The 1982–1983 El Niño event recorded in dentinal growth layers in teeth of Peruvian dusky dolphins (Lagenorhynchus obscurus)

1989 ◽  
Vol 67 (9) ◽  
pp. 2120-2125 ◽  
Author(s):  
Silvia R. Manzanilla
Keyword(s):  
El Niño ◽  
El Nino ◽  
Environmental Influence ◽  
Climatic Conditions ◽  
Convincing Evidence ◽  
Lagenorhynchus Obscurus ◽  
El Niño Event ◽  
Engraulis Ringens ◽  
Dusky Dolphins

Dusky dolphins (Lagenorhynchus obscurus) recorded the effects of the 1982–1983 El Niño event in the form of anomalous dentine deposited during 1983. This anomaly, which I call the El Niño mark (ENM), consists of a pair of hypocalcified incremental layers about 75 μm in width, located within the 1983 growth layer group. The anomaly was present in 15 of 18 mature females, 1 of 9 immature females, and only 1 of 14 mature and immature males. Teeth from other species inhabiting the upwelling system were examined and revealed no ENM. Dusky dolphins feed primarily on anchoveta (Engraulis ringens), the stocks of which collapsed during the 1983 El Niño; this collapse severely affected other anchoveta predators. It is possible that the ENM reflects the presumably low foraging success experienced by dusky dolphins in 1983. However, it is unclear why the ENM is present in most mature females and absent from most male specimens. The discovery of the El Niño mark in dusky dolphins provides the first convincing evidence in odontocete cetaceans of a direct environmental influence on the mineral quality of dentine deposited during a period of markedly abnormal climatic conditions.

Analyzing Fish Condition Factor Index Through Skew-Gaussian Information Theory Quantifiers

2016 ◽  
Vol 15 (02) ◽  
pp. 1650013 ◽  
Author(s):  
Javier E. Contreras-Reyes
Keyword(s):  
Time Series ◽  
El Niño ◽  
Shape Parameter ◽  
Condition Factor ◽  
El Nino ◽  
The Body ◽  
Northern Coast ◽  
Threshold Autoregressive ◽  
El Niño Event ◽  
Engraulis Ringens

Biological-fishery indicators have been widely studied. As such the condition factor (CF) index, which interprets the fatness level of a certain species based on length and weight, has been investigated, too. However, CF has been studied without considering its temporal features and distribution. In this paper, we analyze the CF time series via skew-gaussian distributions that consider the asymmetry produced by extreme events. This index is characterized by a threshold autoregressive model and corresponds to a stationary process depending on the shape parameter of the skew-gaussian distribution. Then we use the Jensen–Shannon (JS) distance to compare CF by length classes. This distance has mathematical advantages over other divergences such as Kullback–Leibler and Jeffrey’s, and the triangular inequality property. Our results are applied to a biological catalogue of anchovy (Engraulis ringens) from the northern coast of Chile, for the period 1990–2010 that consider monthly CF time series by length classes and sex. We find that for high values of shape parameter, JS distance tends to be more sensible to detect discrepancies than Jeffrey’s divergence. In addition, the body condition of male anchovies with higher lengths coincides with the ending of the moderate-strong El Niño event 91–92 and for both males and females, the smaller lengths coincide with the beginning of the strong El Niño event 97–98.

scholarly journals Tropical forests did not recover from the strong 2015–2016 El Niño event

2020 ◽  
Vol 6 (6) ◽  
pp. eaay4603 ◽  
Author(s):  
Jean-Pierre Wigneron ◽  
Lei Fan ◽  
Philippe Ciais ◽  
Ana Bastos ◽  
Martin Brandt ◽  
...  
Keyword(s):  
Tropical Forests ◽  
El Niño ◽  
El Nino ◽  
Low Frequency ◽  
Climatic Conditions ◽  
Carbon Stocks ◽  
Severe Drought ◽  
Carryover Effects ◽  
El Niño Event ◽  
Tropical Vegetation

Severe drought and extreme heat associated with the 2015–2016 El Niño event have led to large carbon emissions from the tropical vegetation to the atmosphere. With the return to normal climatic conditions in 2017, tropical forest aboveground carbon (AGC) stocks are expected to partly recover due to increased productivity, but the intensity and spatial distribution of this recovery are unknown. We used low-frequency microwave satellite data (L-VOD) to feature precise monitoring of AGC changes and show that the AGC recovery of tropical ecosystems was slow and that by the end of 2017, AGC had not reached predrought levels of 2014. From 2014 to 2017, tropical AGC stocks decreased by 1.31.21.5 Pg C due to persistent AGC losses in Africa (−0.9−1.1−0.8 Pg C) and America (−0.5−0.6−0.4 Pg C). Pantropically, drylands recovered their carbon stocks to pre–El Niño levels, but African and American humid forests did not, suggesting carryover effects from enhanced forest mortality.

