Diatom diversity in the lakes of the Pyrenees: An iconographic reference

Rivera-Rondón C.A., Catalan J. (2017) Diatom diversity in the lakes of the Pyrenees: An iconographic reference. Limnetica. 36: 127-395.
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Doi: 10.23818/limn.36.10

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Environmental assessments and palaeoreconstructions can take advantage of the high diatom diversity present in mountain lakes. There are only a few studies dealing with the diatom flora of the Pyrenees and research on species taxonomy, distribution and ecology are still at an initial stage. With the aim of updating the list of species present and providing iconographic information for harmonising past and future studies, we report 549 taxa from a survey of 83 lakes across the geographical extent of the Pyrenean lakes comprising a broad range of environmental conditions and in the sedimentary record of the Burg lake. This study is a first step in the development of a comprehensive on-line atlas of Pyrenean diatoms including species occurrence, distribution and ecology (www.diatopyr.com). Samples were collected both from littoral epilithic substrates and the top of the sediment in the deepest zone of the lake. Additionally, we include also taxa that were present in the Late Glacial and Holocene sedimentary records of the Burg palaeolake, which were not found in the survey. The genera including more diversity were Pinnularia, Gomphonema, Eunotia and Nitzschia. About 25% of taxa remain to be determined at fine taxonomic resolution, many of them are likely to be species or varieties not described yet. © Asociación Ibérica de Limnología, Madrid. Spain.

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The ratio between chrysophycean cysts and diatoms in temperate, mountain lakes: some recommendations for its use in paleolimnology

Rivera-Rondón, C.A., Catalan, J. (2017) The ratio between chrysophycean cysts and diatoms in temperate, mountain lakes: some recommendations for its use in paleolimnology. Journal of Paleolimnology. 57: 273-285.
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Doi: 10.1007/s10933-017-9946-2

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Nematode distributions as spatial null models for macroinvertebrate species richness across environmental gradients: A case from mountain lakes

de Mendoza, G., Traunspurger, W., Palomo, A., Catalan, J. (2017) Nematode distributions as spatial null models for macroinvertebrate species richness across environmental gradients: A case from mountain lakes. Ecology and Evolution. : 0-0.
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Doi: 10.1002/ece3.2842

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Spatial And Temporal Trends Of Organic Pollutants In Vegetation From Remote And Rural Areas

Bartrons M., Catalan J., Penuelas J. (2016) Spatial And Temporal Trends Of Organic Pollutants In Vegetation From Remote And Rural Areas. Scientific Reports. 6: 0-0.
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Doi: 10.1038/srep25446

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Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) used in agricultural, industrial, and domestic applications are widely distributed and bioaccumulate in food webs, causing adverse effects to the biosphere. A review of published data for 1977-2015 for a wide range of vegetation around the globe indicates an extensive load of pollutants in vegetation. On a global perspective, the accumulation of POPs and PAHs in vegetation depends on the industrialization history across continents and distance to emission sources, beyond organism type and climatic variables. International regulations initially reduced the concentrations of POPs in vegetation in rural areas, but concentrations of HCB, HCHs, and DDTs at remote sites did not decrease or even increased over time, pointing to a remobilization of POPs from source areas to remote sites. The concentrations of compounds currently in use, PBDEs and PAHs, are still increasing in vegetation. Differential congener specific accumulation is mostly determined by continent - in accordance to the different regulations of HCHs, PCBs and PBDEs in different countries - and by plant type (PAHs). These results support a concerning general accumulation of toxic pollutants in most ecosystems of the globe that for some compounds is still far from being mitigated in the near future. © 2016, Nature Publishing Group. All rights reserved.

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Foraging success under uncertainty: Search tradeoffs and optimal space use

Bartumeus, F., Campos, D., Ryu, W.S., Lloret-Cabot, R., Méndez, V., Catalan, J. (2016) Foraging success under uncertainty: Search tradeoffs and optimal space use. Ecology Letters. : 0-0.
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Doi: 10.1111/ele.12660

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Trace metal accumulation as complementary dietary information for the isotopic analysis of complex food webs

Soto D.X., Benito J., Gacia E., García-Berthou E., Catalan J. (2016) Trace metal accumulation as complementary dietary information for the isotopic analysis of complex food webs. Methods in Ecology and Evolution. : 0-0.
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Doi: 10.1111/2041-210X.12546

