Search

We investigated the roles of acclimation and different components involved in evolution (adaptation, chance and history) on the changes in the growth rate of the model freshwater microalga Chlamydomonas reinhardtii P. A. Dang. exposed to selective temperature and salinity. Three C. reinhardtii strains previously grown during one year in freshwater medium and 20 °C were exposed to 5 °C temperature increase and a salinity of 5 g L−1 NaCl. Cultures under each selective scenario and in combination (increase of salinity and temperature), were propagated until growth rate achieved an invariant mean value for 6 months (100–350 generations, varying as a function of scenario and strain). The changes of the growth rate under increased temperature were due to both adaptation and acclimation, as well as history. However, acclimation was the only mechanism detected under salinity increase as well as in the selective scenario of both temperature and salinity, suggesting that genetic variability would not allow survival at salinity higher than that to which experimental populations were exposed. Therefore, it could be hypothesized that under a global change scenario an increase in salinity would be a greater challenge than warming for some freshwater phytoplankton. This work was financially supported by the project CGL2017-87314-P (Ministerio de Economía, Industria y Competitividad, Spain) and the project PID2020-118045-GB-I00 (Ministerio de Ciencia e Innovación, Spain). Funding for open access charge: Universidad de Málaga/CBUA.

Se muestran los resultados obtenidos en dos Proyectos de Innovación Educativa de la Universidad de Málaga (PIE10-013 y PIE13-047), cuyos principales objetivos fueron la creación de Atlas Virtuales de Prácticas de Botánica, Flora y Vegetación, y su aplicación práctica mediante cuestionarios de autoevaluación a través del Campus Virtual. Estos atlas están publicados en la web del Departamento de Biología Vegetal de esta universidad. El Atlas de Prácticas de Botánica consta de 10 carpetas, cada una de ellas correspondientes a diferentes grupos vegetales, y un total de 482 páginas de composición de imágenes fotográficas. Actualmente, el Atlas de Flora cuenta con más de 1000 fotografías, y en él se incluyen índices alfabéticos de taxones (775) y familias (111), cada uno de ellos con su correspondiente enlace a la página de imágenes. Constituye, por tanto, un rápido y práctico buscador de imágenes de plantas, avalado además por profesores universitarios con experiencia, por lo que presenta garantía y calidad científica. El Atlas de Vegetación cuenta con cerca de 500 páginas de imágenes fotográficas, repartidas en cuatro bloques: Bosques (137), Arbustedas y Matorrales (86), Comunidades riparias (67) y Otras comunidades (103). En cada uno de ellos se incluye un índice ordenado y numerado, con objeto de facilitar la búsqueda de determinadas formaciones vegetales, así como de conocer su identidad y clasificación. Se ha creado también Atlas de Paisajes Vegetales y Atlas de Angiospermas-Flores. Todos contribuyen de manera sustancial a mejorar el proceso de enseñanza-aprendizaje en varias asignaturas de los grados de Biología y Ciencias Ambientales. Su uso y aplicación en pruebas de evaluación evita la sobrecarga de trabajo del profesorado.

La Alcarria is one of the most significant regions for honey production in Spain. Times series data of the annual Alcarria honey production from 2000 to 2013 revealed that the total production was highly variable ranging from ca. 60,000 kg in 2000 to almost three times as much in 2011, but without a remarkable trend through time. We hypothesized that these local fluctuations in honey production may be explained by broad-scale climatic patterns. Based on the multiple linear models, we found a significant positive relationship between honey production as a function of the overall means of the North Atlantic Oscillation (NAO) index and precipitation in January, which accounts for 80% of the variability in the Alcarria honey production. We propose that the effect of a negative phase of the NAO and precipitation in January could predict the Alcarria honey production a few months in advance.

Sulphide is proposed to have influenced the evolution of primary stages of oxygenic photosynthesis in cyanobacteria. However, sulphide is toxic to most of the species of this phylum, except for some sulphide-tolerant species showing various sulphide-resistance mechanisms. In a previous study, we found that this tolerance can be induced by environmental sulphidic conditions, in which two experimentally derived strains with an enhanced tolerance to sulphide were obtained from Microcystis aeruginosa, a sensitive species, and Oscillatoria, a sulphide-tolerant genus. We have now analysed the photosynthetic performance of the wild-type and derived strains in the presence of sulphide to shed light on the characteristics underlying the increased tolerance. We checked whether the sulphide tolerance was a result of higher PSII sulphide resistance and/or the induction of sulphide-dependent anoxygenic photosynthesis. We observed that growth, maximum quantum yield, maximum electron transport rate and photosynthetic efficiency in the presence of sulphide were less affected in the derived strains compared to their wild-type counterparts. Nevertheless, in 14C photoincoporation assays, neither Oscillatoria nor M. aeruginosa exhibited anoxygenic photosynthesis using sulphide as an electron donor. On the other hand, the content of photosynthetic pigments in the derived strains was different to that observed in the wild-type strains. Thus, an enhanced PSII sulphide resistance appears to be behind the increased sulphide tolerance displayed by the experimentally derived strains, as observed in most natural sulphide-tolerant cyanobacterial strains. However, other changes in the photosynthetic machinery cannot be excluded. This work was financially supported by the projects CGL2014-53862-P (Ministerio de Economía y Competitividad, Spain) and CGL2017-87314-P (Ministerio de Economía, Industria y Competitividad, Spain). EM-C was supported by grant BES-2015-072984 (Ministerio de Economía y Competitividad, Spain) and grant from Plan Propio de Investigación y Transferencia (Universidad de Málaga, Spain). Funding for open access charge: Universidad de Málaga / CBUA.

