scholarly journals Biogeochemical Responses and Seasonal Dynamics of the Benthic Boundary Layer Microbial Communities during the El Niño 2015 in an Eastern Boundary Upwelling System

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 180
Author(s):  
Verónica Molina ◽  
Marcela Cornejo-D’Ottone ◽  
Eulogio H. Soto ◽  
Eduardo Quiroga ◽  
Guillermo Alarcón ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Microbial Communities ◽  
El Niño ◽  
Bottom Water ◽  
El Nino ◽  
Southern Oscillation ◽  
Amplicon Sequencing ◽  
Benthic Boundary Layer ◽  
Oxygen Utilization ◽  
Eastern Boundary

The Eastern South Pacific coastal zone is characterized by seasonal and interannual variability, driven by upwelling and El Niño Southern Oscillation (ENSO), respectively. These oceanographical conditions influence microbial communities and their contribution to nutrient and greenhouse gases recycling, especially in bottom waters due to oxygenation. This article addresses the seasonal hydrographic and biogeochemical conditions in the water and sediments during El Niño 2015. Bottom water active microbial communities, including nitrifiers, were studied using amplicon sequencing of 16S rRNA (cDNA) and RT-qPCR, respectively. The results of the hydrographic analysis showed changes in the water column associated with the predominance of sub-Antarctic Waters characterized by warmed and low nutrients in the surface and more oxygenated conditions at the bottom in comparison with El Niño 2014. The organic matter quantity and quality decreased during fall and winter. The bottom water active microbial assemblages were dominated by archaea (Ca. Poseidoniales) and putative ammonia oxidizing archaea. Active bacteria affiliated to SAR11, Marinimicrobia and Nitrospina, and oxygen deficient realms (Desulfobacterales, SUP05 clade and anammox) suffered variations, possibly associated with oxygen and redox conditions in the benthic boundary layer. Nitrifying functional groups contributed significantly more during late fall and winter which was consistent with higher bottom water oxygenation. Relationships between apparent oxygen utilization nitrate and nitrous oxide in the water support the contribution of nitrification to this greenhouse gas distribution in the water. In general, our study suggests that seasonal oceanographic variability during an El Niño year influences the microbial community and thus remineralization potential, which supports the need to carry out longer time series to identify the relevance of seasonality under ENSO in Eastern Boundary Upwelling Systems (EBUS) areas.

scholarly journals Hemispheric transport and influence of meteorology on global aerosol climatology

2012 ◽  
Vol 12 (16) ◽  
pp. 7609-7624 ◽  
Author(s):  
T. L. Zhao ◽  
S. L. Gong ◽  
P. Huang ◽  
D. Lavoué
Keyword(s):  
Boundary Layer ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Late Summer ◽  
Late Winter ◽  
Aerosol Transport ◽  
Transport Pathways ◽  
Annual Variations ◽  
Annual Variability

Abstract. Based on a 10-yr simulation with the global air quality modeling system GEM-AQ/EC, the northern hemispheric aerosol transport with the inter-annual and seasonal variability as well as the mean climate was investigated. The intercontinental aerosol transport is predominant in the zonal direction from west to east with the ranges of inter-annual variability between 14% and 63%, and is 0.5–2 orders of magnitude weaker in the meridional direction but with larger inter-annual variability. The aerosol transport is found to fluctuate seasonally with a factor of 5–8 between the maximum in late winter and spring and the minimum in late summer and fall. Three meteorological factors controlling the intercontinental aerosol transport and its inter-annual variations are identified from the modeling results: (1) Anomalies in the mid-latitude westerlies in the troposphere. (2) Variations of precipitation over the intercontinental transport pathways and (3) Changes of meteorological conditions within the boundary layer. Changed only by the meteorology, the aerosol column loadings in the free troposphere over the source regions of Europe, North America, South and East Asia vary inter-annually with the highest magnitudes of 30–37% in January and December and the lowest magnitudes of 16–20% in August and September, and the inter-annual aerosol variability within the boundary layer influencing the surface concentrations with the magnitudes from 6% to 20% is more region-dependent. As the strongest climatic signal, the El Niño-Southern Oscillation (ENSO) can lead the anomalies in the intercontinental aerosols in El Niño- and La Niña-years respectively with the strong and weak transport of the mid-latitude westerlies and the low latitude easterlies in the Northern Hemisphere (NH).

