Abstract
Considerable drawdown of total dissolved inorganic carbon (CT) and oversaturation of oxygen (O2) within a cold (∼15°C) oligotrophic eddy in the extratropical North Atlantic Ocean (46°N, 20.5°W) indicate that, despite the absence of nitrate (NO3 -), the eddy was highly productive. Estimates of net community production using the mass balances of CT and O2 were two to five times greater than those obtained using the mass balance of NO 3 -. The remineralization rates obtained using the integrated rates of CT and NO3 - accumulation and O2 utilization for the upper thermocline waters (35-300-m depth) were in agreement with CT- and O2-based net community production over the same period; however, all the estimates exceeded the NO 3 --based net community production by a factor of two to five, pointing to a considerable accumulation of NO3 - in the upper thermocline in excess of changes in the mixed-layer NO 3 - inventory. The amount of this excess NO 3 - suggests that a considerable fraction of the net community production was not supported by the mixed-layer NO3 - inventory and that an external source of NO3 - must be present. Of the various mechanisms that might explain the inequity between NO3 - drawdown in the surface layer and NO 3 - accumulation in the upper thermocline, N2 fixation is the most viable yet surprising mechanism for producing such excess NO3 - in this oligotrophic eddy. A significant fraction of net community production in oligotrophic extratropical waters could be supported by processes that are not fully explored or to date have been considered to be insignificant.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1697-1704 |
| Number of pages | 8 |
| Journal | Limnology and Oceanography |
| Volume | 53 |
| Issue number | 5 |
| State | Published - Sep 2008 |
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ASJC Scopus subject areas
- Oceanography
- Aquatic Science
Cite this
Large, non-Redfieldian drawdown of nutrients and carbon in the extratropical North Atlantic Ocean (46°N) : Evidence for dinitrogen fixation? / Park, Geun Ha; Lee, Kitack; Wanninkhof, Rik; Zhang, Jia Zhong; Hansell, Dennis A; Feely, Richard A.
In: Limnology and Oceanography, Vol. 53, No. 5, 09.2008, p. 1697-1704.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Large, non-Redfieldian drawdown of nutrients and carbon in the extratropical North Atlantic Ocean (46°N)
T2 - Evidence for dinitrogen fixation?
AU - Park, Geun Ha
AU - Lee, Kitack
AU - Wanninkhof, Rik
AU - Zhang, Jia Zhong
AU - Hansell, Dennis A
AU - Feely, Richard A.
PY - 2008/9
Y1 - 2008/9
N2 - Considerable drawdown of total dissolved inorganic carbon (CT) and oversaturation of oxygen (O2) within a cold (∼15°C) oligotrophic eddy in the extratropical North Atlantic Ocean (46°N, 20.5°W) indicate that, despite the absence of nitrate (NO3 -), the eddy was highly productive. Estimates of net community production using the mass balances of CT and O2 were two to five times greater than those obtained using the mass balance of NO 3 -. The remineralization rates obtained using the integrated rates of CT and NO3 - accumulation and O2 utilization for the upper thermocline waters (35-300-m depth) were in agreement with CT- and O2-based net community production over the same period; however, all the estimates exceeded the NO 3 --based net community production by a factor of two to five, pointing to a considerable accumulation of NO3 - in the upper thermocline in excess of changes in the mixed-layer NO 3 - inventory. The amount of this excess NO 3 - suggests that a considerable fraction of the net community production was not supported by the mixed-layer NO3 - inventory and that an external source of NO3 - must be present. Of the various mechanisms that might explain the inequity between NO3 - drawdown in the surface layer and NO 3 - accumulation in the upper thermocline, N2 fixation is the most viable yet surprising mechanism for producing such excess NO3 - in this oligotrophic eddy. A significant fraction of net community production in oligotrophic extratropical waters could be supported by processes that are not fully explored or to date have been considered to be insignificant.
AB - Considerable drawdown of total dissolved inorganic carbon (CT) and oversaturation of oxygen (O2) within a cold (∼15°C) oligotrophic eddy in the extratropical North Atlantic Ocean (46°N, 20.5°W) indicate that, despite the absence of nitrate (NO3 -), the eddy was highly productive. Estimates of net community production using the mass balances of CT and O2 were two to five times greater than those obtained using the mass balance of NO 3 -. The remineralization rates obtained using the integrated rates of CT and NO3 - accumulation and O2 utilization for the upper thermocline waters (35-300-m depth) were in agreement with CT- and O2-based net community production over the same period; however, all the estimates exceeded the NO 3 --based net community production by a factor of two to five, pointing to a considerable accumulation of NO3 - in the upper thermocline in excess of changes in the mixed-layer NO 3 - inventory. The amount of this excess NO 3 - suggests that a considerable fraction of the net community production was not supported by the mixed-layer NO3 - inventory and that an external source of NO3 - must be present. Of the various mechanisms that might explain the inequity between NO3 - drawdown in the surface layer and NO 3 - accumulation in the upper thermocline, N2 fixation is the most viable yet surprising mechanism for producing such excess NO3 - in this oligotrophic eddy. A significant fraction of net community production in oligotrophic extratropical waters could be supported by processes that are not fully explored or to date have been considered to be insignificant.
UR - http://www.scopus.com/inward/record.url?scp=52149085173&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=52149085173&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:52149085173
VL - 53
SP - 1697
EP - 1704
JO - Limnology and Oceanography
JF - Limnology and Oceanography
SN - 0024-3590
IS - 5
ER -