scholarly journals High-resolution estimates of net community production and air-sea CO2flux in the northeast Pacific

2012 ◽  
Vol 26 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Deirdre Lockwood ◽  
Paul D. Quay ◽  
Maria T. Kavanaugh ◽  
Lauren W. Juranek ◽  
Richard A. Feely
Keyword(s):  
High Resolution ◽  
Net Community Production ◽  
Northeast Pacific ◽  
Community Production

scholarly journals High-resolution view of the spring bloom initiation and net community production in the Subantarctic Southern Ocean using glider data

2015 ◽  
Vol 72 (6) ◽  
pp. 1999-2020 ◽  
Author(s):  
Sandy J. Thomalla ◽  
Marie-Fanny Racault ◽  
Sebastiaan Swart ◽  
Pedro M. S. Monteiro
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Southern Ocean ◽  
High Growth ◽  
Biomass Accumulation ◽  
Horizontal Resolution ◽  
Early Summer ◽  
Detection Methods ◽  
Net Community Production ◽  
Community Production

Abstract In the Southern Ocean, there is increasing evidence that seasonal to subseasonal temporal scales, and meso- to submesoscales play an important role in understanding the sensitivity of ocean primary productivity to climate change. This drives the need for a high-resolution approach to resolving biogeochemical processes. In this study, 5.5 months of continuous, high-resolution (3 h, 2 km horizontal resolution) glider data from spring to summer in the Atlantic Subantarctic Zone is used to investigate: (i) the mechanisms that drive bloom initiation and high growth rates in the region and (ii) the seasonal evolution of water column production and respiration. Bloom initiation dates were analysed in the context of upper ocean boundary layer physics highlighting sensitivities of different bloom detection methods to different environmental processes. Model results show that in early spring (September to mid-November) increased rates of net community production (NCP) are strongly affected by meso- to submesoscale features. In late spring/early summer (late-November to mid-December) seasonal shoaling of the mixed layer drives a more spatially homogenous bloom with maximum rates of NCP and chlorophyll biomass. A comparison of biomass accumulation rates with a study in the North Atlantic highlights the sensitivity of phytoplankton growth to fine-scale dynamics and emphasizes the need to sample the ocean at high resolution to accurately resolve phytoplankton phenology and improve our ability to estimate the sensitivity of the biological carbon pump to climate change.

scholarly journals Relationship between Surface Dissolved Iron Inventories and Net Community Production during a Marine Heatwave in the Subarctic Northeast Pacific

2020 ◽  
Author(s):  
Robyn Taves ◽  
David J. Janssen ◽  
M. Angelica Peña ◽  
Andrew R.S. Ross ◽  
William Crawford ◽  
...  
Keyword(s):  
Net Community Production ◽  
Dissolved Iron ◽  
Northeast Pacific ◽  
Community Production

scholarly journals Physicochemical and biological controls on primary and net community production across northeast Pacific seascapes

2014 ◽  
Vol 59 (6) ◽  
pp. 2013-2027 ◽  
Author(s):  
Maria T. Kavanaugh ◽  
Steven R. Emerson ◽  
Burke Hales ◽  
Deirdre M. Lockwood ◽  
Paul D. Quay ◽  
...  
Keyword(s):  
Net Community Production ◽  
Northeast Pacific ◽  
Community Production

scholarly journals High-resolution distributions of O<sub>2</sub> / Ar on the northern slope of the South China Sea and estimates of net community production

Ocean Science ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 249-264
Author(s):  
Chuan Qin ◽  
Guiling Zhang ◽  
Wenjing Zheng ◽  
Yu Han ◽  
Sumei Liu
Keyword(s):  
High Resolution ◽  
South China Sea ◽  
Mixed Layer ◽  
South China ◽  
Inorganic Nitrogen ◽  
Gross Primary Production ◽  
Net Community Production ◽  
Study Region ◽  
China Sea ◽  
Community Production

