atmospheric deposition
; cyanobacterium
; dust
; geographical distribution
; growth rate
; iron
; nitrogen cycle
; nitrogen fixation
; oligotrophic environment
; Atlantic Ocean
; Atlantic Ocean (North)
; Portugal
; United Kingdom
; Trichodesmium
英文摘要:
Studies of the nitrogen cycle in the ocean generally assume that the distribution of the marine diazotroph, Trichodesmium, is restricted to warm, tropical, and subtropical oligotrophic waters. Here we show evidence that Trichodesmium are widely distributed in the North Atlantic. We report an approximately fivefold increase during the 1980s and 1990s in Trichodesmium presence near the British Isles with respect to the average over the last 50 years. A potential explanation is an increase in the Saharan dust source starting in the 1980s, coupled with changes in North Atlantic winds that opened a pathway for dust transport. Results from a coarse-resolution model in which winds vary but iron deposition is climatologically fixed suggest frequent nitrogen limitation in the region and reversals of the Portugal current, but it does not simulate the observed changes in Trichodesmium. Our results suggest that Trichodesmium may be capable of growth at temperatures below 20�C and challenge assumptions about their latitudinal distribution. Therefore, we need to reevaluate assumptions about the temperature limitations of Trichodesmium and the dinitrogen (N2) fixation capabilities of extratropical strains, which may have important implications for the global nitrogen budget. �2016. American Geophysical Union. All Rights Reserved.
Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, MD, United States; Now at Department of Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States; Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States; Climate and Radiation Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States; Universities Space Research Association, Columbia, MD, United States; Sir Alister Hardy Foundation for Ocean Science, Plymouth, United Kingdom
Recommended Citation:
Rivero-Calle S,, Del Castillo C,E,et al. Interdecadal Trichodesmium variability in cold North Atlantic waters[J]. Global Biogeochemical Cycles,2016-01-01,30(11)