The contamination of aquatic environments with organic micropollutants (OMPs) resulting from huma... more The contamination of aquatic environments with organic micropollutants (OMPs) resulting from human activities is becoming a widespread, serious environmental issue. The problem is mainly rooted in a general inefficiency of conventional wastewater treatment plants to deal with this type of pollutants, which causes treated wastewaters to still contain significant amounts of
Natural CO 2 vents have received growing interest in the last years due to their relation to CO 2... more Natural CO 2 vents have received growing interest in the last years due to their relation to CO 2 capture and storage (CCS) risk assessment studies. Despite the increasing body of knowledge, mostly focused on microbial communities, scarce information is available on how geological CO 2 affects mesofauna and microfauna, and their interactions. We studied microorganisms, microfauna i.e. protists and nematodes, and mesofauna communities, i.e. collembola and mites and their relationships in a natural CO 2 vent at La Sima (Spain). Four CO 2 flux intensities from Control (7e19 g m À2 d À1) to low (40e55 g m À2 d À1) and high fluxes (260e1600 g m À2 d À1), including extreme emissions (more than 10 4 g m À2 d À1) were studied. We found that increasing CO 2 emissions from Control to high fluxes strongly affected biota abundances and richness, cascading from microorganisms to mesofauna, and resulting in reduced and less diverse populations in each of the groups levels assayed. Nevertheless, at extreme fluxes edaphic biota biomass recovered in most of the communities, suggesting that the extreme CO 2 conditions are associated with high abundances of well adapted communities, although with very low diversity. Increases in abundance of bacteria, fungi and amoebae, but not ciliates, were related to increases in mesofauna richness and nematode and mesofauna abundances. Our results help to indicate the CO 2 threshold from which accidental losses from CCS operations can be detected in the long-term.
International Journal of Greenhouse Gas Control, 2016
A natural carbon dioxide (CO 2) vent sited in Ciudad Real (Spain) was studied to understand how C... more A natural carbon dioxide (CO 2) vent sited in Ciudad Real (Spain) was studied to understand how CO 2 emissions affect microbial communities along a CO 2 gradient. We used different molecular methods (quantitative PCR, DGGE and Biolog EcoPlates TM) to assess changes in abundance, diversity and functionality of the main groups of soil microbiota (bacteria, archaea and fungi). A general decrease for all studied variables (gene copies and band richness of bacteria, archaea and fungi, and Biolog activities) was observed from control (7-19 g m −2 d −1) to high CO 2 fluxes (260-1600 g m −2 d −1). On the contrary, at extreme fluxes (more than 10 kg m −2 d −1) the microbial community increased their abundance and activity, though remained less diverse. PCA from carbon use substrate pattern and DGGE dendograms clearly differentiated low fluxes from high and extreme. This paper proves that high CO 2 fluxes (between 260 and 1600 g m −2 d −1) cause losses in both structural and functional community diversity, and a decrease in metabolic activities.
Chytridiomycosis, which is caused by Batrachochytrium dendrobatidis, is an emerging infectious di... more Chytridiomycosis, which is caused by Batrachochytrium dendrobatidis, is an emerging infectious disease of amphibians. The disease is one of the main causes of the global decline in amphibians. The aetiological agent is ubiquitous, with worldwide distribution, and affects a large number of amphibian species in several biomes. In the last decade, scientific research has substantially increased knowledge of the aetiological agent and the associated infection. However, important epidemiological aspects of the environment-mediated interactions between the aetiological agent and the host are not yet clear. The objective of the present review is to describe chytridiomycosis with regard to the major features of the aetiological agent, the host and the environment.
In comparison with conventional activated sludge treatment systems, for which a large body of res... more In comparison with conventional activated sludge treatment systems, for which a large body of research has been carried out on their microfauna and their role in bacteria and pollutant removal, only a few studies have focused on microfaunal communities inhabiting constructed wetlands (CWs). The aim of this study was to evaluate the microfaunal communities of horizontal CWs with differing design configurations in order to determine those design factors affecting their abundance and community structure and to discover their role in bacteria removal. Total bacteria, ciliates, amoebae and metazoa were counted in the effluents of an experimental plant combining the most common design configurations of CWs. Three different hydraulic designs (hydroponic, free water surface-FWS and subsurface flow-SSF), presence vs. absence of vegetation, two plant species (Typha angustifolia vs. Phragmites australis) and two organic loading rates were compared. SSF and vegetation favoured bacteria removal whereas abundance of protozoa and diversity of metazoa was greater in FWS-planted wetlands. Microfauna community structure and bacterial removal were clearly affected by vegetation and flow type, although no significant relationships were observed between microfauna and bacteria abundance at the outflow. Therefore, other mechanisms such as filtration, sedimentation or adsorption, seem to be more important than predation in removing bacteria from constructed wetlands.
