scholarly journals Transition to El Niño conditions in the eastern tropical Pacific in October 2015

2016 ◽  
Author(s):  
Lothar Stramma ◽  
Tim Fischer ◽  
Damian S. Grundle ◽  
Gerd Krahmann ◽  
Hermann W. Bange ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Galapagos Islands ◽  
Tropical Pacific ◽  
Nutrient Concentrations ◽  
Galápagos Islands ◽  
Eastern Tropical Pacific ◽  
Weak Current ◽  
Equatorial Undercurrent ◽  
Oxygen Concentrations

Abstract. A strong El Niño developed in early 2015. Measurements from a research cruise on the RV Sonne in October 2015 near the equator east of the Galapagos Islands and off the shelf of Peru, are used to investigate changes related to El Niño in the upper ocean in comparison with earlier cruises in this region. At the equator at 85°30’ W, a clear temperature increase leading to lower densities in the upper 350 m, despite a concurrent salinity increase from 40 to 350 m, developed in October 2015. Lower nutrient concentrations were also present in the upper 200 m, and higher oxygen concentrations were observed between 40 and 130 m. Except for the upper 60 m at 2°30’ S, however, there was no obvious increase in oxygen concentrations at sampling stations just north (1° N) and south (2°30’ S) of the equator at 85°30’ W. In the equatorial current field, the Equatorial Undercurrent (EUC) east of the Galapagos Islands almost disappeared in October 2015, with a transport of only 0.02 Sv in the equatorial channel between 1° S and 1° N, and a weak current band of 0.78 Sv located between 1° S and 2°30’ S. Such near-disappearances of the EUC in the eastern Pacific seem to occur only during strong El Niño events. Off the Peruvian shelf at ~9° S, where the sea surface temperature (SST) was elevated, upwelling was modified, and warm, saline and oxygen rich water was upwelled. Despite some weak El Niño related SST increase at ~12 to 16° S, the upwelling of cold, low salinity and oxygen-poor water was still active at the easternmost stations at three sections at ~12° S, ~14° S and ~16° S, while further west on these sections a transition to El Niño conditions appeared. Although in early 2015 the El Niño was strong and in October 2015 showed a clear El Niño influence on the EUC, in the eastern tropical Pacific the measurements only showed developing El Niño water mass distributions. In particular the oxygen distribution indicated the ongoing transition from ‘typical’ to El Niño conditions progressing southward along the Peruvian shelf.

scholarly journals Observed El Niño conditions in the eastern tropical Pacific in October 2015

Ocean Science ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 861-873 ◽  
Author(s):  
Lothar Stramma ◽  
Tim Fischer ◽  
Damian S. Grundle ◽  
Gerd Krahmann ◽  
Hermann W. Bange ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Galapagos Islands ◽  
Tropical Pacific ◽  
Nutrient Concentrations ◽  
Galápagos Islands ◽  
Eastern Tropical Pacific ◽  
Weak Current ◽  
Equatorial Undercurrent ◽  
Mass Distributions

Abstract. A strong El Niño developed in early 2015. Measurements from a research cruise on the R/V Sonne in October 2015 near the Equator east of the Galapagos Islands and off the shelf of Peru are used to investigate changes related to El Niño in the upper ocean in comparison with earlier cruises in this region. At the Equator at 85°30′ W, a clear temperature increase leading to lower densities in the upper 350 m had developed in October 2015, despite a concurrent salinity increase from 40 to 350 m. Lower nutrient concentrations were also present in the upper 200 m, and higher oxygen concentrations were observed between 40 and 130 m. In the equatorial current field, the Equatorial Undercurrent (EUC) east of the Galapagos Islands almost disappeared in October 2015, with a transport of only 0.02 Sv in the equatorial channel between 1° S and 1° N, and a weak current band of 0.78 Sv located between 1 and 2°30′ S. Such near-disappearances of the EUC in the eastern Pacific seem to occur only during strong El Niño events. Off the Peruvian shelf at  ∼  9° S, characteristics of upwelling were different as warm, saline, and oxygen-rich water was upwelled. At  ∼  12,  ∼  14, and  ∼  16° S, the upwelling of cold, low-salinity, and oxygen-poor water was still active at the easternmost stations of these three sections, while further west on these sections a transition to El Niño conditions appeared. Although from early 2015 the El Niño was strong, the October measurements in the eastern tropical Pacific only showed developing El Niño water mass distributions. In particular, the oxygen distribution indicated the ongoing transition from “typical” to El Niño conditions progressing southward along the Peruvian shelf.

scholarly journals The 2015-2016 El Niño increased infection parameters of copepods on Eastern Tropical Pacific dolphinfish populations

PLoS ONE ◽  
2020 ◽  
Vol 15 (5) ◽  
pp. e0232737
Author(s):  
Ana María Santana-Piñeros ◽  
Yanis Cruz-Quintana ◽  
Ana Luisa May-Tec ◽  
Geormery Mera-Loor ◽  
María Leopoldina Aguirre-Macedo ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Eastern Tropical Pacific ◽  
Infection Parameters

scholarly journals Effects of El Niño and La Niña Southern Oscillation events on the adrenocortical responses to stress in birds of the Galapagos Islands

2018 ◽  
Vol 259 ◽  
pp. 20-33 ◽  
Author(s):  
John C. Wingfield ◽  
Michaela Hau ◽  
P. Dee Boersma ◽  
L. Michael Romero ◽  
Nigella Hillgarth ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Galapagos Islands ◽  
La Niña ◽  
Galápagos Islands ◽  
La Nina ◽  
Adrenocortical Responses

El Nino and little ice age effects on upwelling in the eastern tropical pacific

1988 ◽  
Vol 70 (1-2) ◽  
pp. 198
Author(s):  
C.T. Shen ◽  
R.B. Dunbar ◽  
M.W. Colgan ◽  
P.W. Glynn
Keyword(s):  
El Niño ◽  
Little Ice Age ◽  
El Nino ◽  
Tropical Pacific ◽  
Age Effects ◽  
Ice Age ◽  
Eastern Tropical Pacific

scholarly journals Reproduction of the blue-footed booby predicts commercial fish abundance in the eastern tropical Pacific

2013 ◽  
Vol 70 (6) ◽  
pp. 1263-1272
Author(s):  
Juan Meraz ◽  
Sergio Ancona ◽  
Cristina Rodríguez ◽  
Hugh Drummond
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Fish Abundance ◽  
Sea Surface ◽  
Eastern Tropical Pacific ◽  
Prey Fish ◽  
Commercial Fish ◽  
Local Abundance ◽  
Two Factors

Abstract Meraz, J., Ancona, S., Rodríguez, C., and Drummond, H. 2013. Reproduction of the blue-footed booby predicts commercial fish abundance in the eastern tropical Pacific. – ICES Journal of Marine Science, 70: 1263–1272. To establish whether reproduction in a colony of the blue-footed booby in the eastern tropical Pacific predicts local abundance of prey fish several months later, 13 years of data were analysed. Eight reproductive variables assessed during the period of January–May, grouped in two factors, were related to commercial catches in the surrounding 6600 km2 area during the following June–December. The first factor explained 33% of interannual variance in fish captures per unit effort during June–December (future FCUE), and 63% when only El Niño years were considered. Also, the proportion of large clutches present on three single-day censuses in the spring explained 51, 46 and 35% of variance in future FCUE among all years, and 78, 85 and 82% of variance among El Niño years. In contrast, sea surface temperatures in March did not explain variance in future FCUE. Proportion of large clutches is a moderately good predictor of the abundance of commercial fish during the subsequent seven months and can be satisfactorily and cheaply measured on a single day.

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