One of the most important anthropogenic impacts on freshwater aquatic ecosystems close to intensive agriculture areas is the cumulative increase in herbicide concentrations. The threat is especially relevant for phytoplankton organisms because they have the same physiological targets as the plants for which herbicides have been designed. This led us to explore the evolutionary response of three phytoplanktonic species to increasing concentrations of two herbicides and its consequences in terms of growth and photosynthesis performance. Specifically, we used an experimental ratchet protocol to investigate the differential evolution and the limit of resistance of a cyanobacterium (Microcystis aeruginosa) and two chlorophyceans (Chlamydomonas reinhardtii and Dictyosphaerium chlorelloides) to two herbicides in worldwide use: glyphosate and diuron. Initially, the growth rate of M. aeruginosa and D. chlorelloides was completely inhibited when they were exposed to a dose of 0.23 ppm diuron or 40 ppm glyphosate, whereas a higher concentration of both herbicides (0.46 ppm diuron or 90 ppm glyphosate) was necessary to abolish C. reinhardtii growth. However, after running a ratchet protocol, the resistance of the three species to both herbicides increased by an adaptation process. M. aeruginosa and D. chlorelloides were able to grow at 1.84 ppm diuron and 80 ppm glyphosate and C. reinhardtii proliferated at twice these concentrations. Herbicide-resistant strains showed lower growth rates than their wild-type coun- terparts in the absence of herbicides, as well as changes on morphology and differences on photosynthetic pigment content. Besides, herbicide-resistant cells generally showed a lower photosynthetic performance than wild-type strains in the three species. These results indicate that the introduction of both herbicides in freshwater ecosystems could produce a diminution of primary production due to the selection of herbicide-resistant mutants, that would exhibit ... This work was financially supported by the project CGL2017-87314- P (Ministerio de Economía, Industria y Competitividad, Spain). The acquisition of the FlowCAM by the University of Málaga was co-financed by the 2008-2011 FEDER program for scientific-technique infrastructure (Proposal number: UNMA08-1E005). Funding for open access charge: Universidad de Málaga/CBUA.

Evolutionary rescue (ER) occurs when adaptation prevents extinction under lethal selection. However, the lack of empirical studies addressing the possible factors enabling ER limits our understanding of the current biodiversity crisis in the context of global change. Here we addressed the roles of environmental deterioration rate and dispersal of metapopulations on the dynamics of ER in the freshwater cyanobacterium Microcystis aeruginosa exposed to lethal salinity levels. We exposed M. aeruginosa to six combinations of two environmental deterioration rates (control = no deterioration, and progressive deterioration). Populations under progressive deterioration started with five different NaCl concentrations (from 0 to 4 g l���1 NaCl), with 2 g l���1 NaCl added twice at 4-week intervals, followed by a final increase of 4 g l���1 NaCl. Final concentrations in the experiment ranged from 8 to 12 g l���1 NaCl. Populations with no deterioration treatment spent 12 weeks in the initial concentration and were suddenly shifted to the final range concentration. To determine the effects of dispersal on the number of ER events, three dispersal modes were implemented: (i) populations were not mixed (no dispersal); (ii) six replicate populations of the same NaCl concentration were mixed together (local dispersal); and (iii) all populations of the same metapopulation were mixed together (global dispersal). Both dispersal mode and deterioration rate were very strong predictors of the ER outcome in each metapopulation. Specifically, dispersal among populations and prior stress exposure favoured the occurrence of ER events.

The pteridofloras of nine locations in the Gibraltar Arc were analyzed using a taxonomic distinctness index. We found that the index could be a proxy of historical biogeography of the pteridofloras from this area. Moreover, the value of the taxonomic distinctness index of the different locations showed relevant relationships with certain geographic variables. Finally, we hypothesize about the value of the information derived from taxonomic distinctness index for conservation of the pteridoflora in the Gibraltar Arc. La pteridoflora de nueve localidades singulares situadas en el Arco de Gibraltar ha sido analizada utilizando un índice de distinción taxonómica. Encontramos que el índice podría ser una aproximación a la historia biogeográfica de las pteridofloras de esta zona. Además, el valor del índice de distinción taxonómica de las diferentes localidades mostró relaciones relevantes con determinadas variables geográficas. Finalmente, discutimos el posible papel de la información derivada del índice de distinción taxonómica en la conservación de la pteridoflora del Arco de Gibraltar.

Intraspecific variation plays a key role in species’ responses to environmental change; however, little is known about the role of changes in environmental quality (the population growth rate an environment supports) on intraspecific trait variation. Here, we hypothesize that intraspecific trait variation will be higher in ameliorated environments than in degraded ones. We first measure the range of multitrait phenotypes over a range of environmental qualities for three strains and two evolutionary histories ofChlamydomonas reinhardtiiin laboratory conditions. We then explore how environmental quality and trait variation affect the predictability of lineage frequencies when lineage pairs are grown in indirect co-culture. Our results show that environmental quality has the potential to affect intraspecific variability both in terms of the variation in expressed trait values, and in terms of the genotype composition of rapidly growing populations. We found low phenotypic variability in degraded or same-quality environments and high phenotypic variability in ameliorated conditions. This variation can affect population composition, as monoculture growth rate is a less reliable predictor of lineage frequencies in ameliorated environments. Our study highlights that understanding whether populations experience environmental change as an increase or a decrease in quality relative to their recent history affects the changes in trait variation during plastic responses, including growth responses to the presence of conspecifics. This points towards a fundamental role for changes in overall environmental quality in driving phenotypic variation within closely-related populations, with implications for microevolution.

Se ha analizado la pteridoflora del Arco de Alborán mediante la aplicación de índices pteridoflorísticos y su correlación con variables ambientales. Asimismo se han realizado análisis de agrupamiento de taxones para definir corotipos y de componentes principales para delimitar unidades pteridogeográficas. Con todos estos datos se realiza un análisis de conservación de taxones amenazados y se valora desde un punto de vista territorial la posible declaración del área de estudio con alguna figura de protección especial.

