Magnitude and origin of the anthropogenic CO<sub>2</sub> increase and <sup>13</sup>C Suess effect in the Nordic seas since 1981

Olsen, Are; Omar, Abdirahman M; Bellerby, R. G. J.; Johannessen, Truls; Ninnemann, Ulysses S; Brown, K. R.; Olsson, Kristina; Ólafsson, Jón; Nondal, G.; Kivimäe, Caroline; Kringstad, S. B.; Neill, Craig; Ólafsdóttir, Sólveig Rósa

doi:10.1029/2005gb002669

Cited by 95 publications

(144 citation statements)

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“…In the Nordic seas the disequilibrium has changed over the past twenty years. The work presented by Olsen et al [2006] showed that in the northern regions it appears to have increased while decreasing in the south. As a first-order approximation they found that the annual pCO 2 changes in the upper 500 m of the Nordic seas between 1981 and 2002/2003 could be expressed in terms of salinity: 2.074 × S −71.13, r 2 = 0.6, Figure A3.…”

Section: Discussionmentioning

confidence: 99%

“…The transport of DIC ant with this inflow is a key source of DIC ant to the Nordic seas and the present results allows for a rudimentary assessment of the fate of this DIC ant . Olsen et al [2006] estimated an annual influx of 0.12 Gt DIC ant by combining a DIC ant estimate of 53 mmol kg −1 with a volume flux estimate of 6 Sv of NAW flowing into the Nordic seas. Our DIC ant concentration estimates in the NAW are slightly smaller ( Figure 4); 45 mmol kg −1 does not appear unreasonable.…”

Section: Discussionmentioning

confidence: 99%

“…Despite recent observations that indicate otherwise for parts of the Nordic seas over the last two decades [Olsen et al, 2006], this appears to be a reasonable assumption for the region as a whole over the time since the industrial revolution. The effect of assuming otherwise is evaluated in section A1.…”

Section: Determination Of Ttd Parametersmentioning

confidence: 99%

“…A map of the Nordic seas with the stations occupied on these three cruises is provided in Figure 1. The data have been described by Olsen et al [2006], Jeansson et al [2008], and Jutterström et al [2008] and only a brief summary of their stated precision and accuracy is provided here. The precision of the DIC and alkalinity data (Alk) have been estimated to approximately ±1 mmol kg −1 and accuracy was ensured by analyses of certified reference material (CRM) supplied by A. Dickson, Scripps Institution of Oceanography, USA Olsen et al, 2006].…”

Section: Datamentioning

confidence: 99%

“…The Nordic seas (Figure 1) are potentially important in this respect, as they annually generate 6 Sv of overflow water [Hansen and Østerhus, 2000], which is a main source of North Atlantic deep water [Dickson and Brown, 1994]. The overflow water is primarily formed by modification of North Atlantic Water (NAW) that enters from further south as the northward extension of the Gulf Stream, North Atlantic Current and North Atlantic Drift system [Eldevik et al, 2009] and which have high concentrations of DIC ant [Olsen et al, 2006].…”

Section: Introductionmentioning

confidence: 99%

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Nordic seas transit time distributions and anthropogenic CO₂

et al. 2010

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[1] The distribution and inventory of anthropogenic carbon (DIC ant ) in the Nordic seas are determined using the transit time distribution (TTD) approach. To constrain the shape of the TTDs in the Nordic seas, CO 2 is introduced as an age tracer and used in combination with water age estimates determined from CFC-12 data. CO 2 and CFC-12 tracer ages constitute a very powerful pair for constraining the shape of TTDs. The highest concentrations of DIC ant appear in the warm and well-ventilated Atlantic water that flows into the region from the south, and concentrations are typically lower moving west into the colder Arctic surface waters. The depth distribution of DIC ant reflects the extent of ventilation in the different areas. The Nordic seas DIC ant inventory for 2002 was constrained to between 0.9 and 1.4 Gt DIC ant , corresponding to ∼1% of the global ocean DIC ant inventory. The TTD-derived DIC ant estimates were compared with estimates derived using four other approaches, revealing significant differences with respect to the TTD-derived estimates, which can be related to issues with some of the underlying assumptions of these other approaches. Specifically, the Tracer combining Oxygen, inorganic Carbon and total Alkalinity (TrOCA) method appears to underestimate DIC ant in the Nordic seas, the DC* shortcut and the approach of Jutterström et al. (2008) appear to overestimate DIC ant at most depths in this area, and finally the approach of Tanhua et al. (2007) appears to underestimate Nordic seas DIC ant below 3000 m and overestimate it above 1000 m.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Determination Of Ttd Parametersmentioning

confidence: 99%

Section: Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nordic seas transit time distributions and anthropogenic CO₂

