title: Revisiting carbon flux through the ocean's twilight zone.
abstract: 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.
authors.affiliation: Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA. kbuesseler@whoi.edu
authors.forename: Ken O
authors.initials: KO
authors.lastname: Buesseler
authors.forename: Carl H
authors.initials: CH
authors.lastname: Lamborg
authors.forename: Philip W
authors.initials: PW
authors.lastname: Boyd
authors.forename: Phoebe J
authors.initials: PJ
authors.lastname: Lam
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Trull
authors.forename: Robert R
authors.initials: RR
authors.lastname: Bidigare
authors.forename: James K B
authors.initials: JK
authors.lastname: Bishop
authors.forename: Karen L
authors.initials: KL
authors.lastname: Casciotti
authors.forename: Frank
authors.initials: F
authors.lastname: Dehairs
authors.forename: Marc
authors.initials: M
authors.lastname: Elskens
authors.forename: Makio
authors.initials: M
authors.lastname: Honda
authors.forename: David M
authors.initials: DM
authors.lastname: Karl
authors.forename: David A
authors.initials: DA
authors.lastname: Siegel
authors.forename: Mary W
authors.initials: MW
authors.lastname: Silver
authors.forename: Deborah K
authors.initials: DK
authors.lastname: Steinberg
authors.forename: Jim
authors.initials: J
authors.lastname: Valdes
authors.forename: Benjamin
authors.initials: B
authors.lastname: Van Mooy
authors.forename: Stephanie
authors.initials: S
authors.lastname: Wilson
mesh_terms: D000818:Animals; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide; D033342:Copepoda / Q000502:physiology; D017753:Ecosystem; D020387:Food Chain; D019015:Geologic Sediments / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010140:Pacific Ocean; D010839:Phytoplankton / Q000502:physiology; D012623:Seawater / Q000737:chemistry; D015048:Zooplankton / Q000502:physiology
chemical_list: D002245:Carbon Dioxide; D002244:Carbon