Latitudinal distribution of microbial plankton abundance,production, and respiration in the Equatorial Atlantic in autumn 2000 |
| |
| Institution: | 1. Departamento de Ecoloxía e Bioloxía Animal, Facultade de Ciencias do Mar, Universidade de Vigo, Ctra. Colexio Universitario s/n, E-36310 Vigo, Spain;2. Centro Oceanográfico de A Coruña, Instituto Español de Oceanografia, Muelle de Ánimas, Apdo. 130, E-15080A Coruña, Spain;3. Centro Oceanográfico de Xixón, Instituto Español de Oceanografia, Camín de L’Arbeyal s/n, E-33212 Xixón, Asturies, Spain;4. Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth PL1 3DH, UK;5. University of Newcastle, Depart. of Marine Sciences and Coastal Management, Newcastle upon Tyne NE1 7 RU, UK;6. Instituto Español de Oceanografía, Centro Oceanográfico de Santander, Apdo. 240, E-39080 Santander, Spain;1. Sanya Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China;2. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China;1. Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan;2. School of Agricultural Sciences, Nagoya University, Nagoya 464-8601, Japan;1. Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, IA, USA;2. Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA |
| |
| Abstract: | Phytoplankton and bacterial abundance, size-fractionated phytoplankton chlorophyll-a (Chl-a) and production together with bacterial production, microbial oxygen production and respiration rates were measured along a transect that crossed the Equatorial Atlantic Ocean (10°N–10°S) in September 2000, as part of the Atlantic Meridional Transect 11 (AMT 11) cruise. From 2°N to 5°S, the equatorial divergence resulted in a shallowing of the pycnocline and the presence of relatively high nitrate (>1 μM) concentrations in surface waters. In contrast, a typical tropical structure (TTS) was found near the ends of the transect. Photic zone integrated 14C primary production ranged from ～200 mg C m?2 d?1 in the TTS region to ～1300 mg C m?2 d?1 in the equatorial divergence area. In spite of the relatively high primary production rates measured in the equatorial upwelling region, only a moderate rise in phytoplankton biomass was observed as compared to nearby nutrient-depleted areas (22 vs. 18 mg Chl-a m?2, respectively). Picophytoplankton were the main contributors (>60%) to both Chl-a biomass and primary production throughout the region. The equatorial upwelling did not alter the phytoplankton size structure typically found in the tropical open ocean, which suggests a strong top-down control of primary producers by zooplankton. However, the impact of nutrient supply on net microbial community metabolism, integrated over the euphotic layer, was evidenced by an average net microbial community production within the equatorial divergence (1130 mg C m?2 d?1) three-fold larger than net production measured in the TTS region (370 mg C m?2 d?1). The entire region under study showed net autotrophic community metabolism, since respiration accounted on average for 51% of gross primary production integrated over the euphotic layer. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
