scholarly journals A Global Ocean Oxygen Database and Atlas for Assessing and Predicting Deoxygenation and Ocean Health in the Open and Coastal Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Marilaure Grégoire ◽  
Véronique Garçon ◽  
Hernan Garcia ◽  
Denise Breitburg ◽  
Kirsten Isensee ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Health Indicators ◽  
Temporal Variations ◽  
Open Ocean ◽  
Global Ocean ◽  
Model Assessment ◽  
Management Tools ◽  
Biogeochemical Models ◽  
To Come ◽  
Heat Budgets

In this paper, we outline the need for a coordinated international effort toward the building of an open-access Global Ocean Oxygen Database and ATlas (GO2DAT) complying with the FAIR principles (Findable, Accessible, Interoperable, and Reusable). GO2DAT will combine data from the coastal and open ocean, as measured by the chemical Winkler titration method or by sensors (e.g., optodes, electrodes) from Eulerian and Lagrangian platforms (e.g., ships, moorings, profiling floats, gliders, ships of opportunities, marine mammals, cabled observatories). GO2DAT will further adopt a community-agreed, fully documented metadata format and a consistent quality control (QC) procedure and quality flagging (QF) system. GO2DAT will serve to support the development of advanced data analysis and biogeochemical models for improving our mapping, understanding and forecasting capabilities for ocean O2 changes and deoxygenation trends. It will offer the opportunity to develop quality-controlled data synthesis products with unprecedented spatial (vertical and horizontal) and temporal (sub-seasonal to multi-decadal) resolution. These products will support model assessment, improvement and evaluation as well as the development of climate and ocean health indicators. They will further support the decision-making processes associated with the emerging blue economy, the conservation of marine resources and their associated ecosystem services and the development of management tools required by a diverse community of users (e.g., environmental agencies, aquaculture, and fishing sectors). A better knowledge base of the spatial and temporal variations of marine O2 will improve our understanding of the ocean O2 budget, and allow better quantification of the Earth’s carbon and heat budgets. With the ever-increasing need to protect and sustainably manage ocean services, GO2DAT will allow scientists to fully harness the increasing volumes of O2 data already delivered by the expanding global ocean observing system and enable smooth incorporation of much higher quantities of data from autonomous platforms in the open ocean and coastal areas into comprehensive data products in the years to come. This paper aims at engaging the community (e.g., scientists, data managers, policy makers, service users) toward the development of GO2DAT within the framework of the UN Global Ocean Oxygen Decade (GOOD) program recently endorsed by IOC-UNESCO. A roadmap toward GO2DAT is proposed highlighting the efforts needed (e.g., in terms of human resources).

scholarly journals Physiological constraints and energetic costs of diving behaviour in marine mammals: a review of studies using trained Steller sea lions diving in the open ocean

2016 ◽  
Vol 187 (1) ◽  
pp. 29-50 ◽  
Author(s):  
David A. S. Rosen ◽  
Allyson G. Hindle ◽  
Carling D. Gerlinsky ◽  
Elizabeth Goundie ◽  
Gordon D. Hastie ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Open Ocean ◽  
Diving Behaviour ◽  
Steller Sea Lions ◽  
Energetic Costs ◽  
Sea Lions ◽  
Physiological Constraints

scholarly journals The role of continental shelves in nitrogen and carbon cycling

2010 ◽  
Vol 7 (1) ◽  
pp. 177-205
Author(s):  
K. Fennel
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Deep Ocean ◽  
Open Ocean ◽  
Biogeochemical Models ◽  
Inorganic Matter ◽  
Continental Shelves ◽  
Shelf Region ◽  
Transformation Processes

Abstract. Continental shelves play a key role in the cycling of nitrogen and carbon. Here the physical transport and biogeochemical transformation processes affecting the fluxes into and out of continental shelf systems are reviewed, and their role in the global cycling of both elements is discussed. Uncertainties in observation-based estimates of nitrogen and carbon fluxes mostly result from uncertainties in the shelf-open ocean exchange of organic and inorganic matter, which is hard to quantify based on observations alone, but can be inferred from biogeochemical models. Model-based nitrogen and carbon budgets are presented for the Northwestern North Atlantic continental shelf. Results indicate that shelves are an important sink for fixed nitrogen and a source of alkalinity, but are not much more efficient in exporting organic carbon to the deep ocean than the adjacent open ocean for the shelf region considered.

