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  • 1.
    Deininger, Anne
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Faithfull, Carolyn L.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lange, K.
    Bayer, T.
    Vidussi, F.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Simulated terrestrial runoff triggered a phytoplankton succession and changed seston stoichiometry in coastal lagoon mesocosms2016In: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 119, p. 40-50Article in journal (Refereed)
    Abstract [en]

    Climate change scenarios predict intensified terrestrial storm runoff, providing coastal ecosystems with large nutrient pulses and increased turbidity, with unknown consequences for the phytoplankton community. We conducted a 12-day mesocosm experiment in the Mediterranean Thau Lagoon (France), adding soil (simulated runoff) and fish (different food webs) in a 2 x 2 full factorial design and monitored phytoplankton composition, shade adaptation and stoichiometry. Diatoms (Chaetoceros) increased fourfold immediately after soil addition, prymnesiophytes and dinoflagellates peaked after six- and 12 days, respectively. Soil induced no phytoplanlcton shade adaptation. Fish reduced the positive soil effect on dinoflagellates (Scripsiella, Glenodinium), and diatom abundance in general. Phytoplankton community composition drove seston stoichiometry. In conclusion, pulsed terrestrial runoff can cause rapid, low quality (high carbon: nutrient) diatom blooms. However, bloom duration may be short and reduced in magnitude by fish. Thus, climate change may shift shallow coastal ecosystems towards famine or feast dynamics.

  • 2. Drakare, Stina
    et al.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Local factors control the community composition ofcyanobacteria in lakes while heterotrophic bacteriafollow a neutral model2010In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 55, no 12, p. 2447-2457Article in journal (Refereed)
    Abstract [en]

    1. Neutral community models are derived from the proposition that basic probabilities ofspecies loss (extinction, emigration) and gain (immigration, speciation) explain biologicalcommunity structure, such that species with many individuals are very likely to bewidespread. Niche models on the other hand assume that interactions between species anddifferential resource use mediate species coexistence, thus invoking environmental factorsto explain community patterns.2. In this study, we compared neutral and niche models to test how much of the spatialvariability of assemblages of heterotrophic bacteria and phytoplankton in 13 lakes theycould explain. Analysis of phytoplankton was restricted to cyanobacteria, so that theycould be studied with the same molecular fingerprinting method, automated ribosomalintergenic spaces analysis (ARISA), as heterotrophic bacteria. We determined local bioticand abiotic lake variables as well as lake age, glacial history and distance between sites.3. The neutral community model had a good fit to the community composition ofheterotrophic bacteria (R2 = 0.69), whereas it could not produce a significant model for thecommunity composition of cyanobacteria.4. The community composition of cyanobacteria was instead correlated to environmentalvariables. The best model, a combination of total organic carbon, biomass of eukaryoticphytoplankton, pH and conductivity, could explain 8% of the variation. In contrast,variation in the community composition of heterotrophic bacteria was not predicted byany of the environmental variables. Historical and spatial variables were not correlated tothe community composition of either group.5. The pattern found for heterotrophic bacteria suggests that stochastic processes areimportant. The correlation of cyanobacteria with local environmental variables alone isconsistent with the niche model. We suggest that cyanobacteria, a group of organismscontaining bloom-forming species, may be less likely to fit a neutral community model,since these blooms are usually triggered by a particular combination of environmentalconditions.Keywords: automated

  • 3. Francoeur, Steven N.
    et al.
    Sander, Bianca
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Substratum-Associated Microbiota2012In: Water environment research, ISSN 1061-4303, E-ISSN 1554-7531, Vol. 84, no 10, p. 1658-1690Article in journal (Refereed)
    Abstract [en]

    A review of the literature published in 2011 on topics relating to on the subject of ecology of substratum-associated microbiota (algae, bacteria, and fungi). We also highlighted some of the new methods that can be applied to the study of substratum-associated microbiota and included newly described taxa.

  • 4. Furey, Paula C
    et al.
    Deininger, Anne
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Substratum-Associated Microbiota2016In: Water environment research, ISSN 1061-4303, E-ISSN 1554-7531, Vol. 88, no 10, p. 1638-1672Article in journal (Refereed)
    Abstract [en]

    This survey of literature on substratum associated microbiota from 2015 highlights research findings associated with benthic algae and bacteria from a variety of aquatic environments, but primarily freshwaters. It focuses on topics of interest to the Water Environment Federation along with those of current emerging interest such as global change, oil spills, and environmental contaminants like pharmaceutical compounds, microplastics, nanoparticles and organic pollutants. Other interesting findings briefly covered include areas of general ecology, nutrient cycling, trophic interactions, water quality, nuisance and invasive species, bioindicators, and bioremediation.

