Julia Boras - Academia.edu (original) (raw)

Papers by Julia Boras

Frontiers in Microbiology, 2021

Anthropogenic carbon emissions are causing changes in seawater carbonate chemistry including a de... more 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 anthropogenic stressor, i.e., human-induced nutrient loads. In this study, two mesocosm acidification experiments with Mediterranean waters from different seasons revealed distinct effects of OA on viruses and viral-mediated prokaryotic mortality depending on the trophic state and the successional stage of the plankton community. In the winter bloom situation, low fluorescence viruses, the most abundant virus-like particle (VLP) subpopulation comprising mostly bacteriophages, were negatively affected by lowered pH with nutrient addition, while the bacterial host abundance was stimulated. High fluorescence viruses, containing cyanophages, were stimul...

Trabajo presentado en ASLO Aquatic Sciences Meeting (2011), celebrado en San Juan (Puerto Rico), ... more Trabajo presentado en ASLO Aquatic Sciences Meeting (2011), celebrado en San Juan (Puerto Rico), del 13 al 17 de febrero de 2011

Memoria de tesis doctoral presentada por Julia Anna Boras para optar al grado de Doctora por la U... more Memoria de tesis doctoral presentada por Julia Anna Boras para optar al grado de Doctora por la Universitat de Barcelona (UB), realizada bajo la direccion de la Dra. Ma Dolors Vaque Vidal y la Dra. Maria Montserrat Sala Farre del Institut de Ciencies del Mar (ICM-CSIC) y la Dra. Montserrat Vidal.-- 222 pages

Poster presentado en el VIII Simposio de Estudios Polares (8th Symposium on Polar Studies), celeb... more Poster presentado en el VIII Simposio de Estudios Polares (8th Symposium on Polar Studies), celebrado del 7 al 9 de septiembre de 2011 en Palma de Mallorca (Espana)

Trabajo presentado en Arctic Frontiers 2011, Arctic Tipping Points, celebrado en Tromso (Noruega)... more Trabajo presentado en Arctic Frontiers 2011, Arctic Tipping Points, celebrado en Tromso (Noruega), del 23 al 28 de enero de 2011. El libro de abstracts se publico como: 2011 Abstracts. Arctic Frontiers. The Arctic in the Earth System Perspective: the role of tiping points. Tromso: [University of Tromso, 2011]

Microorganisms, 2021

The ocean surface microlayer (SML), with physicochemical characteristics different from those of ... more The ocean surface microlayer (SML), with physicochemical characteristics different from those of subsurface waters (SSW), results in dense and active viral and microbial communities that may favor virus–host interactions. Conversely, wind speed and/or UV radiation could adversely affect virus infection. Furthermore, in polar regions, organic and inorganic nutrient inputs from melting ice may increase microbial activity in the SML. Since the role of viruses in the microbial food web of the SML is poorly understood in polar oceans, we aimed to study the impact of viruses on prokaryotic communities in the SML and in the SSW in Arctic and Antarctic waters. We hypothesized that a higher viral activity in the SML than in the SSW in both polar systems would be observed. We measured viral and prokaryote abundances, virus-mediated mortality on prokaryotes, heterotrophic and phototrophic nanoflagellate abundance, and environmental factors. In both polar zones, we found small differences in en...

Limnology and Oceanography, 2010

The effect of oceanic eddies on microbial processes, with emphasis on bacterial losses due to pro... more The effect of oceanic eddies on microbial processes, with emphasis on bacterial losses due to protists and phages, was examined in the Canary Current region (subtropical northeast Atlantic) through ...

Environmental Microbiology, 2009

Aquatic Microbial Ecology, 2013

Journal of Plankton Research, 2011

Science Advances

Viruses are a key component of marine ecosystems, but the assessment of their global role in regu... more Viruses are a key component of marine ecosystems, but the assessment of their global role in regulating microbial communities and the flux of carbon is precluded by a paucity of data, particularly in the deep ocean. We assessed patterns in viral abundance and production and the role of viral lysis as a driver of prokaryote mortality, from surface to bathypelagic layers, across the tropical and subtropical oceans. Viral abundance showed significant differences between oceans in the epipelagic and mesopelagic, but not in the bathypelagic, and decreased with depth, with an average power-law scaling exponent of −1.03 km −1 from an average of 7.76 × 10 6 viruses ml −1 in the epipelagic to 0.62 × 10 6 viruses ml −1 in the bathypelagic layer with an average integrated (0 to 4000 m) viral stock of about 0.004 to 0.044 g C m −2 , half of which is found below 775 m. Lysogenic viral production was higher than lytic viral production in surface waters, whereas the opposite was found in the bathypelagic, where prokaryotic mortality due to viruses was estimated to be 60 times higher than grazing. Free viruses had turnover times of 0.1 days in the bathypelagic, revealing that viruses in the bathypelagic are highly dynamic. On the basis of the rates of lysed prokaryotic cells, we estimated that viruses release 145 Gt C year −1 in the global tropical and subtropical oceans. The active viral processes reported here demonstrate the importance of viruses in the production of dissolved organic carbon in the dark ocean, a major pathway in carbon cycling.

Frontiers in microbiology, 2017

During the Austral summer 2009 we studied three areas surrounding the Antarctic Peninsula: the Be... more During the Austral summer 2009 we studied three areas surrounding the Antarctic Peninsula: the Bellingshausen Sea, the Bransfield Strait and the Weddell Sea. We aimed to investigate, whether viruses or protists were the main agents inducing prokaryotic mortality rates, and the sensitivity to temperature of prokaryotic heterotrophic production and mortality based on the activation energy (Ea) for each process. Seawater samples were taken at seven depths (0.1-100 m) to quantify viruses, prokaryotes and protists abundances, and heterotrophic prokaryotic production (PHP). Viral lytic production, lysogeny, and mortality rates of prokaryotes due to viruses and protists were estimated at surface (0.1-1 m) and at the Deep Fluorescence Maximum (DFM, 12-55 m) at eight representative stations of the three areas. The average viral lytic production ranged from 1.0 ± 0.3 × 10(7) viruses ml(-1) d(-1) in the Bellingshausen Sea to1.3 ± 0.7 × 10(7) viruses ml(-1) d(-1) in the Bransfield Strait, while...