The atmosphere of the northwestern (NW) Mediterranean Sea is affected by continuous inputs of ant... more The atmosphere of the northwestern (NW) Mediterranean Sea is affected by continuous inputs of anthropogenic aerosols and episodic Saharan dust events. These atmospheric inputs deliver to the surface waters high amounts of macronutrients and trace metals that can constitute their main source at certain times of the year. The effect of both anthropogenic and crustal particles over the autotrophic and heterotrophic planktonic community assembles was evaluated through three microcosm experiments carried out in the summer of 2013 and in the winter and spring of 2014 at an urban coastal location of the NW Mediterranean (Barcelona, Spain). Particles were added to seawater at a concentration of 0.8 mg l −1. The results showed that (i) a greater stimulation of the whole community was observed in summer and spring than in winter; (ii) both kinds of aerosols produced an increase in the growth of phytoplankton, although the stimulation of nanoeukaryotes was significantly larger with anthropogenic aerosols; and (iii) bacterial abundance increased more with mineral dust, whereas bacterial production
Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 1 pageIn aquatic s... more Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 1 pageIn aquatic systems phytoplankton and bacteria compete for inorganic nitrogen and phosphorus. It has been shown that the outcome of this competition will be in favour of diatoms when silicate (Si) is in excess and in favour of bacteria when Si is depleted [Havskum et al, 2003; Thingstad et al 2007]. We postulate that turbulence could change this competition interaction. Shear derived from turbulence increases nutrient flux to large cells, thus it should increase the phytoplankton competition capability for nutrients and reduce the organic matter utilisation by bacteria. Then, when Si is in excess diatom growth should be further enhanced by turbulence. We evaluated the effect of turbulence on the competition between bacteria and diatoms in experiments with natural plankton communities enclosed in microcosms. The response of plankton to turbulence versus still conditions was evaluated in four different nutrient conditions: C (glucose addition), Si (silicate addition), CSi (glucose and silicate addition), and B (no addition). In general, turbulence increased both heterotrophic and autotrophic biomass under all nutrient addition conditions, and enhanced the diatom competition for nutrients when Si was available. However turbulence did not change the ratio between autotrophic and heterotrophic biomass. We discuss the discrepancy between these results and previous data in terms of the level and frequency of nutrient additions, trophic interactions and initial conditions. References HAVSKUM, H, TF THINGSTAD, R SCHAREK, F PETERS, E BERDALET, MM SALA, M ALCARAZ , JCBANSGHOLT, UL ZWEIFEL, Å HAGSTRÖM, M PEREZ AND JR DOLAN (2003) Silicate and labile DOC interfere in structuring food web via algal-bacteria competition for mineral nutrients: Results of a mesocosm experiment. Limnol. Oceanogr. 48(1): 129-140. THINGSTAD TF, H HAVSKUM, UL ZWEIFEL, E BERDALET, MM SALA, F PETERS, M ALCARAZ, R SCHAREK, M PEREZ, S JACQUET, GA FONNES FLATEN, JR DOLAN, C MARRASE, F RASSOULZADEGAN, ÅHAGSTRØM, D VAULOT (2007). Ability of a minimum microbial food web model to reproduce response patterns observed in mesocosms manipulated with N and P, glucose and Si. Journal of Marine systems. 64: 15-3
Thalassa va dedicar un reportatge al gran naturalista català. Home cabdal en els estudis de la na... more Thalassa va dedicar un reportatge al gran naturalista català. Home cabdal en els estudis de la natura i dels oceans i un dels primers que va concebre el concepte d'ecologia. Reconegut arreu del món, Margalef va ser un científic creatiu que va obrir moltes línies d'investigacions vigents encara avui dia. Es diu que analitzava el que veia amb la curiositat d'un infant i amb la rigorositat d'un científic. A finals de l'any 2011 es va fer a la mar, a Vigo, un nou i modern vaixell de l'Institut Espanyol d'Oceanografia amb el nom de "Ramon Margalef". Un homenatge merescut al primer catedràtic d'Ecologia que va tenir l'estat espanyol. La seva tasca com a professor ha tingut una marcada influència en molts investigadors actuals, capdavanters en el camp de l'ecologia i l'oceanografia, que han estat alumnes seus i segueixen els camins que ell va obrirPeer reviewe
Datos oceanograficos basicos de las campanas “FRONTS- 1992” (octubre-noviembre 1992) y “Variabili... more Datos oceanograficos basicos de las campanas “FRONTS- 1992” (octubre-noviembre 1992) y “Variabilidad de mesoescala en el Mediterraneo occidental" (junio 1993): 3-117 (1995).-- Maso, Mercedes ... et. al.-- 115 pages
