Search

Teeth root morphology and integrity are essential to provide appropriate attachment, allowing for continuous and functional movement, with implications for adequate food processing, animal performance, and longevity. We studied the occurrence of supernumerary roots in mandibular molariform teeth of red deer ( Cervus elaphus Linnaeus, 1758) from seven separate populations spanning a range of latitudes in the Iberian Peninsula. We analyzed the influence of several factors, including sex, origin (native vs. reintroduced), lineage, and habitat, to assess extra root prevalence variations. The highest prevalence in deciduous teeth was found in pm3 (14%) and in permanent teeth in M1 (3%). We found significant differences between areas, lineages, and soil type; however, no significant relationships were found with the origin or the sex of individuals. We speculate that the high prevalence of supernumerary roots in M1 might be related to increased wear in grazers. Furthermore, we suggest that this high prevalence in deciduous teeth might be associated with a hard diet, dry climatic conditions, and a harsh weaning period, which indicate that supernumerary roots might have an adaptive value.

Integrative studies of animals and associated microbial assemblages (Here we used the endemic Balearic wall lizardAll the three populations showed a remarkable conservation of the major microbial taxonomic profile, while carrying their unique microbial signature at finer level of taxonomic resolution (Amplicon Sequence Variants (ASVs)). Microbiota distances across populations were compatible with both host genetics (based on microsatellites) and trophic niche distances (based on stable isotopes and fecal content). Within populations, a large proportion of ASVs (30-50%) were recurrently found along the four sampling dates. The microbial diversity was strongly marked by seasonality, with no sex effect and a marginal life stage and annual effect. The microbiota showed seasonal fluctuations along the two sampled years, primarily due to changes in the relative abundances of fermentative bacteria (mostly families Lachnospiraceae and Ruminococcaceae), without any major compositional turnover.These results support a large resilience of the major compositional aspects of the

Background Integrative studies of animals and associated microbial assemblages (i.e., the holobiont) are rapidly changing our perspectives on organismal ecology and evolution. Insular vertebrates provide ideal natural systems to understand patterns of host-gut microbiota coevolution, the resilience and plasticity these microbial communities over temporal and spatial scales, and ultimately their role in the host ecological adaptation. Methods Here we used the endemic Balearic wall lizard Podarcis lilfordi to dissect the drivers of the microbial diversity within and across host allopatric populations/islets. By focusing on three extensively studied populations/islets of Mallorca (Spain) and fecal sampling from individually identified lizards along two years (both in spring and autumn), we sorted out the effect of islet, sex, life stage, year and season on the microbiota composition. We further related microbiota diversity to host genetics, trophic ecology and expected annual metabolic changes. Results All the three populations showed a remarkable conservation of the major microbial taxonomic profile, while carrying their unique microbial signature at finer level of taxonomic resolution (Amplicon Sequence Variants (ASVs)). Microbiota distances across populations were compatible with both host genetics (based on microsatellites) and trophic niche distances (based on stable isotopes and fecal content). Within populations, a large proportion of ASVs (30–50%) were recurrently found along the four sampling dates. The microbial diversity was strongly marked by seasonality, with no sex effect and a marginal life stage and annual effect. The microbiota showed seasonal fluctuations along the two sampled years, primarily due to changes in the relative abundances of fermentative bacteria (mostly families Lachnospiraceae and Ruminococcaceae), without any major compositional turnover. Conclusions These results support a large resilience of the major compositional aspects of the P. lilfordi gut microbiota over the short-term evolutionary divergence of their host allopatric populations (

Recent studies have demonstrated that projected climate change will likely enhance nitrogen (N) and phosphorus (P) loss from farms and farmland, with the potential to worsen freshwater eutrophication. Here, we investigate the relative importance of the climate and land use drivers of nutrient loss in nine study catchments in Europe and a neighboring country (Turkey), ranging in area from 50 to 12,000 km2 . The aim was to quantify whether planned large-scale, land use change aimed at N and P loss reduction would be effective given projected climate change. To this end, catchment-scale biophysical models were applied within a common framework to quantify the integrated effects of projected changes in climate, land use (including wastewater inputs), N deposition, and water use on river and lake water quantity and quality for the mid-21st century. The proposed land use changes were derived from catchment stakeholder workshops, and the assessment quantified changes in mean annual N and P concentrations and loads. At most of the sites, the projected effects of climate change alone on nutrient concentrations and loads were small, whilst land use changes had a larger effect and were of sufficient magnitude that, overall, a move to more environmentally focused farming achieved a reduction in N and P concentrations and loads despite projected climate change. However, at Beyşehir lake in Turkey, increased temperatures and lower precipitation reduced water flows considerably, making climate change, rather than more intensive nutrient usage, the greatest threat to the freshwater ecosystem. Individual site responses did however vary and were dependent on the balance of diffuse and point source inputs. Simulated lake chlorophyll-a changes were not generally proportional to changes in nutrient loading. Further work is required to accurately simulate the flow and water quality extremes and determine how reductions in freshwater N and P translate into an aquatic ecosystem response.

The continental shelf and submarine canyon off Cap de Creus (NW Mediterranean) were declared a Site of Community Importance (SCI) within the Natura 2000 Network in 2014. Implementing an effective management plan to preserve its biological diversity and monitor its evolution through time requires a detailed character ization of its benthic ecosystem. Based on 60 underwater video transects performed between 2007 and 2013 (before the declaration of the SCI), we thoroughly describe the composition and structure of the main mega benthic communities dwelling from the shelf down to 400 m depth inside the submarine canyon. We then mapped the spatial distribution of the benthic communities using the Random Forest algorithm, which incor porated geomorphological and oceanographic layers as predictors, as well as the intensity of the bottom-trawling fishing fleet. Although the study area has historically been exposed to commercial fishing practices, it still holds a rich benthic ecosystem with over 165 different invertebrate (morpho)species of the megafauna identified in the video footage, which form up to 9 distinct megabenthic communities. The continental shelf is home to coral gardens of the sea fan Eunicella cavolini, sea pen and soft coral assemblages, dense beds of the crinoid Leptometra phalangium, diverse sponge grounds and massive aggregations of the brittle star Ophiothrix fragilis. The submarine canyon off Cap de Creus is characterized by a cold-water coral community dominated by the scleractinian coral Madrepora oculata, found in association with several invertebrate species including oysters, brachiopods and a variety of sponge species, as well as by a community dominated by cerianthids and sea urchins, mostly in sedimentary areas. The benthic communities identified in the area were then compared with habitats/biocenoses described in reference habitat classification systems that consider circalittoral and bathyal environments of the Mediterranean. The complex environmental setting characteristic of the marine area off Cap de Creus likely produces the optimal conditions for communities dominated by suspension- and filter-feeding species to develop. The uniqueness of this ecosystem and the anthropogenic pressures that it faces should prompt the development of effective management actions to ensure the long-term conservation of the benthic fauna representative of this marine area, Hermes, Inventariación y designación de la Red Notura 2000 en Áreas Marinas del Estado Español, INDEMARES, DEEP CORAL, SI

There is evidence that both omega-3 polyunsaturated fatty acids (n-3 PUFAs) and choline can influence sports performance, but information establishing their combined effects when given in the form of krill oil during power training protocols is missing. The purpose of this study was therefore to characterize n-3 PUFA and choline profiles after a one-hour period of high-intensity physical workout after 12 weeks of supplementation. Thirty-five healthy power training athletes received either 2.5 g/day of Neptune krill oilTM (550 mg EPA/DHA and 150 mg choline) or olive oil (placebo) in a randomized double-blind design. After 12 weeks, only the krill oil group showed a significant HS-Omega-3 Index increase from 4.82 to 6.77% and a reduction in the ARA/EPA ratio (from 50.72 to 13.61%) (p < 0.001). The krill oil group showed significantly higher recovery of choline concentrations relative to the placebo group from the end of the first to the beginning of the second exercise test (p = 0.04) and an 8% decrease in total antioxidant capacity post-exercise versus 21% in the placebo group (p = 0.35). In conclusion, krill oil can be used as a nutritional strategy for increasing the HS-Omega-3 Index, recover choline concentrations and address oxidative stress after intense power trainings.

