Gustavo Ferreyra

Gustavo Ferreyra
Université du Québec à Rimouski UQAR | uqar · Institut des Sciences de la Mer de Rimouski (ISMER)

PhD Biological Oceanography

About

104
Publications
15,225
Reads
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2,220
Citations
Citations since 2017
7 Research Items
852 Citations
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2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140
2017201820192020202120222023020406080100120140
Additional affiliations
January 2005 - December 2009
Université du Québec à Rimouski UQAR
January 2001 - December 2012
Instituto Antártico Argentino

Publications

Publications (104)
Book
Full-text available
Cuando uno se dispone a escribir el prefacio de un libro, sobre todo si se trata de un libro de ecología, es imposible no tener en cuenta la ilustre referencia del prefacio más famoso de nuestra disciplina: el que escribió Eduardo H. Rapoport para la primera edición de 1975 de su magnífico libro Areografía: estrategias geográficas de las especies,...
Chapter
Despite the importance of benthic algal communities to Antarctic coastal ecosystems, much information about their dynamics is still needed. Primary succession processes in the Antarctic benthos are frequently initiated by ice-mediated disturbance and by the creation of denuded substrate following glacier retreat, both expected to increase in the fu...
Article
Since the early 1990s phytoplankton has been studied and monitored in Potter Cove (PC) and Admiralty Bay (AB), King George/25 de Mayo Island, South Shetlands. Phytoplankton biomass is typically low compared to other Antarctic shelf environments, with average spring - summer values below 1 mg chlorophyll a m-3. The physical conditions in the area (r...
Chapter
Temperature and ultraviolet B radiation (UVB, 280–315 nm) are external stressors that affect organisms in mid and high latitudes in a combined way. The combined effects of both variables on natural marine phytoplankton from the Beagle Channel (Argentina) were examined during a 7-day mesocosm experiment. We tested the hypothesis that increased tempe...
Article
Full-text available
Tidal fronts are interfaces that separate stratified from mixed waters. The stratified surface zone of a front has lower inorganic nutrient concentrations than the mixed side, and thus, phytoplankton assemblages are expected to differ from one side of the front to the other. Here, we characterize the physics, nutrient dynamics, and biology of the s...
Article
A natural marine phytoplankton assemblage from a coastal environment of Antarctica was experimentally exposed to low salinity sea water (30 vs 34 in the control) during 8 days in order to study their physiological and community responses to hypoosmotic stress conditions. Hypoosmotic conditions favour water influx into the cells, which results in in...
Article
Full-text available
ABSTRACT: Transparent exopolymer particles (TEP) contribute to carbon export and can represent a significant fraction of the carbon pool, most notably in estuarine systems. This study investigates, for the first time, TEP seasonal variability, vertical distribution and contribution to the carbon pool in the Lower St. Lawrence Estuary (LSLE), a high...
Article
Full-text available
Lectio doctoralis pronunciada el 21 de noviembre de 2014 con motivo de la recepcion del doctorado Honoris Causa por el Centro de Ensino Superior de Sao Gotardo, Minas Gerais, Brasil. La laudatio fue compuesta por el Prof. Dr. Paulo Bonavides; no pudo concurrir por razones de salud y fue leida en su representacion por el Prof. Dr. Paulo Lupo Saraiva...
Article
Intense regional warming was observed in the Western Antarctic Peninsula (WAP) over the last 50 years. Here we investigate the impact of climate change on primary production (PP) in this highly productive region. This study is based on temporal data series of ozone thickness (1972-2010), sea ice concentration (1978-2010), sea surface temperature (1...
Data
Full-text available
ABSTRACT Marine planktonic communities can be affected by the increase in temperature associated with global change, as well as by the increase in ultraviolet B radiation (UVBR, 280-320 nm) through stratospheric ozone layer thinning. The goal of this work was to study the individual and combined effects of increased temperature and UVBR on the pla...
Data
Full-text available
Marine planktonic communities can be affected by increased temperatures associated with global climate change, as well as by increased ultraviolet B radiation (UVBR, 280-320 nm) through stratospheric ozone layer thinning. We studied individual and combined effects of increased temperature and UVBR on the plankton community of the Beagle Channel, so...