Using new observations and Machine Learning to improve organic sinking processes in the PlankTOM global ocean biogeochemical model 

2021 ◽  
Author(s):  
Anna Denvil-Sommer ◽  
Corinne Le Quéré ◽  
Erik Buitenhuis ◽  
Lionel Guidi ◽  
Jean-Olivier Irisson
Keyword(s):  
Organic Carbon ◽  
Carbon Cycle ◽  
Deep Ocean ◽  
Ecosystem Dynamics ◽  
Global Ocean ◽  
Biogeochemical Model ◽  
Carbon Export ◽  
Mixing Depth ◽  
Chl A ◽  
Biogeochemical Models

<p>A lot of effort has been put in the representation of surface ecosystem processes in global carbon cycle models, in particular through the grouping of organisms into Plankton Functional Types (PFTs) which have specific influences on the carbon cycle. In contrast, the transfer of ecosystem dynamics into carbon export to the deep ocean has received much less attention, so that changes in the representation of the PFTs do not necessarily translate into changes in sinking of particulate matter. Models constrain the air-sea CO<sub>2</sub> flux by drawing down carbon into the ocean interior. This export flux is five times as large as the CO<sub>2</sub> emitted to the atmosphere by human activities. When carbon is transported from the surface to intermediate and deep ocean, more CO<sub>2 </sub>can be absorbed at the surface. Therefore, even small variability in sinking organic carbon fluxes can have a large impact on air-sea CO<sub>2</sub> fluxes, and on the amount of CO<sub>2</sub> emissions that remain in the atmosphere.</p><p>In this work we focus on the representation of organic matter sinking in global biogeochemical models, using the PlankTOM model in its latest version representing 12 PFTs. We develop and test a methodology that will enable the systematic use of new observations to constrain sinking processes in the model. The approach is based on a Neural Network (NN) and is applied to the PlankTOM model output to test its ability to reconstruction small and large particulate organic carbon with a limited number of observations. We test the information content of geographical variables (location, depth, time of year), physical conditions (temperature, mixing depth, nutrients), and ecosystem information (CHL a, PFTs). These predictors are used in the NN to test their influence on the model-generation of organic particles and the robustness of the results. We show preliminary results using the NN approach with real plankton and particle size distribution observations from the Underwater Vision Profiler (UVP) and plankton diversity data from Tara Oceans expeditions and discuss limitations.</p>

The Southern Ocean carbon sink 1985-2018: first results of the RECCAP2 project

2021 ◽  
Author(s):  
Judith Hauck ◽  
Luke Gregor ◽  
Cara Nissen ◽  
Eric Mortenson ◽  
Seth Bushinsky ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Seasonal Cycle ◽  
Carbon Sink ◽  
Global Ocean ◽  
Biogeochemical Models ◽  
Wide Range ◽  
Data Products ◽  
First Results ◽  
Ocean Carbon ◽  
Indian Sector