Abstract. The dissolved oxygen-to-argon ratio (O2∕Ar) in the oceanic mixed layer has been widely used to estimate net community production (NCP), which is the difference between gross primary production and community respiration; it is a measure of the strength of the biological pump. In order to obtain the high-resolution distribution of NCP and improve our understanding of its regulating factors in the slope region of the northern South China Sea (SCS), we conducted continuous measurements of dissolved O2, Ar, and CO2 with membrane inlet mass spectrometry (MIMS) during two cruises in October 2014 and June 2015. An overall autotrophic condition was observed in the study region in both cruises with an average Δ(O2∕Ar) of 1.1 % ± 0.9 % in October 2014 and 2.7 % ± 2.8 % in June 2015. NCP was on average 11.5 ± 8.7 mmol C m−2 d−1 in October 2014 and 11.6 ± 12.7 mmol C m−2 d−1 in June 2015. Correlations between dissolved inorganic nitrogen (DIN), Δ(O2∕Ar), and NCP were observed in both cruises, indicating that NCP is subject to the nitrogen limitation in the study region. In June 2015, we observed a rapid response of the ecosystem to the episodic nutrient supply induced by eddies. Eddy-entrained shelf water intrusion, which supplied large amounts of terrigenous nitrogen to the study region, promoted NCP in the study region by potentially more than threefold. In addition, upwelling brought large uncertainties to the estimation of NCP in the core region of the cold eddy (cyclone) in June 2015. The deep euphotic depth in the SCS and the absence of correlation between NCP and the average photosynthetically available radiation (PAR) in the mixed layer in the autumn indicate that light availability may not be a significant limitation on NCP in the SCS. This study helps us to understand the carbon cycle in the highly dynamic shelf system.

scholarly journals ΔO2/N2′ as a New Tracer of Marine Net Community Production: Application and Evaluation in the Subarctic Northeast Pacific and Canadian Arctic Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Robert W. Izett ◽  
Roberta C. Hamme ◽  
Craig McNeil ◽  
Cara C. M. Manning ◽  
Annie Bourbonnais ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Mixed Layer ◽  
Vertical Mixing ◽  
Spatial Coherence ◽  
Canadian Arctic ◽  
Field Measurements ◽  
Net Community Production ◽  
Mass Spectrometers ◽  
Northeast Pacific ◽  
Community Production

We compared field measurements of the biological O2 saturation anomalies, ΔO2/Ar and ΔO2/N2, 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 ΔO2/N2 as an alternative to ΔO2/Ar for estimates of mixed layer net community production (NCP). We observed strong spatial coherence between ΔO2/Ar and ΔO2/N2, with small offsets resulting from differences in the solubility properties of Ar and N2 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 N2 and Ar, deriving the tracer ΔO2/N2′. Over most of our survey regions, ΔO2/N2′ provided a better analog for ΔO2/Ar, and thus more accurate NCP estimates than ΔO2/N2. However, in coastal Arctic waters, ΔO2/N2 and ΔO2/N2′ performed equally well as NCP tracers. On average, mixed layer NCP estimated from ΔO2/Ar and ΔO2/N2′ agreed to within ∼2 mmol O2 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 O2/N2 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.

scholarly journals High-resolution distributions of O<sub>2</sub>/Ar on the northern slope of the South China Sea and estimates of net community production

2020 ◽  
Author(s):  
Chuan Qin ◽  
Guiling Zhang ◽  
Wenjing Zheng ◽  
Yu Han ◽  
Sumei Liu
Keyword(s):  
High Resolution ◽  
South China Sea ◽  
South China ◽  
Inorganic Nitrogen ◽  
Mixed Layer Depth ◽  
Northern South China Sea ◽  
Net Community Production ◽  
Study Region ◽  
China Sea ◽  
Community Production

Abstract. Net community production (NCP) is a proxy of carbon export from the surface ocean and can be estimated based on O2/Ar. In order to obtain the high-resolution distribution of NCP and improve our understanding of its regulating factors in the slope region of the Northern South China Sea (SCS), we conducted continuous measurements of dissolved O2, Ar, and CO2 by membrane inlet mass spectrometry during cruises in October 2014 and June 2015. An overall autotrophic condition was observed in the study region in both cruises with an average ∆(O2/Ar) of 1.1 % ± 0.9 % in October 2014 and 2.7 % ± 2.8 % in June 2015. NCP was on average 11.5 ± 8.7 mmol C m−2 d−1 in October 2014 and 11.6 ± 12.7 mmol C m−2 d−1 in June 2015. Correlations between dissolved inorganic nitrogen (DIN), ∆(O2/Ar), and NCP were observed in both cruises, indicating that NCP is subject to the nitrogen limitation in the study region. In June 2015, we observed a rapid response of the ecosystem to the episodic nutrient supply induced by eddies. Eddy-entrained shelf water injection, which supplied large amounts of terrigenous nitrogen to the study region, resulted in high productivity along a transect. In addition, upwelling brought large uncertainties to the estimation of NCP at the core region of the cold eddy (cyclone) in June 2015. The correlation between the volumetric NCP (NCPvol) and the mixed layer depth (MLD) indicated that light availability may have also been a factor in influencing NCP in the SCS.

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