性。这些方法的结合应该可以确定海洋浮游植物中这种改变的叶绿素的真实性及其相对于叶绿素a的活动。悬浮在海洋表层的微型植物负责大部分海洋的生物生产，这些植物含有吸收阳光的色素，就像它们的陆地同行一样。长期以来，诸如叶绿素a这样的色素一直被用来通过对给定水体中存在的叶绿素进行直接化学分析来量化海洋浮游植物。韦尔内特博士将研究在热带水域中发现的一种不同寻常的色素，这种色素在化学上与叶绿素a相似。由于叶绿素a在生物海洋学中被广泛用于估计植物生物量，这种最近发现的色素对我们解释表层海洋生物学的潜在影响是巨大的。通过与该领域公认的专家(W.Gieskes博士)合作进行的化学和生物学研究，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。Vernet博士非常有资格进行这项研究，这将对我们了解海水中的植物色素产生重大好处。

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.