As regards constructed wetlands (CWs), there is a great deal of research on metals removal, altho... more As regards constructed wetlands (CWs), there is a great deal of research on metals removal, although comparison of different parameters under the same conditions is scarce. The aim of this study was to determine the most important factors affecting the removal efficiency and dynamics of metals and metalloids according to different configurations of horizontal CWs. An experimental plant, including the most commonly used CWs, was analysed for several metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn and Zn). Arsenic, which was under the detection limits at the influent, presented a release in those wetlands with subsurface flow (SSF) and followed the same pattern as iron and manganese. The presence of vegetation and flow type were key design factors affecting metals removal from urban wastewater. Free water surface (FWS) flow provided favourable conditions for the removal of As, Fe and Mn, which are sensitive to redox changes, whereas SSF slightly enhanced the removal of other metals, such as Cu or Pb. On the other hand, vegetation was not able to maintain steady oxidised conditions to guarantee redox dependent metals removal by combination with oxides in SSF systems. In contrast, constant reduced conditions promoted the long-term removal of metals by sulphide combination and precipitation. 2014 Elsevier B.V. All rights reserved.
The ability of several mesocosm-scale and full-scale constructed wetlands (CWs) to remove pharmac... more The ability of several mesocosm-scale and full-scale constructed wetlands (CWs) to remove pharmaceuticals and personal care products (PPCPs) from urban wastewater was assessed. The results of three previous works were considered as a whole to find common patterns in PPCP removal. The experiment took place outdoors under winter and summer conditions. The mesocosm-scale CWs differed in some design parameters, namely the presence of plants, the vegetal species chosen (Typha angustifolia versus Phragmites australis), the flow configuration (surface flow versus subsurface flow), the primary treatment (sedimentation tank versus HUSB), the feeding regime (batch flow versus continuous saturation) and the presence of gravel bed. The full-scale CWs consisted of a combination of various subsystems (ponds, surface flow CWs and subsurface flow CWs). The studied PPCPs were ketoprofen, naproxen, ibuprofen, diclofenac, salicylic acid, carbamazepine, caffeine, methyl dihydrojasmonate, galaxolide and...
The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW)... more The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW) design parameters on solids distribution, loss of hydraulic conductivity over time and hydraulic behaviour, in order to assess clogging processes in wetlands. For this purpose, an experimental plant with eight CWs was built at mesocosm scale. Each CW presented a different design characteristic, and the most common CW configurations were all represented: free water surface flow (FWS) with different effluent pipe locations, FWS with floating macrophytes and subsurface flow (SSF), and the presence of plants and specific species (Typha angustifolia and Phragmites australis) was also considered. The loss of the hydraulic conductivity of gravel was greatly influenced by the presence of plants and organic load (representing a loss of 20% and c.a. 10% in planted wetlands and an overloaded system, respectively). Cattail seems to have a greater effect on the development of clogging since its below-ground biomass weighed twice as much as that of common reed. Hydraulic behaviour was greatly influenced by the presence of a gravel matrix and the outlet pipe position. In strict SSF CW, the water was forced to cross the gravel and tended to flow diagonally from the top inlet to the bottom outlet (where the inlet and outlet pipes were located). However, when FWS was considered, water preferentially flowed above the gravel, thus losing half the effective volume of the system. Only the presence of plants seemed to help the water flow partially within the gravel matrix.
The aim of this study was to conduct a comparative evaluation of evapotranspiration (ET) rates fo... more The aim of this study was to conduct a comparative evaluation of evapotranspiration (ET) rates for eight different mesocosm constructed wetlands (CWs), and the relationship with redox potential (E H). Inflow, outflow and E H were measured over 4 years in winter and summer campaigns as well as over 24 h on selected days in summer. Vegetation was the main design parameter which affected water loss in the wetlands (on average, ET in planted wetlands was 4 times higher than in unplanted ones), and Typha angustifolia was more active than Phragmites australis (mean daily ET-expressed as the average of ET rate measured every 2 h in selected days in summer-was 36.8 ± 2.3 mm d −1 and 23.0 ± 1.9 mm d −1 for hydroponic wetlands planted with cattail and common reed, respectively), although P. australis water use efficiency was lower. Positive relationships were found between ET and E H for planted wetlands. Cattail presented a stronger linear regression than common reed, demonstrating that ET and consequently redox conditions are plant species-dependent.
