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En los últimos 20 años, más de la mitad del océano se está poniendo más verde debido al impacto de la acción humana, según un nuevo análisis de las imágenes por satélite

El pasado 15 de febrero se entregaban los premios Ciudad de Barcelona, entre los premiados, los investigadores del Instituto de Ciencias del Mar de Barcelona, Carmen García-Comas y Pedro Cermeño, en la categoría de Ciencias Ambientales y de la Tierra. Hablamos con los dos en el programa

Un estudi de l'Institut de Ciències del Mar, publicat a "Nature" i guardonat als Premis Ciutat de Barcelona, concilia les dues teories de l'ecologia evolutiva

Els jurats dels Premis Ciutat de Barcelona 2022 en la categoria de Ciències han fet públic aquest diumenge els veredictes i han acordat distingir els investigadors Carmen García-Comas i Pedro Cermeño, de l'Institut de Ciències del Mar CSIC, amb el guardó de Ciències Ambientals i de la Terra; la investigadora Marta Villegas, del grup Life Sciencies-Text Mining del Barcelona Supercomputing Center (BSC), amb el premi de Ciències Experimentals i Tecnologia; i la biòloga molecular i genetista turca Elvan Böke amb el guardó de Ciències de la Vida. Els Premis Ciutat de Barcelona tenen una dotació econòmica de 9.500 euros i la cerimònia d'entrega es farà el proper 15 de febrer al Saló de Cent de la capital catalana

[EN] Marine phytoplankton are responsible for approximately half of the photosynthetic production of organic matter (OM) and oxygen in Earth. The composition and reactivity of phytoplankton- derived OM influences two of the main C-sequestration mechanisms of the ocean: the biological carbon pump and the microbial carbon pump. Phytoplankton-derived OM can be classified as particulate (POM) or dissolved (DOM) and these size-fractions are subject to diverse production, consumption and transport processes involving biotic and abiotic interactions. Understanding how these processes influence OM composition and reactivity is essential to accurately describe the role of phytoplankton ecology in the marine Carbon cycle and ultimately in the regulation of Earth climate. This thesis aims, precisely, to better understand the controls over these processes. To do so, we combined fluorescence spectroscopy and elemental analysis of POM and DOM with multiple biotic and abiotic parameters during the development and decay of phytoplankton proliferations in micro- and mesocosm experiments and under natural conditions. The microcosm degradation experiment revealed that POM derived from diatom-dominated proliferations is degraded at a much slower rate than that of POM produced by a mixed phytoplankton community. In addition, accumulation of DOM of apparent recalcitrant nature was observed during the processing of diatom-derived POM. The analysis of four phytoplankton proliferations in Antarctic waters revealed that protein-like fluorescent OM was contributed by dissolved and particulate materials. The abundance and composition of phytoplankton and their interactions with viruses and grazers were identified as the main controls over the quantity and fractionation of protein-like fluorescent OM. By contrast, humic-like substances were mostly in the dissolved fraction, and their composition was related to photochemical degradation and microbial transformation. The mesocosm experiment showe, [ES] El fitoplancton marino es responsable de aproximadamente la mitad de la producción fotosintética de materia orgánica (OM) y de oxígeno en la Tierra. La composición y reactividad de la OM fitoplanctónica influye en dos de los principales mecanismos de captura de carbono del océano: la bomba biológica y la bomba microbiana. La OM derivada del fitoplancton se puede clasificar como particulada (POM) o disuelta (DOM) y estas dos fracciones están sujetas a diversos procesos de producción, consumo y transporte que involucran tanto interacciones bióticas como abióticas. Entender cómo estos procesos influyen en la composición y reactividad de la OM es esencial para describir de forma precisa el papel de la ecología del fitoplancton en el ciclo marino del carbono y, en última instancia, en la regulación del clima de la Tierra. Esta tesis está enfocada, precisamente, en comprender mejor los controles sobre estos procesos. Para hacerlo, combinamos análisis espectrofluorométricos y elementales de POM y DOM con múltiples parámetros bióticos y abióticos durante el desarrollo y el colapso de proliferaciones de fitoplancton en experimentos de micro- y mesocosmos y en condiciones naturales. El experimento de degradación de microcosmos desveló que la POM derivada de proliferaciones dominadas por diatomeas es degradada a un ritmo mucho más lento que aquella producida por comunidades fitoplanctónicas mixtas. Además, se observó una acumulación de DOM aparentemente recalcitrante durante el procesado de POM derivada de diatomeas. El análisis de cuatro proliferaciones de fitoplancton en aguas antárticas reveló que la OM fluorescente proteinácea tenía contribuciones de materiales disueltos y particulados. La abundancia y composición del fitoplancton y sus interacciones con virus y zooplancton fueron identificados como los principales controles sobre la cantidad y el fraccionamiento de la OM fluorescente proteinácea. Por el contrario, las sustancias húmicas se hallaban mayoritariamente e

