Massana R.,CSIC - Institute of Marine Sciences
Annual Review of Microbiology | Year: 2011
The eukaryotic picoplankton is a heterogeneous collection of small protists 1 to 3 μm in size populating surface oceans at abundances of 10 2 to 10 4 cells ml -1. Pigmented cells are important primary producers that are at the base of food webs. Colorless cells are mostly bacterivores and play key roles in channeling bacteria to higher trophic levels as well as in nutrient recycling. Mixotrophy and parasitism are relevant but less investigated trophic paths. Molecular surveys of picoeukaryotes have unveiled a large phylogenetic diversity and new lineages, and it is critical to understand the ecological and evolutionary significance of this large and novel diversity. A main goal is to assess how individuals are organized in taxonomic units and how they participate in ecological processes. Picoeukaryotes are convincingly integral members of marine ecosystems in terms of cell abundance, biomass, activity, and diversity and they play crucial roles in food webs and biogeochemical cycles. © 2011 by Annual Reviews. All rights reserved.
Montoya J.M.,CSIC - Institute of Marine Sciences |
Raffaelli D.,University of York
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2010
Climate change is real. The wrangling debates are over, and we now need to move onto a predictive ecology that will allow managers of landscapes and policy makers to adapt to the likely changes in biodiversity over the coming decades. There is ample evidence that ecological responses are already occurring at the individual species (population) level. The challenge is how to synthesize the growing list of such observations with a coherent body of theory that will enable us to predict where and when changes will occur, what the consequences might be for the conservation and sustainable use of biodiversity and what we might do practically in order to maintain those systems in as good condition as possible. It is thus necessary to investigate the effects of climate change at the ecosystem level and to consider novel emergent ecosystems composed of new species assemblages arising from differential rates of range shifts of species. Here, we present current knowledge on the effects of climate change on biotic interactions and ecosystem services supply, and summarize the papers included in this volume. We discuss how resilient ecosystems are in the face of the multiple components that characterize climate change, and suggest which current ecological theories may be used as a starting point to predict ecosystem-level effects of climate change. © 2010 The Royal Society.
Pelejero C.,Catalan Institution for Research and Advanced Studies |
Calvo E.,CSIC - Institute of Marine Sciences |
Hoegh-Guldberg O.,University of Queensland
Trends in Ecology and Evolution | Year: 2010
The anthropogenic rise in atmospheric CO2 is driving fundamental and unprecedented changes in the chemistry of the oceans. This has led to changes in the physiology of a wide variety of marine organisms and, consequently, the ecology of the ocean. This review explores recent advances in our understanding of ocean acidification with a particular emphasis on past changes to ocean chemistry and what they can tell us about present and future changes. We argue that ocean conditions are already more extreme than those experienced by marine organisms and ecosystems for millions of years, emphasising the urgent need to adopt policies that drastically reduce CO2 emissions. © 2010 Elsevier Ltd.
Garcia-Olivares A.,CSIC - Institute of Marine Sciences
Environmental Innovation and Societal Transitions | Year: 2015
Photovoltaic (PV) energy is reaching full grid parity in many regions, which can trigger a global deployment of home PV panels and PV systems near municipalities. The scaling-up of conventional crystalline silicon panels to the terawatt range is not feasible due to insufficient global silver reserves. However, recent copper metallization in front and rear contacts of silicon cells avoids the use of silver. This opens the door to a rapid and wide diffusion of PV energy. Intelligent grids allow the integration of decentralized and centralized generators of all types and size. A regional integration based on such grids can compensate the intermittency of PV production with the storage capacity of hydroelectricity and Concentrating Solar Power stations. It makes the best of both systems: local autonomy through home PV and supply stability through large renewable stations. © 2015 Elsevier B.V. All rights reserved.
Piferrer F.,CSIC - Institute of Marine Sciences
Developmental Dynamics | Year: 2013
Epigenetics is commonly defined as the study of heritable changes in gene function that cannot be explained by changes in DNA sequence. The three major epigenetic mechanisms for gene expression regulation include DNA methylation, histone modifications, and non-coding RNAs. Epigenetic mechanisms provide organisms with the ability to integrate genomic and environmental information to modify the activity of their genes for generating a particular phenotype. During development, cells differentiate, acquire, and maintain identity through changes in gene expression. This is crucial for sex determination and differentiation, which are among the most important developmental processes for the proper functioning and perpetuation of species. This review summarizes studies showing how epigenetic regulatory mechanisms contribute to sex determination and reproductive organ formation in plants, invertebrates, and vertebrates. Further progress will be made by integrating several approaches, including genomics and Next Generation Sequencing to create epigenetic maps related to different aspects of sex determination and gonadogenesis. Epigenetics will also contribute to understand the etiology of several disorders of sexual development. It also might play a significant role in the control of reproduction in animal farm production and will aid in recognizing the environmental versus genetic influences on sex determination of sensitive species in a global change scenario. Developmental Dynamics 242:360-370, 2013. © 2013 Wiley Periodicals, Inc.