The prokaryotic microbial communities (Bacteria and Archaea) of three different systems operating... more The prokaryotic microbial communities (Bacteria and Archaea) of three different systems operating in Denmark for the treatment of domestic wastewater (horizontal flow constructed wetlands (HFCW), vertical flow constructed wetlands (VFCW) and biofilters (BF)) was analysed using endpoint PCR followed by Denaturing Gradient Gel Electrophoresis (DGGE). Further sequencing of the most representative bacterial bands revealed that diverse and distinct bacterial communities were found in each system unit, being γ-Proteobacteria and Bacteroidetes present mainly in all of them, while Firmicutes was observed in HFCW and BF. Members of the Actinobacteria group, although found in HFCW and VFCW, seemed to be more abundant in BF units. Finally, some representatives of α, ß and δ-Proteobacteria, Acidobacteria and Chloroflexi were also retrieved from some samples. On the other hand, a lower archaeal diversity was found in comparison with the bacterial population. Cluster analysis of the DGGE bacterial band patterns showed that community structure was related to the design of the treatment system and the organic matter load, while no clear relation was established between the microbial assemblage and the wastewater influent.
ABSTRACT The influence of the loading rate and the seasonal environmental conditions on the bacte... more ABSTRACT The influence of the loading rate and the seasonal environmental conditions on the bacterial communities established in High Rate Algal Ponds (HRAPs) treating diluted swine manure was investigated using 16S rRNA Denaturing Gradient Gel Electrophoresis (DGGE) and further phylogenetic analysis. Two HRAPs were successfully operated at different loading rates (10 and 20 times diluted swine manure, resulting in average Surface Organic Loading Rates (SOLR) ranging from 13 to 99 g m−2 d−1 and from 21 to 180 g m−2 d−1, respectively) for 9 months. The DGGE analysis revealed a high diversity of bacteria symbiotically living with microalgae. The environmental conditions rather than the organic loading rate were the most significant factors determining the bacterial community structure. Hence, despite a higher biodiversity was recorded in summer, both HRAPs presented a similar community regardless of their different organic loading. Most of the species (≈54%) belonged to Verrucomicrobium, an ubiquitous phylum of aerobic bacteria commonly found in eutrophic environments. Firmicutes and Proteobacteria (Gammaproteobacteria) were the other dominant phyla. Some of the bacteria present in the HRAPs were highly resistant to UV radiation and floc-forming species, which might explain the reasonable good settling characteristics of the algal–bacterial biomass in the ponds. The present work provides new insights on the complex interactions between microalgae and bacteria in algal-based wastewater treatment systems.
1. Responses of zooplankton to nutrient enrichment and fish predation were studied in 1998 and 19... more 1. Responses of zooplankton to nutrient enrichment and fish predation were studied in 1998 and 1999 by carrying out parallel mesocosm experiments in six lakes across Europe. 2. Zooplankton community structure, biomass and responses to nutrient and fish manipulation showed geographical and year-to-year differences. Fish had a greater influence than nutrients in regulating zooplankton biomass and especially the relative abundances of different functional groups of zooplankton. When fish reduced the biomass of large crustaceans, there was a complementary increase in the biomasses of smaller crustacean species and rotifers. 3. High abundance of submerged macrophytes provided refuge for zooplankton against fish predation but this refuge effect differed notably in magnitude among sites. 4. Large crustacean grazers (Daphnia, Diaphanosoma, Sida and Simocephalus) were crucial in controlling algal biomass, while smaller crustacean grazers and rotifers were of minor importance. Large grazers were able to control phytoplankton biomass even under hypereutrophic conditions (up to 1600 lg TP L)1) when grazer biomass was high (>80-90 lg dry mass L)1) or accounted for >30% of the grazer community. 5. The littoral zooplankton community was less resistant to change following nutrient enrichment in southern Spain, at high temperatures (close to 30°C), than at lower temperatures (17-23°C) characterising the other sites. This lower resistance was because of a greater importance of nutrients than zooplankton in controlling algal biomass. 6. Apart from the reduced role of large crustacean grazers at the lowest latitude, no consistent geographical patterns were observed in the responses of zooplankton communities to nutrient and fish manipulation.