As climate change unravels, ecosystems are facing a warming of the climate and an increase in extreme heat events that are unprecedented in recent geological history. We know very little of the ability of oceanic phytoplankton communities, key players in the regulation of Earth's climate by the oceans, to adapt to these changes. Quantifying the resilience of phytoplankton communities to environmental stressors by means of adaptive evolution is however crucial to accurately predict the response of marine ecosystems to climate change. In this work, we use an eco-evolutionary model to simulate the adaptive response of marine phytoplankton to temperature changes in an initially temperate oligotrophic water-column. By exploring a wide range of scenarios of phytoplankton adaptive capacity, we find that phytoplankton can adapt to temperature increases –even very large ones– as long as they occur over the time scale of a century. However, when rapid and extreme events of temperature change are considered, the phytoplankton adaptive capacity breaks down in a number of our scenarios in which primary productivity plummets as a result. This suggests that current Earth System Models assuming perfect phytoplankton adaptatedness to temperature might be overestimating the phytoplankton's resilience to climate change

Microbial communities are rich and complex in interactions. High-throughput sequencing platforms, allow to explore the microbial diversity, potential interaction networks and functioning. Microbial interactions are complex and dynamic which imply that traditional linear statistical approaches are not suitable to grasp these interactions. One nonlinear statistical tool available is the empirical dynamic modeling (EDM) and its variants, which are proving very promising. With EDM we can detect + versus - causal (i.e., who affects who) relationships. In this project we aim at exploring with metabarcoding and EDM tools the relationships between the complexity of microbial interactions and biomass production (i.e., functioning). A lot of experimental and observation work has been done on the relationships between biodiversity and ecosystem functioning (BEF) across systems, but to our knowledge, very little has been done on the relationships between the interaction network structure and functioning, especially in microbes. To address this topic, we will analyze two available datasets: (1) the microbial community in the Blanes Bay Microbial Observatory (BBMO) throughout a decade of monthly sampling and (2) the microbial community in an algal production raceway sampled 2 times per week during 9 months within the framework of the H2020 project PRODIGIO. Our results will contribute to better understand the fundamentals of aquatic microbial community structuring and functioning. Furthermore, understanding microbial interactions and their role in biomass production is key for improving biofuel production

As climate change unravels, ecosystems are facing a warming of the climate and an increase in extreme heat events that are unprecedented in recent geological history. We know very little of the ability of oceanic phytoplankton communities, key players in the regulation of Earth’s climate by the oceans, to adapt to these changes. Quantifying the resilience of phytoplankton communities to environmental stressors by means of adaptive evolution is however crucial to accurately predict the response of marine ecosystems to climate change. In this work, we use an eco-evolutionary model to simulate the adaptive response of marine phytoplankton to temperature changes in an initially temperate oligotrophic water column. By exploring a wide range of scenarios of phytoplankton adaptive capacity, we find that phytoplankton can adapt to temperature increases –even very large ones– as long as they occur over the time scale of a century. However, when rapid and extreme events of temperature change are considered, the phytoplankton adaptive capacity breaks down in a number of our scenarios in which primary productivity plummets as a result. This suggests that current Earth System Models implicitly assuming perfect and instantaneous phytoplankton adaptation to temperature might be overestimating the phytoplankton’s resilience to climate change