Sarmento H.,CSIC - Institute of Marine Sciences
Hydrobiologia | Year: 2012
Limnology has traditionally been a science of temperate regions. Long-term studies are not common in tropical regions despite the number of large tropical lakes that constitute a significant proportion of global freshwater resources. A number of comparative studies have shown that tropical lakes are different from temperate lakes in some fundamental ways. Constantly high temperature and radiation have strong consequences for stratification and biological processes. Previous studies suggested that higher primary production on a given nutrient base in tropical lakes is related to their higher decomposition rates. Moreover, lower efficiency in transforming primary production to higher trophic levels in tropical lakes also has been postulated as a difference. Data on the microbial processes in tropical lakes are scarce, but fail showing any significant difference in epilimnetic decomposition (bacterial) processes between temperate and tropical aquatic systems. The most significant differences found so far are in autotrophic and consumer community composition and body size, which constrain the upper compartments of the food web in a deterministic way. The reconciliation of ecological theory and observations yields a conceptual framework that illustrates likely structural variations in food webs along the latitudinal gradient. © 2012 Springer Science+Business Media B.V.
Puig P.,CSIC - Institute of Marine Sciences |
Palanques A.,CSIC - Institute of Marine Sciences |
Martin J.,CSIC - Institute of Marine Sciences
Annual Review of Marine Science | Year: 2014
Submarine canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through canyons. Additionally, internal waves periodically resuspend ephemeral deposits within canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches for decades or centuries before being completely or partially flushed farther down-canyon by large sediment failures. Copyright © 2014 by Annual Reviews.
Viudez A.,CSIC - Institute of Marine Sciences
Quarterly Journal of the Royal Meteorological Society | Year: 2015
The mass anomaly associated with piecewise constant symmetric potential vorticity (PV) vortices in rotating and stratified fluids is investigated. It is found that the absolute value of this mass anomaly depends linearly on the distance to the vortex centre and is therefore unbounded. This property of PV ball vortices is found under quasi-geostrophic and semi-geostrophic approximations, as well as the more general Euler dynamics. To overcome this difficulty, a new class of vortices is introduced. These vortices occupy, in all senses, a limited amount of volume and are therefore bounded. Unlike PV ball vortices, which have homogeneous PV, the new vortices have a central core of continuous PV of one sign and an outer shell of opposite signed PV, such that the amount of PV anomaly is zero. © 2015 Royal Meteorological Society.
Sarmento H.,CSIC - Institute of Marine Sciences |
Gasol J.M.,CSIC - Institute of Marine Sciences
Environmental Microbiology | Year: 2012
Phytoplankton and heterotrophic prokaryotes are major components of the microbial food web and interact continuously: heterotrophic prokaryotes utilize the dissolved organic carbon derived from phytoplankton exudation or cell lysis (DOCp), and mineralization by heterotrophic prokaryotes provides inorganic nutrients for phytoplankton. For this reason, these communities are expected to be closely linked, although the study of the interactions between them is still a major challenge. Recent studies have presented interactions between phytoplankton and heterotrophic prokaryotes based on coexistence or covariation throughout a time-series. However, a real quantification of the carbon flow within these networks (defined as the interaction strength, IS) has not been achieved yet. This is critical to understand the selectivity degree of bacteria responding to specific algal DOCp. Here we used microautoradiography to quantify the preferences of the major heterotrophic prokaryote phylogenetic groups on DOC derived from several representative phytoplankton species, and expressed these preferences as an IS value. The distribution of the ISs was not random but rather skewed towards weak interactions, in a similar way as the distributions described for stable complex non-microbial ecosystems, indicating that there are some cases of high specificity on the use of specific algal DOCp by some bacterial groups, but weak interactions are more common and may be relevant as well. The variety of IS patterns observed supports the view that the vast range of different resources (different types of organic molecules) available in the sea selects and maintains the high levels of diversity described for marine bacterioplankton. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.
Pedrs-Ali C.,CSIC - Institute of Marine Sciences
Annual Review of Marine Science | Year: 2012
All communities are dominated by a few species that account for most of the biomass and carbon cycling. On the other hand, a large number of species are represented by only a few individuals. In the case of bacteria, these rare species were until recently invisible. Owing to their low numbers, conventional molecular techniques could not retrieve them. Isolation in pure culture was the only way to identify some of them, but current culturing techniques are unable to isolate most of the bacteria in nature. The recent development of fast and cheap high-throughput sequencing has begun to allow access to the rare species. In the case of bacteria, the exploration of this rare biosphere has several points of interest. First, it will eventually produce a reasonable estimate of the total number of bacterial taxa in the oceans; right now, we do not even know the right order of magnitude. Second, it will answer the question of whether "everything is everywhere." Third, it will require hypothesizing and testing the ecological mechanisms that allow subsistence of many species in low numbers. And fourth, it will open an avenue of research into the immense reserve of genes with potential applications hidden in the rare biosphere. Copyright © 2012 by Annual Reviews. All rights reserved.