The overall mean levels of different environmental variables are changing rapidly in the present Anthropocene, in some cases creating lethal conditions for organisms. Under this new scenario, it is crucial to know whether the adaptive potential of organisms allows their survival under different rates of environmental change. Here, we used an eco‐evolutionary approach, based on a ratchet protocol, to investigate the effect of environmental change rate on the limit of resistance to salinity of three strains of the toxic cyanobacterium Microcystis aeruginosa. Specifically, we performed two ratchet experiments in order to simulate two scenarios of environmental change. In the first scenario, the salinity increase rate was slow (1.5‐fold increase), while in the second scenario, the rate was faster (threefold increase). Salinity concentrations ranging 7–10 gL‐1 NaCl (depending on the strain) inhibited growth completely. However, when performing the ratchet experiment, an increase in salinity resistance (9.1–13.6 gL‐1 NaCl) was observed in certain populations. The results showed that the limit of resistance to salinity that M. aeruginosa strains were able to reach depended on the strain and on the rate of environmental change. In particular, a higher number of populations were able to grow under their initial lethal salinity levels when the rate of salinity increment was slow. In future scenarios of increased salinity in natural freshwater bodies, this could have toxicological implications due to the production of microcystin by this species., We used an eco‐evolutionary approach based on a ratchet protocol to investigate the effect of environmental change rate on the limit of resistance to salinity of three strains of the toxic cyanobacterium Microcystis aeruginosa. The limit of resistance to salinity that M. aeruginosa strains were able to reach depended on the strain and on the rate of environmental change.

The cyanobacterium Microcystis aeruginosa is a mesophilic freshwater organism, which cannot tolerate sulphide. However, it was possible to isolate a sulphide-resistant (S r ) mutant strain that was able to survive in a normally lethal medium sulphide. In order to evaluate the cost of the mutation conferring sulphide resistance in the S r strain of M. aeruginosa, the morphology and the photosynthetic performance were compared to that found in the wild-type, sulphide-sensitive (S s ) strain. An increase in size and a disrupted morphology was observed in S r cells in comparison to the S s counterpart. Phycoerythrin and phycocyanin levels were higher in the S r than in the S s cells, whereas a higher carotenoid content, per unit volume, was found in the S s strain. The irradiance-saturated photosynthetic oxygen-production rate (GPR max) and the photosynthetic efficiency (measured both by oxygen production and fluorescence, α GPR and α ETR) were lower in the S r strain than in the wild-type. These results appear to be the result of package effect. On the other hand, the S r strain showed higher quantum yield of non-photochemical quenching, especially those regulated mechanisms (estimated throughout q N and Y(NPQ)) and a significantly lower slope in the maximum quantum yield of light-adapted samples (F v ′/F m ′) compared to the S s strain. These findings point to a change in the regulation of the quenching of the transition states (q T ) in the S r strain which may be generated by a change in the distribution of thylakoidal membranes, which somehow could protect metalloenzymes of the electron transport chain from the lethal effect of sulphide.

Se realiza una recensión de los 38 volúmenes de Acta Botanica Malacitana, así como de los dos números de Trabajos y Monografías del Departamento de Botánica. Así mismo se realiza un análisis bibliométrico y se construyen varios índices de autores, temáticas y novedades corológicas, taxonómicas y sintaxonómicas.

The continental sedimentary record of the Baza Basin (Guadix–Baza Depression, Betic Cordillera, SE Spain) shows six sedimentary units of lacustrine origin deposited from the latest Miocene to the Middle Pleistocene. Depending on the interval considered, the lacustrine deposits are mainly composed of marls, carbonates or gypsiferous evaporites, showing lithological, mineralogical and geochemical features (i.e., magnesium, strontium and sulfur contents, celestine deposits and travertine growths) that are evidence of intense, tectonically-induced hydrothermal activity. According to the high concentrations of strontium and sulfur as well as the abundance of travertines and magnesium clays, the supply of hot waters was greater during the Zanclean, the Gelasian and the Calabrian, as a result of tectonic activity. Hydrothermal activity has continued until the present time and is responsible of the hot springs that are nowadays active in the Guadix–Baza Depression. The paleoenvironmental consequences of these sublacustrine hot springs were that during some intervals the lakes maintained a relatively permanent water table, not subject to periodic desiccations in the dry season, and warmer temperatures throughout the year. This resulted in a high level of organic productivity, especially for the Calabrian, which allowed the development of a rich and well diversified mammalian community, similar to those of modern African savannas with tree patches. In this mild environment, the permanent water sheet favored the presence of drought intolerant megaherbivores such as the giant extinct hippo Hippopotamus antiquus. The high standing crop biomass of ungulates resulted in the availability of abundant carcasses for scavengers such as hyenas and hominins, which explains the very high densities of skeletal remains preserved in the sediments distributed along the lake surroundings.

English. The cyanobacterium Microcystis aeruginosa (Kützing) Kützing is notorious for forming extensive and toxic blooms but the genetic structure of natural populations, and in particular during blooms, remains to be explored. In order to add more knowledge about the genetic structure of M. aeruginosa, we compared phenotypic and genetic variabilities in seventeen strains of M. aeruginosa isolated from three adjacent water bodies in SW Spain (the consecutive reservoirs La Minilla and El Gergal, and small pools in Doñana National Park). For this purpose, a phenetic tree, based on six phenotypic traits (including morphology of cells, photosynthetic and respiratory performance, and toxin production) was compared with a phylogenetic tree built by using the 16S-23S rDNA Internal Transcribed Spacer sequence. Whereas the strains isolated from La Minilla showed a relatively homogeneous phenotype, the phenotypic traits of the remaining strains did not discriminate between the other two water bodies. On the other hand, only a strain isolated in Doñana National Park showed a slightly different ITS sequence, but the sequences from the remaining strains were similar. Possible explanations for this discrepancy between phenotypic and genetic diversities are discussed.Español. La cianobacteria Microcystis aeruginosa (Kützing) Kützing puede dar lugar a extensas floraciones tóxicas pero la estructura genética de las poblaciones naturales, y en particular durante las floraciones, ha sido escasamente estudiada. Con el objeto de profundizar en la estructura genética de M. aeruginosa, se han comparado las variabilidades fenotípica y genética de diecisiete cepas aisladas de tres cuerpos de agua adyacentes en el SW de España (los embalses consecutivos de La Minilla y El Gergal, y charcas en el Parque Nacional de Doñana). Para este fin, un árbol de similitud fenética basado en seis caracteres fenotípicos (que incluyen la morfología de las células, el rendimiento fotosintético y respiratorio y la producción de toxina) se comparó con un árbol filogenético construido mediante el uso de la secuencia de ITS 16S - 23S del ADNr. Las cepas aisladas en La Minilla mostraron un fenotipo relativamente homogéneo pero no se detectó un patrón de fenotipos que discriminase los otros dos cuerpos de agua. Por otro lado, sólo una cepa aislada en el Parque Nacional de Doñana mostró una secuencia ITS diferente, pero las secuencias de las cepas restantes fueron idénticas. Se discuten las posibles explicaciones para esta discrepancia entre la diversidad fenotípica y genética en M. aeruginosa.