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Increasing carbon inventory of the intermediate layers of the Arctic Ocean

Ericson

Ulfsbo

Heuven

et al. 2014

J. Geophys. Res. Oceans

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Concentrations of dissolved inorganic carbon (DIC), total alkalinity (TA), nutrients, and oxygen in subsurface waters of the central Arctic Ocean have been investigated for conceivable time trends over the last two decades. Data from six cruises that cover the Nansen, Amundsen, and Makarov Basins were included in this analysis. In waters deeper than 2000 m, no statistically significant trend could be observed for DIC, TA, phosphate, or nitrate, but a small rate of increase in apparent oxygen utilization (AOU) was noticeable. For the individual stations, differences in concentration of each property were computed between the mean concentrations in the Arctic Atlantic Water (AAW) or the upper Polar Deep Water (uPDW), i.e., between about 150 and 1400 m depth, and in the deep water (assumed invariable over time). In these shallower water layers, we observe significant above-zero time trends for DIC, in the range of 0.6-0.9 lmol kg 21 yr 21 (for AAW) and 0.4-0.6 mmol kg 21 yr 21 (for uPDW). No time trend in nutrients could be observed, indicating no change in the rate of organic matter mineralization within this depth range. Consequently, the buildup of DIC is attributed to increasing concentrations of anthropogenic carbon in the waters flowing into these depth layers of the Arctic Ocean. The resulting rate of increase of the column inventory of anthropogenic CO 2 is estimated to be between 0.6 and 0.9 mol C m 22 yr 21 , with distinct differences between basins.

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Multidecadal accumulation of anthropogenic and remineralized dissolved inorganic carbon along the Extended Ellett Line in the northeast Atlantic Ocean

Humphreys

Griffiths

Achterberg

et al. 2016

Global Biogeochemical Cycles

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Marine carbonate chemistry measurements have been carried out annually since 2009 during UK research cruises along the Extended Ellett Line (EEL), a hydrographic transect in the northeast Atlantic Ocean. The EEL intersects several water masses that are key to the global thermohaline circulation, and therefore the cruises sample a region in which it is critical to monitor secular physical and biogeochemical changes. We have combined results from these EEL cruises with existing quality-controlled observational data syntheses to produce a hydrographic time series for the EEL from 1981 to 2013. This reveals multidecadal increases in dissolved inorganic carbon (DIC) throughout the water column, with a near-surface maximum rate of 1.80 ± 0.45 μmol kg À1 yr À1 . Anthropogenic CO 2 accumulation was assessed, using simultaneous changes in apparent oxygen utilization (AOU) and total alkalinity (TA) as proxies for the biogeochemical processes that influence DIC. The stable carbon isotope composition of DIC (δ 13 C DIC ) was also determined and used as an independent test of our method. We calculated a volume-integrated anthropogenic CO 2 accumulation rate of 2.8 ± 0.4 mg C m À3 yr À1 along the EEL, which is about double the global mean. The anthropogenic CO 2 component accounts for only 31 ± 6% of the total DIC increase. The remainder is derived from increased organic matter remineralization, which we attribute to the lateral redistribution of water masses that accompanies subpolar gyre contraction. Output from a general circulation ecosystem model demonstrates that spatiotemporal heterogeneity in the observations has not significantly biased our multidecadal rate of change calculations and indicates that the EEL observations have been tracking distal changes in the surrounding North Atlantic and Nordic Seas.

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Magnitude and origin of the anthropogenic CO₂ increase and ¹³C Suess effect in the Nordic seas since 1981

Cited by 95 publications

References 60 publications

Nordic seas transit time distributions and anthropogenic CO₂

Nordic seas transit time distributions and anthropogenic CO₂

Increasing carbon inventory of the intermediate layers of the Arctic Ocean

Multidecadal accumulation of anthropogenic and remineralized dissolved inorganic carbon along the Extended Ellett Line in the northeast Atlantic Ocean

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Magnitude and origin of the anthropogenic CO2 increase and 13C Suess effect in the Nordic seas since 1981

Cited by 95 publications

References 60 publications

Nordic seas transit time distributions and anthropogenic CO2

Nordic seas transit time distributions and anthropogenic CO2

Increasing carbon inventory of the intermediate layers of the Arctic Ocean

Multidecadal accumulation of anthropogenic and remineralized dissolved inorganic carbon along the Extended Ellett Line in the northeast Atlantic Ocean

Contact Info

Product

Resources

About

Magnitude and origin of the anthropogenic CO₂ increase and ¹³C Suess effect in the Nordic seas since 1981

Nordic seas transit time distributions and anthropogenic CO₂

Nordic seas transit time distributions and anthropogenic CO₂