Journal articles on the topic 'Ocean Change'
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1
Prescot, Victor. "Ocean changes in global change." Marine Policy 15, no. 6 (November 1991): 465. http://dx.doi.org/10.1016/0308-597x(91)90057-i.
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Liang, Xinfeng, Christopher G. Piecuch, Rui M. Ponte, Gael Forget, Carl Wunsch, and Patrick Heimbach. "Change of the Global Ocean Vertical Heat Transport over 1993–2010." Journal of Climate 30, no. 14 (July 2017): 5319–27. http://dx.doi.org/10.1175/jcli-d-16-0569.1.
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A dynamically and data-consistent ocean state estimate during 1993–2010 is analyzed for bidecadal changes in the mechanisms of heat exchange between the upper and lower oceans. Many patterns of change are consistent with prior studies. However, at various levels above 1800 m the global integral of the change in ocean vertical heat flux involves the summation of positive and negative regional contributions and is not statistically significant. The nonsignificance of change in the global ocean vertical heat transport from an ocean state estimate that provides global coverage and regular sampling, spatially and temporally, raises the question of whether an adequate observational database exists to assess changes in the upper ocean heat content over the past few decades. Also, whereas the advective term largely determines the spatial pattern of the change in ocean vertical heat flux, its global integral is not significantly different from zero. In contrast, the diffusive term, although regionally weak except in high-latitude oceans, produces a statistically significant extra downward heat flux during the 2000s. This result suggests that besides ocean advection, ocean mixing processes, including isopycnal and diapycnal as well as convective mixing, are important for the decadal variation of the heat exchange between upper and deep oceans as well. Furthermore, the analyses herein indicate that focusing on any particular region in explaining changes of the global ocean heat content is misleading.
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Vallega, Adalberto. "Ocean change in global change." GeoJournal 25, no. 4 (December 1991): 437. http://dx.doi.org/10.1007/bf02439496.
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Piecuch, Christopher G., and Rui M. Ponte. "Mechanisms of Global-Mean Steric Sea Level Change." Journal of Climate 27, no. 2 (January 15, 2014): 824–34. http://dx.doi.org/10.1175/jcli-d-13-00373.1.
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Abstract Global-mean sea level change partly reflects volumetric expansion of the oceans because of density change, otherwise known as global-mean steric sea level change. Owing to nonlinearities in the equation of state of seawater, the nature of processes contributing to recent observed global-mean steric sea level changes has not been well understood. Using a data-constrained ocean state estimate, global-mean steric sea level change over 1993–2003 is revisited, and contributions from ocean transports and surface exchanges are quantified using closed potential temperature and salinity budgets. Analyses demonstrate that estimated decadal global-mean steric sea level change results mainly from a slight, time-mean imbalance between atmospheric forcing and ocean transports over the integration period: surface heat and freshwater exchanges produce a trend in global-mean steric sea level that is mainly offset by the redistribution of potential temperature and salinity through small-scale diffusion and large-scale advection. A set of numerical experiments demonstrates that global-mean steric sea level changes simulated by ocean general circulation models are sensitive to the regional distribution of ocean heat and freshwater content changes.
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Steele, Michael, and Wendy Ermold. "Steric Sea Level Change in the Northern Seas." Journal of Climate 20, no. 3 (February 1, 2007): 403–17. http://dx.doi.org/10.1175/jcli4022.1.
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Abstract Ocean temperature and salinity data over the period 1950–2000 in the Northern Seas, defined here as the North Atlantic Ocean (north of 50°N), North Pacific Ocean (north of 40°N), and Arctic Oceans, are combined to diagnose the steric (i.e., density) contribution to sea level variation. The individual contributions to steric height from temperature (thermosteric height) and salinity (halosteric height) are also analyzed. It is found that during 1950–2000, steric height rose over the study’s domain, mostly as a result of halosteric increases (i.e., freshening). Over a shorter time period (late 1960s to early 1990s) during which climate indices changed dramatically, steric height gradients near the Nordic Seas minimum were reduced by 18%–32%. It is speculated that this may be associated with a local slowing of both the Meridional Overturning Circulation and the southward flow through Fram Strait. However, steric height increases in the North Pacific Ocean during this time imply a possible acceleration of flow through the poorly measured Canadian Arctic. Evidence that the Great Salinity Anomaly of the late 1960s and 1970s had two distinct Arctic Ocean sources is also found: a late 1960s export of sea ice, and a delayed but more sustained 1970s export of liquid (ocean) freshwater. A simple calculation indicates that these Arctic Ocean freshwater sources were not sufficient to create the 1970s freshening observed in the North Atlantic Ocean.
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Voigt, Christina. "Oceans, IUU Fishing, and Climate Change: Implications for International Law." International Community Law Review 22, no. 3-4 (August 20, 2020): 377–88. http://dx.doi.org/10.1163/18719732-12341436.
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Abstract Illegal, unregulated and unreported (IUU) fishing poses a significant threat to marine fisheries and biodiversity only outpaced by the projected impacts of climate change and greenhouse gas emissions. Ocean warming might affect fish stocks, their health and migratory routes. Ocean acidification and de-oxygenation are another two phenomena that might affect certain marine species as well as entire marine ecosystems. Rebuilding of overexploited and depleted fisheries and managing fisheries sustainably will require comprehensive governance structures for port, flag, coastal and market states, which also address the causes and impacts of climate change. Addressing those concerns could open for opportunities for comprehensive and synergetic regulation. This article addresses potential synergies between oceans and climate governance; focusing on the role of oceans in addressing climate change and its adverse impacts. Suggestions to this end include (i) increasing ocean-based renewable energy, (ii) decarbonizing ocean-based transport, and (iii) pursuing integrated management of fisheries and aquaculture.
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Denman, KL. "Climate change, ocean processes and ocean iron fertilization." Marine Ecology Progress Series 364 (July 29, 2008): 219–25. http://dx.doi.org/10.3354/meps07542.
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Cronin, Thomas M., and Gary S. Dwyer. "Deep Sea Ostracodes and Climate Change." Paleontological Society Papers 9 (November 2003): 247–64. http://dx.doi.org/10.1017/s1089332600002230.
