scholarly journals Protistan plankton communities in the Galapagos Archipelago respond to changes in deep water masses resulting from the 2015/16 El Nino

2021 ◽  
Author(s):  
Erika F Neave ◽  
Harvey Seim ◽  
Scott Gifford ◽  
Olivia Torano ◽  
Zackary I Johnson ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Deep Water ◽  
El Niño ◽  
El Nino ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Equatorial Pacific Ocean ◽  
Equatorial Undercurrent ◽  
Galapagos Archipelago ◽  
Eastern Equatorial Pacific

The Galapagos Archipelago lies within the eastern equatorial Pacific Ocean at the convergence of major ocean currents that are subject to changes in circulation. The nutrient-rich Equatorial Undercurrent upwells from the west onto the Galapagos platform, stimulating primary production, but this source of deep water weakens during El Nino events. From measurements collected on repeat cruises, the 2015/16 El Nino was associated with declines in phytoplankton biomass at most sites throughout the archipelago and reduced utilization of nitrate, particularly in large-sized phytoplankton in the western region. Protistan assemblages were identified by sequencing the V4 region of the 18S rRNA gene. Dinoflagellates, chlorophytes, and diatoms dominated most sites. Shifts in dinoflagellate communities were most apparent between the years; parasitic dinoflagellates, Syndiniales, were highly detected during the El Nino (2015) while the dinoflagellate genus, Gyrodinium dominated many sites during the neutral period (2016). Variations in protistan communities were most strongly correlated with changes in subthermocline water density. These findings indicate that marine protistan communities in this region are regimented by deep water mass sources and thus could be profoundly affected by altered ocean circulation.

scholarly journals Galápagos upwelling driven by localized wind–front interactions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Forryan ◽  
Alberto C. Naveira Garabato ◽  
Clément Vic ◽  
A. J. George Nurser ◽  
Alexander R. Hearn
Keyword(s):  
Ocean Circulation ◽  
Realistic Model ◽  
Surface Mixed Layer ◽  
Equatorial Pacific Ocean ◽  
World Heritage Sites ◽  
Theory Of Evolution ◽  
Heritage Sites ◽  
Galapagos Archipelago ◽  
Eastern Equatorial Pacific ◽  
Eastern Equatorial Pacific Ocean

AbstractThe Galápagos archipelago, rising from the eastern equatorial Pacific Ocean some 900 km off the South American mainland, hosts an iconic and globally significant biological hotspot. The islands are renowned for their unique wealth of endemic species, which inspired Charles Darwin’s theory of evolution and today underpins one of the largest UNESCO World Heritage Sites and Marine Reserves on Earth. The regional ecosystem is sustained by strongly seasonal oceanic upwelling events—upward surges of cool, nutrient-rich deep waters that fuel the growth of the phytoplankton upon which the entire ecosystem thrives. Yet despite its critical life-supporting role, the upwelling’s controlling factors remain undetermined. Here, we use a realistic model of the regional ocean circulation to show that the intensity of upwelling is governed by local northward winds, which generate vigorous submesoscale circulations at upper-ocean fronts to the west of the islands. These submesoscale flows drive upwelling of interior waters into the surface mixed layer. Our findings thus demonstrate that Galápagos upwelling is controlled by highly localized atmosphere–ocean interactions, and call for a focus on these processes in assessing and mitigating the regional ecosystem’s vulnerability to 21st-century climate change.

scholarly journals Protistan plankton communities in the Galápagos Archipelago respond to changes in deep water masses resulting from the 2015/16 El Niño

2021 ◽  
Author(s):  
Erika F. Neave ◽  
Harvey Seim ◽  
Scott M. Gifford ◽  
Olivia Torano ◽  
Zackary I. Johnson ◽  
...  
Keyword(s):  
Deep Water ◽  
El Niño ◽  
El Nino ◽  
Water Masses ◽  
Galapagos Archipelago ◽  
Plankton Communities

scholarly journals Mammalia, Carnivora, Otariidae, Arctocephalus galapagoensis Heller, 1904: first continental record for Costa Rica

Check List ◽  
2010 ◽  
Vol 6 (4) ◽  
pp. 630 ◽  
Author(s):  
Andrea Montero-Cordero ◽  
Damián Martínez Fernández ◽  
Gabriela Hernández-Mora
Keyword(s):  
Costa Rica ◽  
El Niño ◽  
El Nino ◽  
First Record ◽  
Costa Rican ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Eastern Equatorial Pacific ◽  
Fur Seal ◽  
Eastern Equatorial Pacific Ocean

This is the first record of Arctocephalus galapagoensis for the mainland coast of Costa Rica, which is outside the geographical distribution of this species about 1,300 km from its type locality. Changes in environmental conditions during El Niño events might be responsible for a higher incidence of these sightings. The presence of a moderate El Niño along the central and eastern equatorial Pacific Ocean during this month coincides with the occurrence of the fur seal in Costa Rican coasts. No photo record had ever been registered before for this country.

scholarly journals Impact of natural disasters on consumer behavior: Case of the 2017 El Niño phenomenon in Peru

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244409
Author(s):  
Hugo Alatrista-Salas ◽  
Vincent Gauthier ◽  
Miguel Nunez-del-Prado ◽  
Monique Becker
Keyword(s):  
El Niño ◽  
El Nino ◽  
Coarse Grained ◽  
Equatorial Pacific Ocean ◽  
Economic Activities ◽  
Fine Grained ◽  
Multi Scale ◽  
Eastern Equatorial Pacific ◽  
Eastern Equatorial Pacific Ocean ◽  
Purchasing Patterns