Los Baños de Vilo (S Spain) is a natural spa characterized by extreme sulphureous waters; however, populations of chlorophyceans inhabit in the spa. The adaptation mechanisms allowing resistance by photosynthetic microorganisms to the extreme sulphureous waters were studied by using a modified Luria-Delbrück fluctuation analysis. For this purpose, the adaptation of the chlorophycean Dictyosphaerium chlorelloides and the cyanobacterium Microcystis aeruginosa (both isolated from non-sulphureous water) were analysed in order to distinguish between physiological adaptation (acclimation) and genetic adaptation by the selection of rare spontaneous mutations. Acclimation to the extreme water was achieved by D. chlorelloides; however, M. aeruginosa cells proliferated as a consequence of selection of favoured mutants (i.e. genetic adaptation). The resistant cells of M. aeruginosa appeared with a frequency of 7.1 × 10(-7) per cell per generation, and the frequency of the resistant allele, under non-selective conditions, was estimated to be 1.1 × 10(-6) per cells as a consequence of the balance mutation-selection. It could be hypothesized that the populations of eukaryotic algae living in the Los Baños de Vilo could be the descendants of chlorophyceans that arrived fortuitously at the spa in the past. On the other hand, cyanobacteria could quickly adapt by the selection of favoured mutants. The single mutation that allows resistance to sulphureous water from Baños de Vilo in M. aeruginosa represents a phenotypic burden impairing growth rate and photosynthetic performance. The resistant-variant cells of M. aeruginosa showed a lower acclimated growth rate and a decreased maximum quantum yield and photosynthetic efficiency, in comparison to the wild-type cells.

The cyanobacterium Microcystis aeruginosa forms blooms that can consist of colonies. We have investigated how M. aeruginosa acclimatizes to changing light conditions such as can occur during blooms. Three different strains were exposed to two irradiance levels: lower (LL) and higher (HL) than the irradiance-onset saturation parameter. We measured the photosynthetic pigment concentrations, PSII photochemical efficiency, electron transport rate (ETR), irradiance-saturated ETR and ETR efficiency. The relationship between ETR and photosynthetic oxygen production and the excess in PSII capacity were also studied for one strain. Higher values of chlorophyll a and phycocyanin and lower values of total carotenoids were found under LL conditions in the three strains. The strains showed clear differences in the irradiance-saturated ETR and in ETR efficiency under both LL and HL treatments. No differences were found in the linear relationship between ETR and photosynthetic oxygen production under both irradiance treatments. LL-acclimated cells showed higher PSII excess capacity than HL ones, possibly because their higher pigment content could result in a higher light stress than HL cells when forming surface blooms. The fact that the genetically different strains show different photosynthetic physiologies suggests that the very dynamic light climate observed in lakes may allow their coexistence.

The roles of adaptation, chance, and history on evolution of the toxic dinoflagellate Alexandrium minutum Halim, under selective conditions simulating global change, have been addressed. Two toxic strains (AL1V and AL2V), previously acclimated for two years at pH 8.0 and 20°C, were transferred to selective conditions: pH 7.5 to simulate acidification and 25°C. Cultures under selective conditions were propagated until growth rate and toxin cell quota achieved an invariant mean value at 720 days (ca. 250 and ca. 180 generations for strains AL1V and AL2V, respectively). Historical contingencies strongly constrained the evolution of growth rate and toxin cell quota, but the forces involved in the evolution were not the same for both traits. Growth rate was 1.5–1.6 times higher than the one measured in ancestral conditions. Genetic adaptation explained two-thirds of total adaptation while one-third was a consequence of physiological adaptation. On the other hand, the evolution of toxin cell quota showed a pattern attributable to neutral mutations because the final variances were significantly higher than those measured at the start of the experiment. It has been hypothesized that harmful algal blooms will increase under the future scenario of global change. Although this study might be considered an oversimplification of the reality, it can be hypothesized that toxic blooms will increase but no predictions can be advanced about toxicity.

Toxic blooms of the cyanobacterium Microcystis aeruginosa affect humans and animals in inland water systems worldwide, and it has been hypothesized that the development of these blooms will increase under the future scenario of global change, considering eutrophication and temperature increase as two important consequences. The importance of genetic adaptation, chance and history on evolution of growth rate, and toxin production of M. aeruginosa was studied under these new conditions. The experiment followed the idea of "replaying life's tape" by means of the simultaneous propagation of 15 independent isolates of three M. aeruginosa strains, which were grown under doubled nutrient concentration and temperature during c. 87 generations. Adaptation by new mutations that resulted in the enhancement of growth rate arose during propagation of derived cultures under the new environmental conditions was the main component of evolution; however, chance also contributed in a lesser extension to evolution of growth rate. Mutations were selected, displacing the wild-type ancestral genotypes. In contrast, the effect of selection on mutations affecting microcystin production was neutral. Chance and history were the pacemakers in evolution of toxin production. Although this study might be considered an oversimplification of the reality, it suggest that a future scenario of global change might lead to an increase in M. aeruginosa bloom frequency, but no predictions about the frequency of toxicity can be made.

Aquatic ecosystems located close to agricultural areas are increasingly polluted by herbicides. We evaluated the capacity for adaptation of green microalgae to lethal concentrations of the herbicide simazine in one strain of Dictyosphaerium chlorelloides and two strains of Scenedesmus intermedius, as well as adaptation to the herbicide diquat in one of the strains of S. intermedius. A Luria–Delbruck fluctuation analysis was carried out in order to distinguish between resistant cells arising from physiological adaptation (acclimatization) or post-adaptive mutation (both events occurring after the exposure to the herbicides), and adaptation due to mutations before the exposure to the herbicides. Simazine-resistant cells arose by rare spontaneous mutations before the exposure to simazine, with a rate of 3.0 × 10−6 mutants per cell per generation in both strains of S. intermedius, and of 9.2 × 10−6 mutants per cell per generation in D. chlorelloides. Diquat-resistant cells in S. intermedius arose by pre-selective mutations with a rate of 17.9 × 10−6 per cell per generation. Rare, pre-selective mutations may allow the survival of green microalgae in simazine- or diquat-polluted waters, via herbicide-resistant selection. Therefore, human-synthesized pollutants, such as the herbicides simazine and diquat, could cause the emergence of evolutionary novelties in aquatic environments.