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Ostracodes are bivalved Crustacea whose fossil shells constitute the most abundant and diverse metazoan group preserved in sediment cores from deep and intermediate ocean water depths. The ecology, zoogeography, and shell chemistry of many ostracode taxa makes them useful for paleoceanographic research on topics ranging from deep ocean circulation, bottom-water temperature, ecological response to global climate change and many others. However, the application of ostracodes to the study of climate change has been hampered by a number of factors, including the misconception that they are rare or absent in deep-sea sediments and the lack of taxonomic and zoogeographic data. In recent years studies from the Atlantic, Pacific, and Arctic Oceans show that ostracodes are abundant enough for quantitative assemblage analysis and that the geochemistry of their shells can be a valuable tool for paleotemperature reconstruction. This paper presents practical guidelines for using ostracodes in investigations of climate-driven ocean variability and the ecological and evolutionary impacts of these changes.
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Krakauer, Nir Y., Michael J. Puma, Benjamin I. Cook, Pierre Gentine, and Larissa Nazarenko. "Ocean–atmosphere interactions modulate irrigation's climate impacts." Earth System Dynamics 7, no. 4 (November 10, 2016): 863–76. http://dx.doi.org/10.5194/esd-7-863-2016.
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Abstract. Numerous studies have focused on the local and regional climate effects of irrigated agriculture and other land cover and land use change (LCLUC) phenomena, but there are few studies on the role of ocean–atmosphere interaction in modulating irrigation climate impacts. Here, we compare simulations with and without interactive sea surface temperatures of the equilibrium effect on climate of contemporary (year 2000) irrigation geographic extent and intensity. We find that ocean–atmosphere interaction does impact the magnitude of global-mean and spatially varying climate impacts, greatly increasing their global reach. Local climate effects in the irrigated regions remain broadly similar, while non-local effects, particularly over the oceans, tend to be larger. The interaction amplifies irrigation-driven standing wave patterns in the tropics and midlatitudes in our simulations, approximately doubling the global-mean amplitude of surface temperature changes due to irrigation. The fractions of global area experiencing significant annual-mean surface air temperature and precipitation change also approximately double with ocean–atmosphere interaction. Subject to confirmation with other models, these findings imply that LCLUC is an important contributor to climate change even in remote areas such as the Southern Ocean, and that attribution studies should include interactive oceans and need to consider LCLUC, including irrigation, as a truly global forcing that affects climate and the water cycle over ocean as well as land areas.
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Sullivan, Kathleen M. "Documenting Sea Change." Environment and Society 11, no. 1 (September 1, 2020): 82–99. http://dx.doi.org/10.3167/ares.2020.110106.
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This review examines social science and practitioner literature regarding the relationship between ocean sciences big data projects and ocean governance. I contend that three overarching approaches to the study of the development of ocean sciences big data techne (the arts of data creation, management, and sharing) and data technologies can be discerned. The first approach traces histories of ocean sciences data technologies, highlighting the significant role of governments in their development. The second approach is comprised of an oceanic contribution to the study of ontological politics. The third takes a human-social centered approach, examining the networks of people and practices responsible for creating and maintaining ocean sciences big data infrastructure. The three approaches make possible a comparative reflection on the entangled ethical strands at work in the literature.
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Vermeersen, B. "Effects of ice-melt induced gravity changes and solid earth deformation in the Netherlands." Netherlands Journal of Geosciences - Geologie en Mijnbouw 87, no. 3 (September 2008): 215. http://dx.doi.org/10.1017/s0016774600023295.
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Determining sea-level change caused by continental ice mass variations is a far more complicated matter than one might think. Even if effects like induced changes in ocean currents or thermal expansion of ocean water are neglected, melt water does not redistribute uniformly and homogeneously over the world’s oceans. If land ice melts, the gravity field of the earth changes due to the redistribution of the ice and melt water masses.
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Frajka-Williams, E. "Sustaining observations of the unsteady ocean circulation." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2025 (September 28, 2014): 20130335. http://dx.doi.org/10.1098/rsta.2013.0335.
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Sustained observations of ocean properties reveal a global warming trend and rising sea levels. These changes have been documented by traditional ship-based measurements of ocean properties, whereas more recent Argo profiling floats and satellite records permit estimates of ocean changes on a near real-time basis. Through these and newer methods of observing the oceans, scientists are moving from quantifying the ‘state of the ocean’ to monitoring its variability, and distinguishing the physical processes bringing signals of change. In this paper, I give a brief overview of the UK contributions to the physical oceanographic observations, and the role they have played in the wider global observing systems. While temperature and salinity are the primary measurements of physical oceanography, new transbasin mooring arrays also resolve changes in ocean circulation on daily timescales. Emerging technologies permit routine observations at higher-than-ever spatial resolutions. Following this, I then give a personal perspective on the future of sustained observations. New measurement techniques promise exciting discoveries concerning the role of smaller scales and boundary processes in setting the large-scale ocean circulation and the ocean's role in climate. The challenges now facing the scientific community include sustaining critical observations in the case of funding system changes or shifts in government priorities. These long records will enable a determination of the role and response of the ocean to climate change.
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Giraud, Xavier. "The Ocean and Climate Change: Variations in Ocean Circulation." La lettre du Collège de France, no. 7 (October 29, 2015): 46. http://dx.doi.org/10.4000/lettre-cdf.2694.
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Udovydchenkov, Ilya A., and Timothy F. Duda. "Ocean noise level change in response to ocean acidification." Journal of the Acoustical Society of America 126, no. 4 (2009): 2211. http://dx.doi.org/10.1121/1.3248732.
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Kenny, Tiff-Annie, Philippe Archambault, Pierre Ayotte, Malek Batal, Hing Man Chan, William Cheung, Tyler D. Eddy, et al. "Oceans and human health—navigating changes on Canada’s coasts." FACETS 5, no. 1 (January 1, 2020): 1037–70. http://dx.doi.org/10.1139/facets-2020-0035.