<p>The Southern Ocean is the main gateway for anthropogenic CO<sub>2</sub> into the ocean owing to the upwelling of old water masses with low anthropogenic CO<sub>2</sub> concentration, and the transport of the newly equilibrated surface waters into the ocean interior through intermediate, deep and bottom water formation. Here we present first results of the Southern Ocean chapter of RECCAP2, which is the Global Carbon Project’s second systematic study on Regional Carbon Cycle Assessment and Processes. In the Southern Ocean chapter, we aim to assess the Southern Ocean carbon sink 1985-2018 from a wide range of available models and data sets, and to identify patterns of regional and temporal variability, model limitations and future challenges.</p><p>We gathered global and regional estimates of the air-sea CO<sub>2</sub> flux over the period 1985-2018 from global ocean biogeochemical models, surface pCO<sub>2</sub>-based data products, and data-assimilated models. The analysis on the Southern Ocean quantified geographical patterns in the annual mean and seasonal amplitude of air-sea CO<sub>2</sub> flux, with results presented here aggregated to the level of large-scale ocean biomes.</p><p>Considering the suite of observed and modelled estimates, we found that the subtropical seasonally stratified (STSS) biome stands out with the largest air-sea CO<sub>2</sub> flux per area and a seasonal cycle with largest ocean uptake of CO<sub>2</sub> in winter, whereas the ice (ICE) biome is characterized by a large ensemble spread and a pronounced seasonal cycle with the largest ocean uptake of CO<sub>2</sub> in summer. Connecting these two, the subpolar seasonally stratified (SPSS) biome has intermediate flux densities (flux per area), and most models have difficulties simulating the seasonal cycle with strongest uptake during the summer months.</p><p>Our analysis also reveals distinct differences between the Atlantic, Pacific and Indian sectors of the aforementioned biomes. In the STSS, the Indian sector contributes most to the ocean carbon sink, followed by the Atlantic and then Pacific sectors. This hierarchy is less pronounced in the models than in the data-products. In the SPSS, only the Atlantic sector exhibits net CO<sub>2</sub> uptake in all years, likely linked to strong biological production. In the ICE biome, the Atlantic and Pacific sectors take up more CO<sub>2</sub> than the Indian sector, suggesting a potential role of the Weddell and Ross Gyres.</p><p>These first results confirm the global relevance of the Southern Ocean carbon sink and highlight the strong regional and interannual variability of the Southern Ocean carbon uptake in connection to physical and biogeochemical processes.</p>

scholarly journals Photobleaching as a factor controlling spectral characteristics of chromophoric dissolved organic matter in open ocean

2013 ◽  
Vol 10 (11) ◽  
pp. 7207-7217 ◽  
Author(s):  
Y. Yamashita ◽  
Y. Nosaka ◽  
K. Suzuki ◽  
H. Ogawa ◽  
K. Takahashi ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Surface Waters ◽  
Spectral Characteristics ◽  
Open Ocean ◽  
Global Ocean ◽  
Chromophoric Dissolved Organic Matter ◽  
Spectral Slope ◽  
Subtropical Region ◽  
Subarctic Region

Abstract. Chromophoric dissolved organic matter (CDOM) ubiquitously occurs in marine environments and plays a significant role in the marine biogeochemical cycles. Basin scale distributions of CDOM have recently been surveyed in the global ocean and indicate that quantity and quality of oceanic CDOM are mainly controlled by in situ production and photobleaching. However, factors controlling the spectral parameters of CDOM in the UV region, i.e., spectral slope of CDOM determined at 275–295 nm (S275–295) and the ratio of two spectral slope parameters (SR); the ratio of S275–295 to S350–400, have not been well documented. To evaluate the factor controlling the spectral characteristics of CDOM in the UV region in the open ocean, we determined the quantitative and qualitative characteristics of CDOM in the subarctic and subtropical surface waters (5–300 m) of the western North Pacific. Absorption coefficients at 320 nm in the subarctic region were higher than those in the subtropical region throughout surface waters, suggesting that magnitudes of photobleaching were different between the two regions. The values of S275–295 and SR were also higher in the subtropical region than the subarctic region. The dark microbial incubation showed biodegradation of DOM little affected S275–295, but slightly decreased SR. On the other hand, increases in S275–295 and relative stableness of SR were observed during photo-irradiation incubations respectively. These experimental results indicated that photobleaching of CDOM mainly induced qualitative differences in CDOM at UV region between the subarctic and subtropical surface waters. The results of this study imply that S275–295 can be used as a tracer of photochemical history of CDOM in the open ocean.

scholarly journals The role of continental shelves in nitrogen and carbon cycling: Northwestern North Atlantic case study

Ocean Science ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 539-548 ◽  
Author(s):  
K. Fennel
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Deep Ocean ◽  
Open Ocean ◽  
Biogeochemical Models ◽  
Inorganic Matter ◽  
Continental Shelves ◽  
Shelf Region

Abstract. Continental shelves play a key role in the cycling of nitrogen and carbon. Here the physical transport and biogeochemical transformation processes affecting the fluxes into and out of continental shelf systems are reviewed, and their role in the global cycling of both elements is discussed. Uncertainties in the magnitude of organic and inorganic matter exchange between shelves and the open ocean is a major source of uncertainty in observation-based estimates of nitrogen and carbon fluxes. The shelf-open ocean exchange is hard to quantify based on observations alone, but can be inferred from biogeochemical models. Model-based nitrogen and carbon budgets are presented for the Northwestern North Atlantic continental shelf. Results indicate that shelves are an important sink for fixed nitrogen and a source of alkalinity, but are not much more efficient in exporting organic carbon to the deep ocean than the adjacent open ocean for the shelf region considered.

scholarly journals What prevents nitrogen depletion in the oxygen minimum zone of the eastern tropical South Pacific?