scholarly journals Contributions from California Coastal-Zone Surface Fluxes to Heavy Coastal Precipitation: A CALJET Case Study during the Strong El Niño of 1998

2005 ◽  
Vol 133 (5) ◽  
pp. 1175-1198 ◽  
Author(s):  
P. Ola G. Persson ◽  
P. J. Neiman ◽  
B. Walter ◽  
J-W. Bao ◽  
F. M. Ralph
Keyword(s):  
Boundary Layer ◽  
Latent Heat ◽  
El Niño ◽  
Model Simulation ◽  
El Nino ◽  
Southern Oscillation ◽  
Surface Flux ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
Sst Anomalies

Abstract Analysis of the case of 3 February 1998, using an extensive observational system in the California Bight during an El Niño winter, has revealed that surface sensible and latent heat fluxes within 150 km of the shore contributed substantially to the destabilization of air that subsequently produced strong convection and flooding along the coast. Aircraft, dropsonde, and satellite observations gathered offshore documented the sea surface temperatures (SSTs), surface fluxes, stratification, and frontal structures. These were used to extrapolate the effects of the fluxes on the warm-sector, boundary layer air ahead of a secondary cold front as this air moved toward the coast. The extrapolated structure was then validated in detail with nearshore aircraft, wind profiler, sounding, and buoy observations of the frontal convection along the coast, and the trajectory transformations were confirmed with a model simulation. The results show that the surface fluxes increased CAPE by about 26% such that the nearshore boundary layer values of 491 J kg−1 were near the upper end of those observed for cool-season California thunderstorms. The increased CAPE due to upward sensible and latent heat fluxes was a result of the anomalously warm coastal SSTs (+1°–3°C) typical of strong El Niño events. Applications of the extrapolation method using a surface flux parameterization scheme and different SSTs suggested that convective destabilization due to nearshore surface fluxes may only occur during El Niño years when positive coastal SST anomalies are present. The fluxes may have no effect or a stabilizing effect during non–El Niño years, characterized by zero or negative coastal SST anomalies. In short, during strong El Niños, it appears that the associated coastal SST anomalies serve to further intensify the already anomalously strong storms in southern California, thus contributing to the increased flooding. This modulating effect by El Niño–Southern Oscillation (ENSO) of a mesoscale process has not been considered before in attempts at assessing the impacts of ENSO on U.S. west coast precipitation.

scholarly journals On the role of climate modes in modulating the air–sea CO<sub>2</sub> fluxes in eastern boundary upwelling systems

2019 ◽  
Vol 16 (2) ◽  
pp. 329-346 ◽  
Author(s):  
Riley X. Brady ◽  
Nicole S. Lovenduski ◽  
Michael A. Alexander ◽  
Michael Jacox ◽  
Nicolas Gruber
Keyword(s):  
Climate Variability ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Mixed Layer Depth ◽  
Positive Phase ◽  
Co2 Fluxes ◽  
The North ◽  
Eastern Boundary

Abstract. The air–sea CO2 fluxes in eastern boundary upwelling systems (EBUSs) vary strongly in time and space, with some of the highest flux densities globally. The processes controlling this variability have not yet been investigated consistently across all four major EBUSs, i.e., the California (CalCS), Humboldt (HumCS), Canary (CanCS), and Benguela (BenCS) Current systems. In this study, we diagnose the climatic modes of the air–sea CO2 flux variability in these regions between 1920 and 2015, using simulation results from the Community Earth System Model Large Ensemble (CESM-LENS), a global coupled climate model ensemble that is forced by historical and RCP8.5 radiative forcing. Differences between simulations can be attributed entirely to internal (unforced) climate variability, whose contribution can be diagnosed by subtracting the ensemble mean from each simulation. We find that in the CalCS and CanCS, the resulting anomalous CO2 fluxes are strongly affected by large-scale extratropical modes of variability, i.e., the North Pacific Gyre Oscillation (NPGO) and the North Atlantic Oscillation (NAO), respectively. The CalCS has anomalous uptake of CO2 during the positive phase of the NPGO, while the CanCS has anomalous outgassing of CO2 during the positive phase of the NAO. In contrast, the HumCS is mainly affected by El Niño–Southern Oscillation (ENSO), with anomalous uptake of CO2 during an El Niño event. Variations in dissolved inorganic carbon (DIC) and sea surface temperature (SST) are the major contributors to these anomalous CO2 fluxes and are generally driven by changes to large-scale gyre circulation, upwelling, the mixed layer depth, and biological processes. A better understanding of the sensitivity of EBUS CO2 fluxes to modes of climate variability is key in improving our ability to predict the future evolution of the atmospheric CO2 source and sink characteristics of the four EBUSs.