Boletín de la Real Sociedad Española de Historia Natural, 2021
An Encyonema population collected in the Zambeze River near the Victoria Falls, Namibia, is here ... more An Encyonema population collected in the Zambeze River near the Victoria Falls, Namibia, is here described and illustrated in detail with the aid of LM and SEM microscopy. This taxon had already been presented in the literature under the name E. volkii, the reasons leading to treat this species as a new, independent taxon are here discussed. Encyonema ratpanati sp. nov. can be easily distinguished from E. volkii by its more linear outline (length-to-width ratio up to 4.3 vs. up to 3.5 in E. volkii), its lower degree of dorsiventrality, lack of rostrate apices throughout the whole diminution series, wider axial area and denser areolation (>26 lineolae per 10 µm and not 20–22 as in E. volkii) Se describe una población de Encyonema recogida en el río Zambeze, cerca de las cataratas Victoria, Namibia, y se ilustra en detalle con la ayuda de microscopía óptica y electrónica. Este taxón ya había sido presentado en la literatura bajo el nombre de E. volkii, se discuten aquí las razones que llevan a tratar esta especie como un nuevo taxón independiente. Encyonema ratpanati sp. nov. Puede ser fácilmente diferenciado de E. volkii por su contorno más lineal (cociente largo/ancho de hasta 4.3 vs. hasta 3.5 en E. volkii), su menor grado de dorsiventralidad, la ausencia de ápices rostrados a lo largo de toda la serie decreciente, el área central más ancha una areolación más densa (>26 lineolas cada 10 µm y no 20–22 como en E. volkii).
International Journal of Greenhouse Gas Control, Oct 1, 2015
Abstract This paper evaluates the effect of CO2 on protozoan communities, a neglected group in CO... more Abstract This paper evaluates the effect of CO2 on protozoan communities, a neglected group in CO2 related studies, despite their potential role in influencing bacterial communities, and vegetation growth. For this purpose, the effect of increased CO2 in the soil upon the abundance of protozoa (amoebae, flagellates, and ciliates) and diversity of ciliates was experimentally studied in two soils. Twelve mesocosms were created with 8 m2 cells filled with the upper layer of one of the two soils. The cells were equipped with systems that controlled injection of CO2 at different depths. Two different flows of CO2 (20 and 40 l/h) were studied simulating a potential CO2 leakage from early CSS sites. Water content and pH levels were measured by continuous monitoring systems. There were no clear patterns in the abundance of amoebae, ciliates, or flagellates in response to the injection of CO2. The analysis used to evaluate the community structure of ciliates, such as Equitability, Margalef index, or the Colpodea to Polyhymenophorea ratio showed significant differences with increases in CO2. The results of this study indicate that controlled increments of CO2 in the soil influence the composition of the ciliate community, but have no effect on their total abundance. This paper supports the use of ciliates as promising biological indicators of CO2 effects in Carbon Capture and Storage operations.
Diatoms are microalgae, known to present several characteristics that make them excellent bioindi... more Diatoms are microalgae, known to present several characteristics that make them excellent bioindicators. In this study, we analyzed the epiphytic diatom communities of shallow lakes, with the aim of exploring the genetic variability explained by physical, chemical or geographical variables. We selected 77 lakes within the Spanish part of the Duero River Basin characterized by wide chemical variability. In each lake, physical parameters were measured in situ and water samples were taken to determine nutrient levels in the laboratory. Diatom communities were collected and identified by both microscopy and DNA-metabarcoding, amplifying a genetic barcode of rbcL gene. We analyzed the phylogenetic signal for several environmental parameters at the genus level for the three most representative genera of these lakes. Our results indicate significant phylogenetic signals that differ from a genus to another. Processes related to spatial scales appear to be the main predictors controlling the...
In the ablation zone of glacier habitats, cryoconite holes are known to harbor diverse microbial ... more In the ablation zone of glacier habitats, cryoconite holes are known to harbor diverse microbial communities, including unique diatom floras distinct from those of surrounding aquatic and terrestrial systems. Besides descriptive studies, little is known about the diversity of cryoconite diatoms and their response to environmental stressors, particularly in low-latitude glaciers. This paper documents an extremely diversified diatom community in Antisana Glacier (Ecuador), reporting 278 taxa found in 54 surface holes, although with low individual abundances. Contrary to our expectations, assemblage structure did not respond to water physical or chemical characteristics, nor to cryoconite hole morphology, but to elevation. We demonstrate that elevation is a driver of diatom assemblages. Both alpha diversity (measured as Fisher's index) and species richness (corrected for unequal sample sizes) correlated negatively with elevation, suggesting a replacement toward simplified, poorer c...