Article
Since the early 1990s phytoplankton has been studied and monitored in Potter Cove (PC) and Admiralty Bay (AB), King George/25 de Mayo Island, South Shetlands. Phytoplankton biomass is typically low compared to other Antarctic shelf environments, with average spring - summer values below 1 mg chlorophyll a m-3. The physical conditions in the area (r...
Article
Full-text available
Constitutionalism is a result of the enlightened thinking of the 17th and 18th centuries. Constitutional Law is one of the most important human creations to program and order the coexistence of citizens within the State. Constitutional Law stems from constitutions, a concept born in the 17th century. Now, in the modern age, this branch of the law i...
Article
Full-text available
The Weddell Sea is known to be a CO2 sink due to active biological and physical pumps. Here we study the relationships of phytoplankton biomass and composition and microbial community metabolism, estimated from simulated in situ incubations and from nutrient's difference between surface and subsurface waters, with ΔpCO2 in the Weddell Sea, during f...
Article
Full-text available
The main objective of this study was to investigate the role of mycosporine-like amino acids (MAAs) in the short-term (hours) and long-term (sev-eral days) photoacclimation to solar ultraviolet radia-tion (UVR) of a marine Antarctic diatom (Thalassiosira sp.). The cultures were exposed to natural solar radia-tion and grown over 72 h and 6 days unde...
Data
Full-text available
The reduction of Antarctic stratospheric ozone results in significant increases in ultraviolet B radiation (UVB-R, 280–320 nm) reaching ocean's surface, potentially damaging phytoplankton. Several studies refer to the negative direct and indirect effects of UVB-R and ultraviolet A (UVA-R, 320–400 nm, which is not modified by ozone concentration) on...
Data
Full-text available
RESUMEN Se analizó la producción de peróxido de hidrógeno (H 2 O 2) en función de la dosis de radiación solar en aguas del Canal Beagle, en la desembocadura del Río Lapataia, Ushuaia (Tierra del Fuego, Argentina). El estudio se realizó entre Octubre y Noviembre de 2004. Durante dicho período se produce anualmente una disminución en la concentración...
Article
Full-text available
The production of hydrogen peroxide (H2O2) based on solar radiation was analyzed in waters of the Beagle Channel at the mouth of the Lapataia River, Ushuaia, Tierra del Fuego. Between October and November 2004, we incubated the samples in coincidence with the spring stratospheric ozone depletion, which regularly produces an increase in the doses of...
Article
Full-text available
RESUMEN Se analizó la producción de peróxido de hidrógeno (H 2 O 2) en función de la dosis de radiación solar en aguas del Canal Beagle, en la desembocadura del Río Lapataia, Ushuaia (Tierra del Fuego, Argentina). El estudio se realizó entre Octubre y Noviembre de 2004. Durante dicho período se produce anualmente una disminución en la concentración...
Article
Full-text available
We studied CO2 and O2 dynamics in the western Antarctic Peninsula (WAP) waters in relation to (1) phytoplankton biomass, (2) microbial community primary production and respiration, and (3), for the first time, phytoplankton composition, during summer and fall in 3 consecutive years (2002, 2003 and 2004). The areal average of ΔpCO2 (the difference b...
Article
Full-text available
The combined effects of increased UV-B and temperature on natural marine phytoplankton from the St. Lawrence Estuary (Canada) were examined in an 8 d mesocosm experiment carried out in Rimouski (Quebec, Canada) in August 2008. We tested the hypothesis that in creased temperature (+3 degrees C) will offset algal growth suppression by UV-B (78% UV-B...
Article
Full-text available
In January 1999, unialgal cultures of the diatom Thalassiosira sp., solate from natural phyto-plankton assemblages from Potter Cove, Antarctica, were exposed to solar ultraviolet radiation (UVR, 280400 nm) in order to study the long-term acclimation of this species. Ultraviolet radiation B (UVBR, 280-315 nm) inhibited the growth rate during the fir...
Article
In January 1999, unialgal cultures of the diatom Thalassiosira sp., solate from natural phyto-plankton assemblages from Potter Cove, Antarctica, were exposed to solar ultraviolet radiation (UVR, 280400 nm) in order to study the long-term acclimation of this species. Ultraviolet radiation B (UVBR, 280-315 nm) inhibited the growth rate during the fir...