scholarly journals Observational analysis of the daily cycle of the planetary boundary layer in the central Amazon during a non-El Niño year and El Niño year (GoAmazon project 2014/5)

2020 ◽  
Vol 20 (9) ◽  
pp. 5547-5558 ◽  
Author(s):  
Rayonil G. Carneiro ◽  
Gilberto Fisch
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Microwave Radiometer ◽  
Enso Event ◽  
Strong Impact ◽  
Daily Cycle ◽  
Central Amazon

Abstract. The Amazon biome contains more than half of the remaining tropical forests of the planet and has a strong impact on aspects of meteorology such as the planetary boundary layer (PBL). In this context, the objective of this study was to conduct observational evaluations of the daily cycle of the height of the PBL during its stable (night) and convective (day) phases from data that were measured and/or estimated using instruments such as a radiosonde, sodar, ceilometer, wind profiler, lidar and microwave radiometer installed in the central Amazon during 2014 (considered a typical year) and 2015 during which an intense El Niño–Southern Oscillation (ENSO) event predominated during the GoAmazon experiment. The results from the four intense observation periods (IOPs) show that during the day and night periods, independent of dry or rainy seasons, the ceilometer is the instrument that best describes the depth of the PBL when compared with in situ radiosonde measurements. Additionally, during the dry season in 2015, the ENSO substantially influenced the growth phase of the PBL, with a 15 % increase in the rate compared to the same period in 2014.

scholarly journals Hemispheric transport and influence of meteorology on global aerosol climatology

2012 ◽  
Vol 12 (4) ◽  
pp. 10181-10221 ◽  
Author(s):  
T. L. Zhao ◽  
S. L. Gong ◽  
P. Huang ◽  
D. Lavoué
Keyword(s):  
Boundary Layer ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Late Summer ◽  
Late Winter ◽  
Free Troposphere ◽  
Aerosol Transport ◽  
Transport Pathways ◽  
Annual Variability

Abstract. Based on a 10-yr simulation with the global air quality modeling system GEM-AQ/EC, the inter-annual and seasonal variability as well as the mean climate of hemispheric aerosol transport (HAT) was investigated. The intercontinental aerosol transport is predominant in the zonal direction from west to east with the magnitudes of inter-annual variability between 14% and 63%, and are 0.5–2 orders of magnitude weaker in the meridional direction but with larger inter-annual variability. The HAT is found to fluctuate seasonally with a factor of 5–8 between the maximum in late winter and spring and the minimum in late summer and fall. Three meteorological factors controlling the inter-annual aerosol variations in the source-receptor (S-R) relationships are identified from the modeling results: (1) Anomalies in the mid-latitude westerlies in the troposphere. (2) Variations of precipitation over the intercontinental transport pathways and (3) Changes of meteorological conditions in the boundary layer. Changed only by the meteorology, the aerosol column loadings in the free troposphere over the HTAP-regions vary inter-annually with the highest magnitudes of 30–37% in January and December and the lowest magnitudes of 16–20% in August and September, and the magnitudes of inter-annual variability within the boundary layer influencing the surface concentrations over the HTAP-regions are 30–70% less than in the free troposphere and more region-dependent. As the strongest climatic signal, the El Niño–Southern Oscillation (ENSO) can lead the anomalies in the S-R relationships for intercontinental aerosols in the Northern Hemisphere (NH) with the strong/weak transport in the mid-latitude westerlies and the low latitude easterlies for the HAT in El Niño/ La Niña-years.

scholarly journals On the role of climate modes in modulating the air-sea CO<sub>2</sub> fluxes in Eastern Boundary Upwelling Systems

