Testing the effects of food quality, as well as chemical contamination of water and sediments, on aquatic detrital systems using laboratory experiments.

136 p.Materia organikoaren kalitate aldaketek eta kutsadura kimikoak sistema detritikoetan duten eragina aztertzea izan da tesi honen helburu nagusia. Horretarako, laborategiko mikrokosmo esperimentuak erabili dira tesian zehar. Materia organikoaren kalitateak eta eskuragarritasunak esangarriki baldintzatzen dute deskonposaketa tasa baina ez ornogabe zatitzaileen (Echinogammarus berilloni) gorputz egoera. Kontsumo tasa eta RNA:BM ratioa ezin dira seinale goiztiar bezala erabili. Inkubazio denborak inkoherentziak sortzen ditu neurtutako aldagaietan eta gure emaitzak kontutan hartuta, 16 eguneko inkubazioa minimoa gomendatzen dugu. Hirugarren kapituluan ikusi genuen araztegietako efluenteak (0 %tik 100 %era) orokorrean komunitate mikrobiarraren eta zatitzaileen portaera aktibatu zuela. Laugarren kapituluan, sedimentuetako kutsatzaile nahasketa baten eragina aztertu genuen Monoporeia affinis indibiduoetan biomarkatzaile desberdinak neurtuta. Kutsadura gradienteari linealki eta ez-linealki erantzuten dioten biomarkatzaileen arteko korrelazioak indibiduoek jasotzen duten estres maila detektatzeko tresna egokia zirela ikusi genuen

Germinación de semillas de especies adaptadas a un medio extremófilo: Río Tinto

Se presentan los porcentajes de germinación de 12 especies representativas de la vegetación de ribera y matorral del ecosistema del río Tinto en diferentes condiciones de pH (5,4; 3,2; 1,8 y agua del río Tinto). Se observan distintas respuestas de germinación en las especies estudiadas, encontrando los mayores porcentajes de germinación en Nerium oleander y Salicornia ramosissima. Dada la respuesta positiva de estas dos especies, se discute su utilidad para la restauración de los territorios afectados en los alrededores del río Tinto. Para el resto de especies, se observan bajos porcentajes de germinación y en la mayoría de las especies analizadas el pH no influye en la germinación. Hay muchos factores que limitan la germinación de las semillas tales como la latencia que requiere de un pre-tratamiento (de frío o de calor), variación en las condiciones naturales que son difíciles de recrear en el laboratorio o la baja calidad de las semillas

Testing the effects of food quality, as well as chemical contamination of water and sediments, on aquatic detrital systems using laboratory experiments.

136 p.Materia organikoaren kalitate aldaketek eta kutsadura kimikoak sistema detritikoetan duten eragina aztertzea izan da tesi honen helburu nagusia. Horretarako, laborategiko mikrokosmo esperimentuak erabili dira tesian zehar. Materia organikoaren kalitateak eta eskuragarritasunak esangarriki baldintzatzen dute deskonposaketa tasa baina ez ornogabe zatitzaileen (Echinogammarus berilloni) gorputz egoera. Kontsumo tasa eta RNA:BM ratioa ezin dira seinale goiztiar bezala erabili. Inkubazio denborak inkoherentziak sortzen ditu neurtutako aldagaietan eta gure emaitzak kontutan hartuta, 16 eguneko inkubazioa minimoa gomendatzen dugu. Hirugarren kapituluan ikusi genuen araztegietako efluenteak (0 %tik 100 %era) orokorrean komunitate mikrobiarraren eta zatitzaileen portaera aktibatu zuela. Laugarren kapituluan, sedimentuetako kutsatzaile nahasketa baten eragina aztertu genuen Monoporeia affinis indibiduoetan biomarkatzaile desberdinak neurtuta. Kutsadura gradienteari linealki eta ez-linealki erantzuten dioten biomarkatzaileen arteko korrelazioak indibiduoek jasotzen duten estres maila detektatzeko tresna egokia zirela ikusi genuen

