Javier Aristegui

Javier Aristegui
Universidad de Las Palmas de Gran Canaria | ULPGC · Instituto Universitario de Oceanografía y Cambio Global (Iocag)

PhD

About

221
Publications
44,666
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9,424
Citations
Citations since 2017
35 Research Items
4105 Citations
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20172018201920202021202220230200400600800
20172018201920202021202220230200400600800

Publications

Publications (221)
Thesis
Full-text available
Phytoplankton growth mainly depends on nutrient and light availability. Highly dynamic oceanic environments are dominated by physical processes that generally alter phytoplankton dynamics by controlling the access to these resources. Mesoscale motions have been considered the most important factor modulating the distribution of biogeochemical prope...
Article
The Cape Verde Frontal Zone (CVFZ) is a highly dynamic region located in the southern boundary of the Canary Current Eastern Boundary Upwelling Ecosystem. Due to the interaction of the Cape Verde Front with the Mauritanian coastal upwelling, the area features large vertical and horizontal export fluxes of organic matter. While the flux, composition...
Article
Full-text available
Abstract During the summer of 2017, recurrent extensive blooms of the diazotrophic cyanobacterium Trichodesmium invaded the beaches and coastal waters of the Canary Islands, causing great social alarm. Some local media and public sectors ascribed, without any strong scientific evidence, the origin and reactivation of these blooms to untreated sewag...
Article
Full-text available
Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The production of organic material is fueled by upwelling of nutrient-rich deep waters and high incident light at the sea surface. However, biotic and abiotic factors can modify surface production and related biogeochemical processes. Determining the...
Preprint
Full-text available
Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The high productivity in surface waters is facilitated by upwelling of nutrient-rich deep waters, with high light availability enabling fast phytoplankton growth and nutrient utilization. However, there are numerous biotic and abiotic factors modifyi...
Article
Full-text available
Observational evidence demonstrates the signature of near‐inertial wave (NIW) trapping by a long‐lived westward propagating mesoscale anticyclonic eddy under normal atmospheric conditions. Cross‐eddy sections of density and shipboard acoustic Doppler current profiler data show the downward (upward phase) propagation of NIW packets with vertical wav...
Preprint
Full-text available
The Coastal-Ocean Carbon Exchange in the Canary Region Project (COCA) arises in order to analyse and get to understand the impact of lateral export of nutrients and organic matter from the highly productive Coastal Upwelling System off NW Africa in the biogeochemical cycles during two different seasons. The circulation patterns off NW African Upwel...
Article
Fluorescent dissolved organic matter (FDOM) in the Mediterranean Sea was analysed by excitation–emission matrix (EEM) spectroscopy and parallel factor (PARAFAC) analysis during the cruise HOTMIX 2014. A 4–component model, including 3 humic–like and 1 protein–like compounds, was obtained. To decipher the environmental factors that dictate the distri...
Chapter
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This Special Report on the Ocean and Cryosphere1 in a Changing Climate (SROCC) was prepared following an IPCC Panel decision in 2016 to prepare three Special Reports during the Sixth Assessment Cycle2 . By assessing new scientific literature3 , the SROCC4 responds to government and observer organization proposals. The SROCC follows the other two Sp...
Article
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Ocean acidification, the change in seawater carbonate chemistry due to the uptake of anthropogenic CO2, affects the physiology of marine organisms in multiple ways. Diverse competitive and trophic interactions transform the metabolic responses to changes in community composition, seasonal succession and potentially geographical distribution of spec...
Article
Full-text available
The subtropical oceans are home to the largest phytoplankton biome on the planet. Yet, little is known about potential impacts of ocean acidification (OA) on phytoplankton community composition in the vast oligotrophic ecosystems of the subtropical gyres. To address this question, we conducted an experiment with 9 in situ mesocosms (∼35 m 3) off th...
Article
Zooplankton vertical distribution, migrant biomass, and respiratory flux were studied in two transects performed in the Canary Current at 21°N and 26°N from the eu- and mesotrophic upwelling zone off Northwest Africa to the oligotrophic central gyre waters. Migrant biomass was estimated by sampling during day and night using a Longhurst-Hardy Plank...
Article
Determining the factors that influence marine microbial growth and community structure are critical for the understanding of global carbon cycling. Since the early twentieth century, it has been known that B vitamins play an important role in phytoplankton community dynamics. Limited oceanic dissolved B vitamin distributions indicate that these imp...
Article
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The enzymatic electron transport system (ETS) assay is frequently used as a proxy of respiratory activity in planktonic communities. It is thought to estimate the maximum overall activity of the enzymes associated with the respiratory ETS systems in both eukaryotic and prokaryotic organisms. Thus, in order to derive actual respiration rates (R) fro...
