Energetics and growth kinetics of a deep Prochlorococcus spp. population in the Arabian Sea |
| |
| Institution: | 1. Botany Department/Nicholas School of the Environment, Duke University Marine Laboratory, 135 Duke Marine Lab Rd., Beaufort, NC 28516, USA;2. Department of Oceanography, University of Hawaii at Manoa, 1000 Pope Rd., Honolulu, HI 96822, USA;3. Department of Oceanography, Texas A&M University, College Station, TX 77843-3146, USA;4. Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA;5. CHORS/SDSU, 6505 Alvarado Rd., No. 206, San Diego CA, 92120, USA;1. Central Queensland University, School of Human, Health, and Social Sciences, Rockhampton, QLD, Australia;2. Maastricht University, Psychology and Neuroscience, Maastricht, The Netherlands;3. University of Adelaide, School of Medicine, SA, Australia;4. University of Newcastle, School of Medicine & Public Health, Priority Research Centre for Physical Activity and Nutrition, Faculty of Health and Medicine, NSW, Australia;5. The University of Queensland, School of Human Movement Studies, Brisbane, QLD, Australia;1. Department of Energy Resources Engineering, Stanford University, Stanford, CA, USA;2. Utah Geological Survey, Salt Lake City, UT, USA;1. Department of Energy Resources Engineering, Stanford University, Stanford, CA, USA;2. Utah Geological Survey, Salt Lake City, UT, USA;3. Total, Pau, France |
| |
| Abstract: | During the US JGOFS process studies in the Arabian Sea (1995), secondary fluorescence maxima (SFM) were observed frequently at the oxic–anoxic interface at the extreme base of the euphotic zone. These secondary peaks were most prominent during the early NE monsoon in the central oligotrophic portion of the Arabian Sea, although they were spatially and temporally variable. Based on high performance liquid chromatography (HPLC) and flow cytometry analyses, SFM were determined to be populated almost exclusively by the marine cyanobacterium Prochlorococcus spp. While SFM were about half the magnitude of primary fluorescence peaks, chlorophyll a biomass was typically an order of magnitude less than at the primary maxima (although total chlorophyll (a+b) differed only by a factor of two). Photosynthesis versus irradiance response curves revealed an efficient population adapted to extremely low light (～0.02–0.05% surface irradiance) largely through increased light absorption capabilities. A theoretical spectral irradiance absorption efficiency model based on available spectral irradiance, individual cell properties, and bulk particulate spectral absorption also supports a well-adapted low-light population. Deck-incubated C-14 uptake as well as dilution growth experiments revealed instantaneous growth rates on the order of μ=0.01 d?1. However, additional in situ observations suggest SFM populations may be more dynamic than the growth rates estimates from shipboard bottle incubations predict. We advance four hypotheses for the regulation of SFM populations including: (1) reduced loss rates, (2) discontinuous environmental conditions, (3) enhanced sub-oxic growth, and (4) physical mechanisms. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