  • 5.
    Furey, Paula C.
    et al.
    St. Catherine University, Department Biology, St. Paul, MN 55105, USA.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Substratum-Associated Microbiota2014In: Water environment research, ISSN 1061-4303, E-ISSN 1554-7531, Vol. 86, no 10, p. 1774-1831Article in journal (Refereed)
    Abstract [en]

    A review of literature on substratrum-associated microbiotia from 2013 covers topics on benthic algae, bacteria and viruses from a range of aquatic environments, but focuses on freshwater ecosystems. Advances in laboratory, field, and assessment methods are highlighted as are updates in taxonomy and systematics. Aspects of water quality, waste-water treatment, biofuels, nutrient cycling, food-web interactions, land use changes, and environmental challenges such as climate change, pollutants, and impacts of medical substances are presented.

  • 6. Furey, Paula C.
    et al.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Substratum-Associated Microbiota2015In: Water environment research, ISSN 1061-4303, E-ISSN 1554-7531, Vol. 87, no 10, p. 1611-1678Article in journal (Refereed)
    Abstract [en]

    This review of literature on substratum-associated microbiota from 2014 highlights topics on benthic algae and bacteria from a range of aquatic environments, but focuses on freshwater habitats. Advances in pollution and toxin detection, assessment methods, and applications of new technologies are highlighted as are updates in taxonomy and systematics. Aspects of general ecology, water quality, nutrient cycling, trophic interactions, land use changes, biofuels, biofouling, and environmental challenges such as climate change, pollutants, tar sands and fracking, oil spills and nuisance blooms are presented.

  • 7. Furey, Paula C.
    et al.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Substratum-Associated Microbiota2013In: Water environment research, ISSN 1061-4303, E-ISSN 1554-7531, Vol. 85, no 10, p. 1786-1827Article in journal (Refereed)
    Abstract [en]

    This review of literature published in 2012 covers topics on substratum-associated microbiota (algae and bacteria) from a variety of aquatic environments, especially freshwater ecosystems. It is not a comprehensive review, rather aims to highlight aspects of methods, taxonomy and systematics, ecology, and current environmental issues such as nuisance taxa, pollutants and climate change.

  • 8. Lange, Katharina
    et al.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Piggott, Jeremy J.
    Townsend, Colin R.
    Matthaei, Christoph D.
    Light, nutrients and grazing interact to determine stream diatom community composition and functional group structure2011In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 56, no 2, p. 264-278Article in journal (Refereed)
    Abstract [en]

    P>1. Benthic algal communities are shaped by the availability of nutrients and light and by herbivore consumption. Many studies have examined how one of these factors affects algal communities, but studies simultaneously addressing all three are rare. 2. We investigated the effects of nutrients, light and a herbivore (the snail Potamopyrgus antipodarum) on benthic stream algae in a fully factorial experiment in 128 circular streamside channels. Four nutrient levels (none added to highly enriched), four snail grazing pressures (no snails to 777 individuals m-2) and two light levels (ambient and 65% reduced) were applied. Colonising algae were dominated by diatoms (Bacillariophyta), which were determined to species using acid-cleaned samples and assigned to functional groups according to their physiognomic growth form. 3. Diatom community structure changed considerably in response to our manipulations. Light had the strongest influence (as indicated by manova effect size), whereas nutrients had an intermediate effect and grazing was fairly weak. Relative abundances of six common diatom taxa decreased under reduced light, whereas five others became more prevalent. Eight taxa benefitted from nutrient enrichment, while three became rarer. Grazing affected the relative density of only one common taxon, which increased at higher grazing pressure. 4. Diatom functional groups also responded strongly. 'Low profile' taxa dominated at low resource levels (nutrients and especially light), whereas 'high profile' and 'motile' taxa became markedly more prevalent at higher resource levels. 5. Two-way interactions between experimental factors were quite common. For example, Planothidium lanceolatum and Rossithidium petersenii responded more strongly to nutrient enrichment at reduced than at ambient light, whereas Cocconeis placentula responded more strongly at ambient light. For diatom functional groups, the benefit of nutrient enrichment for 'motile' diatoms was greater at ambient than at reduced light. 6. Our results imply that multifactor experiments are required to determine the main forces driving the composition of benthic algal communities. Further, our findings highlight the considerable potential of using functional algal groups as indicators of changing environmental conditions to complement the traditional taxonomic approach.