XXXIV Trobades Cientifiques de la Mediterrania : Fisica i ecologia: reptes de frontera, celebrada... more XXXIV Trobades Cientifiques de la Mediterrania : Fisica i ecologia: reptes de frontera, celebradas del 9 al 11 de octubre de 2018 en Mao, Menorca
1 page, 1 figureWe studied physico-chemical (temperature, salinity, inorganic nutrients) and biol... more 1 page, 1 figureWe studied physico-chemical (temperature, salinity, inorganic nutrients) and biological (phytoplakton pigment composition, bacterial numbers, protein, DNA, RNA, and POM) characteristics of a hydrographically diverse area of the northern Catalan sea during the stratification period (June 2000). The sampled stations were affected by a) continental shelf (coastal waters), and b) low salinity surface waters from the Gulf of Lions in?uenced by the Rhone runnoff (called Plume), carried by the shelf-slope Catalan current. We compared these areas with oceanic waters. The relative fertilising effect of the Plume for the plankton communities is discussedPeer Reviewe
POLAR 2018 - XXXV SCAR Meetings and SCAR/IASC Open Science Conference, 19-23 June 2018, Davos, Sw... more POLAR 2018 - XXXV SCAR Meetings and SCAR/IASC Open Science Conference, 19-23 June 2018, Davos, Switzerland.-- 1 page
IX Simposio de Estudios Polares del Comite Espanol del Scientific Committee on Antarctic Research... more IX Simposio de Estudios Polares del Comite Espanol del Scientific Committee on Antarctic Research (SCAR), 5-7 September 2018, Madrid, Espana.-- 1 page
Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 1 pageNutrient ava... more Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 1 pageNutrient availability is a major constraint for phytoplankton growth and dynamics in the NW Mediterranean. The poorly understood nutrient concentration dynamics in coastal waters raises the question whether atmospheric inputs may be more important than often presumed. Despite wet deposition being the main source of atmospheric nutrient supply in the NW Mediterranean Sea, dry fluxes may also play a key role in several marine locations. Barcelona is a densely populated area with multiple anthropogenic emissions, particularly severe for N and P species (e.g. NOx from industrial combustion and vehicle traffic, HNO3from vehicle traffic, P compounds from incinerators and domestic and industrial substances). A series of experiments were conducted to assess the short-term impact of atmospheric dry deposition on the concentration of nutrients in Barcelona’s inshore waters. Acid-washed polyethylene tubes, containing 20 to 25ml of seawater, were exposed to the open air for 24 h. The results show a high temporal variability with mean dry fluxes of about 40-60 µ mol NO3 m-2 d-1. Consequently, estimated daily median increases in dissolved available inorganic nitrogen in the water column were 1-10%. The estimated atmospheric nutrient inputs could not fully explain nutrient concentration increases observed in Barcelona’s coastal waters, and further experiments may be carried out to determine long-term values for dry deposition. This may help clarify the dynamics of nutrients whenever increases in concentration are not matched by either changes in the water masses or freshwater inflow
1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de... more 1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de Ecología Terrestre (AEET), Ecology: an integrative science in the Anthropocene, 4-7 February 2019, Barcelona, SpainThe Margalef’s Mandala visualizes in a two-dimensional space the role of nutrients and turbulence in shaping the phytoplankton communities. This Mandala, published in 1978, comprises fundamental concepts of plankton ecology related to species succession and energy fluxes. During forty years this conceptual framework has been continuously evolving and numerous authors adapted it to integrate the variety of processes underlying plankton dynamics at different spatio-temporal scales. We now know that turbulence affects different interactions and activities of plankton components such as predator-prey encounter rates and nutrient uptake by osmotrophs. These processes also depend on the nutrient load for a particular system and ultimately determine ecosystem metabolism. We show empirical evidence of plankton responses to turbulence under a range of nutrient concentration and osmotroph abundance conditions. These data led to building-up an extended version of Margalef’s mandala, that we call “the fan”, applicable to system metabolismPeer Reviewe
