Browsing by Author "Mosquera, Pablo"

Now showing 1 - 8 of 8

250-year records of mercury and trace element deposition in two lakes from Cajas National Park, SW Ecuadorian Andes
(2021) Schneider, Tobias; Musa Bandowe, Benjamin; Mestrot, Adrien; Mestrot, Adrien; Hampel, Henrietta; Mosquera, Pablo; Frankl, Lea; Wienhues, Giulia; Vogel, Hendrik; Tylmann, Wojciech; Grosjean, Martin
Historical records of trace elements in lake sediments provide source-to-sink information about potentially toxic pollutants across space and time. We investigated two lakes located at different elevations in the Ecuadorian Andes to understand how trace element fluxes are related to (i) geology, (ii) erosion in the watersheds, and (iii) local point sources and atmospheric loads. In remote Lake Fondococha (4150 m a.s.l.), total Hg fluxes stay constant between ca. 1760 and 1950 and show an approximately 4.4-fold increase between pre-1950 and post-1950 values. The post-1950 increase in fluxes of other trace elements (V, Cr, Co, Ni, Cu, Zn, As, Cd, and Pb) is lower (2.1–3.0-fold) than for Hg. Mostly lithogenic sources and enhanced soil erosion contribute to their post-1950 increase (lithogenic contribution: > 85%, Hg: ~ 58%). Average post-1950 Hg fluxes are approximately 4.3 times higher in peri-urban Lake Llaviucu (3150 m a.s.l.) than in the remote Lake Fondococha. Post-1950 fluxes of the other trace elements showed larger differences between Lakes Fondococha and Llaviucu (5.2 < 25–29.5-fold increase; Ni < Pb–Cd). The comparison of the post-1950 average trace element fluxes that are derived from point and airborne sources revealed 5–687 (Hg–Pb) times higher values in Lake Llaviucu than in Lake Fondococha suggesting that Lake Llaviucu’s proximity to the city of Cuenca strongly influences its deposition record (industrial emissions, traffic, caged fishery). Both lakes responded with temporary drops in trace element accumulations to park regulations in the 1970s and 1990s, but show again increasing trends in recent times, most likely caused by increase in vehicular traffic and openings of copper and gold mines around Cajas National Park.
A 150-year record of polycyclic aromatic compound (PAC) deposition from high Andean Cajas National Park, southern Ecuador
(2018) Musa Bandowe, Benjamin; Frankl, Lea; Grosjean, Martin; Tylmann, Wojciech; Mosquera, Pablo; Hampel, Henrietta; Schneider, Tobias
The temporal profiles of polycyclic aromatic compounds (PACs) in lake sediments reflect past changes in emissions, transport and deposition of these pollutants and, thus, record natural and anthropogenic processes. We document fluxes of PACs [(polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs) and azaarenes (AZAs)] deposited in two tropical high-altitude lakes in the CajasNational Park (Ecuadorian Andes, 2°50′S, 79°10′ W). In remote and high elevation Laguna Fondococha (4130 m a.s.l.), the temporal fluxes of OPAHs and AZAs were similar to those of PAHs suggesting similar sources. A significant increase of PAC deposition after the 1950s reflects Ecuador's economic development. PAH fluxes were relatively low (Σ27PAHs (without retene and perylene): 0.86–11.21 ng cm−2 yr−1) with a composition pattern typical for long-range atmospheric transport (high 9-fluorenone/fluorene ratios) and biomass burning (30% lowmolecularweight PAHs). PAHs diagnostic of high temperature combustion (industry, traffic) make up 20–25% of total PAHs. Perylene concentrations increase linearly with increasing sediment depth suggesting diagenetic in-situ production. At lower elevations (Laguna Llaviucu, 3140 m a.s.l.) and closer to urban areas, PAC fluxes in the past decades were 4–5 times higher than in the remote high-elevation lake. Laguna Llaviucu also showed higher concentrations of high molecular weight pyrogenic PAHs and a greater diversity of AZAs. Individual OPAHs and AZAs reflect mainly combustion activities. In Laguna Llaviucu, which is at a lower elevation (3140 m a.s.l.) and closer to the city, molecular ratios suggest short-range atmospheric transport and deposition of PACs.A very foggy climate (170 rainy days per year) with the precipitation maximum at 3500 m removes PACs very efficiently (by wet deposition) from the atmosphere at very short distances from emission sources. This partly explains why L. Llaviucu shows higher fluxes of PACs than the higher elevation L. Fondococha. This study presents the first historical record of organic pollutants from environmental archives in Ecuador.