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Ocean conditions can affect human health in a variety of ways that are often overlooked and unappreciated. Oceans adjacent to Canada are affected by many anthropogenic stressors, with implications for human health and well-being. Climate change further escalates these pressures and can expose coastal populations to unique health hazards and distressing conditions. However, current research efforts, education or training curriculums, and policies in Canada critically lack explicit consideration of these ocean–public health linkages. The objective of this paper is to present multiple disciplinary perspectives from academics and health practitioners to inform the development of future directions for research, capacity development, and policy and practice at the interface of oceans and human health in Canada. We synthesize major ocean and human health linkages in Canada, and identify climate-sensitive drivers of change, drawing attention to unique considerations in Canada. To support effective, sustained, and equitable collaborations at the nexus of oceans and human health, we recommend the need for progress in three critical areas: ( i) holistic worldviews and perspectives, ( ii) capacity development, and ( iii) structural supports. Canada can play a key role in supporting the global community in addressing the health challenges of climate and ocean changes.
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Hasselmann, Klaus. "Ocean circulation and climate change." Tellus B: Chemical and Physical Meteorology 43, no. 4 (January 1991): 82–103. http://dx.doi.org/10.3402/tellusb.v43i4.15399.
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HASSELMANN, KLAUS. "Ocean circulation and climate change." Tellus A 43, no. 4 (August 1991): 82–103. http://dx.doi.org/10.1034/j.1600-0870.1991.00008.x.
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HASSELMANN, KLAUS. "Ocean circulation and climate change." Tellus B 43, no. 4 (September 1991): 82–103. http://dx.doi.org/10.1034/j.1600-0889.1991.t01-2-00008.x.
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Hasselmann, Klaus. "Ocean circulation and climate change." Tellus A: Dynamic Meteorology and Oceanography 43, no. 4 (January 1991): 82–103. http://dx.doi.org/10.3402/tellusa.v43i4.11939.
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Williamson, Phillip, and Patrick M. Holligan. "Ocean productivity and climate change." Trends in Ecology & Evolution 5, no. 9 (September 1990): 299–303. http://dx.doi.org/10.1016/0169-5347(90)90085-r.
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Wunsch, Carl, and Patrick Heimbach. "Bidecadal Thermal Changes in the Abyssal Ocean." Journal of Physical Oceanography 44, no. 8 (August 1, 2014): 2013–30. http://dx.doi.org/10.1175/jpo-d-13-096.1.
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Abstract A dynamically consistent state estimate is used for the period 1992–2011 to describe the changes in oceanic temperatures and heat content, with an emphasis on determining the noise background in the abyssal (below 2000 m) depths. Interpretation requires close attention to the long memory of the deep ocean, implying that meteorological forcing of decades to thousands of years ago should still be producing trendlike changes in abyssal heat content. Much of the deep-ocean volume remained unobserved. At the present time, warming is seen in the deep western Atlantic and Southern Oceans, roughly consistent with those regions of the ocean expected to display the earliest responses to surface disturbances. Parts of the deeper ocean, below 3600 m, show cooling. Most of the variation in the abyssal Pacific Ocean is comparatively featureless, consistent with the slow, diffusive approach to a steady state expected there. In the global average, changes in heat content below 2000 m are roughly 10% of those inferred for the upper ocean over the 20-yr period. A useful global observing strategy for detecting future change has to be designed to account for the different time and spatial scales manifested in the observed changes. If the precision estimates of heat content change are independent of systematic errors, determining oceanic heat uptake values equivalent to 0.1 W m−2 is possibly attainable over future bidecadal periods.
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Zanna, Laure, Samar Khatiwala, Jonathan M. Gregory, Jonathan Ison, and Patrick Heimbach. "Global reconstruction of historical ocean heat storage and transport." Proceedings of the National Academy of Sciences 116, no. 4 (January 7, 2019): 1126–31. http://dx.doi.org/10.1073/pnas.1808838115.
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Most of the excess energy stored in the climate system due to anthropogenic greenhouse gas emissions has been taken up by the oceans, leading to thermal expansion and sea-level rise. The oceans thus have an important role in the Earth’s energy imbalance. Observational constraints on future anthropogenic warming critically depend on accurate estimates of past ocean heat content (OHC) change. We present a reconstruction of OHC since 1871, with global coverage of the full ocean depth. Our estimates combine timeseries of observed sea surface temperatures with much longer historical coverage than those in the ocean interior together with a representation (a Green’s function) of time-independent ocean transport processes. For 1955–2017, our estimates are comparable with direct estimates made by infilling the available 3D time-dependent ocean temperature observations. We find that the global ocean absorbed heat during this period at a rate of 0.30 ± 0.06 W/m2 in the upper 2,000 m and 0.028 ± 0.026 W/m2 below 2,000 m, with large decadal fluctuations. The total OHC change since 1871 is estimated at 436 ± 91 ×1021 J, with an increase during 1921–1946 (145 ± 62 ×1021 J) that is as large as during 1990–2015. By comparing with direct estimates, we also infer that, during 1955–2017, up to one-half of the Atlantic Ocean warming and thermosteric sea-level rise at low latitudes to midlatitudes emerged due to heat convergence from changes in ocean transport.
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Hu, Shineng, Shang-Ping Xie, and Wei Liu. "Global Pattern Formation of Net Ocean Surface Heat Flux Response to Greenhouse Warming." Journal of Climate 33, no. 17 (September 1, 2020): 7503–22. http://dx.doi.org/10.1175/jcli-d-19-0642.1.
