DOI: 10.1002/gbc.20037
Scopus记录号: 2-s2.0-84881115023
论文题名: Phosphorus cycling in the Sargasso Sea: Investigation using the oxygen isotopic composition of phosphate, enzyme-labeled fluorescence, and turnover times
作者: McLaughlin K ; , Sohm J ; A ; , Cutter G ; A ; , Lomas M ; W ; , Paytan A
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2013
卷: 27, 期: 2 起始页码: 375
结束页码: 387
语种: 英语
英文关键词: Atlantic Ocean
; DOP
; isotopes
; phosphorus
Scopus关键词: Atlantic Ocean
; Biogeochemical cycling
; Dissolved inorganic phosphorus
; Dissolved phosphates
; DOP
; Extracellular enzymes
; Oxygen isotopic composition
; Primary productivity
; Dissolution
; Dissolved oxygen
; Enzyme activity
; Fluorescence
; Phosphatases
; Phosphorus
; Photosynthesis
; Phytoplankton
; Surface waters
; Isotopes
; bacterium
; biogeochemistry
; concentration (composition)
; dissolved organic phosphorus
; isotopic composition
; mass balance
; oxygen isotope
; phosphate
; phosphorus cycle
; phytoplankton
; primary production
; remineralization
; turnover
; Atlantic Ocean
; Sargasso Sea
英文摘要: Dissolved inorganic phosphorus (DIP) concentrations in surface water of vast areas of the ocean are extremely low (<10 nM) and phosphorus (P) availability could limit primary productivity in these regions. We explore the use of oxygen isotopic signature of dissolved phosphate (δ 18OPO4) to investigate biogeochemical cycling of P in the Sargasso Sea, Atlantic Ocean. Additional techniques for studying P dynamics including 33P-based DIP turnover time estimates and percent of cells expressing alkaline phosphatase (AP) activity as measured by enzyme-labeling fluorescence are also used. In surface waters, δ18O PO4 values were lower than equilibrium by 3-6‰, indicative of dissolved organic phosphorous (DOP) remineralization by extracellular enzymes. An isotope mass balance model using a variety of possible combinations of enzymatic pathways and substrates indicates that DOP remineralization in the euphotic zone can account for a large proportion on P utilized by phytoplankton (as much as 82%). Relatively short DIP turnover times (4-8 h) and high expression of AP (38-77% of the cells labeled) are consistent with extensive DOP utilization and low DIP availability in the euphotoc zone. In deep water where DOP utilization rates are lower, δ18OPO4 values approach isotopic equilibrium and DIP turnover times are longer. Our data suggests that in the euphotic zone of the Sargasso Sea, DOP may be appreciably remineralized and utilized by phytoplankton and bacteria to supplement cellular requirements. A substantial fraction of photosynthesis in this region is supported by DOP uptake. ©2013. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/77614
Appears in Collections: 气候变化事实与影响
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作者单位: Southern California Coastal Water Research Project, Costa Mesa, CA, United States; Marine Environmental Biology, University of Southern California, Zumberge Hall of Science, Los Angeles, CA, United States; Ocean Earth and Atmospheric Sciences, Old Dominion University, Norfolk, VA, United States; Bermuda Institute of Ocean Sciences, St. George's, Bermuda; Institute of Marine Sciences, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
Recommended Citation:
McLaughlin K,, Sohm J,A,et al. Phosphorus cycling in the Sargasso Sea: Investigation using the oxygen isotopic composition of phosphate, enzyme-labeled fluorescence, and turnover times[J]. Global Biogeochemical Cycles,2013-01-01,27(2)