scholarly journals An autonomous, in situ light-dark bottle device for determining community respiration and net community production

2018 ◽  
Vol 16 (6) ◽  
pp. 323-338 ◽  
Author(s):  
James R. Collins ◽  
Paul D. Fucile ◽  
Glenn McDonald ◽  
Justin E. Ossolinski ◽  
Richard G. Keil ◽  
...  
Keyword(s):  
Community Respiration ◽  
Net Community Production ◽  
Dark Bottle ◽  
Community Production

scholarly journals Climatic, physical, and biogeochemical changes drive rapid oxygen loss and recovery in a marine ecosystem

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jesse Wilson ◽  
Gerda Ucharm ◽  
J. Michael Beman
Keyword(s):  
Southern Oscillation ◽  
Gross Primary Production ◽  
Climatic Variability ◽  
Marine Ecosystem ◽  
Temporal Variations ◽  
Community Respiration ◽  
Net Community Production ◽  
Oxygen Loss ◽  
Community Production

Abstract Dissolved oxygen (DO) concentrations shape the biogeochemistry and ecological structure of aquatic ecosystems; as a result, understanding how and why DO varies in space and time is of fundamental importance. Using high-resolution, in situ DO time-series collected over the course of a year in a novel marine ecosystem (Jellyfish Lake, Palau), we show that DO declined throughout the marine lake and subsequently recovered in the upper water column. These shifts were accompanied by variations in water temperature and were correlated to changes in wind, precipitation, and especially sea surface height that occurred during the 2015–2016 El Niño-Southern Oscillation event. Multiple approaches used to calculate rates of community respiration, net community production, and gross primary production from DO changes showed that DO consumption and production did not accelerate nor collapse; instead, their variance increased during lake deoxygenation and recovery, and then stabilized. Spatial and temporal variations in rates were significantly related to climatic variability and changes in DO, and causality testing indicated that these relationships were both correlative and causative. Our data indicate that climatic, physical, and biogeochemical properties and processes collectively regulated DO, producing linked feedbacks that drove DO decline and recovery.

scholarly journals Neural network-based estimates of Southern Ocean net community production from in situ O<sub>2</sub> / Ar and satellite observation: a methodological study

2014 ◽  
Vol 11 (12) ◽  
pp. 3279-3297 ◽  
Author(s):  
C.-H. Chang ◽  
N. C. Johnson ◽  
N. Cassar
Keyword(s):  
Neural Network ◽  
Organic Carbon ◽  
Southern Ocean ◽  
Mixed Layer ◽  
Sea Surface ◽  
Carbon Export ◽  
Net Community Production ◽  
Basin Scale ◽  
Community Production

Abstract. Southern Ocean organic carbon export plays an important role in the global carbon cycle, yet its basin-scale climatology and variability are uncertain due to limited coverage of in situ observations. In this study, a neural network approach based on the self-organizing map (SOM) is adopted to construct weekly gridded (1° × 1°) maps of organic carbon export for the Southern Ocean from 1998 to 2009. The SOM is trained with in situ measurements of O2 / Ar-derived net community production (NCP) that are tightly linked to the carbon export in the mixed layer on timescales of one to two weeks and with six potential NCP predictors: photosynthetically available radiation (PAR), particulate organic carbon (POC), chlorophyll (Chl), sea surface temperature (SST), sea surface height (SSH), and mixed layer depth (MLD). This nonparametric approach is based entirely on the observed statistical relationships between NCP and the predictors and, therefore, is strongly constrained by observations. A thorough cross-validation yields three retained NCP predictors, Chl, PAR, and MLD. Our constructed NCP is further validated by good agreement with previously published, independent in situ derived NCP of weekly or longer temporal resolution through real-time and climatological comparisons at various sampling sites. The resulting November–March NCP climatology reveals a pronounced zonal band of high NCP roughly following the Subtropical Front in the Atlantic, Indian, and western Pacific sectors, and turns southeastward shortly after the dateline. Other regions of elevated NCP include the upwelling zones off Chile and Namibia, the Patagonian Shelf, the Antarctic coast, and areas surrounding the Islands of Kerguelen, South Georgia, and Crozet. This basin-scale NCP climatology closely resembles that of the satellite POC field and observed air–sea CO2 flux. The long-term mean area-integrated NCP south of 50° S from our dataset, 17.9 mmol C m−2 d−1, falls within the range of 8.3 to 24 mmol C m−2 d−1 from other model estimates. A broad agreement is found in the basin-wide NCP climatology among various models but with significant spatial variations, particularly in the Patagonian Shelf. Our approach provides a comprehensive view of the Southern Ocean NCP climatology and a potential opportunity to further investigate interannual and intraseasonal variability.

