Dimethyl sulphide biogeochemistry within a coccolithophore bloom (DISCO): an overview
Dimethyl sulphide biogeochemistry within a coccolithophore bloom (DISCO): an overview
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DOI：
10.1016/s0967-0645(02)00061-9
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发表时间：
2002-01-01
影响因子：
3
通讯作者：
Zubkov, MV
中科院分区：
文献类型：
--
作者：
Burkill, PH;Archer, SD;Zubkov, MV
本文概述了一颗颗石藻水华 (DISCO) 中的二甲硫醚生物地球化学，这是一项综合的多学科拉格朗日过程研究，研究了颗石藻水华中二甲硫醚 (DMS) 的生物地球化学循环的路径、速率和控制。拉格朗日研究于1999年6月16日至26日在北海北部进行。在此之前，对该地区大约 52,000 公里(2) 的区域进行了为期 8 天的调查，以找到适合研究的赫胥黎藻华。尽管最初没有计划，但由于浓云覆盖，无法使用遥感来定位合适的水华，因此进行了调查。赫胥黎藻花通常在仲夏期间在该地区常见，但在研究区域却异常稀疏。为过程研究选择的水华最初位于类似于 58°56'N 02°52'E 的中心位置，并且 6 月 16 日用类似 30 克六氟化硫 (SF6) 标记了一块 40 公里(2) 的水域进行研究。 6 月 24 日，原来的补丁又重新注入了 SF6。在过程研究期间，SF6标记的斑块向东南方向移动，当斑块俯冲到密度较低的挪威沿海水域下方时，研究结束。过程研究包括对斑块随时间变化的生物、光学和物理特性的分析，以及对DMS、二甲磺基丙酸酯(DMSP)、二甲亚砜、营养物、卤代烃、甲胺、一氧化碳、溶解有机碳和总溶解氮的研究。研究了病毒、细菌、浮游植物、微型浮游动物和中型浮游动物的作用，以及初级、新的和细菌产生的动态、浮游生物呼吸、微型浮游动物的放牧和沉降，与 DMS 的生物地球化学循环有关。尽管颗石藻水华表现出高光学反向散射，但存在的藻类群落具有高度异质性。人们发现，除赫胥氏埃里氏菌以外的鞭毛虫在浮游植物中占主导地位。 DMSP池的预算表明，赫胥黎桉仅占颗粒DMSP库存的13%，表明在这次“赫胥黎桉水华”中，赫胥黎桉以外的类群是DMSP的重要来源。在这个年轻的水华中，表面混合层中颗粒和溶解的DMSP和DMS浓度平均分别为1360、155和60μM m(-2)。在研究期间，地表水颗粒 DMSP 浓度以 13% d(-1) 的净速率增加，包括赫胥黎 E. huxleyi 在内的浮游植物浓度也增加，证实水华正在发展。在整个研究过程中，混合层的营养条件较低，由较强的密纹斜层维持，硝酸盐上流量估计类似于2nM dm(-3) d(-1)。尽管发现地表水中的硝化率很高，但初级生产是由再生营养物质推动的。微型浮游动物的放牧占颗粒 DMSP 降解的 91%，被认为是 DMSP 浓度的主要控制因素。微型浮游动物的旺盛摄食以及细菌对溶解 DMSP 的快速摄取表明，微型浮游动物是溶解 DMSP 生产的主要途径。细菌群落以一个分类群为主，这是一种与玫瑰杆菌相关的α变形菌，通过代谢溶解的DMSP来满足其全部硫需求。细菌产生的DMS产量达到2nM d(-1)，被认为是DMS生产的主要途径。体外 DMSPlyase 活性非常高，但几乎没有证据表明原位活性很高。在研究期间，DMS 进入大气的通量估计为 7 μM m(-2) d(-1)，相当于表面混合层中产生的 DMSP 硫的 1%。基于 DISCO 研究中的分析和实验测量，提出了上混合层 DMS 循环的预算。 (C) 2002 年，爱思唯尔科学有限公司出版。
This paper presents an overview of dimethyl sulphide biogeochemistry within a coccolithophore bloom (DISCO), an integrated, multidisciplinary Lagrangian process study of the routes, rates and controls on the biogeochemical cycling of dimethyl sulphide (DMS) within a growing bloom of the coccolithophorid alga, Emiliania huxleyi. The Lagrangian study took place between 16 and 26 June 1999 in the northern North Sea. It was preceded by an 8-d survey of similar to52,000 km(2) of the region to locate an E huxleyi bloom suitable for study. Although not originally planned, the survey was carried out because heavy cloud cover precluded use of remote sensing to locate a suitable bloom. E huxleyi blooms, typically common in the region during mid-summer, were unusually sparse in the study area. The bloom chosen for the process study was initially centred similar to 58degrees56'N 02degrees52'E, and a 40-km(2) patch of water was labelled for study with similar to30 g sulphur hexafluoride (SF6) on 16 June. The original patch was reinfused with further SF6 on 24 June. During the process study, the SF6-labelled patch moved in a south-easterly direction and the study ended when the patch subducted underneath less dense Norwegian coastal water.The process study comprised analyses of the time-varying biological, optical and physical properties of the patch as well as studies of DMS, dimethylsulphonioproprionate (DMSP), dimethylsulphoxide, nutrients, halocarbons, methylamines, carbon monoxide, dissolved organic carbon, and total dissolved nitrogen. The role of viruses, bacteria, phytoplankton, microzooplankton, and mesozooplankton, together with the dynamics of primary, new and bacterial production, plankton respiration, microzooplankton grazing, and sedimentation, were studied in relation to the biogeochemical cycling of DMS. Although the coccolithophore bloom water exhibited high optical backscatter, the algal community present was highly heterogeneous. Flagellates other than E. huxleyi were found to dominate the phytoplankton. A budget of the DMSP pools suggested that E huxleyi accounted for only 13% of the stocks of particulate DMSP, showing that in this "E huxleyi bloom", taxa other than E. huxleyi were important sources of DMSP. In this young bloom, particulate and dissolved DMSP and DMS concentrations averaged 1360, 155 and 60 muM m(-2), respectively, in the surface mixed layer. Surface-water particulate DMSP concentrations increased during the study at a net rate of 13% d(-1), as did concentrations of phytoplankton including E. huxleyi, confirming that the bloom was developing. Nutrient conditions were low in the mixed layer throughout the study, maintained by a strong pycnocline across which nitrate upflux was estimated to be similar to2nM dm(-3) d(-1). Primary production was fuelled by regenerated nutrients, although nitrification rates in surface waters were found to be significant. Microzooplankton grazing accounted for 91% of the particulate DMSP degradation and was considered to be a major control on the DMSP concentration. Vigorous microzooplankton grazing together with rapid uptake of dissolved DMSP by bacteria suggest that microzooplankton were the main route for the production of dissolved DMSP. The bacterial community was dominated by one taxon, an alpha proteobacteria related to Roseobacter that satisfied its entire sulphur demand by metabolising dissolved DMSP. Bacteriogenic DMS production amounted to 2 nM d(-1) and was considered the main route for DMS production. In vitro DMSPlyase activity was very high, but there was little evidence for high in situ activity. Over the study period, DMS flux to the atmosphere was estimated to be 7 muM m(-2) d(-1), equivalent to similar to1% of the DMSP sulphur produced in the surface mixed layer. A budget for DMS cycling in the upper mixed layer is presented based on the analytical and experimental measurements made in the DISCO study. (C) 2002 Published by Elsevier Science Ltd.