Andrea Malits

Andrea Malits
National Scientific and Technical Research Council | conicet · CADIC - Centro Austral de Investigaciones cientificas

PhD

About

31
Publications
6,892
Reads
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1,607
Citations
Additional affiliations
April 2011 - October 2012
Institut de Ciències del Mar
Position
  • PostDoc Position
November 2003 - October 2005
Sorbonne Université
Position
  • PostDoc Position
February 2003 - October 2005

Publications

Publications (31)
Presentation
The Beagle Channel (BC) is a sub-Antarctic coastal marine environment (~54.5ºS) that connects the Pacific and Atlantic oceans and is influenced by runoff, wind and seasonal mixing. Along its 300 km length, the BC has hydrological sub-basins (SC) separated from each other by bathymetric barriers. The object of this study focuses on the internal SC (...
Article
Since the impacts of climate change on marine benthic organisms are already detectable in many aspects, it is crucial to address the potential responses of marine organisms and their interactions with the environment. In particular, the study of phenotype traits along latitudinal gradients is a powerful tool for exploring species responses in a cha...
Presentation
Full-text available
Category Scientific Program Abstract > Special Sessions > SS80 Dynamics of organic matter in the river-ocean continuum: From analytical methods, molecular and isotope geochemistry, to ecosystem modelling Preference: Oral
Article
Full-text available
Anthropogenic carbon emissions are causing changes in seawater carbonate chemistry including a decline in the pH of the oceans. While its aftermath for calcifying microbes has been widely studied, the effect of ocean acidification (OA) on marine viruses and their microbial hosts is controversial, and even more in combination with another anthropoge...
Article
Full-text available
We provide a 16S rRNA gene dataset of prokaryotic assemblages of a subantarctic marine ecosystem. Samples were collected at 2 stations (one near Ushuaia Bay and the other close to Bridges islands in the Beagle Channel). At each station, 2 depths (subsurface and bottom waters) were sampled in february, march, may and september during 2018, giving a...
Article
The sub-Antarctic Namuncurá Marine Protected Area at Burdwood Bank (NMPA/BB) is an area of favorable conditions for the development of planktonic organisms and the sustenance of numerous species of ecological importance. The current study aimed to evaluate the spatial distribution of the abundance, biomass, community structure, and functional diver...
Article
Full-text available
Marine microbial plankton hold high structural and functional diversity, however, high-resolution data are lacking in a large part of the Global Ocean, such as in subpolar areas of the SW Atlantic. The Burdwood Bank (BB) is a submerged plateau (average depth 100 m) that constitutes the westernmost segment of the North Scotia Ridge (54°-55°S; 56°-62...
Conference Paper
Full-text available
The Beagle Channel and in particular Ushuaia Bay, are subantarctic environments where mixing processes between oceanic and continental waters, and strong land-to-sea exchanges of water and particulate matter are taking place. Multiple sources of particulate matter to the channel can be identified: glaciers, rivers, direct runoff from forests along...
Conference Paper
Full-text available
El Canal Beagle (CB) es un ambiente marino costero austral complejo, que conecta los océanos Pacífico y Atlántico, y que recibe en su recorrido importantes aportes terrígenos por parte de las cadenas montañosas de los Andes Fueguinos y otros aportes de materia orgánica de origen antrópico por parte de la ciudad de Ushuaia. Entre los días 27 a 31 de...
Poster
Full-text available
El Canal Beagle (CB) es un ambiente marino costero austral complejo, que conecta los océanos Pacífico y Atlántico, y que recibe en su recorrido importantes aportes terrígenos por parte de las cadenas montañosas de los Andes Fueguinos y otros aportes de materia orgánica de origen antrópico por parte de la ciudad de Ushuaia. Entre los días 27 a 31 de...
Conference Paper
Se presentan en este trabajo datos de oxígeno disuelto junto con parámetros de contexto (temperatura, salinidad, clorofila, concentración de sólidos en suspensión) en Bahía Ushuaia y zonas adyacentes del Canal Beagle. El muestreo incluyó el perfilado de la columna de agua y análisis de agua simultáneos con alta resolución espacio-temporal durante d...
Conference Paper
Se presentan en este trabajo resultados de un estudio de distribución espacio-temporal de oxígeno disuelto como posible indicador de calidad ambiental en las aguas del Canal Beagle, con particular énfasis en Bahía Ushuaia como punto de intersección de procesos naturales pre-industriales y perturbaciones recientes de origen antrópico. Perfiles vert...
Conference Paper
El Canal Beagle es un pasaje interoceánico conectando los Océanos Pacifico y Atlántico en el extremo sur de Sudamérica, donde confluyen intensos procesos de mezcla entre aguas marinas y continentales y una creciente presión antrópica. Desde julio 2014 se caracterizó la variabilidad estacional y espacial de las estructuras termohalinas en el Canal B...
Article
Full-text available
We investigated the effects of an increase in dissolved CO2 on the microbial communities of the Mediterranean Sea during two mesocosm experiments in two contrasting seasons: winter, at the peak of the annual phytoplankton bloom, and summer, under lownutrient conditions. The experiments included treatments with acidification and nutrient addition, a...