Microalgae production systems have gained significant attention in recent years due to their potential to provide sustainable solutions for various challenges faced by society. Controlling the growth of target microalgal strains in large-scale production systems is challenging and is crucial for sustainable biomass production and a circular bioeconomy. These systems are composed of very diverse microbial communities, whose dynamics could largely explain the reasons why these systems generally operate well below their optimal yield. However, our understanding of these microbial community dynamics remains limited. This study focuses on characterizing the community dynamics of a Tetradesmus almeriensis culture in an open photobioreactor system fed with wastewater. The eukaryotic community was dominated by the microalgae T.almeriensis and species of Fungi. The composition of the fungal community changed as the concentration of microalgae increased, while the bacterial community was dominated by: Gammaproteobacteria, Actinobacteria, Bacteroidota, and Cyanobacteria. Our analysis suggests that these dynamics had both positive and negative implications for the industry. On the one hand, we observed fungal presence in the culture system. On the other hand, our study revealed the presence of highly diverse bacterial communities with high turnover rates at the ASVs level, which may stimulate the growth of microalgae. This knowledge is of potential significance for the industry, as it can contribute to improving the yields of large-scale microalgae production systems

Life originated in the sea about 4 billion years ago and, for the first 3.5 billion years, it was exclusively microscopic. Something happened early in the Cambrian period that made multicellular life to thrive, giving rise to the spectacular biodiversity that has been this planet's hallmark for the past 500 million years. This staggering increase in diversity has raised a fundamental question among evolutionary ecologists: are there limits to the diversity of life in the ocean? To answer this question, we have developed a regional diversification model that allows us to recreate the evolutionary history of the diversity of marine animals. In the model, we let 1 genus to diversify everywhere in the global ocean from 500 million years ago until present according to a model of paleogeography that constrains the diversification time and a paleo Earth System model that constrains the diversification rate as a function of seawater temperature and food supply. By externally imposing mass extinctions, we explore how the oceans filled with life. The regional model fits surprisingly well global fossil diversity curves and modern biodiversity distributions. According to the model, the ocean is far from saturation except for in the biodiversity hotspots, regions of extraordinarily high levels of diversity, which evolved under prolonged conditions of Earth system stability and maximum continental fragmentation. The model allows us to recreate many things, such as the history of biodiversity hotspots and the dynamics of the latitudinal biodiversity gradient

Phytoplankton-derived particles represent one of the main sources of organic matter (OM) for marine systems, fuelling heterotrophic life and sequestering C in the ocean interior. The solubilization of sinking particles and the production of recalcitrant dissolved organic matter (RDOM) linked to microbial activities are two of the main processes influencing the ocean C storage capacity. These processes depend on the seasonally-variable makeup of phytoplankton assemblages, however, our understanding of this relationship is hindered by the difficulty of relating the processing of OM at depth with its phytoplanktonic source. To better understand the effects of the phytoplanktonic origin of particles on their degradation process, we performed three experiments using particles from the surface NW Mediterranean covering a wide range of phytoplankton assemblage compositions. The particulate material was added to mesopelagic water containing natural microbial communities and incubated in the dark during 25 days while monitoring particulate and dissolved organic carbon, and microbial concentrations. In addition, using fluorescence spectroscopy, we were able to track the labile and recalcitrant fluorescent fractions of both the dissolved and total (particulate + dissolved) OM pools. We will describe the fluorescent OM dynamics during the degradation process and discuss the results in relation to the source phytoplankton composition, with special focus on the processes of particle solubilization and production of RDOM within the context of the biological and microbial pump efficiencies

