Rising Sea Surface Temperatures Research Articles

Cosmogenic dating of Late Pleistocene glaciation, southern tropical Andes, Peru

ABSTRACTWe present 30 10Be dates on three moraines formed by small glaciers in the southern tropical Andes of Peru to determine the timing of the local Last Glacial Maximum (LGM) and subsequent deglaciation. Two terminal moraines indicate that the local LGM ended at 23.5 ± 0.5 and 21.2 ± 0.8 ka, or well before the end of the global LGM (20–19 ka). A recessional moraine perched at the base of a steep valley wall has a 10Be age of 19.8 ± 0.3 ka, suggesting that glaciers had largely retreated from the area during the earliest stages of the last termination and before the onset of the deglacial CO2 rise and increase in tropical sea surface temperatures. These ages generally agree with other tropical glacial chronologies and reflect a broad synchroneity between low‐ and high‐latitude deglaciation at the LGM, but the trigger for early deglaciation of the tropics remains unclear.

Rapid increase of observed DIC and pCO2 in the surface waters of the North Sea in the 2001-2011 decade ascribed to climate change superimposed by biological processes

The CO2 system in the North Sea over the 2001-2011 decade was investigated using four comprehensive basin-wide datasets covering the late summer periods of 2001, 2005, 2008 and 2011. We find that rises in surface water DIC and pCO2 exceeded concurrent rises in atmospheric pCO2, which we attribute primarily to biological activity in late summer. After accounting for this biological signal, the observed ocean acidification occurs at a rate that is consistent with concurrent atmospheric and open ocean CO2 increases over the 2001-2011 decade. Nevertheless, we do find a consistent reduction in CO2 undersaturation in the NNS and an increase in CO2 supersaturation in the SNS. We propose that the synergistic effects of increasing atmospheric pCO2 and subsequent decrease in seawater buffering capacity, together with rising sea surface temperatures in the future oceans, may reduce the strength of the North Sea as a CO2 sink. Such a reduction would diminish the efficiency of this region as a continental shelf pump with respect to uptake of CO2 by the sea. Ultimately this would constitute a positive feedback mechanism, i.e. enhancing the airborne fraction of anthropogenic CO2 and thus the net rate of increase of atmospheric pCO2 and subsequent global climate change.

Collapse of the echinoid Paracentrotus lividus populations in the Eastern Mediterranean--result of climate change?

The European purple sea urchin (Paracentrotus lividus) is considered to be a key herbivore throughout its distribution range—North-East Atlantic and Mediterranean Sea. It was also abundant in its eastern distributional edge, on rocky habitats of the coastline of Israel, but its populations have recently collapsed, and today it is an extremely rare species in the region. Field and laboratory experiments, that were carried out in order to examine the impact of the recent sea surface temperature rise in the Eastern Mediterranean, showed massive urchin mortality when temperatures crossed 30.5 °C before reaching peak summer values. These results suggest that elevated seawater temperatures in recent years may be a main cause for the disappearance of P. lividus from the southeast Mediterranean Sea, which may indicate distributional range contraction in this region.

Why is the Bay of Bengal experiencing a reduced rate of sea surface warming?

ABSTRACTThe sea surface temperature (SST) in the Bay of Bengal (BoB) during the period 1960–1995 showed a decadal cycle, riding over a warming trend. The disruption of the decadal cycle was noticed post‐1995 and was followed by a slowdown in the sea surface warming. The cause for the disruption of the SST decadal cycle was the weakening of the link between SST and sunspot number. The rising trend in the SST is due to the increasing atmospheric CO2 concentration. The post‐1995 SST slowdown was due to the increasing influence of the number of depressions, cyclones and severe cyclones in the BoB, the occurrence of which showed an upward trend. Using Price–Weller–Pinkel model we show that cyclonic systems deepen the mixed‐layer through enhanced mechanical‐mixing with cooler sub‐surface waters, thereby reducing the mixed‐layer temperature and consequently the SST. This process opposes the SST rise due to increasing atmospheric CO2 concentration. The net effect of the wind‐mixing caused by the increased number of depressions, cyclones and severe cyclones and the increased CO2 concentration is a SST slowdown in the BoB. This mechanism differs from the SST slowdown mechanisms suggested for the Atlantic and the Pacific.