Testing Wastewater Treatment Plant Effluent Effects on Microbial and Detritivore Performance: a Combined Field and Laboratory Experiment

The amount of pollutants and nutrients entering rivers via point sources is increasing along with human population and activity. Although wastewater treatment plants (WWTPs) greatly reduce pollutant loads into the environment, excess nutrient loading is a problem in many streams. Using a Community and Ecosystem Function (CEF) approach, we quantified the effects of WWTP effluent on the performance of microbes and detritivores associated to organic matter decomposition, a key ecosystem process. We measured organic matter breakdown rates, respiration rates and exo-enzymatic activities of aquatic microbes. We also measured food consumption and growth rates and RNA to body-mass ratios (RNA:BM) of a dominant amphipod Echinogammarus berilloni. We predicted responses to follow a subsidy-stress pattern and differences between treatments to increase over time. To examine temporal effects of effluent, we performed a laboratory microcosm experiment under a range of effluent concentrations (0, 20, 40, 60, 80 and 100%), taking samples over time (days 8, 15 and 30; 4 and 10 replicates to assess microbe and detritivore performance respectively, per treatment and day). This experiment was combined with a field in situ Before-After Control-Impact Paired (BACIP) experiment whereby we added WWTP effluent poured (10 L s(-1) during 20-40 min every 2 h) into a stream and collected microbial and detritivore samples at days 8 and 15 (5 and 15 replicates to assess the microbe and detritivore performance respectively, per period, reach and sampling day). Responses were clearer in the laboratory experiment, where the effluent caused a general subsidy response. Field measures did not show any significant response, probably because of the high dilution of the effluent in stream water (average of 1.6%). None of the measured variables in any of the experiments followed the predicted subsidy-stress response. Microbial breakdown, respiration rates, exo-enzymatic activities and invertebrate RNA:BM increased with effluent concentrations. Differences in microbial respiration and exo-enzymatic activities among effluent treatments increased with incubation time, whereas microbial breakdown rates and RNA:BM were consistent over time. At the end of the laboratory experiment, microbial respiration rates increased 156% and RN:BM 115% at 100% effluent concentration. Detritivore consumption and growth rates increased asymptotically, and both responses increased with by incubation time. Our results indicate that WWTP effluent stimulates microbial activities and alters detritivore performance, and stream water dilution may mitigate these effects.This work has been supported by the EU7th Framework Programme Funding under Grant agreement no. 603629-ENV-2013-6.2.1-Globaqua. We also acknowledge financial support in terms of pre doctoral grants from the University of the Basque Country UPV/EHU (L. Solagaistua) and the Basque Government (I. de Guzman, L. Mijangos). The manuscript benefited greatly from the valuable comments of John Kominoski and two anonymous referees. Also SGIker technical and human support (UPV/EHU, MICINN, GV/EJ, ESF) is gratefully acknowledged

Early-Career Coordinated Distributed Experiments: Empowerment Through Collaboration

Este artículo contiene 7 páginas, 1 tabla, 3 figuras.Coordinated distributed experiments (CDEs) enable the study of large-scale ecological patterns in geographically dispersed areas, while simultaneously providing broad academic and personal benefits for the participants. However, the effective involvement of early-career researchers (ECRs) presents major challenges. Here, we analyze the benefits and challenges of the first CDE exclusively led and conducted by ECRs (i.e. ECR-CDE), which sets a baseline for similar CDEs, and we provide recommendations for successful CDE execution. ECR-CDEs achieve most of the outcomes identified in conventional CDEs as well as extensive benefits for the young cohort of researchers, including: (i) receiving scientific credit, (ii) peer-training in new concepts and methods, (iii) developing leadership and communication skills, (iv) promoting a peer network among ECRs, and (v) building on individual engagement and independence. We also discuss the challenges of ECR-CDEs, which are mainly derived from the lack of independence and instability of the participants, and we suggest mechanisms to address them, such as resource re-allocation and communication strategies. We conclude that ECR-CDEs can be a relevant tool to empower ECRs across disciplines by fostering their training, networking and personal well-being.The authors were supported by the following founding: NC the support of the Beatriu de Pinós postdoctoral program of the Government of Catalonia’s Secretariat for Universities and Research of the Ministry of Economy and Knowledge (BP2016- 00215), EE by a predoctoral grant from the Basque Government (2014-2017), AB by a Generalitat de Catalunya—Beatriu de Pinós (BP-00385-2016), AMG-F by a predoctoral research grant (BES-2013-065770) from the Spanish Ministry of Economy and Competitiveness, MAr by a postdoctoral grant from the Basque Government, MIA by a Juan de la Cierva postdoctoral grant (FJCI-2015-26192), PR-L by a Margalida Comas postdoctoral contract (PD/031/2018) funded by the Government of the Balearic Islands and the European Social Fund, AP by a Ramón Areces Foundation Postdoctoral Scholarship, and AL by a Kempe Foundation stipend. DOMIPEX project was founded by the First Call of Collaborative Projects among Young Researchers of the Iberian Association of Limnology (AIL; 2013-2015).Peer reviewe