Branquiópodos de las masas de agua lacustre del Parque Nacional Cajas (Andes Australes, Ecuador) inventario y notas autoecológicas
(Universidad de Cuenca, 2017) Alonso, Miguel; Mosquera, Pablo; Hampel, Henrietta; Vázquez, Raúl F.
Extensive sampling of 202 lentic water bodies (lakes, lagoons and ponds) located between 3150 and 4460 m a.s.l. in the Cajas National Park (South Ecuadorian Andes) has revealed the high interest of these mountain enclaves in tropical latitudes for the investigation of faunal and ecological aspects of the branchiopod fauna. The first results allowed to recognize 21 species, 15 of them new to Ecuador, of which 2 are in process of description to be published as new to science. All species are characteristic of little mineralized and oligotrophic waters, 8 of them appear in the plankton and the rest in the limnetic littoral benthos.
Branquiópodos de las masas de agua lacustre del Parque Nacional Cajas (Andes Australes, Ecuador) inventario y notas autoecológicas
(2017) Alonso Garcia-amilivia, Miguel Null; Mosquera, Pablo; Hampel, Henrietta; Vázquez Zambrano, Raúl Fernando
Extensive sampling of 202 lentic water bodies (lakes, lagoons and ponds) located between 3150 and 4460 m a.s.l. in the Cajas National Park (South Ecuadorian Andes) has revealed the high interest of these mountain enclaves in tropical latitudes for the investigation of faunal and ecological aspects of the branchiopod fauna. The first results allowed to recognize 21 species, 15 of them new to Ecuador, of which 2 are in process of description to be published as new to science. All species are characteristic of little mineralized and oligotrophic waters, 8 of them appear in the plankton and the rest in the limnetic littoral benthos.
Crustáceos bentónicos y macrófitos como indicadores de calidad ecológica en los lagos de los Andes Australes de Ecuador
(Universidad de Cuenca, 2017) Alonso, Miguel; Mosquera, Pablo; Hampel, Henrietta; Vázquez, Raúl F.
The taxonomic composition of the litoral benthic limnetic crustacean communities, (branchiopods, copepods and ostracods) and macrophytes of the lacustrine water bodies of the Cajas National Park located in the Southern Andes of Ecuador have been studied in order to identify the most suitable taxa to be used as indicators of the ecological status of lakes. Among the crustaceans (22 taxa) three groups were differentiated. A first group with taxa of higher indicator value including Branchinecta papillata, Ilyocryptus spinosus, Alonella sp, Pleuroxus sp. Paralona pigra and Alona sp. gr. manueli. A second group with medium indicator value including Alona glabra, Alona guttata, Microcyclops sp. Eucyclops sp. and Paracyclops sp. The third group was formed by taxa of the lower indicator value, either because of its eurioic and / or cosmopolitan character or because of its rarity. Macrophytes have been evaluated as good indicators of the ecological and conservation status of the lakes. The taxa which were submerged, floating and rooted in the sediment were identified to be a good indicator for the water body, and helophytes and hygrophytes for the limnetic litoral zone.
Crustáceos bentónicos y macrófitos como indicadores de calidad ecológica en los lagos de los Andes Australes de Ecuador
(2017) Alonso Garcia-amilivia, Miguel Null; Mosquera, Pablo; Hampel, Henrietta; Vázquez Zambrano, Raúl Fernando
The taxonomic composition of the litoral benthic limnetic crustacean communities, (branchiopods, copepods and ostracods) and macrophytes of the lacustrine water bodies of the Cajas National Park located in the Southern Andes of Ecuador have been studied in order to identify the most suitable taxa to be used as indicators of the ecological status of lakes. Among the crustaceans (22 taxa) three groups were differentiated. A first group with taxa of higher indicator value including Branchinecta papillata, Ilyocryptus spinosus, Alonella sp, Pleuroxus sp. Paralona pigra and Alona sp. gr. manueli. A second group with medium indicator value including Alona glabra, Alona guttata, Microcyclops sp. Eucyclops sp. and Paracyclops sp. The third group was formed by taxa of the lower indicator value, either because of its eurioic and / or cosmopolitan character or because of its rarity. Macrophytes have been evaluated as good indicators of the ecological and conservation status of the lakes. The taxa which were submerged, floating and rooted in the sediment were identified to be a good indicator for the water body, and helophytes and hygrophytes for the limnetic litoral zone.