The contamination of aquatic environments with organic micropollutants (OMPs) resulting from huma... more The contamination of aquatic environments with organic micropollutants (OMPs) resulting from human activities is becoming a widespread, serious environmental issue. The problem is mainly rooted in a general inefficiency of conventional wastewater treatment plants to deal with this type of pollutants, which causes treated wastewaters to still contain significant amounts of
Natural CO 2 vents have received growing interest in the last years due to their relation to CO 2... more Natural CO 2 vents have received growing interest in the last years due to their relation to CO 2 capture and storage (CCS) risk assessment studies. Despite the increasing body of knowledge, mostly focused on microbial communities, scarce information is available on how geological CO 2 affects mesofauna and microfauna, and their interactions. We studied microorganisms, microfauna i.e. protists and nematodes, and mesofauna communities, i.e. collembola and mites and their relationships in a natural CO 2 vent at La Sima (Spain). Four CO 2 flux intensities from Control (7e19 g m À2 d À1) to low (40e55 g m À2 d À1) and high fluxes (260e1600 g m À2 d À1), including extreme emissions (more than 10 4 g m À2 d À1) were studied. We found that increasing CO 2 emissions from Control to high fluxes strongly affected biota abundances and richness, cascading from microorganisms to mesofauna, and resulting in reduced and less diverse populations in each of the groups levels assayed. Nevertheless, at extreme fluxes edaphic biota biomass recovered in most of the communities, suggesting that the extreme CO 2 conditions are associated with high abundances of well adapted communities, although with very low diversity. Increases in abundance of bacteria, fungi and amoebae, but not ciliates, were related to increases in mesofauna richness and nematode and mesofauna abundances. Our results help to indicate the CO 2 threshold from which accidental losses from CCS operations can be detected in the long-term.
International Journal of Greenhouse Gas Control, 2016
A natural carbon dioxide (CO 2) vent sited in Ciudad Real (Spain) was studied to understand how C... more A natural carbon dioxide (CO 2) vent sited in Ciudad Real (Spain) was studied to understand how CO 2 emissions affect microbial communities along a CO 2 gradient. We used different molecular methods (quantitative PCR, DGGE and Biolog EcoPlates TM) to assess changes in abundance, diversity and functionality of the main groups of soil microbiota (bacteria, archaea and fungi). A general decrease for all studied variables (gene copies and band richness of bacteria, archaea and fungi, and Biolog activities) was observed from control (7-19 g m −2 d −1) to high CO 2 fluxes (260-1600 g m −2 d −1). On the contrary, at extreme fluxes (more than 10 kg m −2 d −1) the microbial community increased their abundance and activity, though remained less diverse. PCA from carbon use substrate pattern and DGGE dendograms clearly differentiated low fluxes from high and extreme. This paper proves that high CO 2 fluxes (between 260 and 1600 g m −2 d −1) cause losses in both structural and functional community diversity, and a decrease in metabolic activities.
Chytridiomycosis, which is caused by Batrachochytrium dendrobatidis, is an emerging infectious di... more Chytridiomycosis, which is caused by Batrachochytrium dendrobatidis, is an emerging infectious disease of amphibians. The disease is one of the main causes of the global decline in amphibians. The aetiological agent is ubiquitous, with worldwide distribution, and affects a large number of amphibian species in several biomes. In the last decade, scientific research has substantially increased knowledge of the aetiological agent and the associated infection. However, important epidemiological aspects of the environment-mediated interactions between the aetiological agent and the host are not yet clear. The objective of the present review is to describe chytridiomycosis with regard to the major features of the aetiological agent, the host and the environment.
In comparison with conventional activated sludge treatment systems, for which a large body of res... more In comparison with conventional activated sludge treatment systems, for which a large body of research has been carried out on their microfauna and their role in bacteria and pollutant removal, only a few studies have focused on microfaunal communities inhabiting constructed wetlands (CWs). The aim of this study was to evaluate the microfaunal communities of horizontal CWs with differing design configurations in order to determine those design factors affecting their abundance and community structure and to discover their role in bacteria removal. Total bacteria, ciliates, amoebae and metazoa were counted in the effluents of an experimental plant combining the most common design configurations of CWs. Three different hydraulic designs (hydroponic, free water surface-FWS and subsurface flow-SSF), presence vs. absence of vegetation, two plant species (Typha angustifolia vs. Phragmites australis) and two organic loading rates were compared. SSF and vegetation favoured bacteria removal whereas abundance of protozoa and diversity of metazoa was greater in FWS-planted wetlands. Microfauna community structure and bacterial removal were clearly affected by vegetation and flow type, although no significant relationships were observed between microfauna and bacteria abundance at the outflow. Therefore, other mechanisms such as filtration, sedimentation or adsorption, seem to be more important than predation in removing bacteria from constructed wetlands.
