Delta O-2/N-2 ' as a New Tracer of Marine Net Community Production: Application and Evaluation in the Subarctic Northeast Pacific and Canadian Arctic Ocean
| Type | : | ACL |
|---|---|---|
| Nature | : | Production scientifique |
| Au bénéfice du Laboratoire | : | Non |
| Statut de publication | : | Publié |
| Année de publication | : | 2021 |
| Auteurs (6) | : | IZETT R,w HAMME Roberta,c MCNEILL Caroline,louise MANNING C,c BOURBONNAIS A TORTELL Philippe,d |
| Revue scientifique | : | Frontiers in Marine Science |
| Volume | : | 8 |
| Fascicule | : | |
| Pages | : | |
| DOI | : | 10.3389/fmars.2021.718625 |
| URL | : | - |
| Abstract | : | We compared field measurements of the biological O-2 saturation anomalies, Delta O-2/Ar and Delta O-2/N-2, from simultaneous oceanographic deployments of a membrane inlet mass spectrometer and optode/gas tension device (GTD). Data from the Subarctic Northeast Pacific and Canadian Arctic Ocean were used to evaluate Delta O-2/N-2 as an alternative to Delta O-2/Ar for estimates of mixed layer net community production (NCP). We observed strong spatial coherence between Delta O-2/Ar and Delta O-2/N-2, with small offsets resulting from differences in the solubility properties of Ar and N-2 and their sensitivity to vertical mixing fluxes. Larger offsets between the two tracers were observed across hydrographic fronts and under elevated sea states, resulting from the differential time-response of the optode and GTD, and from bubble dissolution in the ship's seawater lines. We used a simple numerical framework to correct for physical sources of divergence between N-2 and Ar, deriving the tracer Delta O-2/N-2'. Over most of our survey regions, Delta O-2/N-2' provided a better analog for Delta O-2/Ar, and thus more accurate NCP estimates than Delta O-2/N-2. However, in coastal Arctic waters, Delta O-2/N-2 and Delta O-2/N-2' performed equally well as NCP tracers. On average, mixed layer NCP estimated from Delta O-2/Ar and Delta O-2/N-2' agreed to within similar to 2 mmol O-2 m(-2) d(-1), with offsets typically smaller than other errors in NCP calculations. Our results demonstrate a significant potential to derive NCP from underway O-2/N-2 measurements across various oceanic regions. Optode/GTD systems could replace mass spectrometers for autonomous NCP derivation under many oceanographic conditions, thereby presenting opportunities to significantly expand global NCP coverage from various underway platforms. |
| Mots-clés | : | air-sea exchange; CALIBRATION; DYNAMICS; GAS-EXCHANGE; gas dynamics; gas tracer; INLET; N-2; net community metabolism; net community production; nitrogen; NITROGEN; O-2; oxygen; OXYGEN; SOLUBILITY; WATER |
| Commentaire | : | Times Cited in Web of Science Core Collection: 0 |
| Tags | : | - |
| Fichier attaché | : | - |
| Citation | : |
Izett RW, Hamme RC, McNeill CL, Manning CC, Bourbonnais A, Tortell PD (2021) Delta O-2/N-2 ' as a New Tracer of Marine Net Community Production: Application and Evaluation in the Subarctic Northeast Pacific and Canadian Arctic Ocean. Front Mar Sci 8 | doi: 10.3389/fmars.2021.718625
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