Article
Full-text available
The extracellular concentration of H2O2 in surface aquatic environments is controlled by a balance between photochemical production and the microbial synthesis of catalase and peroxidase enzymes to remove H2O2 from solution. In any kind of incubation experiment, the formation rates and equilibrium concentrations of ROS may be sensitive to both the...
Article
Full-text available
The subtropical oceans are home to one of the largest ecosystems on Earth, contributing to nearly one third of global oceanic primary production. Ocean warming leads to enhanced stratification in the oligotrophic ocean but also intensification in cross-shore wind gradients and thus in eddy kinetic energy across eastern boundary regions of the subtr...
Article
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The eruption of a submarine volcano south of El Hierro Island (Canary Islands) in October 2011 led to major physical and chemical changes in the local environment. Large amounts of nutrients were found at specific depths in the water column above the volcano associated with suboxic layers resulting from the oxidation of reduced chemical species ex...
Article
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In the surface ocean, microorganisms are both a source of extracellular H2O2 and, via the production of H2O2 destroying enzymes, also one of the main H2O2 sinks. Within microbial communities, H2O2 sources and sinks may be unevenly distributed and thus microbial community structure could influence ambient extracellular H2O2 concentrations. Yet the b...
Article
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After Bakun (1990) formulated his hypothesis of upwelling intensification caused by increasing global warming, contradictory results have been published on whether primary productivity is increasing or decreasing in Eastern Boundary Upwelling Ecosystems (EBUE). The present work is focused in comparing three net primary production (NPP) models—the V...
Article
Full-text available
Transports of suspended particulate (POCsusp) and dissolved (DOC) organic carbon are inferred from a box-model covering the eastern boundary of the North Atlantic subtropical gyre. Corresponding net respiration rates (R) are obtained from a net organic carbon budget that is based on the transport estimates, and includes both vertical and lateral fl...
Article
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Oceanic fronts are widespread features which separate distinct water masses. They are well known to control the distribution of microbial communities in surface waters, although there is scarce information on their role in delimiting critical functions that microbes perform, and on whether their effects can be translated down into the dark ocean. H...
Article
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Despite of the major role ascribed to marine dissolved organic matter (DOM) in the global carbon cycle, the reactivity of this pool in the dark ocean is still poorly understood. Present hypotheses, posed within the size-reactivity continuum (SRC) and the microbial carbon pump (MCP) conceptual frameworks, need further empirical support. Here, we pro...
Article
Vertical motions play a key role in the enhancement of primary production within mesoscale eddies through the introduction of nutrients into the euphotic layer. However, the details of the vertical velocity field w driving these enhancements remain under discussion. For the first time the mesoscale w associated with an intrathermocline eddy is comp...
Article
An interdisciplinary survey of a subtropical intrathermocline eddy was conducted within the Canary Eddy Corridor in September 2014. The anatomy of the eddy is investigated using near submesoscale fine resolution two-dimensional data and coarser resolution three-dimensional data. The eddy was four months old, with a vertical extension of 500 m and 4...
Article
Full-text available
Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. Increasing evidence indicates that these changes—summarized by the term ocean acidification (OA)—can significantly affect marine food webs and biogeochemical cycles. However, current scientific knowledge is larg...
Article
Full-text available
Recent findings indicate that N2 fixation is significant in aphotic waters, presumably due to heterotrophic diazotrophs depending on organic matter for their nutrition. However, the relationship between organic matter and heterotrophic N2 fixation remains unknown. Here we explore N2 fixation in the deep chlorophyll maximum and underneath deep water...
Article
Full-text available
Remineralization of organic matter in the mesopelagic zone (ca. 150–700 m) is a key controlling factor of carbon export to the deep ocean. By using a tracer conservation model applied to climatological data of oxygen, dissolved inorganic carbon (DIC) and nitrate, we computed mesopelagic respiration at the ESTOC (European Station for Time-Series in...
Article
Diazotrophy-related studies in the North Atlantic have largely focused on its western tropical area, leaving the subtropics and the east undersampled. We studied the longitudinal distribution of Trichodesmium, UCYN-A, UCYN-B, the putative Gammaproteobacterium γ-24774A11 and Richelia (Het1) along 24.5N, using quantitative polymerase chain reaction o...
Article
