Eva Ortega-Retuerta

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Phytoplankton blooms over Arctic Ocean continental shelves are thought to be restricted to waters free of sea ice. Here, we document a massive phytoplankton bloom beneath fully consolidated pack ice far from the ice edge in the Chukchi Sea, where light transmission has increased in recent decades because of thinning ice cover and proliferation of melt(More)
During August 2009, measurements of bacterial abundance and nucleic acid content were made along with production and respiration in coastal waters of the Beaufort Sea (Arctic Ocean), an area influenced by the Mackenzie River inflow. The main purpose was to evaluate bacterial organic carbon processing with respect to local sources, mainly primary production(More)
Marine dissolved organic matter (DOM) is one of the largest reservoirs of reduced carbon on Earth. In the dark ocean (>200 m), most of this carbon is refractory DOM. This refractory DOM, largely produced during microbial mineralization of organic matter, includes humic-like substances generated in situ and detectable by fluorescence spectroscopy. Here we(More)
Global warming in the Arctic Ocean may result in changes to the stock and dynamics of nutrients that drive the activity of heterotrophic prokaryotes, a key component of the microbial food web. We performed 14 enrichment experiments during summer in the Beaufort and Chukchi Seas (Western Arctic Ocean), with C (acetate and/or glucose), N (nitrate and/or(More)
In inland waters, transparent exopolymer particles (TEP) can affect carbon export and sequestration in sediments with consequences for lake C budgets. We measured TEP concentration in 32 lakes from two contrasting lake districts covering wide ranges in biological and chemical characteristics. North temperate lakes, located in a wet region, have low to(More)
The study of transparent exopolymer particles (TEP) in the Mediterranean Sea is particularly relevant as they can be promoters of mucilage events, a frequent phenomenon there. We assessed the influence of bacterioplankton on TEP distribution and dynamics across the west–east axis of the Mediterranean Sea. We performed an extensive study of TEP, dissolved(More)
Chromophoric dissolved organic matter (CDOM), the optically active fraction of dissolved organic matter, is primarily generated by pelagic organisms in the open ocean. In this study, we experimentally determined the quantity and spectral quality of CDOM generated by bacterioplankton using two different substrates (with and without photoproducts) and by(More)
Sunlight reacts with dissolved organic matter (DOM) modifying its availability as bacterial substrate. We assessed the impact of DOM photoproducts and mineral nutrient supply on bacterial growth in seven inland waters from the South of Spain, where DOM is characterized by low chromophoric content and long residence time. Factorial experiments were performed(More)
Spatial increases and temporal shifts in outbreaks of gelatinous plankton have been observed over the past several decades in many estuarine and coastal ecosystems. The effects of these blooms on marine ecosystem functioning and particularly on the dynamics of the heterotrophic bacteria are still unclear. The response of the bacterial community from a(More)
Biogeochemical cycles impose strong restrictions to the organization of the Biosphere (Margalef, 1997). Therefore, Ecology needs to understand the causes and consequences of the global mobilization and distribution of elements. In this sense, the atmosphere is a major component of the Biosphere (sensu Vernadsky) as well as a pathway throughout which(More)