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AbstractThis study examines global patterns of net ocean surface heat flux changes (ΔQnet) under greenhouse warming in an ocean–atmosphere coupled model based on a heat budget decomposition. The regional structure of ΔQnet is primarily shaped by ocean heat divergence changes (ΔOHD): excessive heat is absorbed by higher-latitude oceans (mainly over the North Atlantic and the Southern Ocean), transported equatorward, and stored in lower-latitude oceans with the rest being released to the tropical atmosphere. The overall global pattern of ΔOHD is primarily due to the circulation change and partially compensated by the passive advection effect, except for the Southern Ocean, which requires further investigations for a more definitive attribution. The mechanisms of North Atlantic surface heat uptake are further explored. In another set of global warming simulations, a perturbation of freshwater removal is imposed over the subpolar North Atlantic to largely offset the CO2-induced changes in the local ocean vertical stratification, barotropic gyre, and the Atlantic meridional overturning circulation (AMOC). Results from the freshwater perturbation experiments suggest that a significant portion of the positive ΔQnet over the North Atlantic under greenhouse warming is caused by the Atlantic circulation changes, perhaps mainly by the slowdown of AMOC, while the passive advection effect can contribute to the regional variations of ΔQnet. Our results imply that ocean circulation changes are critical for shaping global warming pattern and thus hydrological cycle changes.
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Trees, V. J. H., and D. M. Stam. "Blue, white, and red ocean planets." Astronomy & Astrophysics 626 (June 2019): A129. http://dx.doi.org/10.1051/0004-6361/201935399.
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Context. An exoplanet’s habitability will depend strongly on the presence of liquid water. Flux and/or polarization measurements of starlight that is reflected by exoplanets could help to identify exo-oceans. Aims. We investigate which broadband spectral features in flux and polarization phase functions of reflected starlight uniquely identify exo-oceans. Methods. With an adding-doubling algorithm, we computed total fluxes F and polarized fluxes Q of starlight that is reflected by cloud-free and (partly) cloudy exoplanets, for wavelengths from 350 to 865 nm. The ocean surface has waves composed of Fresnel reflecting wave facets and whitecaps, and scattering within the water body is included. Results. Total flux F, polarized flux Q, and degree of polarization P of ocean planets change color from blue, through white, to red at phase angles α ranging from ~134° to ~108° for F, and from ~123° to ~157° for Q, with cloud coverage fraction fc increasing from 0.0 (cloud-free) to 1.0 (completely cloudy) for F, and to 0.98 for Q. The color change in P only occurs for fc ranging from 0.03 to 0.98, with the color crossing angle α ranging from ~88° to ~161°. The total flux F of a cloudy, zero surface albedo planet can also change color, and for fc = 0.0, an ocean planet’s F will not change color for surface pressures ps ≿ 8 bars. Polarized flux Q of a zero surface albedo planet does not change color for any fc. Conclusions. The color change of P of starlight reflected by an exoplanet, from blue, through white, to red with increasing α above 88°, appears to identify a (partly) cloudy exo-ocean. The color change of polarized flux Q with increasing α above 123° appears to uniquely identify an exo-ocean, independent of surface pressure or cloud fraction. At the color changing phase angle, the angular distance between a star and its planet is much larger than at the phase angle where the glint appears in reflected light. The color change in polarization thus offers better prospects for detecting an exo-ocean.
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Schneider, Leah J., Timothy J. Bralower, Lee R. Kump, and Mark E. Patzkowsky. "Calcareous nannoplankton ecology and community change across the Paleocene-Eocene Thermal Maximum." Paleobiology 39, no. 4 (2013): 628–47. http://dx.doi.org/10.1666/12050.
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The Paleocene-Eocene Thermal Maximum (PETM; ca. 55.8 Ma) is thought to coincide with a profound but entirely transient change among nannoplankton communities throughout the ocean. Here we explore the ecology of nannoplankton during the PETM by using multivariate analyses of a global data set that is based upon the distribution of taxa in time and space. We use these results, coupled with stable isotope data and geochemical modeling, to reinterpret the ecology of key genera. The results of the multivariate analyses suggest that the community was perturbed significantly in coastal and high-latitudes sites compared to the open ocean, and the relative influence of temperature and nutrient availability on the assemblage varies regionally. The open ocean became more stratified and less productive during the PETM and the oligotrophic assemblage responded primarily to changes in nutrient availability. Alternatively, assemblages at the equator and in the Southern Ocean responded to temperature more than to nutrient reduction. In addition, the assemblage change at the PETM was not merely transient—there is evidence of adaptation and a long-term change in the nannoplankton community that persists after the PETM and results in the disappearance of a high-latitude assemblage. The long-term effect on communities caused by transient warming during the PETM has implications for modern-day climate change, suggesting similar permanent changes to nannoplankton community structure as the oceans warm.
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Heuzé, Céline, Karen J. Heywood, David P. Stevens, and Jeff K. Ridley. "Changes in Global Ocean Bottom Properties and Volume Transports in CMIP5 Models under Climate Change Scenarios*." Journal of Climate 28, no. 8 (April 7, 2015): 2917–44. http://dx.doi.org/10.1175/jcli-d-14-00381.1.
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Abstract Changes in bottom temperature, salinity, and density in the global ocean by 2100 for CMIP5 climate models are investigated for the climate change scenarios RCP4.5 and RCP8.5. The mean of 24 models shows a decrease in density in all deep basins, except the North Atlantic, which becomes denser. The individual model responses to climate change forcing are more complex: regarding temperature, the 24 models predict a warming of the bottom layer of the global ocean; in salinity, there is less agreement regarding the sign of the change, especially in the Southern Ocean. The magnitude and equatorward extent of these changes also vary strongly among models. The changes in properties can be linked with changes in the mean transport of key water masses. The Atlantic meridional overturning circulation weakens in most models and is directly linked to changes in bottom density in the North Atlantic. These changes are the result of the intrusion of modified Antarctic Bottom Water, made possible by the decrease in North Atlantic Deep Water formation. In the Indian, Pacific, and South Atlantic Oceans, changes in bottom density are congruent with the weakening in Antarctic Bottom Water transport through these basins. The authors argue that the greater the 1986–2005 meridional transports, the more changes have propagated equatorward by 2100. However, strong decreases in density over 100 yr of climate change cause a weakening of the transports. The speed at which these property changes reach the deep basins is critical for a correct assessment of the heat storage capacity of the oceans as well as for predictions of future sea level rise.
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Dzieciuch, Matthew A. "Ocean acoustics in the rapidly changing Arctic ocean." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A181. http://dx.doi.org/10.1121/10.0011030.