2015 ◽  
Vol 12 (4) ◽  
pp. 1113-1130 ◽  
Author(s):  
B. Su ◽  
M. Pahlow ◽  
H. Wagner ◽  
A. Oschlies
Keyword(s):  
Nitrogen Fixation ◽  
Ocean Circulation ◽  
Deep Ocean ◽  
South Pacific ◽  
Open Ocean ◽  
Nitrogen Depletion ◽  
Biogeochemical Models ◽  
Model Domain ◽  
Limiting Nutrient ◽  
Oxygen Minimum

Abstract. Local coupling between nitrogen fixation and denitrification in current biogeochemical models could result in runaway feedback in open-ocean oxygen minimum zones (OMZs), eventually stripping OMZ waters of all fixed nitrogen. This feedback does not seem to operate at full strength in the ocean, as nitrate does not generally become depleted in open-ocean OMZs. To explore in detail the possible mechanisms that prevent nitrogen depletion in the OMZ of the eastern tropical South Pacific (ETSP), we develop a box model with fully prognostic cycles of carbon, nutrients and oxygen in the upwelling region and its adjacent open ocean. Ocean circulation is calibrated with Δ14C data of the ETSP. The sensitivity of the simulated nitrogen cycle to nutrient and oxygen exchange and ventilation from outside the model domain and to remineralization scales inside an OMZ is analysed. For the entire range of model configurations explored, we find that the fixed-N inventory can be stabilized at non-zero levels in the ETSP OMZ only if the remineralization rate via denitrification is slower than that via aerobic respiration. In our optimum model configuration, lateral oxygen supply into the model domain is required at rates sufficient to oxidize at least about one fifth of the export production in the model domain to prevent anoxia in the deep ocean. Under these conditions, our model is in line with the view of phosphate as the ultimate limiting nutrient for phytoplankton, and implies that for the current notion of nitrogen fixation being favoured in N-deficit waters, the water column of the ETSP could even be a small net source of nitrate.

Back to the future 3: Analysing tectonically induced tidal resonance with conceptual models

2020 ◽  
Author(s):  
Hannah Davies ◽  
J.A. Mattias Green ◽  
Joao C. Duarte
Keyword(s):  
Subduction Zones ◽  
Open Ocean ◽  
Global Ocean ◽  
Plate Tectonic ◽  
Tidal Dissipation ◽  
Tidal Model ◽  
Continental Plate ◽  
Global Coverage ◽  
Tethys Ocean ◽  
North And South

<p>Recent research of coupled tidal and tectonic modelling has found that during periods in an ocean’s Wilson cycle, (i.e. during dispersal, and subsequent convergence of oceans due to plate tectonic movement), oceans occasionally become resonant for the semi-diurnal component of the tide (M<sub>2</sub>). This results in an approximately 20-Million-year long period of enhanced tidal dissipation in the resonant ocean (assuming continental plate drift rates of ~5 cm yr<sup>-1</sup>). This resonant “Super-tide” has been simulated in numerical tidal models for both past and future tectonic scenarios, and they show that the current tides are among the most energetic found.</p><p>Here we use an established tidal model to analyse the conditions required for open ocean tidal resonance. Our conceptual “Earths” consist of two or more simplified oceans, which are shaped to represent conceptual versions of oceans of the past, present, and future: triangular (Tethys ocean), circular (Pacific and Arctic oceans), rectangular (Southern and Indian oceans), and rhomboid shaped (North, and South Atlantic Ocean). Each scenario was conducted using ocean bathymetry ranging from a “bathtub” ocean (a uniformly deep flat abyssal plane from coast to coast), to a continental shelf with no abyssal bathymetry, to a “realistic” ocean with ocean shelves, ridges, and subduction zones. The global ocean land ratio and ocean volume was conserved to present-day in most conceptual scenarios however, to investigate the maximum tidal dissipation possible on Earth, some scenarios deviated from the ocean volume and global coverage. In every scenario, ocean width is progressively increased relative to the predominant ocean boundaries, simulating plate tectonic opening of each ocean.</p><p>The aim of the work was to assess the frequency of the occurrence of resonance in the open ocean, and the upper limit for tidal dissipation of the semi-diurnal tide on Earth. We found that super-tides are common in the results with their dissipative strength varying from weaker than present day to five times present day.</p><p>The occurrence of tidal resonances in modelled conceptual oceans further confirms the link between tectonics and tidal evolution. These super-tidal periods of markedly increased tidal dissipation alter the ocean’s energy budget, nutrient dispersal and the carrying capacity of coastal and oceanic ecosystems.</p>