Impact of autumn SST in the Japan Sea on winter rainfall and air temperature in Northeast China

We studied the impact of sea surface temperature anomaly (SSTA) in the Japan Sea and the sea area east of Japan on the winter rainfall and air temperature in Northeast (NE) China using the singular value decomposition (SVD) and empirical orthogonal function (EOF). The monthly-mean rainfall data observed at 160 stations in China, monthly-mean sea surface temperature (SST) of the Hadley Center for Climate Prediction and Research and monthly-mean air temperature from the NCEP reanalysis during 1960–2011 were used. Correlation analysis indicates that the SSTAs in the Japan Sea in September may last for three or four months and are an important index for forecasting the winter rainfall and air temperature in NE China. Positive SSTAs in the central Japan Sea and in the sea area east of Tokyo correspond to positive rainfall anomaly and negative air temperature anomaly in NE China. With the rise of SST in the Japan Sea, a weak cyclone appears over the Japan Sea. The northeasterly wind transports water vapor from the Okhotsk to NE China, resulting in more rainfall and lower air temperature. Negative SSTA years are accompanied by warmer air temperature and less snow in NE China. The 1000 hPa geopotential height anomaly and wind anomaly fields are simulated by IAP-9L model, which supports the analysis results.

Effects of Global Warming on Vibrio Ecology.

Vibrio-related infections are increasing worldwide both in humans and aquatic animals. Rise in global sea surface temperature (SST), which is approximately 1 °C higher now than 140 years ago and is one of the primary physical impacts of global warming, has been linked to such increases. In this chapter, major known effects of increasing SST on the biology and ecology of vibrios are described. They include the effects on bacterial growth rate, both in the field and in laboratory, culturability, expression of pathogenicity traits, and interactions with aquatic organisms and abiotic surfaces. Special emphasis is given to the effect of ocean warming on Vibrio interactions with zooplankters, which represent one of the most important aquatic reservoirs for these bacteria. The reported findings highlight the biocomplexity of the interactions between vibrios and their natural environment in a climate change scenario, posing the need for interdisciplinary studies to properly understand the connection between ocean warming and persistence and spread of vibrios in sea waters and the epidemiology of the diseases they cause.

Relationship of convective precipitation with atmospheric heat flux — A regression approach over an Indian tropical location

The response of atmospheric heat fluxes and sea surface temperatures on the convective precipitation over the tropics has been an important area of research in recent decades. A long-term observation (1979–2008) of the increase in convective precipitation in relation to the latent and sensible heat fluxes on a tropical location, Kolkata, has been investigated in the present study. Invigoration of convective precipitation has been caused by vertically integrated divergence of moisture flux, rise in sea surface temperatures, convective cloud cover and surface evaporation rate over the tropical region. A convective precipitation estimation (CPE) index is proposed, considering the Bowen ratio, surface evaporation rate, sea surface temperature and temperatures at 500hpa pressure level during the pre-monsoon season (March–May), to estimate the amount of convective precipitation over the tropics using multiple linear regression technique is also another aim of this study. A good agreement is obtained between the results from the proposed model and the MERRA observations during the years 2009–2013.

Adapting to a warmer ocean--seasonal shift of baleen whale movements over three decades.

Global warming poses particular challenges to migratory species, which face changes to the multiple environments occupied during migration. For many species, the timing of migration between summer and winter grounds and also within-season movements are crucial to maximise exploitation of temporarily abundant prey resources in feeding areas, themselves adapting to the warming planet. We investigated the temporal variation in the occurrence of fin (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) in a North Atlantic summer feeding ground, the Gulf of St. Lawrence (Canada), from 1984 to 2010 using a long-term study of individually identifiable animals. These two sympatric species both shifted their date of arrival at a previously undocumented rate of more than 1day per year earlier over the study period thus maintaining the approximate 2-week difference in arrival of the two species and enabling the maintenance of temporal niche separation. However, the departure date of both species also shifted earlier but at different rates resulting in increasing temporal overlap over the study period indicating that this separation may be starting to erode. Our analysis revealed that the trend in arrival was strongly related to earlier ice break-up and rising sea surface temperature, likely triggering earlier primary production. The observed changes in phenology in response to ocean warming are a remarkable example of phenotypic plasticity and may partly explain how baleen whales were able to survive a number of changes in climate over the last several million years. However, it is questionable whether the observed rate of change in timing can be maintained. Substantial modification to the distribution or annual life cycle of these species might be required to keep up with the ongoing warming of the oceans.