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The Arctic ocean is undergoing rapid climate change, in fact it is the most rapidly warming area of our planet. Underwater sound is a uniquely effective tool for Arctic monitoring, because it can be used under the ice where satellites are blind. The most striking change has been the reduction of summer ice cover, but recent acoustic experiments have started to gather evidence for other changes as well, such as the reduction of ice scattering from the loss of multiyear ice and the formation of subsurface ducted propagation in the Beaufort Sea. The ambient soundscape is also of great interest as human activity increases in the region and as biological activity responds. Due the strategic importance of the Arctic during the cold war, there is a history of experimental work in the area but this short talk will try to show a few recent examples.
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Dommenget, Dietmar. "The Ocean’s Role in Continental Climate Variability and Change." Journal of Climate 22, no. 18 (September 15, 2009): 4939–52. http://dx.doi.org/10.1175/2009jcli2778.1.
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Abstract A characteristic feature of global warming is the land–sea contrast, with stronger warming over land than over oceans. Recent studies find that this land–sea contrast also exists in equilibrium global change scenarios, and it is caused by differences in the availability of surface moisture over land and oceans. In this study it is illustrated that this land–sea contrast exists also on interannual time scales and that the ocean–land interaction is strongly asymmetric. The land surface temperature is more sensitive to the oceans than the oceans are to the land surface temperature, which is related to the processes causing the land–sea contrast in global warming scenarios. It suggests that the ocean’s natural variability and change is leading to variability and change with enhanced magnitudes over the continents, causing much of the longer-time-scale (decadal) global-scale continental climate variability. Model simulations illustrate that continental warming due to anthropogenic forcing (e.g., the warming at the end of the last century or future climate change scenarios) is mostly (80%–90%) indirectly forced by the contemporaneous ocean warming, not directly by local radiative forcing.
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Shen, Hui, William Perrie, and Yongsheng Wu. "Wind drag in oil spilled ocean surface and its impact on wind-driven circulation." Anthropocene Coasts 2, no. 1 (January 1, 2019): 244–60. http://dx.doi.org/10.1139/anc-2018-0019.
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The drag coefficient is a key parameter to quantify the wind stress over the ocean surface, which depends on the ocean surface roughness. During oil spill events, oil slicks cover the ocean surface and thus change the surface roughness by suppressing multi-scale ocean surface waves, and the drag coefficient is changed. This change has not been included in the current ocean circulation models. In this study, such change in sea surface roughness is studied by satellite remote sensing via synthetic aperture radar (SAR) data to quantify the changes in the wind effect over the oil-covered ocean surface. The concept of effective wind speed is introduced to quantify the wind work on the ocean. We investigate its influence on the wind-driven Ekman current at the ocean surface. Using observations from the Deepwater Horizon oil spill (2010) as an example, we find that the presence of oil can result in an effective wind speed of 50%∼100% less than the conventional wind speed, causing overestimates by 75%∼100% in the wind driven Ekman current. The effect of such bias on oil trajectory predictions is also discussed. Our results suggest that it is important to consider the effect of changes in the drag coefficient over oil-contaminated areas, especially for large-scale oil spill situations.
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Lauvset, Siv K., Jerry Tjiputra, and Helene Muri. "Climate engineering and the ocean: effects on biogeochemistry and primary production." Biogeosciences 14, no. 24 (December 20, 2017): 5675–91. http://dx.doi.org/10.5194/bg-14-5675-2017.
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Abstract. Here we use an Earth system model with interactive biogeochemistry to project future ocean biogeochemistry impacts from the large-scale deployment of three different radiation management (RM) climate engineering (also known as geoengineering) methods: stratospheric aerosol injection (SAI), marine sky brightening (MSB), and cirrus cloud thinning (CCT). We apply RM such that the change in radiative forcing in the RCP8.5 emission scenario is reduced to the change in radiative forcing in the RCP4.5 scenario. The resulting global mean sea surface temperatures in the RM experiments are comparable to those in RCP4.5, but there are regional differences. The forcing from MSB, for example, is applied over the oceans, so the cooling of the ocean is in some regions stronger for this method of RM than for the others. Changes in ocean net primary production (NPP) are much more variable, but SAI and MSB give a global decrease comparable to RCP4.5 (∼ 6 % in 2100 relative to 1971–2000), while CCT gives a much smaller global decrease of ∼ 3 %. Depending on the RM methods, the spatially inhomogeneous changes in ocean NPP are related to the simulated spatial change in the NPP drivers (incoming radiation, temperature, availability of nutrients, and phytoplankton biomass) but mostly dominated by the circulation changes. In general, the SAI- and MSB-induced changes are largest in the low latitudes, while the CCT-induced changes tend to be the weakest of the three. The results of this work underscore the complexity of climate impacts on NPP and highlight the fact that changes are driven by an integrated effect of multiple environmental drivers, which all change in different ways. These results stress the uncertain changes to ocean productivity in the future and advocate caution at any deliberate attempt at large-scale perturbation of the Earth system.
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Craig, Robin Kundis. "Climate Change, Oceans, Public Health, and the Law." Climate Law 4, no. 1-2 (July 25, 2014): 85–93. http://dx.doi.org/10.1163/18786561-00402007.
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The oceans are bearing the brunt of climate change, with significant direct implications for the world’s weather and climate, navigation and maritime commerce, ocean water quality, marine biodiversity, sea-level rise, and storm surge. All of these impacts, in turn, raise public health concerns, albeit in a variety of different ways.
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Ladant, Jean-Baptiste, Christopher J. Poulsen, Frédéric Fluteau, Clay R. Tabor, Kenneth G. MacLeod, Ellen E. Martin, Shannon J. Haynes, and Masoud A. Rostami. "Paleogeographic controls on the evolution of Late Cretaceous ocean circulation." Climate of the Past 16, no. 3 (June 9, 2020): 973–1006. http://dx.doi.org/10.5194/cp-16-973-2020.