Acidic polysaccharides released by phytoplankton and prokaryotic heterotrophs promote the formation of gel-like transparent exopolymer particles (TEPs). TEPs can have a relevant contribution to the biological carbon pump due to their carbon-rich composition and their ability to coagulate and sink towards the deep ocean. However, little is known about TEPs distribution, carbon export, and residence times below the export (200 m) and sequestration (1000 m) depths. We provide the first comprehensive inventory of TEP from the ocean surface to a depth of 4000 meters in the tropical and subtropical Atlantic, Indian, and Pacific Oceans, evaluating its contribution to carbon export and sequestration into the deep ocean. Results indicate that TEP concentration is primarily determined by primary production, with higher concentrations located above the deep chlorophyll maxima. In the deep ocean, TEP concentrations are lower yet mirror the concentrations in the surface, demonstrating the significance of TEP sinking below both the export compartment (2.8 Pg C yr-1; 27% of total POC flux at 200 m) and the sequestration compartment (0.8 Pg C yr-1; 36% of total POC flux at 1000 m). In situ incubation experiments conducted across ocean basins indicate short TEP residence times, averaging 27 and 333 days in the export and sequestration compartments, respectively. These findings reveal that the export and subsequent sequestration of carbon by TEP sinking into the deep ocean diverts it from the long times observed for the dissolved carbon fraction (i.e. centuries) in the global carbon cycle

The dynamics of phytoplankton biomass and community composition is important for the functioning of marine ecosystems and ocean biogeochemical cycles. However, there is a shortage of studies addressing the interannual seasonal patterns of phytoplankton community assembly due to sampling limitations. Here we study the seasonal dynamics of eight major phytoplankton groups over a 12 year period (2006 to 2018) using a time-series of taxonomic composition from the Blanes Bay Microbial Observatory (BBMO) in the North Western Mediterranean Sea: dinoflagellates, diatoms, coccolithophores, Prochlorococcus, Synechococcus, picoeukaryotes, nanoeukaryotes, and photosynthetic nanoflagellates. We combine the analysis of biotic factors (primary production, phytoplankton taxa, cell abundance, cell size, chlorophyll-a concentration, and phytoplankton biomass) and abiotic factors (nutrients, temperature, and irradiance) to provide a coherent picture of the observed seasonal patterns of phytoplankton community assembly. The BBMO ecosystem is seasonally heterogeneous in community composition, displaying large fluctuating alternations in phytoplankton group dominance throughout the year. The seasonal succession of phytoplankton groups tends to repeat itself every year in a regular fashion, being the seasonal variability of the phytoplankton groups larger than their interannual variability. We compute -diversity, a measure of the effective richness of phytoplankton groups. The seasonality of -diversity shows that it is lowest during winter and highest during summer. We compute temporal -diversity, a measure of compositional heterogeneity of the phytoplankton community. The data show a sinusoidal behavior of -diversity as a function of the temporal distance between samples, with a period of one year. We use the mirror index (1 - -diversity) at a temporal distance of one month to compute the phytoplankton group turnover. The seasonality of turnover shows that it is highest during spring and

Marine phytoplankton is responsible for approximately half of the annual global net primary production and thus represent one of the main sources of organic matter in the ocean. The composition of phytoplankton-derived organic matter is of utmost importance for marine ecosystems, as it sustains the majority of non-photosynthetic life in the sea. In temperate regions, such as the Mediterranean basin, phytoplankton communities exhibit seasonal patterns driven by biotic and abiotic factors. These patterns are well identified, with several groups such as diatoms, dinoflagellates, coccolithophores, haptophytes and cryptophytes exhibiting contrasting seasonal changes of abundance and dominance. Despite its biogeochemical relevance, the impact of these changes on organic matter composition remains largely unknown. Optical properties have long been used to characterize the fluorescent organic matter (FOM) pool. However, most studies focus on the dissolved FOM fraction (FDOM), disregarding the possible fluorescence of phytoplankton cells and other particles excluded by filtration. In order to assess the effects of phytoplankton ecological succession on the composition of particulate and dissolved FOM, we compared the composition of phytoplankton communities with measurements of organic matter fluorescence in filtered and unfiltered samples from the Blanes Bay Microbial Observatory (BBMO) from 2011 to 2017. We will discuss how these FOM dynamics are related to phytoplankton abundance and seasonal succession as well as to abiotic factors such as solar radiation, and how these dynamics may influence the fate and turnover of the organic matter in the sea