El Niño is an extreme weather event featuring unusual warming of surface waters in the eastern equatorial Pacific Ocean. This phenomenon is characterized by heavy rains and floods that negatively affect the economic activities of the impacted areas. Understanding how this phenomenon influences consumption behavior at different granularity levels is essential for recommending strategies to normalize the situation. With this aim, we performed a multi-scale analysis of data associated with bank transactions involving credit and debit cards. Our findings can be summarized into two main results: Coarse-grained analysis reveals the presence of the El Niño phenomenon and the recovery time in a given territory, while fine-grained analysis demonstrates a change in individuals’ purchasing patterns and in merchant relevance as a consequence of the climatic event. The results also indicate that society successfully withstood the natural disaster owing to the economic structure built over time. In this study, we present a new method that may be useful for better characterizing future extreme events.

scholarly journals Influence of El Niño on the Upper-Ocean Circulation in the Tropical Atlantic Ocean

2007 ◽  
Vol 20 (19) ◽  
pp. 5012-5018 ◽  
Author(s):  
Katja Lohmann ◽  
Mojib Latif
Keyword(s):  
Atlantic Ocean ◽  
Ocean Circulation ◽  
El Niño ◽  
El Nino ◽  
Equatorial Pacific ◽  
Upper Ocean ◽  
Tropical Atlantic ◽  
Tropical Atlantic Ocean ◽  
Eastern Equatorial Pacific ◽  
Cell Strength

Abstract This study investigates the influence of El Niño on the upper-ocean circulation in the tropical Atlantic Ocean (via changes in the Atlantic trade winds) by analyzing observed sea surface temperature (SST) together with an ocean general circulation model integration forced by the NCEP–NCAR reanalysis. During periods with anomalously warm (cold) eastern equatorial Pacific SST, the southern Atlantic tropical cell is strengthened (weakened). The difference of the cell strength between El Niño and La Niña years is about 20% of the mean cell strength. However, the variability of the cell is not dominated by the remote forcing from the eastern equatorial Pacific but seems to be caused by intrinsic tropical Atlantic variability. A strengthening (weakening) for periods with anomalously warm (cold) eastern equatorial Pacific SST is also found for the zonal surface and subsurface currents. TOPEX/Poseidon altimetry data are used to validate the results based on the OGCM integration.

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 Wind-Driven Response of the Northern Indian Ocean to Climate Extremes*

2007 ◽  
Vol 20 (13) ◽  
pp. 2978-2993 ◽  
Author(s):  
Tommy G. Jensen
Keyword(s):  
Indian Ocean ◽  
Ocean Circulation ◽  
Bay Of Bengal ◽  
El Niño ◽  
Arabian Sea ◽  
El Nino ◽  
Ocean Model ◽  
La Niña ◽  
Northern Indian Ocean ◽  
La Nina

Abstract Composites of Florida State University winds (1970–99) for four different climate scenarios are used to force an Indian Ocean model. In addition to the mean climatology, the cases include La Niña, El Niño, and the Indian Ocean dipole (IOD). The differences in upper-ocean water mass exchanges between the Arabian Sea and the Bay of Bengal are investigated and show that, during El Niño and IOD years, the average clockwise Indian Ocean circulation is intensified, while it is weakened during La Niña years. As a consequence, high-salinity water export from the Arabian Sea into the Bay of Bengal is enhanced during El Niño and IOD years, while transport of low-salinity waters from the Bay of Bengal into the Arabian Sea is enhanced during La Niña years. This provides a venue for interannual salinity variations in the northern Indian Ocean.

scholarly journals Dynamic Downscaling of the Impact of Climate Change on the Ocean Circulation in the Galápagos Archipelago

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Yanyun Liu ◽  
Lian Xie ◽  
John M. Morrison ◽  
Daniel Kamykowski
Keyword(s):  
Climate Change ◽  
Ocean Circulation ◽  
Global Climate Change ◽  
Climate Model ◽  
Global Climate ◽  
Ocean Model ◽  
Reanalysis Dataset ◽  
Equatorial Undercurrent ◽  
Galapagos Archipelago ◽  
The Impact

The regional impact of global climate change on the ocean circulation around the Galápagos Archipelago is studied using the Hybrid Coordinate Ocean Model (HYCOM) configured for a four-level nested domain system. The modeling system is validated and calibrated using daily atmospheric forcing derived from the NCEP/NCAR reanalysis dataset from 1951 to 2007. The potential impact of future anthropogenic global warming (AGW) in the Galápagos region is examined using the calibrated HYCOM with forcing derived from the IPCC-AR4 climate model. Results show that although the oceanic variability in the entire Galápagos region is significantly affected by global climate change, the degree of such effects is inhomogeneous across the region. The upwelling region to the west of the Isabella Island shows relatively slower warming trends compared to the eastern Galápagos region. Diagnostic analysis suggests that the variability in the western Galápagos upwelling region is affected mainly by equatorial undercurrent (EUC) and Panama currents, while the central/east Galápagos is predominantly affected by both Peru and EUC currents. The inhomogeneous responses in different regions of the Galápagos Archipelago to future AGW can be explained by the incoherent changes of the various current systems in the Galápagos region as a result of global climate change.

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