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Abstract. Understanding of the role of ocean circulation on climate during the Late Cretaceous is contingent on the ability to reconstruct its modes and evolution. Geochemical proxies used to infer modes of past circulation provide conflicting interpretations for the reorganization of the ocean circulation through the Late Cretaceous. Here, we present climate model simulations of the Cenomanian (100.5–93.9 Ma) and Maastrichtian (72.1–66.1 Ma) stages of the Cretaceous with the CCSM4 earth system model. We focus on intermediate (500–1500 m) and deep (> 1500 m) ocean circulation and show that while there is continuous deep-water production in the southwestern Pacific, major circulation changes occur between the Cenomanian and Maastrichtian. Opening of the Atlantic and Southern Ocean, in particular, drives a transition from a mostly zonal circulation to enhanced meridional exchange. Using additional experiments to test the effect of deepening of major ocean gateways in the Maastrichtian, we demonstrate that the geometry of these gateways likely had a considerable impact on ocean circulation. We further compare simulated circulation results with compilations of εNd records and show that simulated changes in Late Cretaceous ocean circulation are reasonably consistent with proxy-based inferences. In our simulations, consistency with the geologic history of major ocean gateways and absence of shift in areas of deep-water formation suggest that Late Cretaceous trends in εNd values in the Atlantic and southern Indian oceans were caused by the subsidence of volcanic provinces and opening of the Atlantic and Southern oceans rather than changes in deep-water formation areas and/or reversal of deep-water fluxes. However, the complexity in interpreting Late Cretaceous εNd values underscores the need for new records as well as specific εNd modeling to better discriminate between the various plausible theories of ocean circulation change during this period.
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Cronin, Thomas M., and H. J. Dowsett. "The pliocene record of climatic change: equator-to-pole biotic response." Paleontological Society Special Publications 6 (1992): 78. http://dx.doi.org/10.1017/s2475262200006389.
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Pliocene faunal events in tropical and subtropical regions of the Americas and the Caribbean have been causally linked to global climatic events, particularly, progressive cooling and increased amplitude of climatic cycles between 3.5 and 2.0 Ma. However, the rate and magnitude of Pliocene temperature changes has been determined in only a few climate proxy records. Our study contrasts paleoceanographic conditions at 3 Ma, an extremely warm period in many areas, with conditions 2.4 Ma, a much cooler interval, in equator-to-pole transects for the North Atlantic and the North Pacific Oceans. By using microfaunal data (ostracodes from ocean margin environments and planktic foraminifers from deep sea cores), quantitative factor analytic and modern analog dissimilarity coefficient analyses were carried out on faunas from the following sections.Our studies lead to the following conclusions: (1) Equator-to-pole thermal gradients in the oceans at 3.0 Ma were not as steep as they are today, but thermal gradients at 2.4 Ma were steeper than those today; (2)At 3 Ma middle to high latitudes were substantially warmer than today, but tropical regions were about the same; (3)Substantial cooling occurred in middle and high latitudes in the western North Pacific Ocean and the western North Atlantic between 3 Ma and 2.4 Ma; (4)Ocean water temperatures off the southeastern U.S. remained the same or cooled only slightly between 3 Ma and 2.4 Ma. Our results support the hypothesis that ocean circulation changes, probably resulting from the closure of near surface water by the Isthmus of Panama, had significant impact on equator-to-pole heat transport and global climate between about 3 and 2.4 Ma. They also argue against the hypothesis that climatically induced ocean temperature changes were directly linked to a major marine extinction in the southwestern North Atlantic and Caribbean.
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Thomas, Debbie. "Future Opportunities in Scientific Ocean Drilling: Climate and Ocean Change." Oceanography 32, no. 1 (March 1, 2019): 77. http://dx.doi.org/10.5670/oceanog.2019.123.
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Stanton, B. R. "Ocean circulation and ocean-atmosphere exchanges." Climatic Change 18, no. 2-3 (April 1991): 175–94. http://dx.doi.org/10.1007/bf00138996.
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Macdonald, Robie W., Zou Zou A. Kuzyk, and Sophia C. Johannessen. "The vulnerability of Arctic shelf sediments to climate change." Environmental Reviews 23, no. 4 (December 2015): 461–79. http://dx.doi.org/10.1139/er-2015-0040.
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The sediments of the pan-Arctic shelves contribute an important component to the Arctic Ocean ecosystem by providing a habitat for biota (benthos), a repository for organic and inorganic non-conservative substances entering or produced within the ocean, a reactor and source of transformed substances back to the water column, and a mechanism of burial. Sediments interact with ice, ocean, and the surrounding land over a wide range of space and time scales. We discuss the vulnerability of shelf sediment to changes in (i) organic carbon sources, (ii) pathways of sediment and organic carbon supply, and (iii) physical and biogeochemical alteration (diagenesis). Sedimentary environments of the shelves and basins are likely to exhibit a wide variance in their response to global change because of their wide variation in sediment sources, processes, and metabolic conditions. In particular, the Chukchi and Barents shelves are dominated by inflowing waters from oceans to the south, whereas the interior shelves are more closely tied to terrigenous sources due to river inflow and coastal erosion.
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Lambert, F. Hugo, Mark J. Webb, and Manoj M. Joshi. "The Relationship between Land–Ocean Surface Temperature Contrast and Radiative Forcing." Journal of Climate 24, no. 13 (July 1, 2011): 3239–56. http://dx.doi.org/10.1175/2011jcli3893.1.
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Abstract Previous work has demonstrated that observed and modeled climates show a near-time-invariant ratio of mean land to mean ocean surface temperature change under transient and equilibrium global warming. This study confirms this in a range of atmospheric models coupled to perturbed sea surface temperatures (SSTs), slab (thermodynamics only) oceans, and a fully coupled ocean. Away from equilibrium, it is found that the atmospheric processes that maintain the ratio cause a land-to-ocean heat transport anomaly that can be approximated using a two-box energy balance model. When climate is forced by increasing atmospheric CO2 concentration, the heat transport anomaly moves heat from land to ocean, constraining the land to warm in step with the ocean surface, despite the small heat capacity of the land. The heat transport anomaly is strongly related to the top-of-atmosphere radiative flux imbalance, and hence it tends to a small value as equilibrium is approached. In contrast, when climate is forced by prescribing changes in SSTs, the heat transport anomaly replaces “missing” radiative forcing over land by moving heat from ocean to land, warming the land surface. The heat transport anomaly remains substantial in steady state. These results are consistent with earlier studies that found that both land and ocean surface temperature changes may be approximated as local responses to global mean radiative forcing. The modeled heat transport anomaly has large impacts on surface heat fluxes but small impacts on precipitation, circulation, and cloud radiative forcing compared with the impacts of surface temperature change. No substantial nonlinearities are found in these atmospheric variables when the effects of forcing and surface temperature change are added.
