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 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 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 Biogeochemical cycling and phyto- and bacterio-plankton communities in a large and shallow tropical lagoon (Terminos Lagoon, Mexico) under 2009–2010 El Niño Modoki drought conditions

2016 ◽  
Author(s):  
Pascal Conan ◽  
Mireille Pujo-Pay ◽  
Marina Agab ◽  
Laura Calva-Benitez ◽  
Sandrine Chifflet ◽  
...  
Keyword(s):  
Organic Matter ◽  
Bacterial Community ◽  
El Niño ◽  
El Nino ◽  
Organic Phosphorus ◽  
Biogeochemical Cycling ◽  
Large Set ◽  
El Niño Modoki ◽  
Terminos Lagoon ◽  
Plankton Communities

Abstract. A large set of biogeochemical (nutrients, dissolved and particulate organic matter), phytoplanktonic (biomass and photosynthetic activity) and bacterial (bacterial diversity and ectoenzymatic activities) parameters were determined to understand how the severe drought period relative to the 2009–2010 El Niño Modoki episode influenced biogeochemical cycling and phyto- and bacterio-plankton communities in Terminos Lagoon (Mexico) potentially prefiguring future environmental conditions due to expected trends in climate change. During the study period, the water column of Terminos Lagoon functioned globally as a sink, and especially as a "nitrogen assimilator", because of high production of particulate and dissolved organic matter although exportation of autochthonous matter to the Gulf of Mexico was weak. Coupling between top-down and bottom-up controls accounted for the diverse responses in phytoplankton productivity. Nitrogen and phosphorus stoichiometry mostly accounted for the heterogeneity in phytoplankton and bacteria distribution in the lagoon. In the Eastern part, we found a clear decoupling between areas enriched in dissolved inorganic nitrogen in the North close to Puerto real coastal inlet and areas enriched in phosphate (PO4) in the South close to the Candelaria estuary. Such a decoupling limited the potential for primary production resulting in an accumulation of dissolved organic carbon and nitrogen (DOC and DON, respectively) close to the river mouth. In the Western part of the lagoon, maximal phytoplankton development resulted from the coupling between Palizada river inputs of nitrate (NO3) and particulate organic phosphorus -PP- (but depleted in PO4) and bacterial activity transforming PP and dissolved organic phosphorus (DOP) to available PO4. The Chumpan River only marginally contributed to PO4 inputs due to its very low contribution to overall river inputs. We also found that a complex array of biogeochemical and phytoplanktonic parameters were the driving force behind the geographical distribution of bacterial community structure and activities. Finally, we showed that nutrients brought by the Palizada River supported an abundant bacterial community of polycyclic aromatic hydrocarbon (PAH)-degraders, which are of significance in this important oil production zone.

Water masses and chlorophyll-a distribution in a semi-enclosed bay of the southern Gulf of California, Mexico, after the “Godzilla El Niño”

2019 ◽  
Vol 12 (15) ◽  
Author(s):  
Erik Coria-Monter ◽  
María Adela Monreal-Gómez ◽  
David Alberto Salas de León ◽  
Elizabeth Durán-Campos
Keyword(s):  
Chlorophyll A ◽  
El Niño ◽  
Gulf Of California ◽  
El Nino ◽  
Water Masses ◽  
Enclosed Bay ◽  
Chlorophyll A Distribution

The effect of climate change on the western rock lobster (Panulirus cygnus) fishery of Western Australia

2010 ◽  
Vol 67 (1) ◽  
pp. 85-96 ◽  
Author(s):  
Nick Caputi ◽  
Roy Melville-Smith ◽  
Simon de Lestang ◽  
Alan Pearce ◽  
Ming Feng
Keyword(s):  
Climate Change ◽  
Water Temperature ◽  
Deep Water ◽  
El Niño ◽  
El Nino ◽  
Rock Lobster ◽  
Westerly Winds ◽  
El Niño Events ◽  
Panulirus Cygnus ◽  
El Nino Events

Environmental factors such as the Leeuwin Current (influenced by the El Niño – Southern Oscillation cycle) and westerly winds in late winter – spring significantly affect puerulus settlement of the western rock lobster ( Panulirus cygnus ) fishery. Climate change is causing an increase in water temperature that is seasonally variable, a weakening of westerly winds in winter, and an increase in the frequency of El Niño events. Rising water temperatures over 35 years may have resulted in a decrease in size at maturity and size of migrating lobsters from shallow to deep water, increases in abundance of undersized and legal-sized lobsters in deep water relative to shallow water, and shifts in catch to deep water. The size of migrating lobsters is related to the water temperature about the time of puerulus settlement (four years previously). Climate change effects on puerulus settlement, catchability, females moulting from setose to non-setose, timing of moults, and peak catch rates are assessed. As climate change models project that the warming trend will continue, these biological trends are likely to continue. The changes may have negative (increasing frequency of El Niño events) or positive (increasing water temperature) implications for the fishery, which need to be taken into account in stock assessments and management.

scholarly journals First record of a by-the-wind-sailor (Velella velella Linnaeus, 1758) in the Galápagos Archipelago - Ecuador

2019 ◽  
Vol 7 ◽  
Author(s):  
Martín Carrera ◽  
José Trujillo ◽  
Margarita Brandt
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
First Record ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Santa Cruz ◽  
Galapagos Archipelago ◽  
Official Record

We present the first official record of the by-the-wind-sailor (Velella velella) for Ecuador. Twelve individuals were found along different beaches of San Cristóbal and Santa Cruz Islands in Galápagos Archipelago, Ecuador. These sightings may be influenced by El Niño Southern Oscillation events.

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