Photophysiological variability and its influence on primary production were studied in the NW Africa-Canary Islands coastal transition zone. The region showed strong mesoscale activity, in which upwelling filaments and island eddies interacted to cause significant vertical displacements of the deep chlorophyll maximum (DCM). Oligotrophic stations b...
Conference Paper
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A typical anticyclonic eddy of the Canary Eddy Corridor, located 300 nautical miles southwest of the Canary Islands, was interdisciplinary surveyed on September 2014 in the framework of the PUMP project (ref: CTM2012-33355). This project aims to investigate the modulation of the biogeochemical fluxes by the ageostrophic secondary circulation (SAC)...
Article
In the framework of the CAIBEX (Canaries-Iberian marine Ecosystem Exchanges) experiment an interdisciplinary high-resolution survey was conducted in the NW African region of Cape Ghir (30º38'N) during August 2009. The anatomy of a major filament is investigated on scales down to the submesoscale using in situ and remotely sensed data. The filament...
Article
Full-text available
The submarine volcanic eruption occurring near El Hierro (Canary Islands) in October 2011 provided a unique opportunity to determine the effects of such events on the microbial populations of the surrounding waters. The birth of a new underwater volcano produced a large plume of vent material detectable from space that led to abrupt changes in the...
Article
Full-text available
Submarine volcanic eruptions took place at the island El Hierro (Canary Islands) between October 2011 and March 2012. The event produced plumes of discoloured waters due to the discharge of volcanic matter, magmatic gases, and hydrothermal fluids. The expelled materials, which behaved like oceanic tracers, were detected from the site of the volcano...
Article
Full-text available
The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from sate...
Conference Paper
Full-text available
Se presentan resultados parciales del subproyecto “Ecosistemas y Biodiversidad: vigilancia de espacios arenosos protegidos de Canarias y África”, incluido en el 'Programa para el desarrollo de redes tecnológicas y de aplicación de datos de teledetección en África Occidental', TELECAN (MAC/3/C181), financiado por el Programa de Cooperación Transnaci...
Article
The horizontal and vertical distribution of representatives of diazotrophic unicellular cyanobacteria was investigated in the subtropical northeast Atlantic Ocean (28.87 to 42.00°N; 9.01 to 20.02°W). Samples from stations encompassing different water conditions (from oceanic oligotrophic waters to upwelling areas and a temperature range of 13.1°C t...
Article
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Antarctic krill are known to release large amounts of inorganic and organic nutrients to the water column. Here we test the role of krill excretion of dissolved products in stimulating heterotrophic bacteria on the basis of three experiments where ammonium and organic excretory products released by krill were added to bacterial assemblages, free of...
Article
Full-text available
In this study we estimate diffusive nutrient fluxes in the northern region of Cape Ghir upwelling system (Northwest Africa) during autumn 2010. The contribution of two co-existing vertical mixing processes (turbulence and salt fingers) is estimated through micro- and fine-structure scale observations. The boundary between coastal upwelling and open...
Article
Full-text available
We estimated the bacterial production and losses to predators along an open ocean trophic gradient from coastal upwelling waters to oligotrophic waters in the Subtropical Northern Atlantic Ocean. Two zonal sections (21 and 268N) extending from the NW African shelf to the Open Atlantic Ocean at 268W were sampled during September– October 2002 (autum...
Article
Full-text available
It is generally assumed that episodic nutrient pulses by cyclonic eddies into surface waters support a significant fraction of the primary production in subtropical low-nutrient environments in the northern hemisphere. However, contradictory results related to the influence of eddies on particulate organic carbon (POC) export have been reported. As...
Article
Full-text available
Coccolithophores are calcifying marine phytoplankton of the class Prymnesiophyceae. They are considered to play an import role in the global carbon cycle through the production and export of organic carbon and calcite. We have compiled observations of global coccolithophore abundance from several existing databases as well as individual contributio...
Article
1] Dinitrogen (N 2) fixation and dissolved organic nitrogen (DON) release rates were measured on fractionated samples (>10 mm and <10 mm) along 24.58N in the subtropical North Atlantic. Net N 2 fixation rates (N 2 assimilation into biomass) ranged from 0.01 to 0.4 nmol N L À1 h À1 , and DON release rates ranged from 0.001 to 0.09 nmol N L À1 h À1 ....
Article
We studied the relationship between atmospheric dust deposition, N2 fixation rates, and the abundance of unicellular diazotrophs and Trichodesmium in weekly or biweekly samplings over 3 months in the Canary Islands. On average, N2 fixation rates by unicellular diazotrophs and Trichodesmium were low (0.2 nmol N L-1 h-1 and 1.66 3 10 23 nmol N L-1 h-...
Article
Full-text available
Dinitrogen (N2) fixation rates may be underestimated when recently fixed N2 is released as dissolved organic nitrogen (DON). DON release (DONr) is substantial in the filamentous cyanobacterium Trichodesmium but has never been reported in unicellular diazotrophic cyanobacteria. We used axenic cultures of the marine unicellular diazotroph Cyanothece...