1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de... more 1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de Ecología Terrestre (AEET), Ecology: an integrative science in the Anthropocene, 4-7 February 2019, Barcelona, SpainIn marine plankton ecosystems, diatoms and heterotrophic bacteria (HB) compete for inorganic nitrogen (N) and phosphorus (P). It has been shown that the outcome of this competition is in favor of diatoms when silicate (Si) is in excess and in favor of HB when Si is depleted. However, the supply of organic compounds, so pervasive in marine plankton ecosystems, could alter the outcome of these competitive interactions. Here, we evaluate the response of natural plankton communities to glucose addition, Si addition, and glucose plus Si addition in laboratory microcosms to which N and P were also added by default. The addition of glucose boosted the growth of HB, which prevented diatoms from thriving. We found that HB were superior competitors as long as labile organic compounds fuelled their metabolic activity, yet, once glucose was consumed, the biomass of diatoms increased conspicuously in the glucose plus Si addition treatment. These substrate-mediated competitive interactions contribute to regulating the structure and succession of marine plankton in nature and provide us with technical know-how to design highly efficient synthetic communities with applications in wastewater treatment and quality biomass productionPeer Reviewe
COVID-19 has led to global population lockdowns that have had indirect effects on terrestrial and... more COVID-19 has led to global population lockdowns that have had indirect effects on terrestrial and marine fauna, yet little is known on their effects on marine planktonic communities. We analysed the effect of the spring 2020 lockdown in a marine coastal area in Blanes Bay, NW Mediterranean. We compared a set of 23 oceanographic, microbial and biogeochemical variables sampled right after the strict lockdown in Spain, with data from the previous 15 years after correcting for long-term trends. Our analysis shows a series of changes in the microbial communities which may have been induced by the combination of the decreased nitrogen atmospheric load, the lower wastewater flux and the reduced fishing activity in the area, among other factors. In particular, we detected a slight decrease beyond the long-term trend in chlorophyll a, in the abundance of several microbial groups (phototrophic nanoflagellates and total prokaryotes) and in prokaryotic activity (heterotrophic prokaryotic production and β-glucosidase activity) which, as a whole, resulted in a moderate increase of oligotrophy in Blanes Bay after the lockdown.
The atmosphere of the northwestern (NW) Mediterranean Sea is affected by continuous inputs of ant... more The atmosphere of the northwestern (NW) Mediterranean Sea is affected by continuous inputs of anthropogenic aerosols and episodic Saharan dust events. These atmospheric inputs deliver to the surface waters high amounts of macronutrients and trace metals that can constitute their main source at certain times of the year. The effect of both anthropogenic and crustal particles over the autotrophic and heterotrophic planktonic community assembles was evaluated through three microcosm experiments carried out in the summer of 2013 and in the winter and spring of 2014 at an urban coastal location of the NW Mediterranean (Barcelona, Spain). Particles were added to seawater at a concentration of 0.8 mg l −1. The results showed that (i) a greater stimulation of the whole community was observed in summer and spring than in winter; (ii) both kinds of aerosols produced an increase in the growth of phytoplankton, although the stimulation of nanoeukaryotes was significantly larger with anthropogenic aerosols; and (iii) bacterial abundance increased more with mineral dust, whereas bacterial production
Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 1 pageIn aquatic s... more Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 1 pageIn aquatic systems phytoplankton and bacteria compete for inorganic nitrogen and phosphorus. It has been shown that the outcome of this competition will be in favour of diatoms when silicate (Si) is in excess and in favour of bacteria when Si is depleted [Havskum et al, 2003; Thingstad et al 2007]. We postulate that turbulence could change this competition interaction. Shear derived from turbulence increases nutrient flux to large cells, thus it should increase the phytoplankton competition capability for nutrients and reduce the organic matter utilisation by bacteria. Then, when Si is in excess diatom growth should be further enhanced by turbulence. We evaluated the effect of turbulence on the competition between bacteria and diatoms in experiments with natural plankton communities enclosed in microcosms. The response of plankton to turbulence versus still conditions was evaluated in four different nutrient conditions: C (glucose addition), Si (silicate addition), CSi (glucose and silicate addition), and B (no addition). In general, turbulence increased both heterotrophic and autotrophic biomass under all nutrient addition conditions, and enhanced the diatom competition for nutrients when Si was available. However turbulence did not change the ratio between autotrophic and heterotrophic biomass. We discuss the discrepancy between these results and previous data in terms of the level and frequency of nutrient additions, trophic interactions and initial conditions. References HAVSKUM, H, TF THINGSTAD, R SCHAREK, F PETERS, E BERDALET, MM SALA, M ALCARAZ , JCBANSGHOLT, UL ZWEIFEL, Å HAGSTRÖM, M PEREZ AND JR DOLAN (2003) Silicate and labile DOC interfere in structuring food web via algal-bacteria competition for mineral nutrients: Results of a mesocosm experiment. Limnol. Oceanogr. 