First record of Dichotomaria obtusata (Ellis & Solander) Lamarck (Nemaliales, Rhodophyta) in the Mediterranean Sea

Global climate change is causing the Mediterranean coastal area of Israel to gradually acquire tropical characteristics. Rising sea surface temperatures in the eastern Mediterranean basin have facilitated the introduction, settlement and establishment of hundreds of alien species (Zenetos et al. 2012). The vast majority of these exotic species are of Indo-Pacific origin. We report the occurrence of the genus Dichotomaria in the eastern Mediterranean on the basis of specimens identified as Dichotomaria cf. obtusata (J. Ellis & Solander) Lamarck. Tetrasporophytes with sporangial initials were identified morphologically and confirmed molecularly using plastid rbcL sequences. We also discuss possible paths of introduction of this and other alien species into the Levantine Sea.

Water column productivity and temperature predict coral reef regeneration across the Indo-Pacific.

Predicted increases in seawater temperatures accelerate coral reef decline due to mortality by heat-driven coral bleaching. Alteration of the natural nutrient environment of reef corals reduces tolerance of corals to heat and light stress and thus will exacerbate impacts of global warming on reefs. Still, many reefs demonstrate remarkable regeneration from past stress events. This paper investigates the effects of sea surface temperature (SST) and water column productivity on recovery of coral reefs. In 71 Indo-Pacific sites, coral cover changes over the past 1-3 decades correlated negative-exponentially with mean SST, chlorophyll a, and SST rise. At six monitoring sites (Persian/Arabian Gulf, Red Sea, northern and southern Galápagos, Easter Island, Panama), over half of all corals were <31 years, implying that measured environmental variables indeed shaped populations and community. An Indo-Pacific-wide model suggests reefs in the northwest and central Indian Ocean, as well as the central west Pacific, are at highest risk of degradation, and those at high latitudes the least. The model pinpoints regions where coral reefs presently have the best chances for survival. However, reefs best buffered against temperature and nutrient effects are those that current studies suggest to be most at peril from future ocean acidification.

Species-specific differences in thermal tolerance may define susceptibility to intracellular acidosis in reef corals

It is widely acknowledged that temperature stress affects an organism’s sensitivity to ocean acidification and vice versa, yet it is not clear how the two are mechanistically linked. Here, we induced thermal stress in two coral species with differing bleaching susceptibilities to measure how a reduction in photosynthetic performance impacts intracellular pH (pHi) regulation in the symbiotic dinoflagellates (Symbiodinium sp.) and their host coral cells. Our hypothesis was that thermally induced photosynthetic dysfunction in the symbiont would prevent the efficient removal of additional CO2, lowering its buffering capacity and thus increasing the host cell’s susceptibility to intracellular acidosis. To test this, we exposed Pocillopora damicornis (a thermally sensitive coral) and Montipora capitata (a thermally resilient coral) to four different temperature treatments (23.8, 25.5, 28 and 31 °C) for 1 week. We then isolated intact symbiotic coral endodermal cells, placed them in a live-cell chamber attached to a confocal microscope and bathed them in CO2-acidified seawater (~pH 7.6) for 30 min, before measuring the light-adapted pHi of both the host cell and its symbiont. Cells isolated from P. damicornis were more prone to cellular acidosis (declines in pHi of 11 and 8 % in host and symbiont, respectively, at 31 °C relative to 23.8 °C) than cells isolated from M. capitata (5 and 4 %, respectively). These results highlight the important role of Symbiodinium productivity (in addition to a range of physico-chemical factors such as skeletal morphology and tissue pigmentation) in determining the sensitivity of corals to rising sea surface temperatures and ocean acidification.