2018 ◽  
Author(s):  
Riley X. Brady ◽  
Nicole S. Lovenduski ◽  
Michael A. Alexander ◽  
Michael Jacox ◽  
Nicolas Gruber
Keyword(s):  
Climate Variability ◽  
El Niño ◽  
Radiative Forcing ◽  
Dissolved Inorganic Carbon ◽  
El Nino ◽  
Southern Oscillation ◽  
Mixed Layer Depth ◽  
Co2 Fluxes ◽  
The North ◽  
Eastern Boundary

Abstract. The air-sea CO2 fluxes in Eastern Boundary Upwelling Systems (EBUS) vary strongly in time and space with some of the highest flux densities globally. The processes controlling this variability have not yet been investigated consistently across all four major EBUS, i.e., the California (CalCS), Humboldt (HumCS), Canary (CanCS), and Benguela (BenCS) Current Systems. In this study, we diagnose the physical and biological mechanisms that contribute to historical (1920–2015) CO2 flux variability in these regions using simulation results from the Community Earth System Model Large Ensemble (CESM-LENS), a global coupled climate model ensemble that is forced by historical and RCP8.5 radiative forcing. Differences between simulations can be attributed entirely to internal climate variability. We find that the deviations from the ensemble mean, i.e., the anomalous CO2 fluxes, in the CalCS and CanCS are strongly affected by modes of variability associated with atmospheric subtropical gyres: the North Pacific Gyre Oscillation (NPGO) and the North Atlantic Oscillation (NAO), respectively. The CalCS (CanCS) has anomalous uptake (outgassing) of CO2 during the positive phase of the NPGO (NAO). The HumCS is mainly affected by El Niño Southern Oscillation (ENSO), with anomalous uptake of CO2 during an El Niño event. Variations in dissolved inorganic carbon (DIC) and sea surface temperature (SST) are the major contributors to these anomalous CO2 fluxes, and are generally driven by changes to gyre circulation, upwelling, the mixed layer depth, and biological processes. A better understanding of the sensitivity of EBUS CO2 fluxes to modes of climate variability may improve our ability to predict the ocean–atmosphere carbon cycle in EBUS, which are particularly susceptible to ocean acidification.

VARIABILIDAD CLIMÁTICA, CAMBIO CLIMÁTICO Y PESQUERÍAS EN EL ECUADOR.

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Johnny Chavarría Viteri ◽  
Dennis Tomalá Solano
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
Pacific Decadal Oscillation ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Current Action ◽  
Palabras Clave

La variabilidad climática es la norma que ha modulado la vida en el planeta. Este trabajo demuestra que las pesquerías y acuicultura costera ecuatorianas no son la excepción, puesto que tales actividades están fuertemente influenciadas por la variabilidad ENSO (El Niño-Oscilación del Sur) y PDO (Oscilación Decadal del Pacífico), planteándose que la señal del cambio climático debe contribuir a esta influencia. Se destaca también que, en el análisis de los efectos de la variabilidad climática sobre los recursos pesqueros, el esfuerzo extractivo también debe ser considerado. Por su parte, la acción actual de la PDO está afectando la señal del cambio climático, encontrándose actualmente en fases opuestas. Se espera que estas señales entren en fase a finales de esta década, y principalmente durante la década de los 20 y consecuentemente se evidencien con mayor fuerza los efectos del Cambio Climático. Palabras Clave: Variabilidad Climática, Cambio Climático, ENSO, PDO, Pesquerías, Ecuador. ABSTRACT Climate variability is the standard that has modulated life in the planet. This work shows that the Ecuadorian  fisheries and aquaculture are not the exception, since such activities are strongly influenced by ENSO variability (El Niño - Southern Oscillation) and PDO (Pacific Decadal Oscillation), considering that the signal of climate change should contribute to this influence. It also emphasizes that in the analysis of the effects of climate variability on the fishing resources, the extractive effort must also be considered. For its part, the current action of the PDO is affecting the signal of climate change, now found on opposite phases. It is hoped that these signals come into phase at the end of this decade, and especially during the decade of the 20’s and more strongly evidencing the effects of climate change. Keywords: Climate variability, climate change, ENSO (El Niño - Southern Oscillation) and PDO  (Pacific Decadal Oscillation); fisheries, Ecuador. Recibido: mayo, 2012Aprobado: agosto, 2012

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