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Chamberlain, M. A., C. Sun, R. J. Matear, M. Feng, and S. J. Phipps. "Downscaling the climate change for oceans around Australia." Geoscientific Model Development 5, no. 5 (September 21, 2012): 1177–94. http://dx.doi.org/10.5194/gmd-5-1177-2012.
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Abstract. At present, global climate models used to project changes in climate poorly resolve mesoscale ocean features such as boundary currents and eddies. These missing features may be important to realistically project the marine impacts of climate change. Here we present a framework for dynamically downscaling coarse climate change projections utilising a near-global ocean model that resolves these features in the Australasian region, with coarser resolution elsewhere. A time-slice projection for a 2060s ocean was obtained by adding climate change anomalies to initial conditions and surface fluxes of a near-global eddy-resolving ocean model. Climate change anomalies are derived from the differences between present and projected climates from a coarse global climate model. These anomalies are added to observed fields, thereby reducing the effect of model bias from the climate model. The downscaling model used here is ocean-only and does not include the effects that changes in the ocean state will have on the atmosphere and air–sea fluxes. We use restoring of the sea surface temperature and salinity to approximate real-ocean feedback on heat flux and to keep the salinity stable. Extra experiments with different feedback parameterisations are run to test the sensitivity of the projection. Consistent spatial differences emerge in sea surface temperature, salinity, stratification and transport between the downscaled projections and those of the climate model. Also, the spatial differences become established rapidly (< 3 yr), indicating the importance of mesoscale resolution. However, the differences in the magnitude of the difference between experiments show that feedback of the ocean onto the air–sea fluxes is still important in determining the state of the ocean in these projections. Until such a time when it is feasible to regularly run a global climate model with eddy resolution, our framework for ocean climate change downscaling provides an attractive way to explore the response of mesoscale ocean features with climate change and their effect on the broader ocean.
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Watson, Andrew J., Timothy M. Lenton, and Benjamin J. W. Mills. "Ocean deoxygenation, the global phosphorus cycle and the possibility of human-caused large-scale ocean anoxia." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2102 (August 7, 2017): 20160318. http://dx.doi.org/10.1098/rsta.2016.0318.
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The major biogeochemical cycles that keep the present-day Earth habitable are linked by a network of feedbacks, which has led to a broadly stable chemical composition of the oceans and atmosphere over hundreds of millions of years. This includes the processes that control both the atmospheric and oceanic concentrations of oxygen. However, one notable exception to the generally well-behaved dynamics of this system is the propensity for episodes of ocean anoxia to occur and to persist for 10 5 –10 6 years, these ocean anoxic events (OAEs) being particularly associated with warm ‘greenhouse’ climates. A powerful mechanism responsible for past OAEs was an increase in phosphorus supply to the oceans, leading to higher ocean productivity and oxygen demand in subsurface water. This can be amplified by positive feedbacks on the nutrient content of the ocean, with low oxygen promoting further release of phosphorus from ocean sediments, leading to a potentially self-sustaining condition of deoxygenation. We use a simple model for phosphorus in the ocean to explore this feedback, and to evaluate the potential for humans to bring on global-scale anoxia by enhancing P supply to the oceans. While this is not an immediate global change concern, it is a future possibility on millennial and longer time scales, when considering both phosphate rock mining and increased chemical weathering due to climate change. Ocean deoxygenation, once begun, may be self-sustaining and eventually could result in long-lasting and unpleasant consequences for the Earth's biosphere. This article is part of the themed issue ‘Ocean ventilation and deoxygenation in a warming world’.
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Kelley, Amanda L., Paul R. Hanson, and Stephanie A. Kelley. "Demonstrating the Effects of Ocean Acidification on Marine Organisms to Support Climate Change Understanding." American Biology Teacher 77, no. 4 (April 1, 2015): 258–63. http://dx.doi.org/10.1525/abt.2015.77.4.5.
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Ocean acidification, a product of CO2 absorption by the world’s oceans, is largely driven by the anthropogenic combustion of fossil fuels and has already lowered the pH of marine ecosystems. Organisms with calcium carbonate shells and skeletons are especially susceptible to increasing environmental acidity due to reduction in the saturation state of CaCO3 that accompanies ocean acidification. Creating a connection between human-mediated changes to our environment and the effect it will have on biota is crucial to establishing an understanding of the potential effects of global climate change. We outline two low-cost laboratory experiments that eloquently mimic the biochemical process of ocean acidification on two timescales, providing educators with hands-on, hypothesis-driven experiments that can easily be conducted in middle and high school biology or environmental science courses.
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Fu, Yunyun, Richard B. Rivkin, and Andrew S. Lang. "Effects of Vertical Water Mass Segregation on Bacterial Community Structure in the Beaufort Sea." Microorganisms 7, no. 10 (September 24, 2019): 385. http://dx.doi.org/10.3390/microorganisms7100385.
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The Arctic Ocean is one of the least well-studied marine microbial ecosystems. Its low-temperature and low-salinity conditions are expected to result in distinct bacterial communities, in comparison to lower latitude oceans. However, this is an ocean currently in flux, with climate change exerting pronounced effects on sea-ice coverage and freshwater inputs. How such changes will affect this ecosystem are poorly constrained. In this study, we characterized the bacterial community compositions at different depths in both coastal, freshwater-influenced, and pelagic, sea-ice-covered locations in the Beaufort Sea in the western Canadian Arctic Ocean. The environmental factors controlling the bacterial community composition and diversity were investigated. Alphaproteobacteria dominated the bacterial communities in samples from all depths and stations. The Pelagibacterales and Rhodobacterales groups were the predominant taxonomic representatives within the Alphaproteobacteria. Bacterial communities in coastal and offshore samples differed significantly, and vertical water mass segregation was the controlling factor of community composition among the offshore samples, regardless of the taxonomic level considered. These data provide an important baseline view of the bacterial community in this ocean system that will be of value for future studies investigating possible changes in the Arctic Ocean in response to global change and/or anthropogenic disturbance.