River ecosystem processes: A synthesis of approaches, criteria of use and sensitivity to environmental stressors

River ecosystems are subject to multiple stressors that affect their structure and functioning. Ecosystem structure refers to characteristics such as channel form, water quality or the composition of biological communities, whereas ecosystem functioning refers to processes such as metabolism, organic matter decomposition or secondary production. Structure and functioning respond in contrasting and complementary ways to environmental stressors. Moreover, assessing the response of ecosystem functioning to stressors is critical to understand the effects on the ecosystem services that produce direct benefits to humans. Yet, there is more information on structural than on functional parameters, and despite the many approaches available to measure river ecosystem processes, structural approaches are more widely used, especially in management. One reason for this discrepancy is the lack of synthetic studies analyzing river ecosystem functioning in a way that is useful for both scientists and managers. Here, we present a synthesis of key river ecosystem processes, which provides a description of the main characteristics of each process, including criteria guiding their measurement as well as their respective sensitivity to stressors. We also discuss the current limitations, potential improvements and future steps that the use of functional measures in rivers needs to face.Science of The Total Environment (2017), 596-597: 465-48

Testing the effects of food quality, as well as chemical contamination of water and sediments, on aquatic detrital systems using laboratory experiments.

136 p.Materia organikoaren kalitate aldaketek eta kutsadura kimikoak sistema detritikoetan duten eragina aztertzea izan da tesi honen helburu nagusia. Horretarako, laborategiko mikrokosmo esperimentuak erabili dira tesian zehar. Materia organikoaren kalitateak eta eskuragarritasunak esangarriki baldintzatzen dute deskonposaketa tasa baina ez ornogabe zatitzaileen (Echinogammarus berilloni) gorputz egoera. Kontsumo tasa eta RNA:BM ratioa ezin dira seinale goiztiar bezala erabili. Inkubazio denborak inkoherentziak sortzen ditu neurtutako aldagaietan eta gure emaitzak kontutan hartuta, 16 eguneko inkubazioa minimoa gomendatzen dugu. Hirugarren kapituluan ikusi genuen araztegietako efluenteak (0 %tik 100 %era) orokorrean komunitate mikrobiarraren eta zatitzaileen portaera aktibatu zuela. Laugarren kapituluan, sedimentuetako kutsatzaile nahasketa baten eragina aztertu genuen Monoporeia affinis indibiduoetan biomarkatzaile desberdinak neurtuta. Kutsadura gradienteari linealki eta ez-linealki erantzuten dioten biomarkatzaileen arteko korrelazioak indibiduoek jasotzen duten estres maila detektatzeko tresna egokia zirela ikusi genuen