As regards constructed wetlands (CWs), there is a great deal of research on metals removal, altho... more As regards constructed wetlands (CWs), there is a great deal of research on metals removal, although comparison of different parameters under the same conditions is scarce. The aim of this study was to determine the most important factors affecting the removal efficiency and dynamics of metals and metalloids according to different configurations of horizontal CWs. An experimental plant, including the most commonly used CWs, was analysed for several metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn and Zn). Arsenic, which was under the detection limits at the influent, presented a release in those wetlands with subsurface flow (SSF) and followed the same pattern as iron and manganese. The presence of vegetation and flow type were key design factors affecting metals removal from urban wastewater. Free water surface (FWS) flow provided favourable conditions for the removal of As, Fe and Mn, which are sensitive to redox changes, whereas SSF slightly enhanced the removal of other metals, such as Cu or Pb. On the other hand, vegetation was not able to maintain steady oxidised conditions to guarantee redox dependent metals removal by combination with oxides in SSF systems. In contrast, constant reduced conditions promoted the long-term removal of metals by sulphide combination and precipitation. 2014 Elsevier B.V. All rights reserved.
The ability of several mesocosm-scale and full-scale constructed wetlands (CWs) to remove pharmac... more The ability of several mesocosm-scale and full-scale constructed wetlands (CWs) to remove pharmaceuticals and personal care products (PPCPs) from urban wastewater was assessed. The results of three previous works were considered as a whole to find common patterns in PPCP removal. The experiment took place outdoors under winter and summer conditions. The mesocosm-scale CWs differed in some design parameters, namely the presence of plants, the vegetal species chosen (Typha angustifolia versus Phragmites australis), the flow configuration (surface flow versus subsurface flow), the primary treatment (sedimentation tank versus HUSB), the feeding regime (batch flow versus continuous saturation) and the presence of gravel bed. The full-scale CWs consisted of a combination of various subsystems (ponds, surface flow CWs and subsurface flow CWs). The studied PPCPs were ketoprofen, naproxen, ibuprofen, diclofenac, salicylic acid, carbamazepine, caffeine, methyl dihydrojasmonate, galaxolide and...
The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW)... more The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW) design parameters on solids distribution, loss of hydraulic conductivity over time and hydraulic behaviour, in order to assess clogging processes in wetlands. For this purpose, an experimental plant with eight CWs was built at mesocosm scale. Each CW presented a different design characteristic, and the most common CW configurations were all represented: free water surface flow (FWS) with different effluent pipe locations, FWS with floating macrophytes and subsurface flow (SSF), and the presence of plants and specific species (Typha angustifolia and Phragmites australis) was also considered. The loss of the hydraulic conductivity of gravel was greatly influenced by the presence of plants and organic load (representing a loss of 20% and c.a. 10% in planted wetlands and an overloaded system, respectively). Cattail seems to have a greater effect on the development of clogging since its below-ground biomass weighed twice as much as that of common reed. Hydraulic behaviour was greatly influenced by the presence of a gravel matrix and the outlet pipe position. In strict SSF CW, the water was forced to cross the gravel and tended to flow diagonally from the top inlet to the bottom outlet (where the inlet and outlet pipes were located). However, when FWS was considered, water preferentially flowed above the gravel, thus losing half the effective volume of the system. Only the presence of plants seemed to help the water flow partially within the gravel matrix.
The aim of this study was to conduct a comparative evaluation of evapotranspiration (ET) rates fo... more The aim of this study was to conduct a comparative evaluation of evapotranspiration (ET) rates for eight different mesocosm constructed wetlands (CWs), and the relationship with redox potential (E H). Inflow, outflow and E H were measured over 4 years in winter and summer campaigns as well as over 24 h on selected days in summer. Vegetation was the main design parameter which affected water loss in the wetlands (on average, ET in planted wetlands was 4 times higher than in unplanted ones), and Typha angustifolia was more active than Phragmites australis (mean daily ET-expressed as the average of ET rate measured every 2 h in selected days in summer-was 36.8 ± 2.3 mm d −1 and 23.0 ± 1.9 mm d −1 for hydroponic wetlands planted with cattail and common reed, respectively), although P. australis water use efficiency was lower. Positive relationships were found between ET and E H for planted wetlands. Cattail presented a stronger linear regression than common reed, demonstrating that ET and consequently redox conditions are plant species-dependent.