scholarly journals Species-Specific Shifts in Diurnal Sap Velocity Dynamics and Hysteretic Behavior of Ecophysiological Variables During the 2015–2016 El Niño Event in the Amazon Forest

2019 ◽  
Vol 10 ◽  
Author(s):  
Bruno O. Gimenez ◽  
Kolby J. Jardine ◽  
Niro Higuchi ◽  
Robinson I. Negrón-Juárez ◽  
Israel de Jesus Sampaio-Filho ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Hysteretic Behavior ◽  
Amazon Forest ◽  
El Niño Event ◽  
Species Specific

scholarly journals Declines and recovery in endangered Galapagos pinnipeds during the El Niño event

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Diego Páez-Rosas ◽  
Jorge Torres ◽  
Eduardo Espinoza ◽  
Adrian Marchetti ◽  
Harvey Seim ◽  
...  
Keyword(s):  
El Niño ◽  
Environmental Variability ◽  
El Nino ◽  
Population Decline ◽  
Annual Rate ◽  
Population Fluctuations ◽  
Galapagos Archipelago ◽  
Population Decrease ◽  
El Niño Event ◽  
Zalophus Wollebaeki

AbstractCurrently, the Galapagos sea lion (GSL, Zalophus wollebaeki) and Galapagos fur seal (GFS, Arctocephalus galapagoensis) are among the most important endemic species for conservation in the Galapagos Archipelago. Both are classified as “Endangered” since their populations have undergone drastic declines over the last several decades. In this study we estimated the abundance of both otariids, and their population trends based using counts conducted between 2014 and 2018 in all their rookeries, and we analyzed the influence of environmental variability on pup production. The GSL population size in 2018 in the archipelago was estimated to be between 17,000 to 24,000 individuals and has increased at an average annual rate of 1% over the last five years after applying correction factors. The highest number of GSL counted in the archipelago was in 2014 followed by a population decline of 23.8% in 2015 that was associated with the El Niño event that occurred during that year. Following this event, the population increased mainly in the northern, central and southeastern rookeries. The GSL pup abundance showed a decreasing trend with the increase in intensity of the El Niño. The GFS population in 2018 was counted in 3,093 individuals and has increased at an annual rate of 3% from 2014 to 2018. A high number of GFS counted in 2014 was followed by a population decrease of 38% in 2015, mainly in the western rookeries. There was interannual population fluctuations and different growth trends among regions of the archipelago. GSL and GFS pup abundance has a strong decreasing tendency with the increase in the subthermocline temperature (ST) and the El Niño 1 + 2 index. Our results provide evidence that both species are highly vulnerable to periodic oceanographic-atmospheric events in the Galapagos Archipelago which impact prey abundance and the flow of energy in the unique Galapagos ecosystem.

scholarly journals Impact of the 2015 El Nino event on winter air quality in China

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Luyu Chang ◽  
Jianming Xu ◽  
Xuexi Tie ◽  
Jianbin Wu
Keyword(s):  
Air Quality ◽  
El Niño ◽  
El Nino ◽  
El Niño Event

Summer Cooling Driven by Large Volcanic Eruptions over the Tibetan Plateau

2018 ◽  
Vol 31 (24) ◽  
pp. 9869-9879 ◽  
Author(s):  
Jianping Duan ◽  
Lun Li ◽  
Zhuguo Ma ◽  
Jan Esper ◽  
Ulf Büntgen ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
El Niño ◽  
El Nino ◽  
Volcanic Eruptions ◽  
The Tibetan Plateau ◽  
Temperature Deviation ◽  
El Niño Event ◽  
El Niño Events ◽  
Large Volcanic Eruptions ◽  
El Nino Events