48(1): 129-140. THINGSTAD TF, H HAVSKUM, UL ZWEIFEL, E BERDALET, MM SALA, F PETERS, M ALCARAZ, R SCHAREK, M PEREZ, S JACQUET, GA FONNES FLATEN, JR DOLAN, C MARRASE, F RASSOULZADEGAN, ÅHAGSTRØM, D VAULOT (2007). Ability of a minimum microbial food web model to reproduce response patterns observed in mesocosms manipulated with N and P, glucose and Si. Journal of Marine systems. 64: 15-3
Thalassa va dedicar un reportatge al gran naturalista català. Home cabdal en els estudis de la na... more Thalassa va dedicar un reportatge al gran naturalista català. Home cabdal en els estudis de la natura i dels oceans i un dels primers que va concebre el concepte d'ecologia. Reconegut arreu del món, Margalef va ser un científic creatiu que va obrir moltes línies d'investigacions vigents encara avui dia. Es diu que analitzava el que veia amb la curiositat d'un infant i amb la rigorositat d'un científic. A finals de l'any 2011 es va fer a la mar, a Vigo, un nou i modern vaixell de l'Institut Espanyol d'Oceanografia amb el nom de "Ramon Margalef". Un homenatge merescut al primer catedràtic d'Ecologia que va tenir l'estat espanyol. La seva tasca com a professor ha tingut una marcada influència en molts investigadors actuals, capdavanters en el camp de l'ecologia i l'oceanografia, que han estat alumnes seus i segueixen els camins que ell va obrirPeer reviewe
Datos oceanograficos basicos de las campanas “FRONTS- 1992” (octubre-noviembre 1992) y “Variabili... more Datos oceanograficos basicos de las campanas “FRONTS- 1992” (octubre-noviembre 1992) y “Variabilidad de mesoescala en el Mediterraneo occidental" (junio 1993): 3-117 (1995).-- Maso, Mercedes ... et. al.-- 115 pages
XXXIV Trobades Cientifiques de la Mediterrania : Fisica i ecologia: reptes de frontera, celebrada... more XXXIV Trobades Cientifiques de la Mediterrania : Fisica i ecologia: reptes de frontera, celebradas del 9 al 11 de octubre de 2018 en Mao, Menorca
1 page, 1 figureWe studied physico-chemical (temperature, salinity, inorganic nutrients) and biol... more 1 page, 1 figureWe studied physico-chemical (temperature, salinity, inorganic nutrients) and biological (phytoplakton pigment composition, bacterial numbers, protein, DNA, RNA, and POM) characteristics of a hydrographically diverse area of the northern Catalan sea during the stratification period (June 2000). The sampled stations were affected by a) continental shelf (coastal waters), and b) low salinity surface waters from the Gulf of Lions in?uenced by the Rhone runnoff (called Plume), carried by the shelf-slope Catalan current. We compared these areas with oceanic waters. The relative fertilising effect of the Plume for the plankton communities is discussedPeer Reviewe
POLAR 2018 - XXXV SCAR Meetings and SCAR/IASC Open Science Conference, 19-23 June 2018, Davos, Sw... more POLAR 2018 - XXXV SCAR Meetings and SCAR/IASC Open Science Conference, 19-23 June 2018, Davos, Switzerland.-- 1 page
IX Simposio de Estudios Polares del Comite Espanol del Scientific Committee on Antarctic Research... more IX Simposio de Estudios Polares del Comite Espanol del Scientific Committee on Antarctic Research (SCAR), 5-7 September 2018, Madrid, Espana.-- 1 page
Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 1 pageNutrient ava... more Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 1 pageNutrient availability is a major constraint for phytoplankton growth and dynamics in the NW Mediterranean. The poorly understood nutrient concentration dynamics in coastal waters raises the question whether atmospheric inputs may be more important than often presumed. Despite wet deposition being the main source of atmospheric nutrient supply in the NW Mediterranean Sea, dry fluxes may also play a key role in several marine locations. Barcelona is a densely populated area with multiple anthropogenic emissions, particularly severe for N and P species (e.g. NOx from industrial combustion and vehicle traffic, HNO3from vehicle traffic, P compounds from incinerators and domestic and industrial substances). A series of experiments were conducted to assess the short-term impact of atmospheric dry deposition