La vida ha evolucionado a lo largo de miles de millones de años creando una asombrosa variedad de formas de vida cada vez más diversas y complejas. Se estima que el número de especies que habitan actualmente en la Tierra podría ser del orden de 8,7 millones. La biodiversidad no se distribuye de forma homogénea sobre la superficie del planeta. A nadie le pasará inadvertido que las selvas tropicales o los arrecifes de coral contienen un mayor número de especies que los desiertos de arena o las llanuras abisales del océano profundo. Tampoco sorprenderá si decimos que los ecosistemas más diversos lo son, en parte, porque disponen de una mayor cantidad de recursos (agua, luz, comida, etc). Los recursos son esenciales, pero al mismo tiempo limitados. Por ello, los científicos llevan décadas debatiendo sobre si existe o no un nivel de equilibrio por encima del cual el número de especies no puede seguir creciendo. En otras palabras, ¿existe un máximo de especies que la Tierra puede albergar? Y, si existe, ¿se ha alcanzado ya?

Un equipo internacional liderado por el ICM-CSIC ha reconstruido la historia de la diversidad de los animales marinos desde el Cámbrico, hace unos 540 millones de años, hasta hoy

To assess the anthropogenic effect on biodiversity, it is essential to understand the global diversity distribution of the major groups at the base of the food chain, ideally before global warming initiation (1850 Common Era CE). Since organisms in the plankton are highly interconnected and carbonate synthesizing species have a good preservation state in the Atlantic Ocean, the diversity distribution pattern of planktonic foraminifera from 1741 core-top surface sediment samples (expanded ForCenS database) provides a case study to comprehend centennial to decadal time-averaged diversity patterns at pre-1970 CE times, the tempo of the substantial increase in tropospheric warming. In this work, it is hypothesized and tested for the first time, that the large-scale diversity patterns of foraminifera communities are determined by sea surface temperature (SST, representing energy), Chl-a (a surrogate for photosynthetic biomass), and ocean kinetic energy (as EKE). Alpha diversity was estimated using species richness (S), Shannon Wiener index (H), and Simpson evenness (E), and mapped using geostatistical approaches. The three indices are significantly related to SST, Chl-a, and EKE (71-88% of the deviance in the generalized additive mixed model, including a spatial component). Beta diversity was studied through species turnover using gradient forest analysis (59% of the variation). The primary community thresholds of foraminifera species turnover were associated with 5-10 °C and 22-28 °C SST, 0.05-0.15 mg m-3 Chl-a, and 1.2-2.0 cm2 s-2 log10 EKE energy, respectively. Six of the most important foraminifera species identified for the environmental thresholds of beta diversity are also fundamental in transfer functions, further reinforcing the approaches used. The geographic location of the transition between the four main biogeographic zones was redefined based on the results of beta diversity analysis and incorporating the new datasets, identifying the major marine latitudin