El objetivo del presente estudio fue identificar las habilidades técnicas del portero de hockey patines en las faltas directas de la alta competición, proponiendo, al mismo tiempo, la estructura funcional de las habilidades técnicas y destacando los encadenamientos más eficaces. Se ha utilizado la metodología observacional analizando las faltas directas en la liga profesional española (n = 637). Se creó un instrumento de observación ad hoc con las habilidades técnicas del portero, del jugador y la lateralidad del jugador. Se validó el instrumento de observación mediante el criterio de autoridad y se calculó la fiabilidad intra e inter observador. Se realizó un análisis correlacional mediante la prueba de chi cuadrado de Pearson para identificar las relaciones entre habilidades. Los resultados constatan la existencia de una relación significativa entre ambas habilidades (χ2 = 273,980, p < .05), siendo las relaciones más estables la pantalla con los disparos y el paso de valla con los driblings, aunque esta última habilidad técnica del portero más utilizada no se presenta como la más eficaz. Se observa que los porteros responden con habilidades diferentes en función de la lateralidad del jugador. Esta información puede ayudar a los entrenadores a crear situaciones específicas de entrenamiento para mejorar el rendimiento de los porteros en las faltas directas y aportar un conocimiento específico para el portero para preparar la estrategia adecuada en las faltas directas. Abstract. The aim of the present study was to identify the technical skills of the rink hockey goalkeeper in the direct free hits in the high competition, proposing, at the same time, the functional structure of the technical skills and highlighting the most effective chains. The observational methodology was used analyzing the direct free hits in the Spanish professional league (n = 637). An ad hoc observation instrument was created with the technical skills of the goalkeeper, the technical skills of player and the laterality of the player. The observation instrument was validated by the authority criterion and intra and inter observer reliability was calculated. Correlation analysis was performed using Pearson's chi-square test to identify the relationships between skills. The results confirm the existence of a significant relationship between both skills (χ2 = 273.980, p < .05), the most stable relationships being the screen with the shots and the fence step with the driblings, although, his last technical skill of the most used goalkeeper is not the most effective. It is observed that the goalkeepers respond with different skills depending on the player's laterality. This information can help the coaches to create specific training situations to improve the performance of the goalkeepers in the direct free hits and provide a specific knowledge for the goalkeeper to prepare the appropriate strategy in the direct free hits.

Co-occurrence networks of bacteria associations are a powerful approach to explore ecologically relevant aspects of the gut microbiota structure, beyond community composition alone. Here we exploit the remarkable diversity of cichlid fishes and their multiple lake assemblages to investigate a) network features and patterns of microbial associations that were robust to major phylogeographical variables, and b) community structure changes along cichlid dietary shifts. We tackled these objectives using the large gut microbiota sequencing dataset available (nine lakes from Africa and America), building geographical and diet-specific networks and performing comparative analyses. Major findings indicated that lake and continental networks were highly resembling in global topology and node taxonomic composition, suggesting important constraints in the cichlid gut community assembling. A small fraction of the observed co-occurrence pairwises was conserved across all lake assemblages; while the origin and ecological relevance of these core associations remains unclear, their persistence suggests a potential functional role in the cichlid gut. Comparison of carnivores and herbivores-specific networks as well as mapping of diet-specific values on the African Lake Tanganyika network revealed a clear community shift as a function of diet, with an increase in complexity and node taxonomic diversity from carnivores-omnivores-plantkivores to herbivores. More importantly, diet-associated nodes in herbivores formed complex modules of positive interactions. By intersecting results from association patterns and experimental trials, future studies will be directed to test the strength of these microbial associations and predict the outcome of community alterations driven by diet.ImportanceThe gut microbiota is a complex community of interacting bacteria. Predicting patterns of co-occurrence among microbes can help understanding key ecological aspects driving community structure, maintenance and dynamics. Here we showed a powerful application of co-occurrence networks to explore gut bacteria interactions in a primary model system to study animal diversification, the cichlid fishes. Taking advantage of the large scale of phylogeographical and ecological diversity of this fish family, we built gut microbiota networks from distinct lake and continental fish assemblages and performed extensive comparative analyses to retrieve conserved and trait-specific patterns of bacteria associations. Our results identified network features that were independent from the fish biogeography and that indicated an important host selection effect on gut community assembling. Focusing on a single lake assemblage, and therefore excluding the major geographical effect, we observed that the gut microbiota structure dramatically shifted from carnivore to herbivore fishes, with a substantial increase in the number and complexity of microbial interactions.

Cichlid fishes, with their repeated colonization of lakes and subsequent radiations at different scales of phylogenetic and ecological diversification, offer an excellent model system to understand the factors shaping the host-gut microbiota association in nature. Here, we characterized the gut microbiota of the Amphilophus species complex from Central America (known as the Midas cichlid complex), encompassing 158 wild specimens (13 species) collected from seven Nicaraguan lakes, and combined these data with previously published data from two African lakes (spanning 29 species). Our aim was to comprehensively explore trends in microbiota variation and persistence along the large spatial and temporal scales of cichlid diversification (from the oldest radiation in L. Tanganyika, 9¿12 My old, to young ones in Nicaraguan crater lakes, This study was funded by the Agencia Estatal de Investigación (AEI), the Fondo Europeo de Desarrollo Regional (FEDER) (CGL2017-82986-C2-2-P to LB), and the Spanish Ministerio de Ciencia e Innovación (CGL2013-42462-P and CGL2017-82986-C2-1-P to MB).

Ecoevolutionary dynamics of the gut microbiota at the macroscale level, that is, in across-species comparisons, are largely driven by ecological variables and host genotype. The repeated explosive radiations of African cichlid fishes in distinct lakes, following a dietary diversification in a context of reduced genetic diversity, provide a natural setup to explore convergence, divergence and repeatability in patterns of microbiota dynamics as a function of the host diet, phylogeny and environment. Here we characterized by 16S rRNA amplicon sequencing the gut microbiota of 29 cichlid species from two distinct lakes/radiations (Tanganyika and Barombi Mbo) and across a broad dietary and phylogenetic range. Within each lake, a significant deviation between a carnivorous and herbivorous lifestyle was found. Herbivore species were characterized by an increased bacterial taxonomic and functional diversity and converged in key compositional and functional community aspects. Despite a significant lake effect on the microbiota structure, this process has occurred with remarkable parallels in the two lakes. A metabolic signature most likely explains this trend, as indicated by a significant enrichment in herbivores/omnivores of bacterial taxa and functions associated with fiber degradation and detoxification of plant chemical compounds. Overall, compositional and functional aspects of the gut microbiota individually and altogether validate and predict main cichlid dietary habits, suggesting a fundamental role of gut bacteria in cichlid niche expansion and adaptation.