on the concentration of nutrients in Barcelona’s inshore waters. Acid-washed polyethylene tubes, containing 20 to 25ml of seawater, were exposed to the open air for 24 h. The results show a high temporal variability with mean dry fluxes of about 40-60 µ mol NO3 m-2 d-1. Consequently, estimated daily median increases in dissolved available inorganic nitrogen in the water column were 1-10%. The estimated atmospheric nutrient inputs could not fully explain nutrient concentration increases observed in Barcelona’s coastal waters, and further experiments may be carried out to determine long-term values for dry deposition. This may help clarify the dynamics of nutrients whenever increases in concentration are not matched by either changes in the water masses or freshwater inflow
1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de... more 1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de Ecología Terrestre (AEET), Ecology: an integrative science in the Anthropocene, 4-7 February 2019, Barcelona, SpainThe Margalef’s Mandala visualizes in a two-dimensional space the role of nutrients and turbulence in shaping the phytoplankton communities. This Mandala, published in 1978, comprises fundamental concepts of plankton ecology related to species succession and energy fluxes. During forty years this conceptual framework has been continuously evolving and numerous authors adapted it to integrate the variety of processes underlying plankton dynamics at different spatio-temporal scales. We now know that turbulence affects different interactions and activities of plankton components such as predator-prey encounter rates and nutrient uptake by osmotrophs. These processes also depend on the nutrient load for a particular system and ultimately determine ecosystem metabolism. We show empirical evidence of plankton responses to turbulence under a range of nutrient concentration and osmotroph abundance conditions. These data led to building-up an extended version of Margalef’s mandala, that we call “the fan”, applicable to system metabolismPeer Reviewe
1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de... more 1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de Ecología Terrestre (AEET), Ecology: an integrative science in the Anthropocene, 4-7 February 2019, Barcelona, SpainIn marine plankton ecosystems, diatoms and heterotrophic bacteria (HB) compete for inorganic nitrogen (N) and phosphorus (P). It has been shown that the outcome of this competition is in favor of diatoms when silicate (Si) is in excess and in favor of HB when Si is depleted. However, the supply of organic compounds, so pervasive in marine plankton ecosystems, could alter the outcome of these competitive interactions. Here, we evaluate the response of natural plankton communities to glucose addition, Si addition, and glucose plus Si addition in laboratory microcosms to which N and P were also added by default. The addition of glucose boosted the growth of HB, which prevented diatoms from thriving. We found that HB were superior competitors as long as labile organic compounds fuelled their metabolic activity, yet, once glucose was consumed, the biomass of diatoms increased conspicuously in the glucose plus Si addition treatment. These substrate-mediated competitive interactions contribute to regulating the structure and succession of marine plankton in nature and provide us with technical know-how to design highly efficient synthetic communities with applications in wastewater treatment and quality biomass productionPeer Reviewe
COVID-19 has led to global population lockdowns that have had indirect effects on terrestrial and... more COVID-19 has led to global population lockdowns that have had indirect effects on terrestrial and marine fauna, yet little is known on their effects on marine planktonic communities. We analysed the effect of the spring 2020 lockdown in a marine coastal area in Blanes Bay, NW Mediterranean. We compared a set of 23 oceanographic, microbial and biogeochemical variables sampled right after the strict lockdown in Spain, with data from the previous 15 years after correcting for long-term trends. Our analysis shows a series of changes in the microbial communities which may have been induced by the combination of the decreased nitrogen atmospheric load, the lower wastewater flux and the reduced fishing activity in the area, among other factors. In particular, we detected a slight decrease beyond the long-term trend in chlorophyll a, in the abundance of several microbial groups (phototrophic nanoflagellates and total prokaryotes) and in prokaryotic activity (heterotrophic prokaryotic production and β-glucosidase activity) which, as a whole, resulted in a moderate increase of oligotrophy in Blanes Bay after the lockdown.
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