  • 9.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Compensatory feeding and low nutrient assimilation efficiencies lead to high nutrient turnover in nitrogen-limited snails2014In: Freshwater Science, ISSN 2161-9549, Vol. 33, no 2, p. 425-434Article in journal (Refereed)
    Abstract [en]

    According to stoichiometric principles, the ratios at which consumers recycle nutrients depend on the elemental compositions of the consumer and its food. However, nutrient assimilation efficiencies and ingestion rates can vary among consumer species and, thus, can affect the rates of consumer-mediated nutrient recycling (CNR). The grazer Theodoxus fluviatilis has high nutrient excretion rates of either P or N, depending on grazer growth limitation, and has a high body N. I examined how a grazer with a high proportion of N in its body tissues can assimilate enough N to maintain that N content despite high N excretion rates by estimating the mass balance for nutrient recycling including nutrient excretion through fecal pellets. I used the snail species Theodoxus fluviatilis and Lymnea peregra fed nutrient-enriched periphyton in a 2-d grazing experiment done in 48 experimental units. I estimated periphyton and grazer nutrient stoichiometry and nutrient excretion rates and ratios in dissolved and fecal-pellet form, and calculated nutrient assimilation efficiencies of the limiting nutrient (N). Theodoxus fluviatilis had higher N excretion rates, lower N assimilation efficiency, and higher ingestion rates than L. peregra. Thus, T. fluviatilis recycled more N by ingesting and processing a larger amount of food per unit time than L. peregra. My study shows that grazers with low nutrient assimilation efficiencies and high nutrient demands can assimilate sufficient nutrients via high ingestion rates. The consequence of this strategy (high ingestion and excretion rates) could be a more rapid nutrient turnover in ecosystems dominated by these grazers.

  • 10.
    Liess, Antonia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Faithfull, Carolyn
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Reichstein, Birte
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rowe, Owen
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Guo, Junwen
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Pete, R.
    Thomsson, Gustaf
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Uszko, Wojciech
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Francoeur, S. N.
    Terrestrial runoff may reduce microbenthic net community productivity by increasing turbidity: a Mediterranean coastal lagoon mesocosm experiment2015In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 753, no 1, p. 205-218Article in journal (Refereed)
    Abstract [en]

    Terrestrial runoff into aquatic ecosystems may have both stimulatory and inhibitory effects, due to nutrient subsidies and increased light attenuation. To disentangle the effects of runoff on microbenthos, we added soil to coastal mesocosms and manipulated substrate depth. To test if fish interacted with runoff effects, we manipulated fish presence. Soil decreased microphytobenthic chlorophyll-a per area and per carbon (C) unit, increased microbenthic phosphorous (P), and reduced microbenthic nitrogen (N) content. Depth had a strong effect on the microbenthos, with shallow substrates exhibiting greater microbenthic net ecosystem production, gross primary production, and community respiration than deep substrates. Over time, micobenthic algae compensated for deeper substrate depth through increased chlorophyll-a synthesis, but despite algal shade compensation, the soil treatment still appeared to reduce the depth where microbenthos switched from net autotrophy to net heterotrophy. Fish interacted with soil in affecting microbenthic nutrient composition. Fish presence reduced microbenthic C/P ratios only in the no soil treatment, probably since soil nutrients masked the positive effects of fish excreta on microbenthos. Soil reduced microbenthic N/P ratios only in the absence of fish. Our study demonstrates the importance of light for the composition and productivity of microbenthos but finds little evidence for positive runoff subsidy effects.

  • 11.
    Liess, Antonia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Francoeur, Steven N.
    Substratum-Associated Microbiota2011In: Water environment research, ISSN 1061-4303, E-ISSN 1554-7531, Vol. 83, no 10, p. 1704-1732Article in journal (Refereed)
    Abstract [en]

    A review of the literature published in 2010 on topics relating to on the subject of ecology of substratum-associated microbiota (algae, bacteria, and fungi). We also highlighted some of the new methods that can be applied to the study of substratum-associated microbiota and included newly described taxa.