Summary Across environmental gradients, some functional strategies are favoured over others resulting in differences in local species composition and distribution of any given functional trait. This generates among-Species Trait Variability (STV) across the gradient (reflecting species turnover), as well as spatial Intraspecific Trait Variability (ITV), which together contribute to Community Trait Variability (CTV). Understanding functional trait responses of freshwater biota is critical for elucidating the mechanisms that operate during community assembly and addressing community level responses to climate warming. In freshwater insects, temperature and ecological conditions regulate growth rates. Here, we examined size-related trait variability components of short-dispersing stoneflies (Insecta: Plecoptera) within and among multispecies stonefly assemblages (henceforth referred to as communities), located along an elevational gradient in Sierra Nevada (Spain) to assess the components of trait-elevation matching (STV, ITV, CTV). Relative to downstream reaches, headwaters hypothetically show greater internal physical habitat heterogeneity (large exposed rocks, tree roots, woody debris) and greater local species richness of cool-water adapted stoneflies. As a result, we expected CTV to increase with elevation, with a higher contribution of STV than ITV in upper reaches due to higher species richness and trait divergence among them. In contrast, the pattern of ITV should vary depending on whether the main driver across elevation is species richness (decrease due to niche partitioning) or ecological conditions (increase associated to physical habitat heterogeneity). Eleven streams were sampled every 2 weeks over 1 year and five size-related traits were measured on 6,893 individuals belonging to 16 species. Overall, STV made a much larger contribution to CTV than ITV, which only became an important contributor in species-poor assemblages, especially in winter and autumn. Within each season, the trait-elevation matching was weak. Functional species-specific responses to the elevational gradient most often did not mirror the response of the entire communities, since highly variable (and even opposed or discontinuous) contributions to ITV were found across species. Overall, ITV contributed little to trait-elevation matching, which suggests high vulnerability of short-dispersing stoneflies to habitat shifting associated to future climate warming due to limited phenotypic plasticity. Moreover, varying functional trait patterns across species emphasise species-specific responses to climate change as opposed to a unique whole community response. However, further trait-based macroecological studies across freshwater macroinvertebrates lineages are needed to compare patterns and establish generalisations.

Este artículo contiene 17 páginas, 5 tablas, 2 figuras., Gipuzkoa (Basque Country, North Spain) is an industrial region where investments in sanitation and wastewater treatment have improved water quality and partially recovered river biological communities. However, further technological improvements are unlikely. Our objective was to assess whether in-stream self-purification may contribute to improvement of the trophic state of rivers. We propose an integrative approach to assessing river water quality, which diagnoses problems, identifies likely causes and prescribes solutions. We first analysed the loads of nutrients transported by Gipuzkoa rivers and compared them with the potential nutrient uptake rates (estimated from published empirical regressions). In reaches where both of them were within one order of magnitude, we considered that the self-purification capacity of river channels may influence nutrient concentrations. Then, we selected some river reaches where no other water quality problems beyond nutrient concentrations occurred and ran the expert system STREAMES 1.0 to diagnose the problems and detect their causes. The studied reaches di ered in their problems and in their potential solutions. We empirically determined nutrient retention in two streams by means of mass balances and slug nutrient additions. We detected large di erences in retention capacity between reaches and siltation as one of the main problems a ecting the self-purification capacity of the study streams. Finally, we used STREAMES 1.0 to identify potential solutions to specific river sections. The results obtained so far point towards an important potential of in-stream bioreactive capacity to reduce nutrient loads and to specific restoration activities that may improve the functionality and trophic status of the streams in Gipuzkoa., This research was funded by the Department of HydraulicWorks, Province Government of Gipuzkoa., We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

© 2020 by the authors., Coenzyme Q10 (CoQ) treatment monitoring is a matter of debate since CoQ distribution from plasma to blood cells and tissues is not fully understood. We aimed to analyze the CoQ levels in a wide set of human biological samples (plasma, blood mononuclear cells (BMCs), platelets, urinary cells, and skeletal muscle) from a group of 11 healthy male runners before and after CoQ supplementation. The CoQ content in the different samples was analyzed by HPLC coupled to electrochemical detection. No significant differences were observed in the CoQ levels measured in the BMCs, platelets, and urine after the one-month treatment period. Plasma CoQ (expressed in absolute values and values relative to total cholesterol) significantly increased after CoQ supplementation (p = 0.003 in both cases), and the increase in CoQ in muscle approached significance (p = 0.074). CoQ levels were increased in the plasma of all supplemented subjects, and muscle CoQ levels were increased in 8 out of 10 supplemented subjects. In conclusion, the analysis of CoQ in plasma samples seems to be the best surrogate biomarker for CoQ treatment monitoring. Moreover, oral CoQ administration was effective for increasing muscle CoQ concentrations in most subjects., This research was supported by grants from the Instituto de Salud Carlos III (ISCIII-FIS PI17/00109 and PI17/01286), the FEDER Funding Program from the European Union and CIBERER-ISCIII. A.J.P.-F. holds a grant from the Instituto de Salud Carlos III (FI18/00253).

Background: Caloric restriction induces mitochondrial biogenesis and improves physical fitness in rodents. We aimed to provide evidence of how caloric restriction affects the body composition and physical performance of trained athletes and to evaluate the possible impact of an every-other-day feeding diet on nutritional deficiencies of micronutrients and essential fatty acids. Methods: The study was performed with 12 healthy male athletes by carrying out a 33% caloric restriction with respect to their usual diet. Athletes performed a maximal exercise stress test both before and after the caloric restriction period. Blood samples were taken before and after the caloric restriction at basal conditions and 30 min post-exercise. Although energy intake was reduced by about 33%, the contribution of carbohydrates, proteins, and lipids to total energy intake during the caloric restriction was similar to the original diet. Results: The caloric restriction reduced the daily specific micronutrient intake to values lower than 90% of recommended dietary allowances. No effects were observed in blood parameters related to iron metabolism and tissue damage, glucose levels, lipid profiles, or erythrocyte fatty acid composition. In addition, oxidative damage markers decreased after the nutritional intervention. The caloric restriction intervention significantly reduced body weight and trunk, arm, and leg weights; it also caused a decrease in fat and lean body mass, the energy expenditure rate when performing a maximal exercise stress test, and the energy cost to run one meter at various exercise intensities. Furthermore, the intervention ameliorated the onset of the anaerobic phase of exercise. Conclusion: A caloric restriction improves athletes' performance and energy efficiency, but reduces the daily intake of micronutrients; so, when caloric restriction programs are implemented micronutrient supplementation should be considered., Accion Estrategica en Salud del Ministerio de Ciencia e Innovacion DPS2008-07033-C03-03, Programme of Promotion of Biomedical Research and Health Sciences, Projects 11/01791, Red Predimed-RETIC RD06/0045/1004, CIBEROBN CB12/03/30038 and Balearic Island Government and FEDER funds (35/2011 and 23/2012). We hereby acknowledge the PhD grant provided by the University of the Balearic Islands.