Several species of microalgae, closely related to mesophilic lineages, inhabit the extreme environment (pH 2.5, high levels of metals) of the Spain’s Aguas Agrias Stream water (AASW). Consequently, AASW constitutes an interesting natural laboratory for analysis of adaptation by microalgae to extremely stressful conditions. To distinguish between the pre-selective or post-selective origin of adaptation processes allowing the existence of microalgae in AASW, a Luria–Delbruck fluctuation analysis was performed with the chlorophycean Dictyosphaerium chlorelloides isolated from non-acidic waters. In the analysis, AASW was used as selective factor. Preselective, resistant D. chlorelloides cells appeared with a frequency of 1.1 × 10 −6 per cell per generation. AASW-resistant mutants, with a diminished Malthusian fitness, are maintained in non-extreme waters as the result of a balance between new AASW-resistant cells arising by mutation and AASW-resistant mutants eliminated by natural selection (equilibrium at c . 12 AASW-resistants per 10 7 wild-type cells). We propose that the microalgae inhabiting this stressful environment could be the descendents of chance mutants that arrived in the past or are even arriving at the present.

Although populations of cyanobacteria are usually considered to be clonal, their capacity to survive environmental changes suggests intrapopulation genetic variation. We therefore estimated the genetic variability on the basis of two processes important for any photoautotroph - photochemical and nonphotochemical quenching - as well as photosynthetic pigment concentrations. For this purpose, two parameters related to photochemical and nonphotochemical quenching were measured using specific experimental and statistical procedures, in 25 strains of the cyanobacterium Microcystis aeruginosa, along with their contents of chlorophyll a, total carotenoids and phycocyanin. The experimental procedure allowed discrimination between genetic and nongenetic (or residual) variability among strains. The high genetic variability found in photosynthetic pigments and both photosynthetic parameters denotes large differences even among strains isolated from the same community. The high genetic diversity within a population could be important for the evolutionary success of cyanobacteria.

Adaptation of Microcystis aeruginosa (Cyanobacteria) to resist the herbicide glyphosate was analysed by using an experimental model. Growth of wild-type, glyphosate-sensitive (Gs) cells was inhibited when they were cultured with 120 ppm glyphosate, but after further incubation for several weeks, occasionally the growth of rare cells resistant (Gr) to the herbicide was found. A fluctuation analysis was carried out to distinguish between resistant cells arising from rare spontaneous mutations and resistant cells arising from other mechanisms of adaptation. Resistant cells arose by rare spontaneous mutations prior to the addition of glyphosate, with a rate ranging from 3.1 × 10−7 to 3.6 × 10−7 mutants per cell per generation in two strains of M. aeruginosa; the frequency of the Gr allele ranged from 6.14 × 10−4 to 6.54 × 10−4. The Gr mutants are slightly elliptical in outline, whereas the Gs cells are spherical. Since Gr mutants have a diminished growth rate, they may be maintained in uncontaminated waters as the result of a balance between new resistants arising from spontaneous mutation and resistants eliminated by natural selection. Thus, rare spontaneous pre-selective mutations may allow the survival of M. aeruginosa in glyphosate-polluted waters via Gr clone selection.

RESUMEN. Revisión crítica de los estudios sobre biogeografía de macroalgas marinas del Mediterráneo. Teniendo en cuenta los procedimientos metodológicos que se siguen en los estudios biogeográficos, se reconocen tres tipos básicos de aproximaciones: biogeografía descriptiva, biogeografía narrativa y biogeografía analítica. En este trabajo se analizan las aportaciones realizadas a la ficogeografía de las macroalgas marinas del mar Mediterráneo, atendiendo a cada una de las tres aproximaciones posibles. Existen escasas floras del Mediterráneo oriental y la costa africana, además de un estancamiento metodológico en los estudios narrativos y analíticos, impidiendo el avance de la ficogeografía. Se discuten las posibles líneas futuras de investigación con el objeto de incentivar un avance significativo en los conocimientos ficogeográficos del Mediterráneo.Palabras clave. Biogeografía analítica, biogeografía descriptiva, biogeografía narrativa, macroalgas, Mediterráneo.SUMARY. Critical review of the studies on biogeography of seaweeds from the Mediterranean Sea. Seaweed biogeography, like subdiscipline of the biogeography, could be divided on the basis of methodological approach used: descriptive biogeography, narrative biogeography and analytic biogeography. In this paper, we analyse the contributions to the biogeography of seaweeds from the Mediterranean Sea, in accordance with each one of these approaches. Scarce floras of the Mediterranean eastern and African coast exist, besides a methodological stagnation, impeding the advance of this science with regard to other branches of the biogeography. Possible future research lines are discussed and proposed.Key words. Analytical biogeography, descriptive biogeography, narrative biogeography, Mediterranean Sea, seaweeds.

