scholarly journals Protection of Turbidity on Reefs along the Southeast Coast of the Kalimantan during the 2015 El Niño

2020 ◽  
Vol 8 (1) ◽  
pp. 45
Author(s):  
Suhaili Asmawi ◽  
Muhammad Ahsin Rifa'i ◽  
Idiannor Mahyudin ◽  
Muhammad Ruslan
Keyword(s):  
Thermal Stress ◽  
Coral Bleaching ◽  
El Niño ◽  
El Nino ◽  
Marine Ecosystem ◽  
Solar Irradiation ◽  
El Niño Event ◽  
Southeast Coast ◽  
Major Disaster ◽  
Turbid Zone

Coral reef, the most diverse and highly valuable marine ecosystem, may be influenced by bleaching. This study aimed to determine the effect of turbidity on the severity of coral bleaching and mortality due to thermal stress and high solar irradiation caused by the 2015 El Niño event. Coral colonies in eighteen permanent bleaching belt transects (50 m x 1 m) in six sites were observed from June to November 2015, coinciding with the 2015 El Niño event. Environmental factors: water depth, sea surface temperature (SST), salinity, turbidity, sedimentation and total suspended solid (TSS) were measured on the same transect. The results of the study showed that the 2015 El Niño event was a major disaster for reefs on the southeast coast of the Kalimantan. Of total colonies (N = 12,954), 45.4% of colonies were bleached and 14.7% of colonies died during the period of July to November 2015. Turbidity, TSS, and sedimentation were negatively correlated with the bleaching mortality index (BMI). Coral bleaching in clear and deep waters occurred earlier and increased rapidly compared to that in turbid waters. However, the severity of coral bleaching in the turbid zone increased dramatically when the turbidity dropped to <3 NTU. Turbidity >5 NTU could provide shade, in which the proportion of dead corals was only 3.5%. The severity of coral bleaching in the turbid zone is not solely due to thermal stress and solar irradiation; it may also be influenced by a history of exposure to high turbidity and low salinity.

scholarly journals Coral bleaching in the Caramuanas reef (Todos os Santos Bay, Brazil) during the 2010 El Niño event

2017 ◽  
Vol 41 (2) ◽  
pp. 351-360
Author(s):  
Ricardo J. Miranda ◽  
Igor C.S. Cruz ◽  
Zelinda M.A.N. Leão
Keyword(s):  
Coral Bleaching ◽  
El Niño ◽  
El Nino ◽  
Coral Cover ◽  
Enso Event ◽  
Sea Surface ◽  
Live Coral ◽  
Thermal Anomalies ◽  
El Niño Event ◽  
Disease Occurrence

Episodes of coral bleaching related to El Niño events have been increasing in frequency and severity. This phenomenon is cited as a major cause of degradation of coral reefs. This study evaluates the effects of coral bleaching on the Caramuanas reef community, which occurred during the southern hemisphere summer of 2009/2010. Within this period the sea surface temperature of 31°C and thermal anomalies up to almost 1°C were recorded. During and after this El Niño event, frequency and severity of bleaching, live coral cover, number of colonies, class size, disease occurrence, and mortality rate were monitored on corals larger than 20 cm in diameter. The samples were taken at twelve fixed transects, in three reef stations. Statistical analysis showed that the severity of bleaching was different between the two periods, during and after the 2010 ENSO event. The Caramuanas reef showed sublethal bleaching effects indicating that this reef is tolerant to bleaching when the temperature anomalies do not exceed 0.75°C within one week.

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 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.

scholarly journals Model study of the cross-tropopause transport of biomass burning pollution

2007 ◽  
Vol 7 (14) ◽  
pp. 3713-3736 ◽  
Author(s):  
B. N. Duncan ◽  
S. E. Strahan ◽  
Y. Yoshida ◽  
S. D. Steenrod ◽  
N. Livesey
Keyword(s):  
Biomass Burning ◽  
El Niño ◽  
Fossil Fuels ◽  
Extreme Event ◽  
El Nino ◽  
Deep Convection ◽  
Tropical Tropopause Layer ◽  
Tropical Tropopause ◽  
El Niño Event ◽  
The Impact

Abstract. We present a modeling study of the troposphere-to-stratosphere transport (TST) of pollution from major biomass burning regions to the tropical upper troposphere and lower stratosphere (UT/LS). TST occurs predominately through 1) slow ascent in the tropical tropopause layer (TTL) to the LS and 2) quasi-horizontal exchange to the lowermost stratosphere (LMS). We show that biomass burning pollution regularly and significantly impacts the composition of the TTL, LS, and LMS. Carbon monoxide (CO) in the LS in our simulation and data from the Aura Microwave Limb Sounder (MLS) shows an annual oscillation in its composition that results from the interaction of an annual oscillation in slow ascent from the TTL to the LS and seasonal variations in sources, including a semi-annual oscillation in CO from biomass burning. The impacts of CO sources that peak when ascent is seasonally low are damped (e.g. Southern Hemisphere biomass burning) and vice-versa for sources that peak when ascent is seasonally high (e.g. extra-tropical fossil fuels). Interannual variation of CO in the UT/LS is caused primarily by year-to-year variations in biomass burning and the locations of deep convection. During our study period, 1994–1998, we find that the highest concentrations of CO in the UT/LS occurred during the strong 1997–1998 El Niño event for two reasons: i. tropical deep convection shifted to the eastern Pacific Ocean, closer to South American and African CO sources, and ii. emissions from Indonesian biomass burning were higher. This extreme event can be seen as an upper bound on the impact of biomass burning pollution on the UT/LS. We estimate that the 1997 Indonesian wildfires increased CO in the entire TTL and tropical LS (>60 mb) by more than 40% and 10%, respectively, for several months. Zonal mean ozone increased and the hydroxyl radical decreased by as much as 20%, increasing the lifetimes and, subsequently TST, of trace gases. Our results indicate that the impact of biomass burning pollution on the UT/LS is likely greatest during an El Niño event due to favorable dynamics and historically higher burning rates.

Sign in / Sign up

Export Citation Format

Share Document