Este artículo contiene 18 páginas, 5 figuras, 3 tablas, Species distribution models (SDMs) have been used to predict potential distributions of habitats and to model the effects of environmental changes. Despite their usefulness, currently there is no standardized sampling strategy that provides suitable and sufficiently representative predictive models for littoral marine benthic habitats. Here we aim to establish the best performing and most cost-effective sample design to predict the distribution of littoral habitats in unexplored areas. We also study how environmental variability, sample size, and habitat prevalence may influence the accuracy and performance of spatial predictions. For first time, a large database of littoral habitats (16,098 points over 562,895 km of coastline) is used to build up, evaluate, and validate logistic predictive models according to a variety of sampling strategies. A regularly interspaced strategy with a sample of 20% of the coastline provided the best compromise between usefulness (in terms of sampling cost and effort) and accuracy. However, model performance was strongly depen upon habitat characteristics. The proposed sampling strategy may help to predict the presence or absence of target species or habitats thus improving extensive cartographies, detect high biodiversity areas, and, lastly, develop (the best) environmental management plans, especially in littoral environments., This study was supported by INTRAMURAL CSIC (0065) and the European Union's Horizon 2020 (689518) MERCES.

Special issue International Society of Environmental Biotechnology 2016.-- 10 pages, 3 figures, 5 tables, supplementary data https://doi.org/10.1016/j.nbt.2017.05.003, An in-depth, long-term, multidisciplinary study was conducted in order to study the microeukaryote community in a partial nitritation (PN) reactor prior to anammox. The PN reactor operated with moving bed biofilm reactor (MBBR) technology, using plastic supports (carriers) for biofilm development. The microeukaryote community from the biofilm (BF) and the surrounding media (mixed liquor or ML) were analysed separately. Despite the physicochemical conditions under which the PN-MBBR operated (an average of 305.9 ± 117 mg TAN l and 328.4 ± 131.9 mg N-NO l), up to 24 microeukaryotic taxa were observed by microscope. Microeukaryote species showed an uneven distribution in the PN-MBBR, thus suggesting the existence of two habitats: the BF, preferred by species with specific structures for adhering to a substrate, such as the stalked Peritrichia, and the ML, preferred by free-swimming or non-substrate dependent species. The results indicated that most ciliate population dynamics mainly responded to the nitrous acid and free ammonia concentrations and, to a lesser extent, to sCOD values. In the BF, variations in the population of Epistylis camprubii and Opercularia coarctata suggest the existence of competition between these species due to niche overlap. A V4 18S rDNA molecular survey (Illumina) was carried out for some samples with the aim of obtaining maximum coverage of the main eukaryote species that were microscopically detected throughout the study. The diversity and abundance data provided by both detection methods were compared. The study helped identify broader tolerance ranges of the microeukaryote taxa to the physicochemical parameters analysed, This work was financially supported by ACCIONA Agua ( 306393 FBG – UB) and partially funded by a grant of the Catalan Government as the Consolidated Research Group VirBaP (2014SRG914)

Las técnicas antropométricas, administradas con el rigor que corresponde, constituyen un método repetitivo, sensible y discriminante para estimar los cambios en la composición corporal de los deportistas y son ampliamente utilizadas en al ámbito de la Medicina del Deporte. A partir de las medidas antropométricas adquiridas en el seguimiento de los deportistas del CAR de Sant Cugat desde 1989 hasta la fecha, se han elaborado unas referencias, que son representativas del nivel nacional de los deportes examinados y que corresponden a los métodos de Yuhasz, Faulkner y Drinkwater, el somatotipo de Heath-Carter y el sumatorio de 6 pliegues, con el objeto de ofrecer una ayuda y orientación a los profesionales que utilicen la cineantropometría

Carbon dioxide emissions from lakes contribute to the continental carbon balance. Water chemistry analyses of reservoirs in Spain suggest that carbonate weathering causes CO2 supersaturation in lakes above a threshold alkalinity.

Compositional variation of the gut microbiota across host allopatric populations can reflect both adaptation and stochasticity since the time of separation. Major factors shaping this variation include the host phylogeographic and demographic history, the microbiota inheritance, environmental inputs and dispersal of bacteria. Here we explored the impact of these factors in driving gut community diversity in seven allopatric populations of the omnivorous lizard Podarcis lilfordi from the Menorcan coastal islets, all descending from an ancestral mainland population. Using 16S rRNA Illumina sequencing, we showed that 'islet' and 'age' (time since islet separation from mainland) were the only significant variables in microbial community clustering, suggesting a partial islet-restricted diversification following these lizards phylogeography. Despite a significant variation, islets/populations were characterized by a remarkably low bacterial uniqueness (2.4% of total OTUs) and a minor differential enrichment of taxa, indicating a negligible impact of local inputs and important host common constraints. Overall, the extant pattern of similarity/dissimilarity among islets is compatible with partial retention of the ancestral mainland microbial pool, with differences among islets potentially explained by a differential loss of bacteria following population fragmentation and bottlenecks (i.e. ecological drift). While more quantitative data are needed to validate this hypothesis, this study unveils the importance of considering both neutral and niche-driven processes in driving contemporary patterns of gut metacommunity diversity.

13 páginas, 4 figuras, 4 tables., We examined the relevance of dissolved inorganic nitrogen (DIN) forms (nitrate and ammonium) in stream water as N sources for different macrophyte species. To do this, we investigated the variability and relationships between 15N natural abundance of DIN forms and of four different macrophyte species in five different streams influenced by inputs from wastewater treatment plants and over time within one of these streams. Results showed that 15N signatures were similar in species of submersed and amphibious macrophytes and in stream water DIN, whereas 15N signatures of the riparian species were not. 15N signatures of macrophytes were generally closer to 15N signatures of nitrate, regardless of the species considered. Our results showed significant relationships between 15N signatures of DIN and those of submersed Callitriche stagnalis and amphibious Veronica beccabunga and Apium nodiflorum, suggesting stream water DIN as a relevant N source for these two functional groups. Moreover, results from a mixing model suggested that stream water DIN taken up by the submersed and amphibious species was mostly in the form of nitrate. Together, these results suggest different contribution to in-stream N uptake among the spatially-segregated species of macrophytes. While submersed and amphibious species can contribute to in-stream N uptake by assimilation of DIN, macrophyte species located at stream channel edges do not seem to rely on stream water DIN as an N source. Ultimately, these results add a functional dimension to the current use of macrophytes for the restoration of stream channel morphology, indicating that they can also contribute to reduce excess DIN in streams., Financial support was provided by the Spanish Ministry of Science and Innovation through the ISONEF (ref: CGL2008-05504-C02-02/ BOS) and MED_FORESTREAM (ref: CGL2011-30590-C02-02) projects and by the European Science Foundation project COMIX (EuroDiversity Collaborative Research program, ref: 05_EDIV_FP065-COMIX). M. Peipoch and M. Ribot were funded through a FPI PhD fellowship and a technical training contract, respectively, from the Spanish Ministry of Science and Innovation through the ISONEF project. A. Blesa was granted a FPI PhD fellowship associated to grant BIO2010-18875 from the Spanish Ministry of Science and Innovation.