Winter mixing and coastal upwelling drive long-term changes in zooplankton in the Bay of Biscay (1993–2010)

Long-term studies are necessary to gain insight into the influence of external climate forcing on zooplankton dynamics. Using monthly time series (1993–2010) collected in the Cantabrian Sea (southern Bay of Biscay), we studied long-term trends and seasonal cycles of zooplankton abundance and biomass along a coastal-ocean gradient. We also analysed changes in environmental variables such as sea surface temperature (SST) and chlorophyll a concentration. Zooplankton abundance and biomass increased during the study period, with greater increases in biomass towards the coast and for larger size classes. These results contrast with the decrease in biomass and size expected under global warming, which is shown in the region by the rise in summer SST, suggesting the operation of other processes. Indeed, winter mixing and coastal upwelling were key drivers of zooplankton dynamics in spring and autumn, respectively. In these seasons, zooplankton inter-annual increases were stronger. Including these hydrographic processes in future models of zooplankton dynamics for the Bay of Biscay and other temperate areas will improve their accuracy. Our results highlight the importance of disentangling the main mechanisms behind long-term changes in zooplankton, especially within the context of climate change.

Study of Impact of Climatic Variability on the Sea Surface Temperature and Chlorophyll-a Concentration Using Statistical Analysis on Satellite Derived Data for the Arabian Sea

The impact of long term variation in sea surface temperature (SST) on marine biomass using long-term satellite remote sensing data (1985 - 2006) for SST and (1998 – 2010) for chlorophyll-a was studies. This paper presents the result of the analysis conducted on t wenty one year’s data on high-quality satellite derived Sea Surface Temperature, and twelve years SeaWiFS chlorophyll-a data from Arabian Sea. The results are extracted after processing the data using statistical methods for computation of inter-annual seasonal mean and standard deviation. The mean winter data show that region consisting on Gulf of Oman is colder (< 21 o C) than the rest of Arabian Sea. However, annual mean of winter show the intermittent rise and fall in SST in response to El-Nino occurred in 1986, 1988, 1991–1995, 1997-1998, 2002, 2006 and La-Nino events which occurred in 1985, 1986, 1989, 1996, 1999 and 2000 years. The results of SST means for summer and Post-Summer seasons differ from the phenomenon observed in winter and Pre-Summer. During summer, SST of major part of the western Arabian Sea lower to 15 o C under the influence of up-welled water off Somalia and Oman coast. The results of chlorophyll-a concentration depict the increase of concentration with the lowering of SST in the area of northern Arabian Sea. Similar results are obtained for standard deviation computations of both parameters of sea surface during winter monsoon season. Whereas, the results of Standard Deviation for summer monsoon show the minimum values (<1) in the northern and central Arabian Sea and maximum in the alignment of zone under Ekman process. The comparison with temperature confirms the dependency of productivity of the sea surface.

Projected SST trends across the Caribbean Sea based on PRECIS downscaling of ECHAM4, under the SRES A2 and B2 scenarios

The Caribbean Sea and adjacent land areas are highly sensitive to the projected impacts of global climate change. The countries bordering the Caribbean Sea depend heavily on coastal and marine assets as a major source of livelihood support. Rising sea surface temperatures (SSTs) are known to be associated with coral bleaching, ocean acidification, and other phenomena that threaten livelihoods in the region. The paucity of SST systematic observations in both the Caribbean Sea and adjoining Western Atlantic waters is a limiting factor in the projection of future climate change impacts on the region’s marine resources. Remote sensing of SST by satellites began only within the last three decades and although the data collected so far might be insufficient to provide conclusive definitions of long-term SST variations in the Caribbean waters, these data along with the output from climate model simulations provide a useful basis for gaining further insights into plausible SST futures under IPCC SRES scenarios. In this paper, we examine the recent SST records from the NESDIS AVHRR satellite data and NOAA Optimum Interpolation (OI) sea surface temperature V2 and provide a comparative analysis of projected SST changes for the Caribbean Sea up to the end of the twenty-first century, under the SRES A2 and B2 scenarios’ simulations of the sea surface skin temperatures (SSsT) using the Hadley Centre’s regional model, PRECIS. The implications of these projected SST changes for bleaching of coral reefs, one of the region’s most valuable marine resource, and for rainfall are also discussed.