scholarly journals Rates and drivers of Red Sea plankton community metabolism

2018 ◽  
Author(s):  
Daffne C. López-Sandoval ◽  
Katherine Rowe ◽  
Paloma Carillo-de-Albonoz ◽  
Carlos M. Duarte ◽  
Susana Agusti
Keyword(s):  
Red Sea ◽  
Gross Primary Production ◽  
Environmental Drivers ◽  
Community Respiration ◽  
Net Community Production ◽  
Chl A ◽  
Warm Environment ◽  
Increasing Temperature ◽  
Community Production ◽  
Planktonic Communities

Abstract. Resolving the environmental drivers shaping planktonic communities is fundamental to understanding their variability, present and future, across the ocean. More specifically, resolving the temperature-dependence of planktonic communities in low productive waters is essential to predict the response of marine ecosystems to warming scenarios, as ocean warming leads to oligotrophication of the subtropical ocean. Here we quantified plankton metabolic rates along the Red Sea, a unique oligotrophic and warm environment, and analysed the drivers that regulate gross primary production (GPP), community respiration (CR) and the net community production (NCP). The study was conducted on six oceanographic surveys following a north-south transect along Saudi Arabian coasts. Our findings revealed that Chl-a specific GPP and CR rates increased with increasing temperature (R2 = 0.41 and 0.19, respectively, P 

scholarly journals Spring net community production and its coupling with the CO<sub>2</sub> dynamics in the surface water of the northern Gulf of Mexico

2019 ◽  
Author(s):  
Zong-Pei Jiang ◽  
Wei-Jun Cai ◽  
John Lehrter ◽  
Baoshan Chen ◽  
Zhangxian Ouyang ◽  
...  
Keyword(s):  
Surface Water ◽  
Gulf Of Mexico ◽  
Co2 Fluxes ◽  
Spring Season ◽  
Biological Production ◽  
Net Community Production ◽  
Northern Gulf Of Mexico ◽  
Co2 Sink ◽  
Community Production

Abstract. Net community production (NCP) in the surface mixed layer of the northern Gulf of Mexico (nGOM) and its coupling with the CO2 system were examined during the productive spring season. NCP was estimated using multiple approaches: (1) underway O2 and Ar ratio, (2) light/dark bottle oxygen incubations, and (3) non-conservative changes in dissolved inorganic carbon and nutrients; in order to assess uncertainties and compare the temporal-spatial scales associated with the different approaches. NCP estimates derived from various methods showed similar pattern along the river-ocean mixing gradient. The NCPO2Ar estimated from the high resolution O2 and Ar underway measurement is characterized by negative rates (−25.4 mmol C m−2 d−1) at the high nutrient and high turbidity river end (salinity  31) oligotrophic offshore waters due to nutrient limitation. Air-sea CO2 fluxes generally showed corresponding changes from being a strong CO2 source in the river channel to a CO2 sink in the plume. CO2 fluxes were near zero in offshore waters indicating balanced autotrophy and heterotrophy at these sites. Overall, the surface water in the nGOM (93–89.25° W, 28.5–29.5° N) was strongly autotrophic during the spring season in spring 2017 with mean NCP rate of 21.2 mmol C m−2 d−1 and as a CO2 sink of −6.7 mmol C m−2 d−1. By using a 1-D model, we demonstrated that a temporal mismatch between in situ biological production and gas exchange of O2 and CO2 could result in decoupling between NCP and CO2 flux (e.g., autotropic water as a CO2 source outside the Mississippi river mouth and heterotopic water as a CO2 sink near the Atchafalaya Delta). This decoupling was a result of in situ biological production superimposed on the lingering background pCO2 from the source water because of the slow air-sea CO2 exchange rate and buffering effect of the carbonate system.

scholarly journals Ecosystem metabolism in a temporary Mediterranean marsh (Doñana National Park, SW Spain)

2010 ◽  
Vol 7 (4) ◽  
pp. 6495-6521 ◽  
Author(s):  
O. Geertz-Hansen ◽  
C. Montes ◽  
C. M. Duarte ◽  
K. Sand-Jensen ◽  
N. Marbá ◽  
...  
Keyword(s):  
National Park ◽  
Submerged Macrophytes ◽  
Community Respiration ◽  
Production Rates ◽  
Doñana National Park ◽  
Net Community Production ◽  
Sw Spain ◽  
Respiration Rates ◽  
R Ratio ◽  
Community Production