n-3-polyunsaturated fatty acids and polyphenols are potential key factors for the treatment and prevention of chronic inflammation associated to ageing and non-communicable diseases. The aim was to analyse effects of an almond and olive oil beverage enriched with alpha-tocopherol and docosahexaenoic, exercise and age on inflammatory plasma markers, and immune gene expression in peripheral blood mononuclear cells (PBMCs). Five young and five senior athletes who were supplemented for five weeks with a functional beverage performed a stress test under controlled conditions before and after beverage supplementation. Blood samples were taken immediately before and 1 h after each test. Plasma, erythrocytes and PBMCs were isolated. Beverage supplementation increased plasmatic Tumour Necrosis Factor alpha (TNF alpha) levels depending on age and exercise. Exercise increased plasma non esterified fatty acids (NEFAs), soluble Intercellular adhesion molecule 3 (sICAM3) and soluble L-selectin (sL-Selectin), and this increase was attenuated by the supplementation. Exercise increased PGE2 plasma levels in supplemented young and in senior placebo athletes. Exercise increased NFk beta-activated levels in PBMCs, which are primed to a pro-inflammatory response increasing pro-inflammatory genes expression after the exercise mainly in the young group after the supplementation. The functional beverage supplementation to young athletes enhances a pro-inflammatory circulating environment in response to the exercise that was less evident in the senior group., Accion Estrategica en Salud del Ministerio de Ciencia e Innovacion DPS2008-07033-C03-03, Programme of Promotion of Biomedical Research and Health Sciences, Projects 11/01791, Red Predimed-RETIC RD06/0045/1004, CIBEROBN CB12/03/30038 and Balearic Island Government and FEDER funds (35/2011 and 23/2012). We hereby acknowledge the PhD grant provided (to X Capo) by the University of the Balearic Islands.

Human activities have resulted in increased nutrient levels in many rivers all over Europe. Sustainable management of river basins demands an assessment of the causes and consequences of human alteration of nutrient flows, together with an evaluation of management options. In the context of an integrated and interdisciplinary environmental assessment (IEA) of nutrient flows, we present and discuss the application of the nutrient emission model MONERIS (MOdelling Nutrient Emissions into River Systems) to the Catalan river basin, La Tordera (north-east Spain), for the period 1996–2002. After a successful calibration and verification process (Nash-Sutcliffe efficiencies E=0.85 for phosphorus and E=0.86 for nitrogen), the application of the model MONERIS proved to be useful in estimating nutrient loads. Crucial for model calibration, in-stream retention was estimated to be about 50 % of nutrient emissions on an annual basis. Through this process, we identified the importance of point sources for phosphorus emissions (about 94% for 1996–2002), and diffuse sources, especially inputs via groundwater, for nitrogen emissions (about 31% for 1996–2002). Despite hurdles related to model structure, observed loads, and input data encountered during the modelling process, MONERIS provided a good representation of the major interannual and spatial patterns in nutrient emissions. An analysis of the model uncertainty and sensitivity to input data indicates that the model MONERIS, even in data-starved Mediterranean catchments, may be profitably used by water managers for evaluating quantitative nutrient emission scenarios for the purpose of managing river basins. As an example of scenario modelling, an analysis of the changes in nutrient emissions through two different future scenarios allowed the identification of a set of relevant measures to reduce nutrient loads.

We used 15N-labelled nitrate (NO3−) additions to investigate pathways of nitrogen (N) cycling at the whole-reach scale in three stream reaches with adjacent forested, urban and agricultural land areas. Our aim was to explore among-stream differences in: (i) the magnitude and relative importance of NO3− retention (i.e. assimilatory uptake) and removal (i.e. denitrification), (ii) the relative contribution of the different primary uptake compartments to NO3− retention, and (iii) the regeneration, transformation and export pathways of the retained N. Streams varied strongly in NO3− concentration, which was highest in the agricultural stream and lowest in the forested stream. The agricultural stream also showed the lowest dissolved oxygen (DO) concentration and discharge. Standing stocks of primary uptake compartments were similar among streams and dominated by detritus compartments (i.e. fine and coarse benthic organic matter). Metabolism was net heterotrophic in all streams, although the degree of heterotrophy was highest in the agricultural stream. The NO3− uptake length was shortest in the agricultural stream, intermediate in the urban stream, and longest in the forested stream. Conversely, the NO3− mass-transfer velocity and the areal NO3− uptake rate were highest in the urban stream. Denitrification was not detectable in the forested stream, but accounted for 9% and 68% of total NO3− uptake in the urban and the agricultural stream, respectively. The relative contribution of detritus compartments to NO3− assimilatory uptake was greatest in the forested and lowest in the agricultural stream. In all streams, the retained N was rapidly regenerated back to the water column. Due to a strong coupling between regeneration and nitrification, most retained N was exported from the experimental reaches in the form of NO3−. This study provides evidence of fast in-stream N cycling, although the relative importance of N retention and removal varied considerably among streams. Results suggest that permanent NO3− removal via denitrification may be enhanced over temporary NO3− retention via assimilatory uptake in heterotrophic human-altered streams characterized by high NO3− and low DO concentrations.

18 Páginas ; 4 Tablas ; 6 Figuras, Headwater streams represent the key sites of nutrient retention, but little is known about temporal variation in this important process. We used monthly measurements over 2 years to examine variation in retention of soluble reactive phosphorus (SRP) and ammonium (NH4 +) in two Mediterranean headwater streams with contrasting hydrological regimes (that is, perennial versus intermittent). Differences in retention between streams were more evident for NH4 +, likely due to strong differences in the potential for nitrogen limitation. In both streams, nutrient-retention efficiency was negatively influenced by abrupt discharge changes, whereas gradual seasonal changes in SRP demand were partially controlled by riparian vegetation dynamics through changes in organic matter and light availability. Nutrient concentrations were below saturation in the two streams; however, SRP demand increased relative to NH4 + demand in the intermittent stream as the potential for phosphorus limitation increased (that is, higher dissolved inorganic nitrogen:SRP ratio). Unexpectedly, variability in nutrient retention was not greater in the intermittent stream, suggesting high resilience of biological communities responsible for nutrient uptake. Within-stream variability of all retention metrics, however, increased with increasing time scale. A review of studies addressing temporal variation of nutrient retention at different time scales supports this finding, indicating increasing variability of nutrient retention with concomitant increases in the variability of environmental factors from the diurnal to the interannual scale. Overall, this study emphasizes the significance of local climate conditions in regulating nutrient retention and points to potential effects of changes in land use and climate regimes on the functioning of stream ecosystems., Financial support was provided by the European Union through the EURO-LIMPACS project (ref: GOCE-CT-2003-505540, www.eurolimpacs.ucl. ac.uk) and by the Spanish Ministry of Education and Science through RENITRAC (ref: REN2002- 03592/HID) and NICON (ref: CGL2005-07362- C02) projects. D. von Schiller and P. Fonolla` were supported by I3P PhD scholarships from the Spanish Council for Scientific Research (CSIC).

Rivers in developed regions are under significant stress due to nutrient enrichment generated mainly by human activities. Excess nitrogen and phosphorus emissions are the product of complex dynamic systems influenced by various factors such as demographic, socio-economic and technological development. Using a Catalan river catchment, La Tordera (North-East of Spain), as a case study of an integrated and interdisciplinary environmental assessment of nutrient flows, we present and discuss the development of narrative socio-economic scenarios through a participatory process for the sustainable management of the anthropogenic sources of nutrients, nitrogen and phosphorus. In this context, scenarios are an appropriate tool to assist nutrient emissions modelling, and to assess impacts, possible pathways for socio-economic development and associated uncertainties. Evaluated against the 1993–2003 baseline period, scenarios target the 2030 horizon, i.e. through the implementation process of the Water Framework Directive (Directive 2000/60/EC). After a critical examination of the methodology used in the participatory development of socio-economic scenarios, we present four possible futures (or perspectives) for the Catalan river catchment conceived by stakeholders invited to a workshop. Keys to the success of such a participatory process were trust, which enhanced openness, and disagreements, which fostered the group's creativity for scenario development. The translation of narrative socio-economic scenarios into meaningful nutrient emission scenarios is also discussed. By integrating findings of natural sciences and socio-economic analysis, we aim to assist decision makers and stakeholders in evaluating optimal management strategies for the anthropogenic sources of nitrogen and phosphorus.