Article
Full-text available
Black Carbon (BC) is the carbonaceous residue of the incomplete combustion of fossil fuels and biomass and encompasses a range of chemically heterogeneous substances from partly charred plant material to highly condensed soot aerosols. We addressed the potential role of BC aerosol deposition on marine microbial processes in the ocean by investigati...
Article
Full-text available
Above the Kerguelen Plateau in the Southern Ocean natural iron fertilization sustains a large phytoplank-ton bloom over 3 months during austral summer. During the KEOPS1 project (KErguelen Ocean and Plateau compared Study1) we sampled this phytoplankton bloom during its declining phase along with the surrounding high-nutrient–low-chlorophyll (HNLC)...
Article
Full-text available
Above the Kerguelen Plateau in the Southern Ocean natural iron fertilization sustains a large phytoplank-ton bloom over 3 months during austral summer. During the KEOPS1 project (KErguelen Ocean and Plateau compared Study1) we sampled this phytoplankton bloom during its declining phase along with the surrounding high-nutrient–low-chlorophyll (HNLC)...
Chapter
Full-text available
Black carbon (BC, soot) has anthropogenic and non-anthropogenic origins. While BC can contribute significantly to dissolved and particulate organic carbon in marine systems, data are still sparse for the water column. Due to the association of BC aerosols with organic acids, the deposition of BC aerosols at the surface of the ocean can decrease the...
Article
We demonstrate here results showing that bottom-up and top-down control mechanisms can operate simultaneously and in concert in marine microbial food webs, controlling prokaryote diversity by a combination of viral lysis and substrate limitation. Models in microbial ecology predict that a shift in the type of bacterial growth rate limitation is exp...
Article
Full-text available
A factorial design was used to assess the roles of turbulence and viral infection in prokaryotic production and diversity in a spring phytoplankton bloom experiment in the Bay of Villefranche, France. Several consistent trends were observed in 2 experiments: (1) turbulence stimulated prokaryotic production, (2) prokaryotic cell length increased in...
Article
Full-text available
Narrow annual ranges of temperature characterize polar waters. Consequently, small increases in temperature could significantly affect the metabolic processes of marine microorganisms. We investigated the response of bacterial heterotrophic production (BHP) and grazing rates to small temperature changes in 3 zones near the western Antarctic Peninsu...
Article
A factorial design was used to assess the roles of turbulence and viral infection in prokaryotic production and diversity in a spring phytoplankton bloom experiment in the Bay of Ville-franche, France, Several consistent trends were observed in 2 experiments: (1) turbulence stimulated prokaryotic production, (2) prokaryotic cell length increased in...
Article
To investigate the potential effects of viruses on bacterial respiration (BR), production (BP) and growth efficiency (BGE), experiments were performed using natural microbial communities from the coastal Mediterranean Sea, from a typical high-nutrient low-chlorophyll (HNLC) region in the Southern Ocean and from a naturally iron (Fe)-fertilized alga...
Article
Full-text available
The availability of iron limits primary productivity and the associated uptake of carbon over large areas of the ocean. Iron thus plays an important role in the carbon cycle, and changes in its supply to the surface ocean may have had a significant effect on atmospheric carbon dioxide concentrations over glacial-interglacial cycles. To date, the ro...
Chapter
One and a half decades ago, it was detected that phages are much more abundant in the water column of freshwater and marine habitats than previously thought and that they can cause significant mortality of bacterioplankton. Methods in phage community ecology have been developed to assess phage-induced mortality of bacterioplankton and its role for...
Article
Full-text available
The results of empirical studies have revealed links between phytoplankton and bacterioplankton, such as the frequent correlation between chlorophyll a and bulk bacterial abundance and production. Nevertheless, little is known about possible links at the level of specific taxonomic groups. To investigate this issue, seawater microcosm experiments w...
Article
We examined the influence of small-scale turbulence and its associated shear on bacterioplankton abundance and cell size. We incubated natural microbial assemblages and bacteria-only fractions and subjected them to treatments with turbulence and additions of mineral nutrients and/or organic carbon. Bacterial abundance was not affected directly by t...
Article
Full-text available
The control exerted by different intensities and temporal inputs of small-scale turbulence on the balance between C production and respiration in planktonic communities has been studied by means of laboratory microcosms. The different turbulence conditions modified the temporal pattern of phytoplankton (chlorophyll a) and total biomass development....
Article
Seawater-atmosphere O(2) exchange rates were experimentally measured in open-top laboratory microcosms. The objective was to establish the relationships between turbulence and oxygen transfer velocity, and thus correct continuously measured day-night changes in dissolved oxygen as estimates of planktonic primary production and respiration. After sa...

