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大洋模糊区域碳通量测量

    在大洋中测量经过其“模糊区域”(twilight zone)的碳量的研究人员发现，在太平洋的两个区域中该量有显著的差别，这对大洋碳吸收的计算可能会产生大的影响。大洋的模糊区域是指有阳光照射和光合作用发生的表面海洋与深海之间的一层人们了解很少的区域。科学家对连接海洋表面二氧化碳的吸收与海洋深处的碳储存的过程感兴趣。下沉的颗粒携带一部分碳通过模糊区域，这个过程中的变化会影响全球的碳循环和气候。Ken Buesseler带领的一个国际研究小组发明了名为中性浮力沉积物捕捉器(neutrally buoyant sediment traps)的新测量仪，比过去用的捕捉器能更准确地收集下沉的颗粒。该小组测量了经过夏威夷模糊区域的碳量，发现只有20%的碳沉到500米的深度，80%的碳被浮游生物消耗了。与此相比，在西北太平洋，50%的碳沉到500米的深度。 (郝炘/译，科学时报) 

Science 27 April 2007:
Vol. 316. no. 5824, pp. 567 - 570

Ken O. Buesseler,1* Carl H. Lamborg,1 Philip W. Boyd,2 Phoebe J. Lam,1 Thomas W. Trull,3 Robert R. Bidigare,4 James K. B. Bishop,5,6 Karen L. Casciotti,1 Frank Dehairs,7 Marc Elskens,7 Makio Honda,8 David M. Karl,4 David A. Siegel,9 Mary W. Silver,10 Deborah K. Steinberg,11 Jim Valdes,12 Benjamin Van Mooy,1 Stephanie Wilson11

The oceanic biological pump drives sequestration of carbon dioxide in the deep sea via sinking particles. Rapid biological consumption and remineralization of carbon in the "twilight zone" (depths between the euphotic zone and 1000 meters) reduce the efficiency of sequestration. By using neutrally buoyant sediment traps to sample this chronically understudied realm, we measured a transfer efficiency of sinking particulate organic carbon between 150 and 500 meters of 20 and 50% at two contrasting sites. This large variability in transfer efficiency is poorly represented in biogeochemical models. If applied globally, this is equivalent to a difference in carbon sequestration of more than 3 petagrams of carbon per year.

1 Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
2 National Institute of Water and Atmospheric Research Centre for Physical and Chemical Oceanography, Department of Chemistry, University of Otago, Dunedin, New Zealand.
3 Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania and Commonwealth Scientific and Industrial Research Organisation, Marine and Atmospheric Research, Hobart, 7001, Australia.
4 Department of Oceanography, University of Hawaii, Honolulu, HI 96822, USA.
5 Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
6 Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA.
7 Analytical and Environmental Chemistry, Free University of Brussels, B-1050 Brussels, Belgium.
8 Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Mutsu Institute for Oceanography, Yokosuka, Kanagawa 237-0061, Japan.
9 Institute for Computational Earth System Science, University of California, Santa Barbara, CA 93106, USA.
10 Ocean Sciences Department, University of California, Santa Cruz, CA 95064, USA.
11 Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062, USA.
12 Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.

* To whom correspondence should be addressed. E-mail: kbuesseler@whoi.edu