16 Páginas ; 5 Figuras ; 3 Tablas, 1. Nutrient diffusing substrata (NDS) were used to determine the relative importance of nutrients and light as potential limiting factors of periphyton biomass and nitrogen (N) uptake in Mediterranean streams subjected to different human impacts. The nutrients examined were phosphorus (P) and N, and we also further differentiated between the response of periphyton communities to N species (i.e. NO3-N and NH4-N). To examine the effect of light and nutrients on periphyton biomass, chlorophyll a accrual rates on NDS located at open and closed canopy sites were compared. The effect of nutrient availability on periphyton uptake was measured by 15N changes on the NDS after NO3-15N short-term nutrient additions. 2. Results show that light was the main factor affecting algal biomass in the study streams. Algal biomass was in general higher at open than at closed canopy sites. Nutrient availability, as simulated with the NDS experiments, did not enhance algal biomass accrual in either of the 2 light conditions. 3. In the control treatments (i.e. ambient concentrations), periphyton NO3-N uptake rates increased and C : N molar ratios decreased consistently with increases in N availability across streams. NO3-N uptake rates were altered when ambient N concentrations were increased artificially in the N amended NDS. Periphyton assemblages growing on N enriched substrata seemed to preferentially take up N diffusing from the substratum rather than N from the water column. This response differed among streams, and depended on ambient N availability. 4. Periphyton biomass was not significantly different between substrata exposed to the two forms of available N sources. Nonetheless, we found differences in the effects of both N sources on the uptake of N from the water column. NH4-N seemed to be the preferred source of N for periphyton growing on NDS. 5. Results suggest that the effect of riparian zones on light availability, although seldom considered by water managers, may be more important than nutrients in controlling eutrophication effects derived from human activities. Finally, our results confirm that not only increases in concentration, but also stoichiometric imbalances should be considered when examining N retention in human altered streams., Financial support was provided by the Spanish Ministry of Education and Science, RENITRAC (ref: REN2002-03592/HID) and NICON (ref: CGL2005- 07362-C02) projects, and the European Commission, Euro-LIMPACS (ref: GOCE-CT-2003-505540) project. D. von Schiller was supported by an I3P PhD scholarship from the Spanish Council for Scientific Research (CSIC).

18 páginas, 3 figuras, 4 tablas, Distribution of aquatic macrophytes in lakes is related to geographical, morphological, catchment and water chemistry variables as well as human impacts, which modify the original environment. Here, we aim at building statistical models to establish the ecological niches of 11 aquatic macrophytes (10 different phanerogams and the genus Nitella) from oligotrophic soft-water lakes and infer their ecological requirements and environmental constraints at the southernmost limit of their distribution. Macrophyte occurrence and environmental variables were obtained from 86 non-exploited oligotrophic soft-water lakes from the Pyrenees (Southern Europe; 42°50´N, 1°00´E); macrophytes inhabited 55 of these lakes. Optimum ranges and macrophyte occurrence were predicted in relation to 18 geographical, morphological, catchment and water chemistry variables using univariate and multivariate logistic models. Lakes at low altitude, in vegetated catchments and with low water concentration of NO3 – and SO4 –2, were the most suitable to host macrophytes. In general, individual species of aquatic macrophytes showed clear patterns of segregation along conductivity and pH gradients, although the specific combination of variables selected in the best models explaining their occurrence differed among species. Based on the species response to pH and conductivity, we found Isoetes lacustris have its optimum in waters with low conductivity and pH (i.e., negative monotonic response). In contrast, Callitriche palustris, Ranunculus aquatilis, Subularia aquatica, Nitella spp., and Myriophyllum alterniflorum showed an optimum at intermediate values (i.e. unimodal response), whereas Potamogeton berchtoldii, Potamogeton alpinus, and Ranunculus trichophyllus as species had their optimum at relatively high water pH and conductivity (i.e. positive monotonic response). This pattern has been observed in other regions for the same species, although with different optima and tolerance ranges. The parsimonious models developed here allowed us to explore niche requirements for each species and to predict the occurrence of macrophytes and of individual species in any particular lake by using only few, easily measured environmental variables. This is of interest to forecast possible changes related to global change and to assist managers in making conservation, management and restoration decisions., Financial support was provided by the Spanish Ministry of Science and Innovation through funding of the AQUAREST project (ref: OAPN 212/2010).

Exercise in thermally stressful environmental conditions can enhance oxidative stress. We sought to measure the plasma antioxidant defenses and cytokine response together with oxidative damage post-exercise in a temperate versus a hot environment. The plasma concentrations of vasoactive endothelin-1 and vascular angiogenic growth factor were also evaluated. Male athletes (n=9) volunteered to participate. The athletes randomly performed two bouts of treadmill exercise of 45min at 75-80% of maximal oxygen uptake in a climatic-controlled chamber under two different conditions: temperate environment (10-12°C, 40-55% humidity) and hot, humid environment (30-32°C, 75-78% humidity). Venous blood samples were obtained immediately pre- and post-bout and on recovery after 2h. Serum glucose, malondialdehyde and lactate concentrations were significantly increased post-exercise in hot but maintained in the temperate environment; these post-exercise values were significantly higher after exercise in hot than in temperate. Urinary 8-hydroxy-2'-deoxyguanosine concentration, plasma phosphocreatine kinase and catalase activities, creatinine and monocyte chemoattractant protein-1, and interleukin-6 significantly increased post-exercise in hot but maintained in temperate environment. The post-exercise circulating values of antioxidant enzyme paraoxonase-1 and endothelin were significantly higher in the hot than in temperate environment. Exercise in a hot and humid environment resulted in mild hyperthermia with elevated perceived exertion and thermal stress. Hyperthermic environment induced hyperglycemia, lactatecidemia and more cellular and oxidative damage than exercise in a temperate environment but also induced a post-exercise antioxidant and anti-inflammatory response in plasma. These results suggest that environmental temperature needs to be taken into account when evaluating exercise-related oxidative stress and inflammation.