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Food web structure is a fundamental feature of ecosystems. Stable isotopes (δ15N and δ13C) are used to estimate the relative contribution of food sources to consumer's diets (e.g. mixing models). In complex food webs, the use of δ15N and δ13C measurements cannot always solve trophic interactions and distinguish among aquatic organisms with different feeding habits if little intra- and interspecific isotopic differentiation occurs. We have developed a method to characterize trophic relationships using Bayesian stable isotope mixing models in combination with trace metal data as prior information. Trace metal information is useful because of the high correspondence between trace metal profiles in consumers and their food sources, as we show here in an example of concentrations of fish and their expected dietary items. Trace metal concentration allows a more accurate estimation of relative contributions of food sources to consumer species compared to estimates based only on stable isotope values. We show the improvement of the procedure using four freshwater fish species with well-known feeding habits. The method provides a better estimation of the inter- and intraspecific dietary variability and correspondence with the feeding habits of these species. The approach described shows a considerable potential as a tool to assess trophic links in situations in which stable isotope methods are not conclusive. The method can be applied using other compounds that bioaccumulate in consumers (e.g. persistent organic pollutants). © 2016 British Ecological Society.

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Increasing and decreasing trends of the atmospheric deposition of organochlorine compounds in European remote areas during the last decade

Arellano L., Fernandez P., Fonts R., Rose N.L., Nickus U., Thies H., Stuchlik E., Camarero L., Catalan J., Grimalt J.O. (2015) Increasing and decreasing trends of the atmospheric deposition of organochlorine compounds in European remote areas during the last decade. Atmospheric Chemistry and Physics. 15: 6069-6085.
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Doi: 10.5194/acp-15-6069-2015

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Bulk atmospheric deposition samples were collected between 2004 and 2007 at four high-altitude European sites encompassing east (Skalnaté Pleso), west (Lochnagar), central (Gossenköllesee) and south (Redòn) regions, and analysed for legacy and current-use organochlorine compounds (OCs). Polychlorobiphenyls (PCBs) generally showed the highest deposition fluxes in the four sites, between 112 and 488 ng m-2 mo-1, and hexachlorobenzene (HCB) the lowest, a few ng m-2 mo-1. Among pesticides, endosulfans were found at higher deposition fluxes (11-177 ng m-2 mo-1) than hexachlorocyclohexanes (HCHs) (17-66 ng m-2 mo-1) in all sites except Lochnagar that was characterized by very low fluxes of this insecticide. Comparison of the present measurements with previous determinations in Redòn (1997-1998 and 2001-2002) and Gossenköllesee (1996-1998) provided for the first time an assessment of the long-term temporal trends in OC atmospheric deposition in the European background areas. PCBs showed increasing deposition trends while HCB deposition fluxes remained nearly constant. Re-emission of PCBs from soils or as a consequence of glacier melting and subsequent precipitation and trapping of the volatilized compounds may explain the observed PCB trends. This process does not occur for HCB due to its high volatility which keeps most of this pollutant in the gas phase. A significant decline of pesticide deposition was observed during this studied decade (1996-2006) which is consistent with the restriction in the use of these compounds in most of the European countries. In any case, degassing of HCHs or endosulfans from ice melting to the atmosphere should be limited because of the low Henry's law constants of these compounds that will retain them dissolved in the melted water. Investigation of the relationship between air mass trajectories arriving at each site and OC deposition fluxes showed no correlation for PCBs, which is consistent with diffuse pollution from unspecific sources as the predominant origin of these compounds in these remote sites. In contrast, significant correlations between current-use pesticides and air masses flowing from the south were observed in Gossenköllesee, Lochnagar and Redòn. In the case of Redòn, the higher proportion of air masses from the south occurred in parallel to higher temperatures, which did not allow us to discriminate between these two determinant factors of pesticide deposition. However, in Gossenköllesee and Lochnagar, the relationship between pesticide concentration and southern air masses was univocal, reflecting the impact of regions with intensive agricultural activities. © Author(s) 2015.

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Background fish feminization effects in European remote sites

Jarque S., Quiros L., Grimalt J.O., Gallego E., Catalan J., Lackner R., Pina B. (2015) Background fish feminization effects in European remote sites. Scientific Reports. 5: 0-0.
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Doi: 10.1038/srep11292

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Human activity has spread trace amounts of chemically stable endocrine-disrupting pollutants throughout the biosphere. These compounds have generated a background level of estrogenic activity that needs to be assessed. Fish are adequate sentinels for feminization effects as male specimens are more sensitive than humans to exogenous estrogenic compounds. High mountain lakes, the most distant environments of continental areas, only receive semi-volatile compounds from atmospheric deposition. We analyzed the expression levels of estrogen-regulated genes in male fish from these mountain lakes in Europe. Incipient feminization involving expression of estrogen receptor and zona radiata genes revealed a widespread diffuse estrogenic impact. This effect was correlated with the concentrations of some organochlorine compounds in fish and was consistent with the persistent occurrence of these tropospheric pollutants in the most remote planet regions. These results should be of general concern given the increasing endocrine disruption effects in human populations. © 2015, Nature Publishing Group. All rights reserved.