Article
Full-text available
In January 1999, unialgal cultures of the diatom Thalassiosira sp., solate from natural phyto-plankton assemblages from Potter Cove, Antarctica, were exposed to solar ultraviolet radiation (UVR, 280-400 nm) in order to study the long-term acclimation of this species. Ultraviolet radiation B (UVBR, 280-315 nm) inhibited the growth rate during the fi...
Article
Full-text available
Among the few existing works on seasonal variation in metabolic rate of polar species, most have been conducted during summer due to logistic constraints and have been focused on species that cease feeding during winter. In this work, we present the first extensive data set on the seasonal variation in metabolic rate of G. antarctica, an abundant a...
Article
Full-text available
One of the adaptations whereby phytoplankton can alleviate damage induced by ultraviolet radiation (280-400 nm) is the synthesis of mycosporine-like amino acids (MAAs). The synthesis of MAAs was studied after exposure of the Antarctic diatom Thalassiosira sp. isolated from Potter Cove (South Shetland Is., Antarctica) to 2 treatments with a solar si...
Article
Full-text available
Although winter conditions play a major role in determining the productivity of the western Antarctic Peninsula (WAP) waters for the following spring and summer, a few studies have dealt with the seasonal variability of microorganisms in the WAP in winter. Moreover, because of regional warming, sea-ice retreat is happening earlier in spring, at the...
Article
Full-text available
The temporal changes in dissolved inorganic (DIC) and organic carbon concentrations (DOC) were monitored from late autumn to spring 2006 in the Scholaert Channel, West Antarctic Peninsula. Surface DIC spanned a small range (2163.3 to 2194.5 mmol kg -1), increasing from late autumn to winter and then decreasing in spring. An excess of DOC (7.0–63.6...
Article
Full-text available
Abstract The effect of UVR on the viability of the culturable bacterial community fraction (CBC), and two of their isolated components (Arthrobacter-UVvi and Bizionia-UVps), was studied in the top few metres of the water column at Potter Cove, King George Island, Antarctica. Quartz flasks containing CBC from surface waters were exposed to solar rad...
Article
Full-text available
Article
The constitutional law captures the democratic decision of the people and organizes fundamentally two processes: that of liberty and that of power, both of which pursue with different tools the same aim: to regulate the coexistence of citizens and to foster tolerance. Democracy is realized and updated thanks to the processes that shall take place w...
Article
Full-text available
El Derecho constitucional capta la decisión democrática del pueblo y organiza fundamentalmente dos procesos: el de la libertad y el del poder, que persiguen con piezas distintas idéntico fin: ordenar la convivencia entre los ciudadanos y facilitar la tolerancia. La democracia se realiza y actualiza merced a los procesos que deben desenvolverse dent...
Article
Full-text available
The studies on the effects of ultraviolet radiation (UVR, 240-400 nm) on bacteria and phytoplankton in Potter Cove started in 1988. A set of publications including PhD theses were produced, while other studies are still ongoing. Here we attempt to synthesize the knowledge gained on this subject along the years in an integral way, additionally inclu...
Article
Full-text available
The distribution of six Pseudo-nitzschia species and their relationship with environmental conditions were studied for the first time in a vast zone of the Weddell Sea (∼61–77°S, Antarctica). Both qualitative and quantitative phytoplankton samples, collected during summer 2004, were examined using light and scanning electron microscopy. Phytoplankt...
Article
Full-text available
und Meeresforschung Am Handelshafen 12 -Geb. E 27570 Bremerhaven * This work is dedicated to the memory of Augusto "Alfa" Thibaud and Teófilo González, who lost their lives in a glacier crevasse near Jubany during the overwintering in 2005.
Article
Full-text available
In the Antarctic marine ecosystem bacteria play a key role in the biogeochemical cycles, processing 80% of the primary production. In these ecosystems UV radiation can significantly penetrate the water column, producing deleterious effects on the inhabiting microorganisms. The increase in the UV radiation caused by the thinning of the ozone layer c...
Conference Paper
En el ecosistema marino antártico, las bacterias juegan un papel fundamental en el ciclo de la materia procesando hasta un 80% de la producción primaria. En estoe ecosistema, la radiación UV puede penetrar profundamente en la columna de agua, ejerciendo efectos deletéreos sobre los microorganismos que los habitan. El incremento de la radiación UV c...