Identifying temporal and spatial patterns of diatom community change in the tropical Andes over the last c. 150 years
(2019) Benito, Xavier; Feitl, Melina; Fritz, Sherilyn; Mosquera, Pablo; Schneider, Tobias; Hampel, Henrietta; Quevedo, Luis; Steinitz Kannan, Miriam
Aim: Lakes in the Ecuadorean Andes span different altitudinal and climatic regions, from inter Andean plateau to the high-elevation páramo, which differ in their historical evolution in the several centuries since the pioneering Humboldt expeditions. Here, we evaluate temporal and spatial patterns of change in diatom assemblages between historical (palaeolimnological) and modern times. Location: Ecuadorean Andes Methods: We compared historical (pre-1850) and modern (2017) diatom assemblages from 21 lakes and determined the relative role of environmental (water chemistry and climate) and spatial factors (distance-based Moran's eigenvectors maps) on both assemblages using non-metric multidimensional scaling (NMDS) with environmental fitting. In addition, we used redundancy analysis (RDA) with variance partitioning to estimate the historical (measured using downcore assemblage composition) effects on modern diatom assemblages and identified diatom species that contributed most to dissimilarity between the two times. Results: Diatom changes between the two time points were limited across the group of lakes, as indicated by the NMDS ordination. Variance partitioning indicated that modern diatom assemblages were affected by environmental and spatial effects, but with non-significant effects of past diatom species composition. Ordination results showed that variables related to elevation and water chemistry affected both modern and historical diatom assemblages. Diatom species with the best fit on NMDS axes (i.e. >70%) were influenced by elevation and climatic variables. The most distinctive change between the two time periods was the higher relative abundance of planktic diatom species in top-core assemblages of some lakes, but in a highly variable fashion across gradients of increased elevation and water depth. Main conclusions: Landscape palaeolimnological analyses of varied Ecuadorean Andean lakes demonstrate both environmental and spatial controls on diatom metacommunities. The multi-faceted ecological control of the altitudinal gradient on both historic and contemporary diatom assemblages suggests species sorting and dispersal constraints operating at centennial time-scale. Although a few individual lakes show substantive change between the 1850s and today, the majority of lakes do not, and the analysis suggests the resilience of lakes at a regional scale. We emphasize the potential of diatom palaeolimnological approaches in biogeography to test ecologically relevant hypotheses of the mechanisms driving recent limnological change in high-elevation tropical lakes.
Limnology and trophic status of glacial lakes in the tropical Andes (Cajas National Park, Ecuador)
(2017) Van Colen, Willem; Mosquera, Pablo; Vanderstukken, Maarten; Goiris, Koen; Carrasco Espinoza, María Cecilia; Decaestecker, Ellen; Alonso, Miguel; León Tamariz, Fabián; Muylaert, Koenraad
The tropical Andes has a high density of glacial lakes that are situated in the high-altitude páramo (3500–4500 m). Ecological information about such lakes is scant despite the fact that these lakes are an important source of water for drinking, irrigation and electricity generation and feed several major tributaries of the Amazon. In this study, we provide data on a survey of 31 lakes in Cajas National Park (Ecuador). Two of the lakes were monitored monthly during one year. In situ nutrient addition experiments were carried out in three of the lakes. Seasonal monitoring in two lakes revealed a thermal stratification of the water column between October and June, with a small temperature difference between epi- and hypolimnion (2–3 °C). Oxygen depletion of the hypolimnion towards the end of the stratification period indicated that no complete mixing of the water column occurred during stratification. There was no evidence of depletion of nutrients in the epilimnion or accumulation in the hypolimnion during stratification. There were also no clear seasonal changes in chlorophyll-a (Chl-a) concentration nor in phytoplankton community composition in the two lakes. Inputs of dissolved organic carbon (DOC) from the vegetated catchment resulted in high DOC concentrations (median 2.9 mg L−1) compared to temperate mountain lakes. Water transparency was relatively low, with a median extinction coefficient for photosynthetic active radiation of 0.50 m−1 and for UV-B radiation of 10.13 m−1. Although the thermocline was deep and water transparency was low, estimates of the critical depth for photosynthesis were deeper than the mean water depth in all lakes, suggesting that phytoplankton was not light limited. The phytoplankton community was dominated by chlorophytes (e.g. Oocystis), diatoms (small Cyclotella spp.) or small colonial cyanobacteria (Aphanocapsa, Merismopedia). The zooplankton community was either dominated by large cladocerans and cyclopoid copepods, or by the calanoid copepod Boeckella occidentalis. Total concentrations of phosphorus (P) and nitrogen (N) were comparable to those in temperate mountain lakes (4–35 μg P L−1 and 162–758 μg N L−1) while Chl-a concentrations were in the lower range (<1 μg L−1). A large part of the total nutrient pool consists of dissolved organic N and P that appeared to have a low bioavailability to phytoplankton. The median seston N:P ratio of 44, a positive correlation between Chl-a and total P concentration, as well as nutrient addition assays carried out in three lakes all pointed to P limitation of phytoplankton. © 2016 John Wiley & Sons Ltd