Copper is one of the most frequently used algaecides to control blooms of toxic cyanobacteria in water supply reservoirs. Among the negative impacts derived from the use of this substance is the increasing resistance of cyanobacteria to copper toxicity, as well as changes in the community structure of native phytoplankton. Here, we used the ratchet protocol to investigate the differential evolution and maximum adaptation capacity of selected freshwater phytoplankton species to the exposure of increasing doses of copper. Initially, a dose of 2.5 μM CuSO4·5H2O was able to completely inhibit growth in three strains of the toxic cyanobacterium Microcystis aeruginosa, whereas growth of the chlorophyceans Dictyosphaerium chlorelloides and Desmodesmus intermedius (represented by two different strains) was completely abolished at 12 μM. A significant increase in resistance was achieved in all derived populations during the ratchet experiment. All the chlorophyceans were able to adapt to up to 270 μM of copper sulfate, but 10 μM was the highest concentration that M. aeruginosa strains were able to cope with, although one of the replicates adapted to 30 μM. The recurrent use and increasing doses of copper in water reservoirs could lead to the selection of copper-resistant mutants of both chlorophyceans and cyanobacteria. However, under high concentrations of copper, the composition of phytoplankton community could undergo a drastic change with cyanobacteria being replaced by copper-resistant chlorophyceans. This result stems from a distinct evolutionary potential of these species to adapt to this substance. © 2014 Springer-Verlag Berlin Heidelberg., This work has been financially supported by the Spanish Ministry of Science and Innovation through the Grants CTM2008-05680 C02-01/MAR, CGL2008-00652/BOS and by Junta de Andalucía Research Group RNM-115.

New records for the macrophytobenthos of Andalusia (Spain). V.Palabras clave. Andalucía, Asparagopsis taxiformis, Desmarestia dresnayi, Macroalgas marinas, Spatoglossum solierii.Key words. Andalusia, Asparagopsis taxiformis, Desmarestia dresnayi, Spatoglossum solierii, scaweeds.

Measurements of photosynthesis, germination capacity and assessment of DNA damage were carried out in the laboratory to determine the effect of different conditions of ultraviolet (UV) and photosynthetically active radiation (PAR) on zoospores of various large brown algae collected on Spitsbergen (Svalbard, High Arctic) and Tarifa (Cadiz, southern Spain). Results were correlated to in situ light conditions and indicated that zoospores suffer photoinhibition of photosynthesis, loss of viability and DNA damage in relation to the growth depth of parental sporophytes. At both sites, germination capacity of zoospores in species collected in deep waters was more strongly impaired after exposure to the same UV doses than in species from shallower waters. In general, zoospores exposed to PAR+UVA+UVB showed higher mortality rates than after exposure to PAR+UVA or PAR alone. For Laminaria digitata from Spitsbergen, it was found that the loss of zoospore viability is the result of DNA damage and photodamage of the photosynthetic apparatus. UVB irradiances occurring in southern Spain at water depths shallower than 7 m prevented the germination of spores of deep water Laminariales from this region.

The effects of full-spectrum solar radiation and of solar radiation deprived of total u.v. radiation (λ

A check-list of the Rhodophyceae from the Andalusian coast, based on literature records (from 1807 to 1996), is presented. Taxa are listed by provinces. The catalogue contains 348 species and infraspecific taxa under current taxonomy.

Se presenta el listado de las Chlorophyceae s. l. de las costas de Andalucía, basado en referencias bibliográficas (desde 1807 a 1995). Los taxa se desglosan por provincias. El catálogo contiene 86 especies y taxa infraespecíficos.

Catálogo de las Phaeophyceae de Andalucía (S. España). Se presenta el listado de las Phaeophyceae de las costas andaluzas a partir de datos bibliográficos (desde 1807 hasta 1995). Los taxa se desglosan por provincias. El catálogo contiene 108 especies y taxa infraespecíficos.

Aquatic macrophyte biomass, diaspore bank distribution and their relationship to spatial variability of depth, nutrients (nitrite, nitrate, ammonium and soluble reactive phosphorus) as well as sediment granulometry in an athalassohaline lake have been studied during one wet hydrological year. The results indicate that species growing in the lake show different spatial distribution patterns throughout the lake. Indirect gradient analysis (canonical analysis) results showed a first axis defined as a function of Ulva flexuosa Wulfen biomass which is, in turn, positively correlated with interstitial ammonium and Soluble Reactive Phosphorus (SRP). The second axis was mainly established due to Lamprothamnium papulosum (Wallr.) J. Groves biomass which correlated positively to depth and negatively to interstitial ammonium and SRP. These results revealed a NESW eutrophic gradient allowing the U. Flexuosa biomass proliferation. This phenomenon could increase the shadow effect over the rest of the macrophytes inhabiting this shallow lake. Moreover, the eutrophic harmful effect on the macrophyte physiology and over the diaspore bank could have important consequences in the survival of such important populations. The results reported in this study show the need for studies as the base to select sampling points for monitoring this wetland.La distribución de la biomasa de los macrófitos acuáticos y de su banco de semillas y oogonios ha sido investigada en relación a la profundidad, los nutrientes (nitrito, nitrato, amonio y fósforo soluble reactivo) y la granulometría del sedimento durante un año hidrológico húmedo. Los resultados muestran patrones de distribución diferentes en las distintas especies. Los resultados del análisis canónico basado en análisis de gradiente indirecto muestran un primer eje definido en función de la biomasa de U. Flexuosa, Wulfen que, a su vez, está positivamente correlacionada con el amonio intersticial y el fosfato soluble. El segundo eje se establecía principalmente en función de la biomasa de Lamprothamnium papulosum (Wallr.) J. Groves, que a su vez estaba positivamente relacionada con la profundidad y negativamente correlacionada con el amonio intersticial y el fosfato soluble. Estos resultados ponen de manifiesto un gradiente NE-SW de eutrofización que induce la proliferación de U. Flexuosa, lo que podría contribuir a aumentar el efecto de sombreo sobre el resto de los macrófitos de la laguna. Además la eutrofización puede ejercer un efecto negativo tanto en la fisiología de los macrófitos como sobre el banco de diásporas poniendo en riesgo la supervivencia de estas poblaciones. Los resultados obtenidos en el presente estudio resaltan la necesidad de disponer de estudios de base para seleccionar los puntos de muestreo necesarios para monitorizar este tipo de humedales.