Abstract. The metabolic balance of the open waters supporting submerged macrophytes of the Doñana marsh (SW Spain) was investigated in spring, when community production is highest. The marsh community was net autotrophic with net community production rates averaging 0.61 g C m−2 d−1, and gross production rates exceeding community respiration rates by, on average, 43%. Net community production increased greatly with increasing irradiance, with the threshold irradiance for communities to become net autotrophic being 42 to 255 μE m−2 s−1, below which communities became net heterotrophic. Examination of the contributions of the benthic and the pelagic compartments showed the pelagic compartment to be strongly heterotrophic (average P/R ratio = 0.27), indicating that the metabolism of the pelagic compartment is strongly subsidised by excess organic carbon produced in the strongly autotrophic benthic compartment (average P/R = 1.58).

scholarly journals Net community production of oxygen derived from in vitro and in situ 1-D modeling techniques in a cyclonic mesoscale eddy in the Sargasso Sea

2009 ◽  
Vol 6 (8) ◽  
pp. 1799-1810 ◽  
Author(s):  
B. Mouriño-Carballido ◽  
L. A. Anderson
Keyword(s):  
Mesoscale Eddy ◽  
Sampling Period ◽  
Sargasso Sea ◽  
Net Community Production ◽  
Mesoscale Dynamics ◽  
In Vitro Incubation ◽  
Net Heterotrophy ◽  
Community Production

Abstract. It has been proposed that the disagreement traditionally reported between in vitro incubation and in situ estimates of oxygen net community production (NCP) could be explained, at least partially, by undersampling episodic pulses of net autotrophy associated with mesoscale dynamics. In this study we compare in vitro incubation estimates of net community production with in situ estimates, derived from oxygen profiles and a 1-D model, within a cyclonic eddy investigated in the Sargasso Sea in summer 2004. The in vitro NCP rates measured at the center of the eddy showed a shift from net autotrophy (7±3 mmol O2 m−2 d−1) to net heterotrophy (−25±5 mmol O2 m−2 d−1) from late June to early August. The model-derived NCP rates also showed a temporal decline (19±6 to −3±7 and 11±8 mmol O2 m−2 d−1), but they were systematically higher than the in vitro estimates and reported net autotrophy or balance for the sampling period. In this comparison episodic pulses in photosynthesis or respiration driven by mesoscale eddies can not explain the discrepancy between the in vitro and in situ estimates of NCP. This points to methodological artefacts or temporal or submesoscale variability as the mechanisms responsible for the disagreement between the techniques, at least in this dataset.

scholarly journals Patterns in planktonic metabolism in the Mediterranean Sea

2009 ◽  
Vol 6 (12) ◽  
pp. 3081-3089 ◽  
Author(s):  
A. Regaudie-de-Gioux ◽  
R. Vaquer-Sunyer ◽  
C. M. Duarte
Keyword(s):  
Mediterranean Sea ◽  
Gross Primary Production ◽  
Western Mediterranean ◽  
Early Summer ◽  
Late Spring ◽  
Community Respiration ◽  
Net Community Production ◽  
R Ratio ◽  
The Mediterranean ◽  
Community Production

Abstract. Planktonic gross community production (GPP), net community production (NCP) and community respiration (CR) across the Mediterranean Sea was examined in two cruises, Thresholds 2006 and 2007, each crossing the Mediterranean from West to East to test for consistent variation along this longitudinal gradient in late spring to early summer. GPP averaged 2.4±0.4 mmol O2 m−3 d−1, CR averaged 3.8±0.5 mmol O2 m−3 d−1, and NCP averaged – 0.8±0.6 mmol O2 m−3 d−1 across the studied sections, indicative of a tendency for a net heterotrophic metabolism in late spring to early summer, prevalent across studied sections of the Mediterranean Sea as reflected in 70% of negative NCP estimates. The median P/R ratio was 0.6, also indicating a strong prevalence of heterotrophic communities (P/R<1) along the studied sections of the Mediterranean Sea. The communities tended to be net heterotrophic (i.e. P/R<1) at GPP less than 2.8 mmol O2 m−3 d−1. The Western Mediterranean tended to support a higher gross primary production and community respiration than the Eastern basin did, but these differences were not statistically significant (t-test, p>0.05). The net heterotrophy of the studied sections of the Mediterranean Sea indicates that allochthonous carbon should be important to subsidise planktonic metabolism during the late spring.

scholarly journals Norwegian Sea net community production estimated from O<sub>2</sub> and prototype CO<sub>2</sub> optode measurements on a Seaglider