  • 12.
    Liess, Antonia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Francoeur, Steven N
    Substratum-Associated Microbiota2010In: Water environment research, ISSN 1061-4303, E-ISSN 1554-7531, Vol. 82, no 10, p. 1903-1944Article in journal (Refereed)
    Abstract [en]

    A review of the literature published in 2009 on topics relating to on the subject of ecology of substratum-associated microbiota (algae, bacteria, fungi and viruses). We also highlighted some of the new methods that can be applied to the study of substratumassociated microbiota and included newly described taxa.

  • 13.
    Liess, Antonia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lange, K
    The snail Potamopyrgus antipodarum grows faster and is more active in the shade, independent of food quality2011In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 167, no 1, p. 85-96Article in journal (Refereed)
    Abstract [en]

    Ecological stoichiometry has advanced food web ecology by emphasising the importance of food quality over food quantity for herbivores. Here, we focus on the effects of abiotic factors such as nutrients and light (known to influence food quality) on grazer growth rates. As model organism we used the mudsnail Potamopyrgus antipodarum that is native to New Zealand but invasive elsewhere. In a stream channel experiment in New Zealand, we manipulated light (two levels) and nutrients (four levels) to achieve a range of primary producer carbon: nutrient ratios and added mudsnails (3 densities + ungrazed control) to 128 periphyton covered stream channels in a 2 × 4 × 4 full factorial design. We measured snail growth rate and activity, food quality and nutritional imbalance, to test the predictions that (1) less light and more nutrients increase periphyton food quality and thus snail growth rates, and (2) less crowding leads to higher food availability and thus higher snail growth rates. We found that snail growth rates were higher under low light than under high light intensities and this difference increased with increasing nutrient addition. These changes in growth rate were not mediated by food quality in terms of periphyton nutrient ratios. Furthermore, experimental treatments strongly affected snail behaviour. Snails grazed more actively in the low light treatments, and thus it is more likely that snail growth rates were directly affected by light levels, maybe as a result of innate predator avoidance behaviour or as a reaction to high UV intensities. We conclude that in our stream channels snail growth rate was limited by factors other than food quality and quantity such as UV exposure, algal defences or the relatively low ambient water temperature.

  • 14. Liess, Antonia
    et al.
    Le Gros, Ariane
    Wagenhoff, Annika
    Townsend, Colin R.
    Matthaei, Christoph D.
    Landuse intensity in stream catchments affects the benthic food web: consequences for nutrient supply, periphyton C:nutrient ratios, and invertebrate richness and abundance2012In: Freshwater Science, ISSN 2161-9549, E-ISSN 2161-9565, Vol. 31, no 3, p. 813-824Article in journal (Refereed)
    Abstract [en]

    Anthropogenic nutrient enrichment increases the supply ratio of N and P to aquatic ecosystems and can affect the identity of the limiting nutrient. Here we focus on how stream communities change along gradients of N and P supply and stream catchment landuse intensity. We used a survey approach in 41 southern New Zealand tributaries to investigate how much changes in water N and P concentrations are reflected in periphyton C:nutrient ratios (C:N or C:P) and how much food quality (high food quality corresponds to low periphyton C:nutrient) is reflected in the abundance and taxonomic richness of benthic invertebrate primary and secondary consumers. We measured streamwater nutrient state, periphyton nutrient ratios, biomass (as chlorophyll a in mu g/cm(2)), algal taxon richness, and macroinvertebrate abundance, taxonomic composition, and richness. We also estimated stream habitat and catchment characteristics, such as current velocity, shading, substrate, geology, and landuse intensity. We calculated the Akaike information criterion (AIC) for each possible multiple linear regression model to select the best predictive models for each response variable. C:nutrient ratios were more strongly negatively related to water-column N than P availability. Neither N nor P availability covaried with periphyton biomass. Lower periphyton C:N partly explained higher grazer, but not predator, abundance. Increased % runoff from pasture and periphyton N:P co-occurred with a decrease in invertebrate taxon richness. For example, a 4x increase in periphyton N:P was related to the loss of similar to 1/2 of invertebrate species, but with high uncertainty (R-2 = 0.13). We conclude landuse intensity affects these southern New Zealand streams, and these effects are mediated by agricultural N runoff into streams (among other factors). Further shifts toward high-intensity farming within stream catchments may lead to losses of benthic species at all trophic levels.