The notion that humankind has changed the biosphere led to the Nobel prize Paul Crutzen to propose, a decade ago, the new term “Anthropocene” to denote the current interval of time in the earth dominated by human driven large-scale activities (Crutzen, 2002). The massive loss of diversity, homogenization of biotas, proliferation of opportunistic species and unpredictable emergent novelties can be considered among the distinctive features of the future biosphere (Myers & Knoll, 2001). Intensive agriculture, supported by the massive use of herbicides, pesticides and compounds with biocidal activity, is a significant cause of the biodiversity crisis (Tilman, 1999). The impact of these toxic compounds on biodiversity threatens all ecosystems, being particularly significant in those characterized by a slow response to change, such as aquatic systems. Phytoplankton are responsible for about half of the global primary production, driving essential biogeochemical cycles, exporting massive amounts of carbon to deep waters and sediments in the open ocean and strongly influencing the water–atmosphere gas exchanges (Rost et al., 2008). Since these organisms represent the basis of the aquatic food web, the repercussions of the impact on phytoplankton populations will undoubtedly affect the rest of the components of the trophic web. Step behind of the risen up of scientific and social concern regarding the environmental pollution control, developed countries have begun to take legislative actions to protect the ecosystems from chemical pollution. For the time being, the monitoring of water quality has generally relied on the collection of spot water samples followed by extraction and laboratory-based instrumental analysis. These analytical methods usually requires the use of sophisticated equipment, skilled laboratory personnel, are time consuming, expensive and difficult to adapt for fieldwork. Besides, this provides only a snapshot of the situation at the sampling time and fails to provide more realistic information due to spatio-temporal variations in water characteristics (Rodriguez-Mozaz et al., 2006). The European Union Water Framework Directive (WFD), one of the most important pieces of environmental legislation, is likely to transform the way that determination of water quality is undertaken. Within the next few years, the implementation of the WFD will require a considerable additional monitoring effort to be undertaken and a wide range of

Two populations of Phyllariopsis purpurascens from the Straits of Gibraltar area were investigated during 1990 and 1991. This area has very strong currents (∼2·5 m s-1 at spring tide). The first sporophytes (less than 0·5 cm in length) were observed in April; they disappeared after the first storm period in October. The estimated number of spores produced in an unilocular sporangium was 64. The fertility period started in May and continued until October, but the maximum sorus surface area (27%) was reached in September. The maximum sporangial density was 1476±236 mm-2. The slow development of fertility and its correlation with the seasonal increase in temperature suggest that sporangial development is controlled by temperature and not by photoperiod. The drag effect produced by the strong currents (at spring tides and storm periods) is sufficient to break adult plants (with 0·01 m2 in surface intercepting the current). At the beginning of the sporophytic production cycle (210 days), the meristematic zone ...

We have studied the plasticity of the photosynthetic apparatus in the endangered aquatic macrophyte Althenia orientalis to the gradient of light availability within its meadow canopy. We determined diurnal change in situ irradiance, light quality, in vivo chlorophyll a fluorescence, ex situ oxygen evolution rates, respiration rate and pigment concentration. The levels of photosynthetic photon flux density (PFD) and ultraviolet radiation (UVR) and the red/far-red ratio decreased with depth within the canopies of A. orientalis. Apical leaves had a greater decrease of the maximal quantum yield (F v/F m) in the morning and a faster recovery rate in the afternoon than those in the basal ones. The relative electron transport rate (ETRr) was not saturated at any time of the day, even in the apical leaves that received the highest light. The maximum light-saturated rate of gross photosynthesis (GPmax) took place in apical leaves around noon. The chlorophyll a/b ratio values were higher, and the chlorophyll/carotenoid ratio values lower, in apical leaves than basal ones. The highest concentrations in total carotenoids were reached in the apical leaves around noon. A. orientalis has a high capacity to acclimatize to the changes in the light environment, both in quality and quantity, presenting sun and shade leaves in the same stem through the vertical gradient in the canopy.

Aspergillus fumigatusFresenius has the capacity to degrade elastin (the principal protein of the lungs) and it is considered that elastase activity (EA) is among the most important pathogenicity factors of this mold. In particular, there is a strong correlation between EA inA. fumigatusand invasive aspergillosis. However, EA is not universal in this mold, and it is unknown whether the capacity to degrade elastin is the consequence of physiological mechanisms and/or genetic changes (putative adaptive mutations) induced after the exposure to this substrate or, on the contrary, it is due to random spontaneous mutations that occur under nonselective conditions. In order to discriminate between these possibilities, a Luria-Delbrück fluctuation analysis was carried out on an elastase-negative (EA−)A. fumigatusstrain, using as selective factor a culture medium containing elastin as the sole source of nitrogen. Here we show that theEA−→EA+transformation inA. fumigatusappears by rare, random mutations before the exposure of the strain to selective conditions. This work represents the first experimental evidence of pathogenicity factor acquisition in mycelial fungi by preselective mutation.

La flora de macroalgas marinas de Andalucía se recoge en los catálogos de Flores- Moya et al. (1995a, 1995b) y Conde et al. (1996a), y las adiciones posteriores de Conde et al. (1996b), Báez et al. (2001) y Altamirano et al. (2006, 2008). En este trabajo se presentan 9 citas nuevas para Andalucía (señaladas con un asterisco), 19 citas nuevas para la provincia de Huelva, 9 citas nuevas y una confirmación para la provincia de Málaga y 25 citas nuevas para la provincia de Granada. Mediante esta contribución el catálogo de Chlorophyceae de Andalucía consta de 90 taxones, mientras que los de Phaeophyceae y Rhodophyceae contienen 109 y 356 taxones, respectivamente. Todo el material recolectado se conservó en formol al 4% en agua de mar para su posterior determinación en el laboratorio. Como medio de montaje y preservación de las muestras microscópicas se ha utilizado sirope de maíz al 25% en agua destilada con unas gotas de formol al 4%. Los ejemplares identificados se han depositado en el herbario de la Universidad de Málaga (MGC Phyc). Para la ordenación taxonómica se ha seguido a Guiry & Guiry (2009)

En el presente artículo se estudian e interpretan al microscopio electrónico de barrido (M.E.B.) algunos caracteres cualitativos de siete especies de algas coralináceas del litoral andaluz, pertenecientes a los géneros Corallina,Jania y Amphiroa. Using the scanning electron microscopy some qualitatives characteristics of seven seaweeds species of the mediterranean coasts of Andalucía (S. of Spain), of the genus Corallina, Junio y Amphiroa have been studied.