Correlation for radio interferometer array applications, including Very Long Baseline Interferometry (VLBI), is a multidisciplinary field that traditionally involves astronomy, geodesy, signal processing, and electronic design. In recent years, however, high-performance computing has been taking over electronic design, complicating this mix with the addition of network engineering, parallel programming, and resource scheduling, among others. High-performance applications go a step further by using specialized hardware like Graphics Processing Units (GPUs) or Field Programmable Gate Arrays (FPGAs), challenging engineers to build and maintain high-performance correlators that efficiently use the available resources. Existing literature has generally benchmarked correlators through narrow comparisons on specific scenarios, and the lack of a formal performance characterization prevents a systematic comparison. This combination of ongoing increasing complexity in software correlation together with the lack of performance models in the literature motivates the development of a performance model that allows us not only to characterize existing correlators and predict their performance in different scenarios but, more importantly, to provide an understanding of the trade-offs inherent to the decisions associated with their design. In this paper, we present a model that achieves both objectives. We validate this model against benchmarking results in the literature, and provide an example for its application for improving cost-effectiveness in the usage of cloud resources

Phytoplankton-derived organic matter sustains heterotrophic marine life in regions away from terrestrial inputs such as the Southern Ocean. Fluorescence spectroscopy has long been used to characterize the fluorescent organic matter (FOM) pool. However, most studies focus only in the dissolved FOM fraction (FDOM) disregarding the contribution of particles. In order to assess the dynamics and drivers of the dissolved and particulate fractions of FOM, we used a Lagrangian approach to follow the time evolution of phytoplankton proliferations at four different sites in the Southern Ocean and compared the FOM in filtered and unfiltered seawater aliquots. We found that filtration had little effects on FOM visible spectrum fluorescence intensities, implying that most of this signal was due to dissolved fluorophores. On the other hand, protein-like fluorescence was strongly supressed by filtration, with fluorescence of particles accounting for up to 90 % of the total protein-like FOM. Photobleaching was identified as the main driver of visible FDOM composition, which was better described by indices of phytoplankton photoacclimation than by measurements of the incident solar radiation dose. In contrast, protein-like FOM intensity and fractionation were primarily related to abundance, composition and physiological state of phytoplankton proliferations. The chlorophyll a concentration from non-diatom phytoplankton explained 91 % of the particulate protein-like FOM variability. The proportion of protein-like fluorescence found in the dissolved phase was predicted by the combination of potential viral and grazing pressures, which accounted for 51 and 29 % of its variability, respectively. Our results show that comparing FOM measurements from filtered and unfiltered seawater provides relevant information on the taxonomic composition and cell integrity of phytoplankton communities. A better understanding of the commonly overlooked FOM fractionation process is essential for the impl

The fossil record of marine invertebrates has long fuelled the debate as to whether or not there are limits to global diversity in the sea1,2,3,4,5. Ecological theory states that, as diversity grows and ecological niches are filled, the strengthening of biological interactions imposes limits on diversity6,7. However, the extent to which biological interactions have constrained the growth of diversity over evolutionary time remains an open question1,2,3,4,5,8,9,10,11. Here we present a regional diversification model that reproduces the main Phanerozoic eon trends in the global diversity of marine invertebrates after imposing mass extinctions. We find that the dynamics of global diversity are best described by a diversification model that operates widely within the exponential growth regime of a logistic function. A spatially resolved analysis of the ratio of diversity to carrying capacity reveals that less than 2% of the global flooded continental area throughout the Phanerozoic exhibits diversity levels approaching ecological saturation. We attribute the overall increase in global diversity during the Late Mesozoic and Cenozoic eras to the development of diversity hotspots under prolonged conditions of Earth system stability and maximum continental fragmentation. We call this the ‘diversity hotspots hypothesis’, which we propose as a non-mutually exclusive alternative to the hypothesis that the Mesozoic marine revolution led this macroevolutionary trend12,13

“Las diatomeas y los bosques invisibles del océano” es el título de la conferencia que pronuncia hoy, a las 19.30 horas, en el Club Prensa asturiana de LA NUEVA ESPAÑA Pedro Cermeño, científico del Instituto de Ciencias del Mar del Consejo Superior de Investigaciones Científicas (CSIC), dentro de ciclo “Qué sabemos de...”.