The gut microbiota structure reflects both a host phylogenetic history and a signature of adaptation to the host ecological, mainly trophic niches. African cichlid fishes, with their array of closely related species that underwent a rapid dietary niche radiation, offer a particularly interesting system to explore the relative contribution of these two factors in nature. Here we surveyed the host intra- and interspecific natural variation of the gut microbiota of five cichlid species from the monophyletic tribe Perissodini of lake Tanganyika, whose members transitioned from being zooplanktivorous to feeding primarily on fish scales. The outgroup riverine species Astatotilapia burtoni, largely omnivorous, was also included in the study. Fusobacteria, Firmicutes and Proteobacteria represented the dominant components in the gut microbiota of all 30 specimens analysed according to two distinct 16S rRNA markers. All members of the Perissodini tribe showed a homogenous pattern of microbial alpha and beta diversities, with no significant qualitative differences, despite changes in diet. The recent diet shift between zooplantkon- and scale-eaters simply reflects on a significant enrichment of Clostridium taxa in scale-eaters where they might be involved in the scale metabolism. Comparison with the omnivorous species A. burtoni suggests that, with increased host phylogenetic distance and/or increasing herbivory, the gut microbiota begins differentiating also at qualitative level. The cichlids show presence of a large conserved core of taxa and a small set of core OTUs (average 13-15%), remarkably stable also in captivity, and putatively favoured by both restricted microbial transmission among related hosts (putatively enhanced by mouthbrooding behavior) and common host constraints. This study sets the basis for a future large-scale investigation of the gut microbiota of cichlids and its adaptation in the process of the host adaptive radiation. This work was supported by the European Research Council (ERC; Starting Grant "INTERGENADAPT") and the Swiss National Science Foundation to WS

8 páginas, 3 figuras, 1 tabla., Understanding the variability of the natural abundance in nitrogen stable isotopes (expressed as δ15N) of primary uptake compartments (PUCs; e.g., epilithon or macrophytes) is important due to the multiple applications of stable isotopes in freshwater research and can give insights into environmental and anthropogenic factors controlling N dynamics in streams. While previous research has shown how δ15N of PUCs varies with δ15N of dissolved inorganic N (DIN) among streams, less is known about how δ15N of PUCs varies over time. Here, we examined monthly variation of δ15N of PUCs and of DIN species (nitrate and ammonium) over a year, and compared it among streams with contrasting human impacts and PUC types. Our results showed no evidence of isotopic seasonal patterns. Temporal variability in δ15N-PUCs increased with human impact, being the highest in the urban stream, probably influenced by the high variability of δ15N-DIN. Among compartments, in-stream PUCs characterized by fast turnover rates, such as filamentous algae, showed the highest temporal variability in δ15N values (from −3.6 to 23.2 ‰). Our study elucidates some of the environmental and biological controls of temporal variability of δ15N in streams, which should be taken into account when using stable isotopes as an ecological tool., This research was supported by project ISONEF, funded by the Spanish Ministry of Science and Innovation (ref CGL2008- 05504-C02-01), and by the European Union seventh Framework Programme REFRESH project under contract 244121. AP and MP were supported by a Formación de Personal Investigador PhD fellowship from the Spanish Ministry of Science and Innovation associated to the ISONEF project.

When ascending to a higher altitude, changes in air density and oxygen levels affect the way in which explosive actions are executed. This study was designed to compare the effects of acute exposure to real or simulated moderate hypoxia on the dynamics of the force-velocity relationship observed in bench press exercise. Twenty-eight combat sports athletes were assigned to two groups and assessed on two separate occasions: G1 (n = 17) in conditions of normoxia (N1) and hypobaric hypoxia (HH) and G2 (n = 11) in conditions of normoxia (N2) and normobaric hypoxia (NH). Individual and complete force-velocity relationships in bench press were determined on each assessment day. For each exercise repetition, we obtained the mean and peak velocity and power shown by the athletes. Maximum power (Pmax) was recorded as the highest Pmean obtained across the complete force-velocity curve. Our findings indicate a significantly higher absolute load linked to Pmax (~3%) and maximal strength (1RM) (~6%) in G1 attributable to the climb to altitude (P, This study has been supported by a Grant from the Ministry of education, culture and Sport of Spain, Reference 14/UPB10/07.

11 páginas, 3 figuras, 2 tablas, Leaf litter decomposition plays a major role in nutrient dynamics in forested streams. The chemical composition of litter affects its processing by microorganisms, which obtain nutrients from litter and from the water column. The balance of these fluxes is not well known, because they occur simultaneously and thus are difficult to quantify separately. Here, we examined C and N flow from streamwater and leaf litter to microbial biofilms during decomposition. We used isotopically enriched leaves (13C and 15N) from two riparian foundation tree species: fast-decomposing Populus fremontii and slow-decomposing Populus angustifolia, which differed in their concentration of recalcitrant compounds. We adapted the isotope pool dilution method to estimate gross elemental fluxes into litter microbes. Three key findings emerged: litter type strongly affected biomass and stoichiometry of microbial assemblages growing on litter; the proportion of C and N in microorganisms derived from the streamwater, as opposed to the litter, did not differ between litter types, but increased throughout decomposition; gross immobilization of N from the streamwater was higher for P. fremontii compared to P. angustifolia, probably as a consequence of the higher microbial biomass on P. fremontii. In contrast, gross immobilization of C from the streamwater was higher for P. angustifolia, suggesting that dissolved organic C in streamwater was used as an additional energy source by microbial assemblages growing on slow-decomposing litter. These results indicate that biofilms on decomposing litter have specific element requirements driven by litter characteristics, which might have implications for whole-stream nutrient retention., The National Science Foundation provided funding through the Frontiers in Integrative Biological Research (DEB-0425908), Integrative Graduate Education and Research Traineeship (DGE-0549505), and Ecosystem Studies (DEB-1120343) research programs. Funding was also provided by the MED-FORESTSTREAMS (CGL2011-30590-C02-01) project. A. P. was supported by a Formación de Personal Investigador Ph.D. fellowship from the Spanish Ministry of Science and Innovation within the context of ISONEF (CGL2008-05504-C02-01).

Landscapes result from the interaction between nature and society. To understand current landscapes, it is essential to disentangle this interaction; to accomplish this, an historical approach is necessary. Here we focus on the interaction between humans and lakes during the last century in two sites in Wisconsin, USA, a state where lakes, in excess of 10,000, have played an important role in the evolution of the landscapes they belong to. We draw contrasts between the two localities, which are set in landscapes that differ in their physiographic setting, environmental history, and current structure. One, in northern Wisconsin, is a forested recreational lake district; the other, in southern Wisconsin, is dominated by agricultural uses and urban and suburban development. We contend that a common development in both localities has been the increase in the value that society attaches to lakes. As a consequence, lakes are playing a bigger role in the evolution of the terrestrial landscapes surrounding them.

SUMMARY 1. We tested the degree to which a lake’s landscape position constrains the expression of limnological features and imposes a characteristic spatial pattern in a glacial lake district, the Northern Highland Lake District in north-central Wisconsin. 2. We defined lake order as a metric to analyze the effect of landscape position on limnological features. Lake order, analogous to stream order, is based solely on geographical information and is simple to measure. 3. We examined the strength of the relationship between lake order and a set of 25 variables, which included measures of lake morphometry, water optical properties, major ions, nutrients, biology, and human settlement patterns. 4. Lake order explained a significant fraction of the variance of 21 of the 25 variables tested with ANOVA. The fraction of variance explained varied from 12% (maximum depth) to 56% (calcium concentration). The variables most strongly related to lake order were: measures of lake size and shape, concentrations of major ions (except sulfate) and silica, biological variables (chlorophyll concentration, crayfish abundance, and fish species richness), and human-use variables (density of cottages and resorts). Lake depth, water optical properties, and nutrient concentrations (other than silica) were poorly associated with lake order. 5. Potential explanations for a relationship with lake order differed among variables. In some cases, we could hypothesize a direct link. For example, major ion concentration is a function of groundwater input, which is directly related to lake order. We see these as a direct influence of the geomorphic template left by the retreat of the glacier that led to the formation of this lake district. 6. In other cases, a set of indirect links was hypothesized. For example, the effect of lake order on lake size, water chemistry, and lake connectivity may ultimately explain the relation between lake order and fish species richness. We interpret these relationships as the result of constraints imposed by the geomorphic template on lake development over the last 12 000 years. 7. By identifying relationships between lake characteristics and a measure of landscape position, and by identifying geomorphologic constraints on lake features and lake evolution, our analysis explains an important aspect of the spatial organization of a lake district.