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Projects

Projects (5)
Project
I am interested in coastal oceanography and marine microbiology. The framework of my PhD research are the spatial and seasonal patterns of the microbial food web dynamics and functioning in Ushuaia Bay and along the Beagle Channel (Tierra del Fuego, South America). Supervisors, Dr. Andrea Malits, Dr. Mariana Lozada, and Dr. Jacobo Martin.
Project
To study the circulation and dynamics of suspended particulate matter in Ushuaia Bay (Tierra del Fuego, Argentina)
Project
The microbial food web is a key component in the carbon transfer and nutrient regeneration in marine ecosystems. Dissolved organic carbon (DOC) released into the ocean through the excretion of phytoplankton and zooplankton, cell lysis by viral infection and hydrolysis of terrigenous particles, is mainly consumed by heterotrophic bacteria (sensu stricto Bacteria and Archaea), which act as an intermediate link between DOC and higher trophic levels through the microbial loop. Viral lysis of bacteria decreases the efficiency of the microbial loop by transferring up to 40% of organic carbon from photosynthetic organisms to the DOC pool. The Beagle Channel (Tierra del Fuego, Argentina) is a glacial valley invaded by the sea that communicates the Atlantic and Pacific oceans. This interoceanic passage receives important freshwater inputs from rivers and glaciers that give an estuarine character to its waters (salinities in the range 28-31). On the other hand, the submerged plateau Burdwood Bank (Southern Atlantic Ocean), located 150 km east of the State Island (Tierra del Fuego) and recently declared marine protected area, represents a purely oceanic environment. The present project aims to study the functioning of the microbial food web and its implications for the biogeochemical fluxes in marine subpolar systems influenced by contrasting environmental conditions. To achieve this objective, we propose a study of the spatio-temporal fluctuations of the abundance, activity, distribution and diversity of microorganisms in the Beagle Channel and on Burdwood Bank, with special attention to the role of viruses and protists in regulating bacterial biomass and diversity and the consequences for biogeochemical fluxes in contrasting marine environments of the same latitude.