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Benefits and limitations of an intercalibration of phytoplankton assessment methods based on the Mediterranean GIG reservoir experience

Pahissa J., Catalan J., Morabito G., Dorflinger G., Ferreira J., Laplace-Treyture C., Girbea R., Marchetto A., Polykarpou P., de Hoyos C. (2015) Benefits and limitations of an intercalibration of phytoplankton assessment methods based on the Mediterranean GIG reservoir experience. Science of the Total Environment. 538: 169-179.
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Doi: 10.1016/j.scitotenv.2015.08.042

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The status of European legislation regarding inland water quality after the enactment of the Water Framework Directive (WFD) originated scientific effort to develop reliable methods, primarily based on biological parameters. An important aspect of the process was to ensure that quality assessment was comparable between the different Member States. The Intercalibration process (IC), required in the WFD ensures the unbiased application of the norm. The presented results were developed in the context of the 2nd IC phase. An overview of the reservoir type definition of the Lake Mediterranean Geographical Intercalibration Group, where four types were considered divided by both alkalinity and climate, together with the results for selection of Maximum Ecological Potential sites (MEP) are presented. MEP reservoirs were selected based on pressure and biological variables. Three phytoplankton-based assessment methods were intercalibrated using data from Mediterranean countries. The Mediterranean Assessment System for Reservoirs Phytoplankton (Spain), the New Mediterranean Assessment System for Reservoirs Phytoplankton (Portugal and Cyprus) and the New Italian Method (Italy) were applied. These three methods were compared through option 3 of the Intercalibration Guide. The similarity of the assessments was quantified, and the Good/Moderate (GM) boundaries assessed. All three methods stood as comparable at the GM boundary except for the MASRP in siliceous wet reservoirs, which was slightly stricter. Finally, the main taxonomic groups represented in the phytoplankton community at MEP conditions were identified, as well as their main changes with an increasing trophic status. MEP sites are dominated by chrysophytes in siliceous wet reservoirs and by the diatoms Cyclotella and Achnanthes in calcareous ones. Cyanobacteria take over the community in both calcareous and siliceous wet reservoirs as eutrophication increases. In summary, the relevance and reliability of the quality assessment methods compared were confirmed both from an ecological perspective and a health risk management point of view. © 2015 Elsevier B.V.

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Acceleration of cyanobacterial dominance in north temperate-subarctic lakes during the Anthropocene

Taranu Z.E., Gregory-Eaves I., Leavitt P.R., Bunting L., Buchaca T., Catalan J., Domaizon I., Guilizzoni P., Lami A., Mcgowan S., Moorhouse H., Morabito G., Pick F.R., Stevenson M.A., Thompson P.L., Vinebrooke R.D. (2015) Acceleration of cyanobacterial dominance in north temperate-subarctic lakes during the Anthropocene. Ecology Letters. 18: 375-384.
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Doi: 10.1111/ele.12420

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Increases in atmospheric temperature and nutrients from land are thought to be promoting the expansion of harmful cyanobacteria in lakes worldwide, yet to date there has been no quantitative synthesis of long-term trends. To test whether cyanobacteria have increased in abundance over the past ~ 200 years and evaluate the relative influence of potential causal mechanisms, we synthesised 108 highly resolved sedimentary time series and 18 decadal-scale monitoring records from north temperate-subarctic lakes. We demonstrate that: (1) cyanobacteria have increased significantly since c. 1800 ce, (2) they have increased disproportionately relative to other phytoplankton, and (3) cyanobacteria increased more rapidly post c. 1945 ce. Variation among lakes in the rates of increase was explained best by nutrient concentration (phosphorus and nitrogen), and temperature was of secondary importance. Although cyanobacterial biomass has declined in some managed lakes with reduced nutrient influx, the larger spatio-temporal scale of sedimentary records show continued increases in cyanobacteria throughout the north temperate-subarctic regions. © 2015 John Wiley & Sons Ltd/CNRS.

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