A mesoscale iron enrichment in the western subarctic Pacific induces a large centric diatom bloom.
We have performed an in situ test of the iron limitation hypothesis in the subarctic North Pacific Ocean. A single enrichment of dissolved iron caused a large increase in phytoplankton standing stock and decreases in macronutrients and dissolved carbon dioxide. The dominant phytoplankton species shifted after the iron addition from pennate diatoms to a centric diatom, Chaetoceros debilis, that showed a very high growth rate, 2.6 doublings per day. We conclude that the bioavailability of iron regulates the magnitude of the phytoplankton biomass and the key phytoplankton species that determine the biogeochemical sensitivity to iron supply of high-nitrate, low-chlorophyll waters.
Hokkaido National Research Institute, Kushiro, Hokkaido 085-0802, Japan.
Atsushi
A
Tsuda
Shigenobu
S
Takeda
Hiroaki
H
Saito
Jun
J
Nishioka
Yukihiro
Y
Nojiri
Isao
I
Kudo
Hiroshi
H
Kiyosawa
Akihiro
A
Shiomoto
Keiri
K
Imai
Tsuneo
T
Ono
Akifumi
A
Shimamoto
Daisuke
D
Tsumune
Takeshi
T
Yoshimura
Tatsuo
T
Aono
Akira
A
Hinuma
Masatoshi
M
Kinugasa
Koji
K
Suzuki
Yoshiki
Y
Sohrin
Yoshifumi
Y
Noiri
Heihachiro
H
Tani
Yuji
Y
Deguchi
Nobuo
N
Tsurushima
Hiroshi
H
Ogawa
Kimio
K
Fukami
Kenshi
K
Kuma
Toshiro
T
Saino
D001110:Arctic Regions; D001272:Atmosphere; D018533:Biomass; D002245:Carbon Dioxide / Q000032:analysis; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D017377:Diatoms / Q000254:growth & development* / Q000378:metabolism; D017753:Ecosystem; D005068:Eutrophication; D005296:Ferrous Compounds; D007501:Iron / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D010140:Pacific Ocean; D010839:Phytoplankton / Q000254:growth & development* / Q000378:metabolism; D012623:Seawater / Q000737:chemistry; D017640:Silicates / Q000032:analysis
D005296:Ferrous Compounds; D009566:Nitrates; D017640:Silicates; D002734:Chlorophyll; D002245:Carbon Dioxide; C020748:ferrous sulfate; D007501:Iron; D000077194:Chlorophyll A