Acidic polysaccharides released by phytoplankton and prokaryotic heterotrophs promote the formation of gel-like transparent exopolymer particles (TEPs). TEPs play a key role in the biological carbon pump due to their carbon-rich composition and their ability to coagulate and sink towards the deep ocean. Yet, very little is known about TEP distribution, export, and turnover at a global scale, particularly at deep ocean depths. We provide the first inventory of TEP from the surface up to 4000 m depth in the Atlantic, Indian, and Pacific Oceans and have assessed their contribution to carbon export into the deep ocean. Primary production determines TEP concentration above the deep chlorophyll maximum, and prokaryotic biomass also contributes in deeper waters. In the deep ocean waters, TEP concentrations are lower and mirror the concentrations in the surface, evidencing the importance of TEP sinking both at the export depth (200 m) with a global value of 2.9 Pg C year-1 and at the sequestration depth (1000 m) of 0.9 Pg C year-1 of particulate carbon. However, incubation experiments across ocean basins depicted rapid TEP turnover rates of 71 and 333 days (on average) within the export and sequestration depths, respectively. These findings reveal that the export of carbon by TEP sinking towards deep oceans escapes from long-term paths of the global carbon cycle

[EN] Marine phytoplankton, including cyanobacteria and microalgae, dominates primary production across two thirds of the earth’s surface, sustaining virtually all marine life and exerting a fundamental control over global climate through carbon sequestration into the deep ocean. These unicellular photoautotrophs are responsible for roughly 50% of global net primary production, which is equivalent to producing 50 gigatons of organic carbon (C) per year (about 140 million t per day). […], [ES] El fitoplancton marino, que incluye tanto a las cianobacterias como a las microalgas, domina la producción primaria en dos tercios de la superficie de la Tierra, sustentando prácticamente toda la vida marina y ejerciendo un control fundamental sobre el clima global mediante el secuestro de carbono en las profundidades del océano. Estos productores primarios unicelulares son responsables de aproximadamente el 50% de la producción primaria neta mundial, lo que equivale a producir 50 gigatoneladas de carbono orgánico (C) al año (alrededor de 140 millones de toneladas al día). […], [CAT] El fitoplàncton marí, que inclou tant als cianobacteris com a les microalgues, domina la producció primària en dos terços de la superfície de la Terra, sustentant pràcticament tota la vida marina i exercint un control fonamental sobre el clima global mitjançant el segrest de carboni en les profunditats de l’oceà. Aquests productors primaris unicel·lulars són responsables d’aproximadament el 50% de la producció primària neta mundial, la qual cosa equival a produir 50 gigatones de carboni orgànic (C) l’any (al voltant de 140 milions de tones al dia). […]