Towards AOD1B RL07

2020 ◽  
Author(s):  
Linus Shihora ◽  
Henryk Dobslaw
Keyword(s):  
General Circulation ◽  
A Priori ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Temporal Variations ◽  
Ocean Dynamics ◽  
Global Ocean ◽  
Ocean Bottom ◽  
Data Set ◽  
Priori Information

<p>The Atmosphere and Ocean De-Aliasing Level-1B (AOD1B) product provides a priori information about temporal variations in the Earth's gravity field caused by global mass variability in the atmosphere and ocean and is routinely used as background model in satellite gravimetry. The current version 06 provides Stokes coefficients expanded up to d/o 180 every 3 hours. It is based on ERA-Interim and the ECMWF operational model for the atmosphere, and simulations with the global ocean general circulation model MPIOM consistently forced with the fields from the same atmospheric data-set.</p> <p>We here present preliminary numerical experiments in the development towards a new release 07 of AOD1B. The experiments are performed with the TP10 configuration of MPIOM and include (I) new hourly atmospheric forcing based on the new ERA-5 reanalysis from ECMWF; (II) an improved bathymetry around Antarctica including cavities under the ice shelves; and (III) an explicit implementation of the feedback effects of self-attraction and loading to ocean dynamics. The simulated ocean bottom pressure variability is discussed with respect to AOD1B version 6 as well as in situ ocean observations. A preliminary timeseries of hourly AOD1B-like coefficients for the year 2019 that incorporate the above mentioned improvements will be made available for testing purposes.</p>

scholarly journals Dolphins Signal Success by Producing a Victory Squeal

2016 ◽  
Vol 29 ◽  
Author(s):  
Dianna Samuelson Dibble ◽  
Kaitlin R. Van Alstyne ◽  
Sam Ridgway
Keyword(s):  
Brain Stimulation ◽  
Dopamine Release ◽  
Prey Capture ◽  
Food Reinforcement ◽  
Secondary Reinforcement ◽  
Open Ocean ◽  
Task Completion ◽  
Brain Dopamine ◽  
Time Gap ◽  
To Come

We have long observed dolphins producing recognizable sounds—bursts of pulses with sweeping peak frequencies—at prey capture. We call this the victory squeal. When dolphins hunt fish, there are three sequential sounds: sonar clicks, terminal buzz, and the victory squeal. When dolphins find a fish with sonar clicks, but reject the fish during the terminal buzz phase, they omit or truncate the victory squeal. We also observe dolphins producing the victory squeal after a trainer’s bridge, which serves as secondary reinforcement that bridges the time gap between the dolphin’s performance and delivery of food reinforcement. It signals the dolphins that they responded correctly and that reward is forthcoming. Before training, the victory squeal came after fish capture, but with successive trials, there was a forward shift in the victory squeal to come about 200 ms after the bridge. The victory squeal immediately following the bridge suggests the dolphin expects reward. Although there are no direct studies of dopamine release in cetaceans, early brain stimulation studies demonstrated consistent timing that may link the victory squeal with brain dopamine release. In the current study, we asked if dolphins might produce the victory squeal after task completion, but without the trainer’s bridge. Dolphins carried cameras, recording video and sound, while performing tasks in the open ocean, away from trainers, during swimmer/mine marking and retrieving. In each task, we observed the victory squeal immediately upon completion of task components. We suggest that the victory squeal signals that these experienced dolphins recognized their success.

Sign in / Sign up

Export Citation Format

Share Document