Warming and circulation change in the eastern South Pacific Ocean

Schaffer, G.; Leth, Ole; Ulloa, Osvaldo; Bendtsen, Jørgen; Daneri, Giovanni; Dellarossa, Víctor; Hormazábal, Samuel; Sehlstedt, Per-Ingvar

doi:10.1029/1999gl010952

Cited by 48 publications

(33 citation statements)

References 21 publications

(6 reference statements)

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“…as the turbulent diffusion). However, the amount of oxygen entering the atmosphere through the ocean surface is known to depend on details of the ocean circulation [31,36,47,55,74]. Although it does not seem likely that ocean hydrodynamics can alter the dependence of oxygen production on temperature, it seems probable that it can delay the oxygen transport through the sea-air interface.…”

Section: Discussionmentioning

confidence: 99%

“…Ocean makes about two-thirds of the Earth surface and also works as a huge heat capacitor, and hence is expected to be heavily affected by the climate change. Discussion of the effect of warming on the ocean dynamics usually focuses on possible changes in the global circulation [74] and on the expected melting of polar ice resulting in the consequential flooding on the global scale [61,62]. Meanwhile, apart from the apparent hydrophysical aspects of the problem, ocean is also a huge ecosystem and the effect of global warming on its functioning may have disastrous consequences comparable or even worse than the global flooding.…”

Section: Introductionmentioning

confidence: 99%

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Mathematical Modelling of Plankton–Oxygen Dynamics Under the Climate Change

2015

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Abstract. Ocean dynamics is known to have a strong effect the global climate change and on the composition of the atmosphere. In particular, it is estimated that about 70% of the atmospheric oxygen is produced in the oceans due to the photosynthetic activity of phytoplankton. However, the rate of oxygen production depends on water temperature and hence can be affected by the global warming. In this paper, we address this issue theoretically by considering a model of a coupled plankton-oxygen dynamics where the rate of oxygen production slowly changes with time to account for the ocean warming. We show that a sustainable oxygen production is only possible in an intermediate range of the production rate. If, in the course of time, the oxygen production rate becomes too low or too high, the system's dynamics changes abruptly resulting in the oxygen depletion and plankton extinction. Our results indicate that the depletion of atmospheric oxygen on global scale (which, if happens, obviously can kill most of life on Earth) is another possible catastrophic consequence of the global warming, a global ecological disaster that has been overlooked.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mathematical Modelling of Plankton–Oxygen Dynamics Under the Climate Change

2015

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“…These decrease to Ϸ0.01°C, 0.002 psu on LCDW . Along-isobar warming and freshening of about 0.02°C and 0.002 psu are detected over 28 yr at about 2000-m depth, zonally averaged from the coast of Chile to 86°-88°W at 43°and 28°S (Shaffer et al 2000;their Fig. 2).…”

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confidence: 99%

“…Though deep ocean sediments and isotope samples provide a long temporal record, data coverage is very sparse so their usage is limited in providing clues on the variability of the thermohaline circulation (e.g., Charles and Fairbanks 1992;Frank et al 2002). Direct observations of ϪS variations within the NADW/CDW density class have been documented, in some locations in the Southern Hemisphere (SH), but they are still currently limited to decadal time scales (e.g., Johnson and Orsi 1997;Bindoff and McDougall 2000;Shaffer et al 2000;Arbic and Owens 2001).…”

Section: Introductionmentioning

confidence: 99%

Circumpolar Deep Water Circulation and Variability in a Coupled Climate Model

Santoso

England

Hirst

2006

Journal of Physical Oceanography

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The natural variability of Circumpolar Deep Water (CDW) is analyzed using a long-term integration of a coupled climate model. The variability is decomposed using a standard EOF analysis into three separate modes accounting for 68% and 82% of the total variance in the upper and lower CDW layers, respectively. The first mode exhibits an interbasin-scale variability on multicentennial time scales, originating in the North Atlantic and flowing southward into the Southern Ocean via North Atlantic Deep Water (NADW). Salinity dipole anomalies appear to propagate around the Atlantic meridional overturning circulation on these time scales with the strengthening and weakening of NADW formation. The anomaly propagates northward from the midlatitude subsurface of the South Atlantic and sinks in the North Atlantic before flowing southward along the CDW isopycnal layers. This suggests an interhemispheric connection in the generation of the first CDW variability mode. The second mode shows a localized ϪS variability in the Brazil-Malvinas confluence zone on multidecadal to centennial time scales. Heat and salt budget analyses reveal that this variability is controlled by meridional advection driven by fluctuations in the strength of the Deep Western Boundary and the Malvinas Currents. The third mode suggests an Antarctic Intermediate Water source in the South Pacific contributing to variability in upper CDW. It is further found that NADW formation is mainly buoyancy driven on the time scales resolved, with only a weak connection with Southern Hemisphere winds. On the other hand, Southern Hemisphere winds have a more direct influence on the rate of NADW outflow into the Southern Ocean. The model's spatial pattern of ϪS variability is consistent with the limited observational record in the Southern Hemisphere. However, some observations of decadal CDW ϪS changes are beyond that seen in the model in its unperturbed state.