The prokaryotic microbial communities (Bacteria and Archaea) of three different systems operating... more The prokaryotic microbial communities (Bacteria and Archaea) of three different systems operating in Denmark for the treatment of domestic wastewater (horizontal flow constructed wetlands (HFCW), vertical flow constructed wetlands (VFCW) and biofilters (BF)) was analysed using endpoint PCR followed by Denaturing Gradient Gel Electrophoresis (DGGE). Further sequencing of the most representative bacterial bands revealed that diverse and distinct bacterial communities were found in each system unit, being γ-Proteobacteria and Bacteroidetes present mainly in all of them, while Firmicutes was observed in HFCW and BF. Members of the Actinobacteria group, although found in HFCW and VFCW, seemed to be more abundant in BF units. Finally, some representatives of α, ß and δ-Proteobacteria, Acidobacteria and Chloroflexi were also retrieved from some samples. On the other hand, a lower archaeal diversity was found in comparison with the bacterial population. Cluster analysis of the DGGE bacterial band patterns showed that community structure was related to the design of the treatment system and the organic matter load, while no clear relation was established between the microbial assemblage and the wastewater influent.
ABSTRACT The influence of the loading rate and the seasonal environmental conditions on the bacte... more ABSTRACT The influence of the loading rate and the seasonal environmental conditions on the bacterial communities established in High Rate Algal Ponds (HRAPs) treating diluted swine manure was investigated using 16S rRNA Denaturing Gradient Gel Electrophoresis (DGGE) and further phylogenetic analysis. Two HRAPs were successfully operated at different loading rates (10 and 20 times diluted swine manure, resulting in average Surface Organic Loading Rates (SOLR) ranging from 13 to 99 g m−2 d−1 and from 21 to 180 g m−2 d−1, respectively) for 9 months. The DGGE analysis revealed a high diversity of bacteria symbiotically living with microalgae. The environmental conditions rather than the organic loading rate were the most significant factors determining the bacterial community structure. Hence, despite a higher biodiversity was recorded in summer, both HRAPs presented a similar community regardless of their different organic loading. Most of the species (≈54%) belonged to Verrucomicrobium, an ubiquitous phylum of aerobic bacteria commonly found in eutrophic environments. Firmicutes and Proteobacteria (Gammaproteobacteria) were the other dominant phyla. Some of the bacteria present in the HRAPs were highly resistant to UV radiation and floc-forming species, which might explain the reasonable good settling characteristics of the algal–bacterial biomass in the ponds. The present work provides new insights on the complex interactions between microalgae and bacteria in algal-based wastewater treatment systems.
1. Responses of zooplankton to nutrient enrichment and fish predation were studied in 1998 and 19... more 1. Responses of zooplankton to nutrient enrichment and fish predation were studied in 1998 and 1999 by carrying out parallel mesocosm experiments in six lakes across Europe. 2. Zooplankton community structure, biomass and responses to nutrient and fish manipulation showed geographical and year-to-year differences. Fish had a greater influence than nutrients in regulating zooplankton biomass and especially the relative abundances of different functional groups of zooplankton. When fish reduced the biomass of large crustaceans, there was a complementary increase in the biomasses of smaller crustacean species and rotifers. 3. High abundance of submerged macrophytes provided refuge for zooplankton against fish predation but this refuge effect differed notably in magnitude among sites. 4. Large crustacean grazers (Daphnia, Diaphanosoma, Sida and Simocephalus) were crucial in controlling algal biomass, while smaller crustacean grazers and rotifers were of minor importance. Large grazers were able to control phytoplankton biomass even under hypereutrophic conditions (up to 1600 lg TP L)1) when grazer biomass was high (>80-90 lg dry mass L)1) or accounted for >30% of the grazer community. 5. The littoral zooplankton community was less resistant to change following nutrient enrichment in southern Spain, at high temperatures (close to 30°C), than at lower temperatures (17-23°C) characterising the other sites. This lower resistance was because of a greater importance of nutrients than zooplankton in controlling algal biomass. 6. Apart from the reduced role of large crustacean grazers at the lowest latitude, no consistent geographical patterns were observed in the responses of zooplankton communities to nutrient and fish manipulation.