Microalgae contributed 60% of the total biomass in the extremely hostile (pH 2 and metal-rich waters) environment of Rio Tinto (which is used as a model for the astrobiology of Mars). These algae are closely related to nonextreme lineages, suggesting that adaptation to Rio Tinto water (RTW) must occur rapidly. Fitness from both the microalga Dictyosphaerium chlorelloides and the cyanobacterium Microcystis aeruginosa was inhibited when they were cultured in RTW. After further incubation for several weeks, D. chlorelloides survived, as a result of the growth of a variant that was resistant to RTW, but RTW-resistant cells did not appear in M. aeruginosa. A Luria-Delbruck fluctuation test revealed that D. chlorelloides RTW-resistant cells arose randomly by rare spontaneous mutations before the RTW exposure (1.38 x 10(-6) mutants per cell division). The mutants with a diminished fitness are maintained in nonextreme waters as the result of a balance between new RTW-resistant cells arising by mutation and RTW-resistant mutants eliminated by natural selection (equilibrium at c. 15 RTW-resistant per 10(7) wild-type cells). Rapid adaptation of eukaryotic algae to RTW could be the result of selection of RTW-resistant mutants occurring spontaneously in nonextreme populations that arrived fortuitously at the river in the past, or in the present continuously.

RESUMEN. Evolucion fenotípica en microalgas: un cambio morfológico espectacular en Dictyosphaerium chlorelloides (Chlorophyta) tras la exposición a TNT. Un cambio morfológico muy rápido tiene lugar en Dictyosphaerium chlorelloides (Chlorophyta) tras la exposición de cepas salvajes al potente alguicida 2,4,6 trinitrotolueno (TNT). Las cepas salvajes, sensibles al TNT, tienen una morfología típica esférico-elipsoidal. Tras exponer dichas cepas a dosis letales de TNT, solamente sobreviven células resistentes al tóxico cuya silueta es fusiforme. Estos resistentes fusiformes aparecen como consecuencia de mutaciones espontáneas que tienen lugar antes de exponer las cepas salvajes al agente selectivo (TNT): es decir, las células fusiformes estaban presentes en la población salvaje. La frecuencia de mutantes fusiformes en las poblaciones salvajes está definida por el equilibrio entre la tasa de acumulación de mutantes y la tasa en que son eliminados por tener una eficiencia biológica menor (10-102 mutantes fusiformes por 106 células salvajes). Se propone que la selección de clones podría ser un mecanismo de evolución adaptativa en poblaciones de microalgas asexuales. Este evento opera mediante la selección de genotipos pre-selectivos que aparecen como consecuencia del incremento de la presión de selección como fruto de eventos catastróficos en el medio ambiente.Palabras clave. Dictyosphaerium, evolución, microalgas, morfología, mutación, TNT.ABSTRACT. Phenotypic evolution in microalgae: a dramatic morphological shift in Dictyosphaerium chlorelloides (Chlorophyta) after exposure to TNT. The occurrence of rapid morphological evolution in the microalga Dictyosphaerium chlorelloides (Chlorophyta) was induced after exposure of the wild strains of the alga to the potent algal poison 2,4,6-trinitrotoluene (TNT). After exposing a wild- type population (consisted of representative spherical-ellipsoidal cells) to doses of TNT that were lethal for most of the cells, a TNT-resistant spindle-shaped mutant was able to proliferate. This spindle- shaped mutant appeared spontaneously by rare mutations before the selective treatment: in deed, it was already present in the wild population. The frequency of the mutants within the ancestral population seemed to be determined by the balance between the rate of accumulation by recurrent mutation and the rate of elimination by selection (ranging 10-102 spindle-shaped mutants per 106 cells). We hypothesize that clone selection could take place in asexual populations of microalgae by selection of rare, pre-selective genotypes, driven by a drastic selective pressure subsequent to a catastrophic environmental change.Key words. Dictyosphaerium, evolution, microalgae, morphology, mutation, TNT.

Adaptation of Spirogyra insignis (Chlorophyceae) to growth and survival in an extreme natural environment (sulphureous waters from La Hedionda Spa, S. Spain) was analysed by using an experimental model. Photosynthesis and growth of the alga were inhibited when it was cultured in La Hedionda Spa waters (LHW), but after further incubation for several weeks, the culture survived due to the growth of a variant that was resistant to LHW. A Luria-Delbruck fluctuation analysis was carried out to distinguish between resistant filaments arising from rare spontaneous mutations and resistant filaments arising from other mechanisms of adaptation. It was demonstrated that the resistant filaments arose randomly by rare spontaneous mutations before the addition of LHW (preselective mutations). The rate of spontaneous mutation from sensitivity to resistance was 2.7 x 10(-7) mutants per cell division. Since LHW(resistant) mutants have a diminished growth rate, they are maintained in nonsulphureous natural waters as the result of a balance between new resistants arising from spontaneous mutation and resistants eliminated by natural selection. Thus, recurrence of rare spontaneous preselective mutations ensures the survival of the alga in sulphureous waters.

A new genetic approach was developed for increasing specificity of microalgal biosensors. This method is based on the use of two different genotypes jointly to detect a given pollutant: (i) a sensitive genotype to obtain sensitivity; and (ii) a resistant mutant to obtain specificity. The method was tested by the development of a microalgal biosensor for the detection of the explosive 2,4,6-trinitrotoluene (TNT) using a wild-type strain (DcG1wt) of Dictyosphaerium chlorelloides (Chlorophyceae) as the sensitive organism, and a TNT-resistant mutant, obtained from DcG1wt strain by a modified Luria–Delbruck fluctuation analysis. The inhibition of chlorophyll a fluorescence of PSII by TNT was used as the biological signal. Significant differences in maximal fluorescence of light-adapted algae ( F m ′) between wild-type DcG1wt cells and TNT-resistant mutants, were observed in all the TNT concentrations tested (from 0.5 to 31.3 mg l −1 ) after only 3 min of exposure. Resistant mutants always exhibited significant higher F m ′ values in the presence of TNT than wild-type cells. These results suggest that the use of two different genotypes (sensitive and resistant to a given pollutant) jointly is a useful method to improve microalgal biosensors specificity.