Germinación de semillas de especies adaptadas a un medio extremófilo: Río Tinto

Se presentan los porcentajes de germinación de 12 especies representativas de la vegetación de ribera y matorral del ecosistema del río Tinto en diferentes condiciones de pH (5,4; 3,2; 1,8 y agua del río Tinto). Se observan distintas respuestas de germinación en las especies estudiadas, encontrando los mayores porcentajes de germinación en Nerium oleander y Salicornia ramosissima. Dada la respuesta positiva de estas dos especies, se discute su utilidad para la restauración de los territorios afectados en los alrededores del río Tinto. Para el resto de especies, se observan bajos porcentajes de germinación y en la mayoría de las especies analizadas el pH no influye en la germinación. Hay muchos factores que limitan la germinación de las semillas tales como la latencia que requiere de un pre-tratamiento (de frío o de calor), variación en las condiciones naturales que son difíciles de recrear en el laboratorio o la baja calidad de las semillas

Consumption and performance responses of the amphipod

Microcosms try to mimic the behaviour of natural ecosystems; however, differences in experimental conditions reduce comparability among studies. A standard incubation duration may increase comparability between experiments without losing realism in the response. Some response variables can respond fast, acting as early warning signals of other, more important oncoming changes. In this experiment, we test the effects of resource quality and incubation duration on the performance of the amphipod Echinogammarus berilloni. Individuals were fed on five leaf species of contrasting quality and we measured their consumption rate, death rate, RNA:body mass (RNA:BM), growth rate, mass body condition and lipid body condition over time. We predicted that (i) resource quality would affect the response variables, (ii) consumption rate and RNA:BM ratio would act as early warning signals of oncoming changes in growth or death rates, and (iii) the inter-individual variation would gradually decrease with time. Resource quality was positively related to consumption rates, although it did not correlate to nutrient concentration and toughness of the materials. Amphipod body mass condition changed with diet, animals feeding on oak and beech showing the lowest values. Death rate, growth rate, RNA:BM, and lipid mass condition did not change with food resources. Consumption, growth rate and mass body condition changed with time. Moreover, consumption, mass body condition and RNA:BM significantly interacted with incubation duration. Variability among individuals in consumption and growth rate decreased with time, as predicted. Our results pointed that special care should be taken when comparing microcosm experiments with different incubation duration.We test the effects of leaf quality and incubation duration on E. berilloni. Resource quality was positively related to consumption. Body mass condition changed with diet. Consumption, mass body condition and RNA:BM significantly interacted with incubation duration. Special care should be taken when comparing experiments with different duration

The nutrient uptake bioassay (NUB): A method to estimate the nutrient uptake capacity of biofilms for the functional assessment of river ecosystems

River ecosystems host a large biodiversity and provide essential ecosystem services but are threatened by multiple anthropogenic activities that degrade their structure and functioning. Although both structure and functioning are key components of ecological status, river monitoring programmes rely almost exclusively on structural indicators, such as community structure, or water quality, neglecting functional attributes. Scientists have pointed towards some promising functions, such as organic matter decomposition, as potential indicators of river functional status. However, it may not be the best indicator to assess the ecosystem functioning of river ecosystem subjected to certain impacts, such as nutrient inputs. Additionally, managers have seldom used functional indicators, probably because of the lack of simple, routine protocols. Here we present the nutrient uptake bioassay (NUB), a simple and straightforward method to measure nutrient uptake by river biofilm that could be developed as a functional indicator of river ecological status. The NUB consists in deploying biofilm carriers in the river for a specific period, allowing biofilm colonization. Biofilm carriers are then incubated in the field in a nutrient-enriched standard solution for one hour and finally the remaining nutrient concentration in the standard medium is measured. Nutrient uptake is calculated from the difference between the initial and final nutrient concentrations. Chlorophyll in the biofilm carriers can also be measured to calculate biofilm accrual rates. The NUB has been developed based on a mesocosm and a field experiments, which showed that the NUB provides additional, non-redundant information to current biomonitoring techniques. Overall, the NUB is a cheap, robust and reliable method that can be applied by most river monitoring practitioners and can be adapted to most river types and situations. As nutrient uptake is linked to the self-purification capacity of rivers, the NUB results provide information about an important ecosystem service. Therefore, we suggest that the NUB can be developed as part of the monitoring toolbox available for managers to improve the assessment of river ecological status and to diagnose the causes of ecosystem impairment