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McMonigal, K., Kathryn L. Gunn, Lisa M. Beal, Shane Elipot, and Josh K. Willis. "Reduction in Meridional Heat Export Contributes to Recent Indian Ocean Warming." Journal of Physical Oceanography 52, no. 3 (March 2022): 329–45. http://dx.doi.org/10.1175/jpo-d-21-0085.1.
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Abstract Since 2000, the Indian Ocean has warmed more rapidly than the Atlantic or Pacific Oceans. Air–sea fluxes alone cannot explain the rapid Indian Ocean warming, which has so far been linked to an increase in temperature transport into the basin through the Indonesian Throughflow (ITF). Here, we investigate the role that the heat transport out of the basin at 36°S plays in the warming. Adding the heat transport out of the basin to the ITF temperature transport into the basin, we calculate the decadal mean Indian Ocean heat budget over the 2010s. We find that heat convergence increased within the Indian Ocean over 2000–19. The heat convergence over the 2010s is of the same order as the warming rate, and thus the net air–sea fluxes are near zero. This is a significant change from previous analyses using transbasin hydrographic sections from 1987, 2002, and 2009, which all found divergences of heat. A 2-yr time series shows that seasonal aliasing is not responsible for the decadal change. The anomalous ocean heat convergence over the 2010s in comparison with previous estimates is due to changes in ocean currents at both the southern boundary (33%) and the ITF (67%). We hypothesize that the changes at the southern boundary are linked to an observed broadening of the Agulhas Current, implying that temperature and velocity data at the western boundary are crucial to constrain heat budget changes.
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Morée, Anne L., Jörg Schwinger, and Christoph Heinze. "Southern Ocean controls of the vertical marine <i>δ</i><sup>13</sup>C gradient – a modelling study." Biogeosciences 15, no. 23 (December 4, 2018): 7205–23. http://dx.doi.org/10.5194/bg-15-7205-2018.
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Abstract. δ13C, the standardised 13C ∕ 12C ratio expressed in per mille, is a widely used ocean tracer to study changes in ocean circulation, water mass ventilation, atmospheric pCO2, and the biological carbon pump on timescales ranging from decades to tens of millions of years. δ13C data derived from ocean sediment core analysis provide information on δ13C of dissolved inorganic carbon and the vertical δ13C gradient (i.e. Δδ13C) in past oceans. In order to correctly interpret δ13C and Δδ13C variations, a good understanding is needed of the influence from ocean circulation, air–sea gas exchange and biological productivity on these variations. The Southern Ocean is a key region for these processes, and we show here that Δδ13C in all ocean basins is sensitive to changes in the biogeochemical state of the Southern Ocean. We conduct a set of idealised sensitivity experiments with the ocean biogeochemistry general circulation model HAMOCC2s to explore the effect of biogeochemical state changes of the Southern and Global Ocean on atmospheric δ13C, pCO2, and marine δ13C and Δδ13C. The experiments cover changes in air–sea gas exchange rates, particulate organic carbon sinking rates, sea ice cover, and nutrient uptake efficiency in an unchanged ocean circulation field. Our experiments show that global mean Δδ13C varies by up to about ±0.35 ‰ around the pre-industrial model reference (1.2 ‰) in response to biogeochemical change. The amplitude of this sensitivity can be larger at smaller scales, as seen from a maximum sensitivity of about −0.6 ‰ on ocean basin scale. The ocean's oldest water (North Pacific) responds most to biological changes, the young deep water (North Atlantic) responds strongly to air–sea gas exchange changes, and the vertically well-mixed water (SO) has a low or even reversed Δδ13C sensitivity compared to the other basins. This local Δδ13C sensitivity depends on the local thermodynamic disequilibrium and the Δδ13C sensitivity to local POC export production changes. The direction of both glacial (intensification of Δδ13C) and interglacial (weakening of Δδ13C) Δδ13C change matches the direction of the sensitivity of biogeochemical processes associated with these periods. This supports the idea that biogeochemistry likely explains part of the reconstructed variations in Δδ13C, in addition to changes in ocean circulation.
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HANAWA, Kimio. "Ocean General Circulation and Climate Change." Journal of Geography (Chigaku Zasshi) 114, no. 3 (2005): 485–95. http://dx.doi.org/10.5026/jgeography.114.3_485.
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Shimmield, Graham. "Ocean Margin Processes in Global Change." Holocene 2, no. 2 (July 1992): 188. http://dx.doi.org/10.1177/095968369200200217.
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Buesseler, K. O. "CLIMATE CHANGE: Will Ocean Fertilization Work?" Science 300, no. 5616 (April 4, 2003): 67–68. http://dx.doi.org/10.1126/science.1082959.
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Pespeni, M. H., E. Sanford, B. Gaylord, T. M. Hill, J. D. Hosfelt, H. K. Jaris, M. LaVigne, et al. "Evolutionary change during experimental ocean acidification." Proceedings of the National Academy of Sciences 110, no. 17 (April 8, 2013): 6937–42. http://dx.doi.org/10.1073/pnas.1220673110.
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Martin, Ellen E. "Ocean circulation and rapid climate change." Nature 517, no. 7532 (December 15, 2014): 30–31. http://dx.doi.org/10.1038/nature14084.
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Levin, Lisa A., and Nadine Le Bris. "The deep ocean under climate change." Science 350, no. 6262 (November 12, 2015): 766–68. http://dx.doi.org/10.1126/science.aad0126.
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Vogt, M. "Adrift in an ocean of change." Science 350, no. 6267 (December 17, 2015): 1466–68. http://dx.doi.org/10.1126/science.aad6946.
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