[EN] Marine phytoplankton are photosynthetic microorganisms that use solar radiation, inorganic carbon and nutrients to produce organic matter (OM) and release molecular oxygen. Phytoplankton photosynthesis produces both particulate organic matter (POM) and dissolved organic matter (DOM), and these two fractions are subject to different biological consumptions and transformations as well as different physical transport processes. Phytoplanktonic POM can be directly ingested by zooplankton (microscopic animals that in turn serve as food for larger organisms), whereas DOM can enter the trophic web through microbes that grow on the dissolved compounds and are then consumed by bacterial grazers. Both fractions can be exported downwards from surface waters: POM can sink on its own or be transported by swimming organisms or downward movements of water masses, while DOM can only be exported until upwelling and vertical mixing bring them back to the surface. […], [ES] El fitoplancton marino son microorganismos fotosintéticos que utilizan radiación solar y carbono y nutrientes inorgánicos para producir materia orgánica (MO) y liberar oxígeno molecular. La fotosíntesis del fitoplancton produce tanto materia orgánica particulada (MOP) como materia orgánica disuelta (MOD), estas dos fracciones están sujetas a diferentes consumos y transformaciones biológicas, así como a distintos procesos de transporte físico. La MOP fitoplanctónica puede ser ingerida directamente por el zooplancton, animales microscópicos que a su vez sirven como alimento para organismos más grandes. Mientras que la MOD entra a la red trófica a través de microbios, que consumen los compuestos disueltos y a su vez luego son ingeridos por otros organismos. Ambas fracciones pueden ser exportadas a aguas profundas; la MOP puede hundirse por sí sola, y ser transportada por organismos y hundimiento de masas océano iluminado por el sol está dominada por la fotosíntesis, que consume nutrientes inorgánicos, mientras que en la oscuridad del océano profundo la respiración de MO libera nutrientes que se acumulan hasta que el afloramiento de aguas y la mezcla vertical los trae de vuelta a la superficie. […], [CAT] El fitoplàncton marí són microorganismes fotosintètics que utilitzen radiació solar i carboni i nutrients inorgànics per produir matèria orgànica (MO) i alliberar oxigen molecular. La fotosíntesi del fitoplàncton produeix tant matèria orgànica particulada (MOP) com a matèria orgànica dissolta (MOD) i aquestes dues fraccions estan subjectes a diferents consums i transformacions biològiques, així com a diferents processos de transport físic. La MOP fitoplanctònica pot ser ingerida directament pel zooplàncton, animals microscòpics que al seu torn serveixen com a aliment per organismes més grans, mentre que la MOD entra a la xarxa tròfica a través de microbis, que consumeixen els compostos dissolts i al seu torn després són ingerits per altres organismes. Les dues fraccions poden ser exportades a aigües profundes; la MOP es pot enfonsar per si sola, i ser transportada per organismes i enfonsament de masses d’aigua, mentre que la en l’oceà profund la respiració de MO allibera nutrients que s’acumulen fins que l’aflorament d’aigües i la barreja vertical els porta de tornada a la superfície. […]

[EN] The word ocean comes from Oceanus (Greek: Ōkeanós), the elder of the Titans in classical Greek mythology, believed to be the divine personification of a gigantic river that encircled the world. The history of humankind is full of mythological water deities, gods of the ocean and the rivers created by ancient civilizations to represent the strengths of nature and human facets. For millennia, the oceans have been a powerful source of inspiration for philosophers, artists and merchants, from the Greeks and Romans to the fearless sailors of the Middle Ages. Today, the oceans remain a source of inspiration and curiosity fuelled by the tremendous scientific knowledge and social awareness acquired in recent times. […], [ES] La palabra océano proviene de Oceanus (griego: Ōkeanós), el mayor de los Titanes en la mitología griega clásica, quienes creían que Oceanus era la personificación divina de un gigantesco río que rodeaba el mundo. La historia de la humanidad está llena de deidades mitológicas relacionadas con el agua, dioses del océano y de los ríos creados por civilizaciones antiguas para representar las fortalezas de la naturaleza y de las diferentes facetas humanas. Durante milenios, los océanos han sido una poderosa fuente de inspiración para filósofos, artistas y comerciantes, desde los griegos y romanos hasta los intrépidos marineros de la Edad Media. Hoy en día, los océanos siguen siendo fuente de inspiración y curiosidad alimentada por los avances científicos y la concienciación social adquirida en los últimos tiempos. […], [CAT] La paraula oceà prové d’Oceanus (grec: Ōkeanós), el major dels Titans en la mitologia grega clàssica, on es creia que Oceanus era la personificació divina d’un riu gegantesc que envoltava el món. La història de la humanitat està plena de deïtats mitològiques relacionades amb l’aigua, déus de l’oceà i dels rius creats per civilitzacions antigues per a representar les fortaleses de la naturalesa i de les diferents facetes humanes. Durant mil·lennis, els oceans han estat una poderosa font d’inspiració per a filòsofs, artistes i comerciants, des dels grecs i romans fins als intrèpids mariners de l’edat mitjana. Avui dia, els oceans continuen sent font d’inspiració i curiositat alimentada pels avanços científics i la conscienciació social adquirida en els últims temps. […]