Ocean Science ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. 593-614
Author(s):  
Luca Possenti ◽  
Ingunn Skjelvan ◽  
Dariia Atamanchuk ◽  
Anders Tengberg ◽  
Matthew P. Humphreys ◽  
...  
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Coastal Current ◽  
Net Community Production ◽  
Norwegian Sea ◽  
Chl A ◽  
Summer Maximum ◽  
Norwegian Coastal Current ◽  
Community Production

Abstract. We report on a pilot study using a CO2 optode deployed on a Seaglider in the Norwegian Sea from March to October 2014. The optode measurements required drift and lag correction and in situ calibration using discrete water samples collected in the vicinity. We found that the optode signal correlated better with the concentration of CO2, c(CO2), than with its partial pressure, p(CO2). Using the calibrated c(CO2) and a regional parameterisation of total alkalinity (AT) as a function of temperature and salinity, we calculated total dissolved inorganic carbon content, c(DIC), which had a standard deviation of 11 µmol kg−1 compared with in situ measurements. The glider was also equipped with an oxygen (O2) optode. The O2 optode was drift corrected and calibrated using a c(O2) climatology for deep samples. The calibrated data enabled the calculation of DIC- and O2-based net community production, N(DIC) and N(O2). To derive N, DIC and O2 inventory changes over time were combined with estimates of air–sea gas exchange, diapycnal mixing and entrainment of deeper waters. Glider-based observations captured two periods of increased Chl a inventory in late spring (May) and a second one in summer (June). For the May period, we found N(DIC) = (21±5) mmol m−2 d−1, N(O2) = (94±16) mmol m−2 d−1 and an (uncalibrated) Chl a peak concentration of craw(Chl a) = 3 mg m−3. During the June period, craw(Chl a) increased to a summer maximum of 4 mg m−3, associated with N(DIC) = (85±5) mmol m−2 d−1 and N(O2) = (126±25) mmol m−2 d−1. The high-resolution dataset allowed for quantification of the changes in N before, during and after the periods of increased Chl a inventory. After the May period, the remineralisation of the material produced during the period of increased Chl a inventory decreased N(DIC) to (-3±5) mmol m−2 d−1 and N(O2) to (0±2) mmol m−2 d−1. The survey area was a source of O2 and a sink of CO2 for most of the summer. The deployment captured two different surface waters influenced by the Norwegian Atlantic Current (NwAC) and the Norwegian Coastal Current (NCC). The NCC was characterised by lower c(O2) and c(DIC) than the NwAC, as well as lower N(O2) and craw(Chl a) but higher N(DIC). Our results show the potential of glider data to simultaneously capture time- and depth-resolved variability in DIC and O2 concentrations.

Impacts of the non-native alga Sargassum horneri on benthic community production in a California kelp forest

2020 ◽  
Vol 637 ◽  
pp. 45-57 ◽  
Author(s):  
GH Sullaway ◽  
MS Edwards
Keyword(s):  
Temporal Dynamics ◽  
Kelp Forest ◽  
Fold Increase ◽  
Sargassum Horneri ◽  
Community Respiration ◽  
Ecosystem Change ◽  
Rocky Reef ◽  
Net Community Production ◽  
Benthic Chambers ◽  
Community Production

The arrival of Sargassum horneri throughout the Southern California Bight and the Baja Peninsula has raised concern regarding kelp forest resilience and ecosystem function following the invasion of this non-native species. To understand how S. horneri impacts native algal abundance and community production, we removed S. horneri from experimental plots over a period of 11 mo. We measured impacts on native algal communities and community productivity using SCUBA surveys and benthic chambers equipped with oxygen, temperature, and light sensors. We observed a nearly 4-fold increase in recruitment of Macrocystis pyrifera and a 9-fold increase in adult M. pyrifera stipe density in S. horneri removal plots, but no discernable changes in net community production among treatments. We found ephemeral increases in gross community production and community respiration in the non-removal plots that coincided with periods of peak S. horneri biomass. To understand the temporal dynamics of community production, we deployed benthic chambers across a rocky reef dominated by S. horneri. Here, temporal variation in community production was most strongly related to corresponding variation in water temperature and changes in S. horneri biomass related to its annual lifecycle. Overall, our study indicates that S. horneri presence contributed to ephemeral increases in gross community production and community respiration, but it did not affect net community production. Moreover, S. horneri removal can lead to increases in native algal abundances given favorable abiotic conditions. We suggest that S. horneri thrives in a disturbed ecosystem rather than being a driver of ecosystem change.

Sign in / Sign up

Export Citation Format

Share Document