Mosquito control pesticides and sea surface temperatures have differential effects on the survival and oxidative stress response of coral larvae.

The declining health of coral reefs is intensifying worldwide at an alarming rate due to the combined effects of land-based sources of pollution and climate change. Despite the persistent use of mosquito control pesticides in populated coastal areas, studies examining the survival and physiological impacts of early life-history stages of non-targeted marine organisms are limited. In order to better understand the combined effects of mosquito pesticides and rising sea surface temperatures, we exposed larvae from the coral Porites astreoides to selected concentrations of two major mosquito pesticide ingredients, naled and permethrin, and seawater elevated +3.5°C. Following 18-20h of exposure, larvae exposed to naled concentrations of 2.96µgL(-1) or greater had significantly reduced survivorship compared to controls. These effects were not detected in the presence of permethrin or elevated temperature. Furthermore, larval settlement, post-settlement survival and zooxanthellae density were not impacted by any treatment. To evaluate the sub-lethal stress response of larvae, several oxidative stress endpoints were utilized. Biomarker responses to pesticide exposure were variable and contingent upon pesticide type as well as the specific biomarker being employed. In some cases, such as with protein carbonylation and catalase gene expression, the effects of naled exposure and temperature were interactive. In other cases pesticide exposure failed to induce any sub-lethal stress response. Overall, these results demonstrate that P.astreoides larvae have a moderate degree of resistance against short-term exposure to ecologically relevant concentrations of pesticides even in the presence of elevated temperature. In addition, this work highlights the importance of considering the complexity and differential responses encountered when examining the impacts of combined stressors that occur on varying spatial scales.

Inter-Annual Variability of Fledgling Sex Ratio in King Penguins.

As the number of breeding pairs depends on the adult sex ratio in a monogamous species with biparental care, investigating sex-ratio variability in natural populations is essential to understand population dynamics. Using 10 years of data (2000–2009) in a seasonally monogamous seabird, the king penguin (Aptenodytes patagonicus), we investigated the annual sex ratio at fledging, and the potential environmental causes for its variation. Over more than 4000 birds, the annual sex ratio at fledging was highly variable (ranging from 44.4% to 58.3% of males), and on average slightly biased towards males (51.6%). Yearly variation in sex-ratio bias was neither related to density within the colony, nor to global or local oceanographic conditions known to affect both the productivity and accessibility of penguin foraging areas. However, rising sea surface temperature coincided with an increase in fledging sex-ratio variability. Fledging sex ratio was also correlated with difference in body condition between male and female fledglings. When more males were produced in a given year, their body condition was higher (and reciprocally), suggesting that parents might adopt a sex-biased allocation strategy depending on yearly environmental conditions and/or that the effect of environmental parameters on chick condition and survival may be sex-dependent. The initial bias in sex ratio observed at the juvenile stage tended to return to 1∶1 equilibrium upon first breeding attempts, as would be expected from Fisher’s classic theory of offspring sex-ratio variation.

Integrated Research Approaches to Coastal Zone Management

Coastal zones around the world are extremely vulnerable today because of the unprecedented pressures of industrial and urban development as well as climate change related devastations, such as the growing intensities of cyclonic storms, the rise in sea surface temperature, sea surges, and sea level rise. In India, where about 35% of the population lives within 100 kilometers of the coastline, fisheries are a major driver and safety net for economic development and coastal livelihoods. Coastal ecosystems are closely linked with socio‐economic systems, which require carefully planned coastal zone management (CZM) actions.