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“…As summarized in Table 1, detectable decreases in O 2 have been found in intermediate waters in the North Pacific, North Atlantic, South Pacific, and South Indian oceans, while small increases have possibly been found in deeper waters in the North Pacific and South Indian Oceans. What caused these O 2 changes is unclear, and different mechanisms, including changes in ocean circulation rates (6)(7)(8)(9), changes in preformed values (10), changing Redfield ratios (11), and changes in biological production (8) have been offered as possible explanations in different regions. While the changes may partly reflect natural decadal variability, the clearest O 2 changes, found at intermediate depths, are in the direction of decreasing O 2 concentrations.…”

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confidence: 99%

The change in oceanic O ₂ inventory associated with recent global warming

Keeling

Garcia

2002

Proc. Natl. Acad. Sci. U.S.A.

281

248

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Oceans general circulation models predict that global warming may cause a decrease in the oceanic O 2 inventory and an associated O 2 outgassing. An independent argument is presented here in support of this prediction based on observational evidence of the ocean's biogeochemical response to natural warming. On time scales from seasonal to centennial, natural O 2 flux͞heat flux ratios are shown to occur in a range of 2 to 10 nmol of O2 per joule of warming, with larger ratios typically occurring at higher latitudes and over longer time scales. The ratios are several times larger than would be expected solely from the effect of heating on the O 2 solubility, indicating that most of the O2 exchange is biologically mediated through links between heating and stratification. The change in oceanic O 2 inventory through the 1990s is estimated to be 0.3 ؎ 0.4 ؋ 10 14 mol of O2 per year based on scaling the observed anomalous long-term ocean warming by natural O 2 flux͞heating ratios and allowing for uncertainty due to decadal variability. Implications are discussed for carbon budgets based on observed changes in atmospheric O 2͞N2 ratio and based on observed changes in ocean dissolved inorganic carbon. R epeated hydrographic surveys indicate that the upper 3 km of the oceans have warmed (1) and intermediate waters of high-latitude origin have freshened (2) over the past few decades. Model studies indicate that upper-ocean warming, high-latitude freshening, and an associated increase in the density stratification of the upper ocean are expected consequences of the changes in atmospheric radiative forcing caused by fossil-fuel burning and other human activities (3-5).Repeated hydrographic surveys also indicate that small detectable changes have occurred in oceanic dissolved O 2 concentrations. As summarized in Table 1, detectable decreases in O 2 have been found in intermediate waters in the North Pacific, North Atlantic, South Pacific, and South Indian oceans, while small increases have possibly been found in deeper waters in the North Pacific and South Indian Oceans. What caused these O 2 changes is unclear, and different mechanisms, including changes in ocean circulation rates (6-9), changes in preformed values (10), changing Redfield ratios (11), and changes in biological production (8) have been offered as possible explanations in different regions. While the changes may partly reflect natural decadal variability, the clearest O 2 changes, found at intermediate depths, are in the direction of decreasing O 2 concentrations. A global reduction in dissolved O 2 is predicted by ocean general circulation models (OGCMs) driven by increasing greenhouse gases (12-15). In the model simulations, most of the O 2 decrease is attributed to enhanced stratification.Stratification has two competing effects on subsurface oxygen concentrations. First, it reduces the upwelling of nutrients from deeper waters into surface waters, thus decreasing photosynthetic production and the associated flux of organic detritus into the ocean interior...

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Warming and circulation change in the eastern South Pacific Ocean

Cited by 48 publications

References 21 publications

Mathematical Modelling of Plankton–Oxygen Dynamics Under the Climate Change

Mathematical Modelling of Plankton–Oxygen Dynamics Under the Climate Change

Circumpolar Deep Water Circulation and Variability in a Coupled Climate Model

The change in oceanic O ₂ inventory associated with recent global warming

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Warming and circulation change in the eastern South Pacific Ocean

Cited by 48 publications

References 21 publications

Mathematical Modelling of Plankton–Oxygen Dynamics Under the Climate Change

Mathematical Modelling of Plankton–Oxygen Dynamics Under the Climate Change

Circumpolar Deep Water Circulation and Variability in a Coupled Climate Model

The change in oceanic O 2 inventory associated with recent global warming

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Resources

About

The change in oceanic O ₂ inventory associated with recent global warming