Boletín de la Real Sociedad Española de Historia Natural, 2021
An Encyonema population collected in the Zambeze River near the Victoria Falls, Namibia, is here ... more An Encyonema population collected in the Zambeze River near the Victoria Falls, Namibia, is here described and illustrated in detail with the aid of LM and SEM microscopy. This taxon had already been presented in the literature under the name E. volkii, the reasons leading to treat this species as a new, independent taxon are here discussed. Encyonema ratpanati sp. nov. can be easily distinguished from E. volkii by its more linear outline (length-to-width ratio up to 4.3 vs. up to 3.5 in E. volkii), its lower degree of dorsiventrality, lack of rostrate apices throughout the whole diminution series, wider axial area and denser areolation (>26 lineolae per 10 µm and not 20–22 as in E. volkii) Se describe una población de Encyonema recogida en el río Zambeze, cerca de las cataratas Victoria, Namibia, y se ilustra en detalle con la ayuda de microscopía óptica y electrónica. Este taxón ya había sido presentado en la literatura bajo el nombre de E. volkii, se discuten aquí las razones que llevan a tratar esta especie como un nuevo taxón independiente. Encyonema ratpanati sp. nov. Puede ser fácilmente diferenciado de E. volkii por su contorno más lineal (cociente largo/ancho de hasta 4.3 vs. hasta 3.5 en E. volkii), su menor grado de dorsiventralidad, la ausencia de ápices rostrados a lo largo de toda la serie decreciente, el área central más ancha una areolación más densa (>26 lineolas cada 10 µm y no 20–22 como en E. volkii).
International Journal of Greenhouse Gas Control, Oct 1, 2015
Abstract This paper evaluates the effect of CO2 on protozoan communities, a neglected group in CO... more Abstract This paper evaluates the effect of CO2 on protozoan communities, a neglected group in CO2 related studies, despite their potential role in influencing bacterial communities, and vegetation growth. For this purpose, the effect of increased CO2 in the soil upon the abundance of protozoa (amoebae, flagellates, and ciliates) and diversity of ciliates was experimentally studied in two soils. Twelve mesocosms were created with 8 m2 cells filled with the upper layer of one of the two soils. The cells were equipped with systems that controlled injection of CO2 at different depths. Two different flows of CO2 (20 and 40 l/h) were studied simulating a potential CO2 leakage from early CSS sites. Water content and pH levels were measured by continuous monitoring systems. There were no clear patterns in the abundance of amoebae, ciliates, or flagellates in response to the injection of CO2. The analysis used to evaluate the community structure of ciliates, such as Equitability, Margalef index, or the Colpodea to Polyhymenophorea ratio showed significant differences with increases in CO2. The results of this study indicate that controlled increments of CO2 in the soil influence the composition of the ciliate community, but have no effect on their total abundance. This paper supports the use of ciliates as promising biological indicators of CO2 effects in Carbon Capture and Storage operations.
Diatoms are microalgae, known to present several characteristics that make them excellent bioindi... more Diatoms are microalgae, known to present several characteristics that make them excellent bioindicators. In this study, we analyzed the epiphytic diatom communities of shallow lakes, with the aim of exploring the genetic variability explained by physical, chemical or geographical variables. We selected 77 lakes within the Spanish part of the Duero River Basin characterized by wide chemical variability. In each lake, physical parameters were measured in situ and water samples were taken to determine nutrient levels in the laboratory. Diatom communities were collected and identified by both microscopy and DNA-metabarcoding, amplifying a genetic barcode of rbcL gene. We analyzed the phylogenetic signal for several environmental parameters at the genus level for the three most representative genera of these lakes. Our results indicate significant phylogenetic signals that differ from a genus to another. Processes related to spatial scales appear to be the main predictors controlling the...
In the ablation zone of glacier habitats, cryoconite holes are known to harbor diverse microbial ... more In the ablation zone of glacier habitats, cryoconite holes are known to harbor diverse microbial communities, including unique diatom floras distinct from those of surrounding aquatic and terrestrial systems. Besides descriptive studies, little is known about the diversity of cryoconite diatoms and their response to environmental stressors, particularly in low-latitude glaciers. This paper documents an extremely diversified diatom community in Antisana Glacier (Ecuador), reporting 278 taxa found in 54 surface holes, although with low individual abundances. Contrary to our expectations, assemblage structure did not respond to water physical or chemical characteristics, nor to cryoconite hole morphology, but to elevation. We demonstrate that elevation is a driver of diatom assemblages. Both alpha diversity (measured as Fisher's index) and species richness (corrected for unequal sample sizes) correlated negatively with elevation, suggesting a replacement toward simplified, poorer c...
Uploads
Papers by Eloy Becares