Multidecadal spatial reorganisation of plankton communities in the North East Atlantic

Changes in the spatial distribution of plankton populations are thought to have a profound effect on the oceanic ecosystem across all levels. This study aims to address how the spatial distribution of different plankton assemblages has changed over a multidecadal period. The multivariate structure on the CPR dataset is analysed using a technique called sparse principal component analysis. We identify functional groups of species and show that there have been changes in the ecoregions in the North East Atlantic over a multidecadal period. This technique is data-driven and can be used to identify biologically defined ecoregions based on dominant assemblages from the dataset without relying on prior knowledge. Whilst there is a change in ecoregions across time for both zooplankton and diatoms, the nature of the changes differs for the two assemblages. For zooplankton species there has been a shift in the ecoregions towards higher latitudes, implying that cold water zooplankton have moved further into arctic waters. For species that were previously restricted to the south of the region, these have been identified with increasing frequency further north. The change in spatial distribution for different species assemblages can be attributed to different factors. For example, the primary driver of zooplankton abundance across all spatial locations appears to be temperature. It is speculated that the observed northward movement of zooplankton species is a response to rising sea surface temperatures. The abundance of diatom species is instead highly correlated with the Atlantic Multidecadal Oscillation (AMO), with the spatial patterns becoming more clearly defined in its positive phase. For the diatom species, changes may be cyclic and so mean reverting to a certain extent, but for the zooplankton, continued changes can be expected if the current warming trend continues.

Interplay between proteases and protease inhibitors in the sea fan—Aspergillus pathosystem

Environmental conditions greatly impact the dynamics of host–pathogen relationships, affecting outbreaks and emergence of new diseases. In corals, epizootics have been a main contributor to the decline of reef ecosystems and rising sea surface temperatures associated with climate change are thought to exacerbate virulence of pathogens and/or compromise the immune responses of coral hosts. Among pathogens strategies, protease secretion is a common virulence factor that promotes colonization of the host. As such, protease inhibitors play an invaluable role to the host for protection against pathogen invasion. This study describes changes in activity of proteases secreted by the fungal pathogen, Aspergillus sydowii, and protease inhibitors of Gorgonia ventalina under ambient and elevated temperatures and health conditions (disease and healthy). G. ventalina colonies were collected from Florida Keys, Florida (24° 34.138N, 81° 22.905W) or La Parguera, Puerto Rico (17° 56.091N, 67° 02.577W) in 2007 and 2012, respectively. At elevated temperatures, protease activity was significantly higher than at ambient temperatures in A. sydowii. Temperature stress did not induce a change in protease inhibitor activity, but in healthy G. ventalina colonies, inhibitor activity against proteases was higher than in diseased individuals. Healthy colonies appear capable of resisting proteolytic activity, but diseased individuals are still likely affected by pathogen infections. These data suggest that rising sea surface temperatures due to climate change may increase levels of virulence (protease activity) of A. sydowii, while immunity (protease inhibitor) of G. ventalina may not be affected.

Numerieal prediction of storm surge in the Qingdao area under the impact of climate change

A typhoon-induced storm surge simulation system was developed for the Qingdao area, including a typhoon diagnostic model for the generation of wind and pressure fields and a 2D Advanced Circulation (ADCIRC) model for simulating the associated storm surge with a 200 m resolution along the Qingdao coastline. The system was validated by an extreme surge event Typhoon Mamie (8509) and the parameters of Typhoon Mamie were used to investigate the sensitivity of typhoon paths to Qingdao storm surges with four selected paths: the paths of Typhoons Mamie (8509), Opal, 3921 and 2413, the selection being made according to their relative position to Qingdao. Experiments based on the Typhoon Mamie (8509) storm surge were also conducted to study the possible influences of future climate changes, including the sea level rise and sea surface temperature (SST) rise, on storm surges along the Qingdao coast. Storm surge conditions under both present day and future (the end of the 21st century) climate scenarios associated with the four selected paths were simulated. The results show that with the same intensity, when typhoons follow the paths of 3921 and 2413, they would lead to the most serious disasters in different areas of Qingdao. Sea level and SST affect storm surges in different ways: sea level rise affects storm surge mainly through its influence on the tide amplitude, while the increased SST has direct impact on the intensity of the surges. The possible maximum risk of storm surges in 2100 in the Qingdao area caused by typhoons like Mamie (8509) was also estimated in this study.