SUMMARY 1. Because people impact lake ecosystems, it is important to consider factors influencing the human use of freshwater resources. We investigated the influence of the landscape position, as well as lake area, recreational facilities, and distance to highways and urban centres, on lake use by boaters in the Northern Highland Lake District of Wisconsin, U.S.A. 2. In aerial surveys of ninety-nine randomly selected lakes, we did not see boats on over half of the lakes. Of the lakes with boats, we found a strong correlation between the number of boats and lake area. Recreational boats tended to be found on large, accessible lakes with good boating facilities. Boats were not seen on small, stained lakes with few recreational facilities. 3. Regression models showed that lake size and landscape position explained 63% of the variability in the average number of boats per lake and landscape position explained 24% of the variability in boat density on all ninety-nine lakes. Social variables representing the quality of boating facilities and the perception of good fishing explained 70% of the variability in number of boats per lake and 54% of the variation in boat density on all lakes. A combined model using both physical and social variables increased the explanatory power for both number and density. Lake use by boaters was correlated with landscape position, the quality of fishing and the availability of recreational facilities. When the analysis was restricted to the forty-six lakes where boats were found, only the availability of recreational facilities proved a significant predictor of boat density. 4. Our results suggest that lake choice by recreational boaters may be best predicted by a combination of the location of a lake in a regional hydrologic landscape, and considerations of available facilities and perceptions regarding fishing.

Although limnologists have long been interested in regional patterns in lake attributes, only recently have they considered lakes connected and organized across the landscape, rather than as spatially independent entities. Here we explore the spatial organization of lake districts through the concept of landscape position, a concept that considers lakes longitudinally along gradients of geomorphology and hydrology. We analyzed long-term chemical and biological data from nine lake chains (lakes in a series connected through surface or groundwater flow) from seven lake districts of diverse hydrologic and geomorphic settings across North America. Spatial patterns in lake variables driven by landscape position were surprisingly common across lake districts and across a wide range of variables. On the other hand, temporal patterns of lake variables, quantified using synchrony, the degree to which pairs of lakes exhibit similar dynamics through time, related to landscape position only for lake chains with lake water residence times that spanned a wide range and were generally long (close to or greater than 1 year). Highest synchrony of lakes within a lake chain occurred when lakes had short water residence times. Our results from both the spatial and temporal analyses suggest that certain features of the landscape position concept are robust enough to span a wide range of seemingly disparate lake types. The strong spatial patterns observed in this analysis, and some unexplained patterns, suggest the need to further study these scales and to continue to view lake ecosystems spatially, longitudinally, and broadly across the landscape.

We investigated carbon dynamics in the water column and CO2 and CH4 exchange across the air-water interface in four closed-basin lakes in northern Wisconsin: two with clear, low dissolved organic carbon (DOC) waters and two bog lakes with stained, high-DOC waters. Clear-water lakes quickly became undersaturated following ice-out and remained undersaturated until fall turnover. Bog lakes were supersaturated in CO2 throughout the ice-free season, although surface CO2 concentrations dropped sharply following ice-out and increased again during autumn turnover. Differences in seasonal patterns of CO2 were attributed to morphometry and the timing and intensity of mixing events. Ice-free season fluxes of CO2 were 6.7 and 10.0 mol·m-2 in the bog lakes and 1.2 and 0.09 mol·m-2 in the clear-water lakes. Fluxes of CH4 were significant only immediately after ice-out and during autumn turnover and were -2 in the bog lakes and -2 in the clear-water lakes. Compared with changes in carbon pools in the lakes, our results indicate rapid carbon turnover rates in bog lakes, as opposed to clear-water lakes. We suggest that allochthonous inputs of CO2 may be responsible for this rapid turnover.

We analyzed the spatial heterogeneity in vegetation indices among 13 North American landscapes by using full Landsat Thematic Mapper images. Landscapes varied broadly in the statistical distribution of vegetation indices, but were successfully ordinated by using a measure of central tendency (the mean) and a measure of dispersion (the standard deviation or the coefficient of variation). Differences in heterogeneity among landscapes were explained by their topographic relief and their land cover. Landscape heterogeneity (standard deviation of the Normalized Difference Vegetation Index, NDVI) tended to increase linearly with topographic relief (standard deviation of elevation), but landscapes with low relief were much more heterogeneous than expected from this relationship. The latter were characterized by a large proportion of agricultural land. Percent agriculture, in turn, was inversely related to topographic relief. The strength of these relationships was evaluated against changes in image spatial resolution (grain size). Aggregation of NDVI images to coarser grain size resulted in steady decline of their standard deviation. Although the relationship between landscape heterogeneity and explanatory variables was generally preserved, rates of decrease in heterogeneity with grain size differed among landscapes. A spatial autocorrelation analysis showed that rates of decrease were related to the scale at which pattern is manifested. On one end of the spectrum are agricultural, low-relief landscapes with low spatial autocorrelation and small-scale heterogeneity associated with fields; their heterogeneity decreased sharply as grain size increased. At the other end, desert landscapes were characterized by low small-scale heterogeneity, high spatial autocorrelation, and almost no change in heterogeneity as grain sized was increased—their heterogeneity, associated with land forms, was present at a large scale.

Marine rocky benthic communities present rich contrasts in spatial pattern. Its quantification is a prerequisite for the comparison of spatial pattern across communities, for the evaluation of temporal changes, and for the analysis of the effects of pattern on ecological processes. This study pursues two goals: (1) to evaluate the potential application of landscape pattern indices to the description of spatial pattern in Mediterranean subtidal rocky benthic communities, and (2) to select a minimal set of informative, non-redundant indices for the description of spatial pattern in these communities. Four communities dwelling along a depth gradient were studied, two dominated by algae, and two dominated by clonal animals. The communities differed in species composition, dynamics and structure. Using traditional methods, previous studies had determined that, along this depth gradient, the heterogeneity of community spatial patterns increases, and their seasonal dynamics becomes dampened. We used a series of photographs (310 cm2 each) of permanent sites taken monthly over a one year period to analyze community spatial pattern. We tested a total of 17 landscape pattern indices that quantify different aspects of spatial pattern (patch size and shape characteristics, diversity, contagion and interspersion), for differences among communities, and for differences through time within each community. Results show clear differences in patch characteristics (number, mean size, size variability and shape), diversity, contagion and interspersion indices, among communities. In some cases, significant temporal patterns were also found, and these were consistent with the seasonal dynamics formerly described for each community. Generally, spatial pattern was less heterogeneous, but more variable seasonally, in the shallower, algae-dominated communities, than in deeper communities dominated by clonal animals. These results indicate the existence of community-related characteristic spatial patterns, and characteristic spatial pattern dynamics, in subtidal rocky benthic communities. Moreover, trends found in this study were in agreement with previous studies of spatial pattern in Mediterranean rocky benthic communities. Based on this study, we selected number of patches, mean patch size, standard deviation of patch size, mean shape patch index, and Shannon's diversity index as the most suitable set of indices for the description of spatial pattern in Mediterranean subtidal rocky benthic communities.