Large volcanic eruptions may cause abrupt summer cooling over large parts of the globe. However, no comparable imprint has been found on the Tibetan Plateau (TP). Here, we introduce a 400-yr-long temperature-sensitive network of 17 tree-ring maximum latewood density sites from the TP that demonstrates that the effects of tropical eruptions on the TP are generally greater than those of extratropical eruptions. Moreover, we found that large tropical eruptions accompanied by subsequent El Niño events caused less summer cooling than those that occurred without El Niño association. Superposed epoch analysis (SEA) based on 27 events, including 14 tropical eruptions and 13 extratropical eruptions, shows that the summer cooling driven by extratropical eruptions is insignificant on the TP, while significant summer temperature decreases occur subsequent to tropical eruptions. Further analysis of the TP August–September temperature responses reveals a significant postvolcanic cooling only when no El Niño event occurred. However, there is no such cooling for all other situations, that is, tropical eruptions together with a subsequent El Niño event, as well as extratropical eruptions regardless of the occurrence of an El Niño event. The averaged August–September temperature deviation ( Tdev) following 10 large tropical eruptions without a subsequent El Niño event is up to −0.48° ± 0.19°C (with respect to the preceding 5-yr mean), whereas the temperature deviation following 4 large tropical eruptions with an El Niño association is approximately 0.23° ± 0.16°C. These results indicate a mitigation effect of El Niño events on the TP temperature response to large tropical eruptions. The possible mechanism is that El Niño events can weaken the Indian summer monsoon with a subsequent decrease in rainfall and cooling effect, which may lead to a relatively high temperature on the TP, one of the regions affected by the Indian summer monsoon.

scholarly journals Global warming in Amazonia: impacts and Mitigation

2009 ◽  
Vol 39 (4) ◽  
pp. 1003-1011 ◽  
Author(s):  
Philip Martin Fearnside
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Forest Fires ◽  
El Niño ◽  
El Nino ◽  
Cost Effective ◽  
Climatic Conditions ◽  
Carbon Accounting ◽  
Amazon Forest ◽  
Temperature Oscillations

Global warming has potentially catastrophic impacts in Amazonia, while at the same time maintenance of the Amazon forest offers one of the most valuable and cost-effective options for mitigating climate change. We know that the El Niño phenomenon, caused by temperature oscillations of surface water in the Pacific, has serious impacts in Amazonia, causing droughts and forest fires (as in 1997-1998). Temperature oscillations in the Atlantic also provoke severe droughts (as in 2005). We also know that Amazonian trees die both from fires and from water stress under hot, dry conditions. In addition, water recycled through the forest provides rainfall that maintains climatic conditions appropriate for tropical forest, especially in the dry season. What we need to know quickly, through intensified research, includes progress in representing El Niño and the Atlantic oscillations in climatic models, representation of biotic feedbacks in models used for decision-making about global warming, and narrowing the range of estimating climate sensitivity to reduce uncertainty about the probability of very severe impacts. Items that need to be negotiated include the definition of "dangerous" climate change, with the corresponding maximum levels of greenhouse gases in the atmosphere. Mitigation of global warming must include maintaining the Amazon forest, which has benefits for combating global warming from two separate roles: cutting the flow the emissions of carbon each year from the rapid pace of deforestation, and avoiding emission of the stock of carbon in the remaining forest that can be released by various ways, including climate change itself. Barriers to rewarding forest maintenance include the need for financial rewards for both of these roles. Other needs are for continued reduction of uncertainty regarding emissions and deforestation processes, as well as agreement on the basis of carbon accounting. As one of the countries most subject to impacts of climate change, Brazil must assume the leadership in fighting global warming.

scholarly journals Roles of initial ocean surface and subsurface states on successfully predicting 2006–2007 El Niño with an intermediate coupled model

Ocean Science ◽  
2015 ◽  
Vol 11 (1) ◽  
pp. 187-194 ◽  
Author(s):  
F. Zheng ◽  
J. Zhu
Keyword(s):  
El Niño ◽  
El Nino ◽  
Surface Condition ◽  
Coupled Model ◽  
Ocean Surface ◽  
Sea Surface ◽  
Initial Surface ◽  
El Niño Event ◽  
Successful Prediction ◽  
Intermediate Coupled Model

Abstract. The 2006–2007 El Niño event, an unusually weak event, was predicted by most models only after the warming in the eastern Pacific had commenced. In this study, on the basis of an El Niño prediction system, roles of the initial ocean surface and subsurface states on predicting the 2006–2007 El Niño event are investigated to determine conditions favorable for predicting El Niño growth and are isolated in three sets of hindcast experiments. The hindcast is initialized through assimilation of only the sea surface temperature (SST) observations to optimize the initial surface condition, only the sea level (SL) data to update the initial subsurface state, or both the SST and SL data. Results highlight that the hindcasts with three different initial states can all successfully predict the 2006–2007 El Niño event 1 year in advance and that the hindcast initialized by both the SST and SL data performs best. A comparison between the various sets of hindcast results further demonstrates that successful prediction is more significantly affected by the initial subsurface state than by the initial surface condition. The accurate initial surface state can trigger the easier prediction of the 2006–2007 El Niño, whereas a more reasonable initial subsurface state can contribute to improving the prediction in the growth of the warm event.

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