Article
Full-text available
The influence of the plankton community structure on carbon dynamics was studied in the surface waters of the Argentinean continental shelf (SW Atlantic Ocean) in summer and fall 2002, 2003 and 2004. The horizontal changes in plankton community respiration (R), net community pro- duction (NCP) and gross primary production (GPP) were (1) compared wi...
Article
Full-text available
The distribution pattern of Pseudo-nitzschia species, associated phytoplankton flora and its relationships with main environmental factors were studied for the first time in continental shelf surface waters of the Argentine Sea (Southwestern Atlantic Ocean, 38–55°S). Both qualitative and quantitative samples, collected during summer and fall 2003,...
Article
Full-text available
The impact of UV-B radiation (UVBR; 280-320 nm) on lower levels of a natural plankton assemblage (bacteria, phytoplankton and microzooplankton) from the St. Lawrence Estuary was studied during 9 days using several immersed outdoor mesocosms. Two exposure treatments were used in triplicate mesocosms: natural UVBR (N treatment, considered as the cont...
Article
Full-text available
In studies of the biological effects of UV radiation, ozone depletion can be mimicked by performing the study under ambient conditions and adding radiation with UV-B lamps. We evaluated this methodology at three different locations along a latitudinal gradient: Rimouski (Canada), Ubatuba (Brazil) and Ushuaia (Argentina). Experiments of the effect o...
Article
Full-text available
We present a mathematical model for a phytoplankton-zooplankton system, based on a predator-prey scheme. The model considers the effects of sinking in the phytoplankton, vertical mixing and attenuation of photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) in the water column. In a first approach, the model was studied under c...
Article
The effect of UVB radiation (UVBR, 290-320 nm) on the dynamics of the lower levels of the marine plankton community was modeled. The model was built using differential equations and shows a good fit to experimental data collected in mesocosms (defined as large enclosures of 1500 L filled with natural marine waters). Some unexpected results appear t...
Article
This article describes the use of group model building to facilitate interaction with stakeholders, synthesize research results and assist in the development of hypotheses about climate change at the global level in relation to UV-B radiation and ecosystem service valuation. The objective was to provide a platform for integration of the various res...
Article
UV irradiance has a broad range of effects on marine planktonic organisms. Direct and indirect effects on individual organisms have complex impacts on food-web structure and dynamics, with implications for carbon and nutrient cycling. Mesocosm experiments are well suited for the study of such complex interrelationships. Mesocosms offer the possibil...
Article
Full-text available
We present a mathematical model for a phytoplankton- zooplankton system, based on a predator-prey scheme. The model considers the effects of sinking in the phytoplankton, vertical mixing and attenuation of photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) in the water column. In a first approach, the model was studied under...
Article
Full-text available
The aim of this work was to investigate the effect of different fractions of UVR on two Antarctic marine bacteria (Arthrobacter UVvi and FCB-related UVps strains) and to study the relationship between the bacterial viability and the UVB dose. Ten experiments exposing strains to natural solar radiation were conducted in Potter Cove, South Shetland I...
Article
Full-text available
The influence of nitrate enrichment on the response of natural phytoplankton populations to enhanced UV-B radiation was tested during a series of week-long mesocosm (1800 l) experiments carried out in Rimouski (Canada), Ubatuba (Brazil) and Ushuaia (southern Argentina). We set up 2 mesocosms at each site, one was submitted to ambient UV-B levels wh...
Article
Solar UVB radiation (280-320 nm) is known to have detrimental effects on marine phytoplankton. Associated with the seasonal ozone hole in Antarctica, stratospheric ozone depletion occasionally influences the sub-Antarctic (Beagle Channel, Argentina) region, enhancing levels of UVB. The primary objective of this work was to study the effects of seve...
Article
Poder de reforma es político. Reforma y control judicial de constitucionalidad son garantías constitucionales. Puede suceder que la reforma, en lugar de defender, ataque la Constitución, por infringir límites prefijados para su actuación. Se describen y clasifican sentencias de la Corte Suprema de Justicia de la Argentina sobre la cuestión. Sosteng...