  • 15.
    Liess, Antonia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Laboratoire Ecosystémes Marins Côtiers, UMR5119 CNRS, Université Montpellier2, IRD, IFREMER, Paris, France.
    Rowe, Owen
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Francoeur, S. N.
    Guo, Junwen
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lange, K.
    Schroeder, A.
    Reichstein, Birte
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lefèbure, Robert
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Deininger, Anne
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Mathisen, Peter
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Faithfull, Carolyn L.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Terrestrial runoff boosts phytoplankton in a Mediterranean coastal lagoon, but these effects do not propagate to higher trophic levels2016In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 766, no 1, p. 275-291Article in journal (Refereed)
    Abstract [en]

    Heavy rainfall events causing significant terrestrial runoff into coastal marine ecosystems are predicted to become more frequent with climate change in the Mediterranean. To simulate the effects of soil runoff on the pelagic food web of an oligotrophic Mediterranean coastal lagoon, we crossed soil extract addition (increasing nutrient availability and turbidity) and fish presence in a full factorial design to coastal mesocosms containing a natural pelagic community. Soil extract addition increased both bacteria and phytoplankton biomass. Diatoms however profited most from soil extract addition, especially in the absence of fish. In contrast zooplankton and fish did not profit from soil extract addition. Furthermore, our data indicate that nutrients (instead of light or carbon) limited basal production. Presumed changes in carbon availability are relatively unimportant to primary and secondary production in strongly nutrient limited systems like the Thau Lagoon. We conclude that in shallow Mediterranean coastal ecosystems, heavy rainfall events causing soil runoff will (1) increase the relative abundance of phytoplankton in relation to bacteria and zooplankton, especially in the absence of fish (2) not lead to higher biomass of zooplankton and fish, possibly due to the brevity of the phytoplankton bloom and the slow biomass response of higher trophic levels.

  • 16.
    Liess, Antonia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rowe, Owen
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Guo, Junwen
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Thomsson, Gustaf
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lind, Martin I.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. University of Sheffield, UK and Uppsala University, Sweden.
    Hot tadpoles from cold environments need more nutrients - life history and stoichiometry reflects latitudinal adaptation2013In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 82, no 6, p. 1316-1325Article in journal (Refereed)
    Abstract [en]

    1. High-latitude species (and populations within species) are adapted to short and cold summers. They often have high growth and development rates to fully use the short growing season and mature before the onset of winter. Within the context of ecological stoichiometry theory, this study combines ecology with evolution by relating latitudinal life-history adaptations to their molecular consequences in body nutrient composition in Rana temporaria tadpoles. Temperature and food quality were manipulated during the development of tadpoles from Arctic and Boreal origins. We determined tadpole growth rate, development rate, body size and nutrient content, to test whether (i) Arctic tadpoles could realize higher growth rates and development rates with the help of higher-quality food even when food quantity was unchanged, (ii) Arctic and Boreal tadpoles differed in their stoichiometric (and life history) response to temperature changes, (iii) higher growth rates lead to higher tadpole P content (growth rate hypothesis) and (iv) allometric scaling affects tadpole nutrient allocation. We found that especially Arctic tadpoles grew and developed faster with the help of higher-quality food and that tadpoles differed in their stoichiometric (and life history) response to temperature changes depending on region of origin (probably due to different temperature optima). There was no evidence that higher growth rates mediated the positive effect of temperature on tadpole P content. On the contrary, the covariate growth rate was negatively connected with tadpole P content (refuting the growth rate hypothesis). Lastly, tadpole P content was not related to body size, but tadpole C content was higher in larger tadpoles, probably due to increased fat storage. We conclude that temperature had a strong effect on tadpole life history, nutrient demand and stoichiometry and that this effect depended on the evolved life history.

  • 17. Maaroufi, Nadia, I
    et al.
    Palmqvist, Kristin
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bach, Lisbet H.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bokhorst, Stef
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Rydberg Laboratory of Applied Science, School of Business, Science and Engineering, Halmstad University, Halmstad, Sweden.
    Gundale, Michael J.
    Kardol, Paul
    Nordin, Annika
    Meunier, Cedric L.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Biologische Anstalt Helgoland, Helgoland, Germany.
    Nutrient optimization of tree growth alters structure and function of boreal soil food webs2018In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 428, p. 46-56Article in journal (Refereed)
    Abstract [en]

    Nutrient optimization has been proposed as a way to increase boreal forest production, and involves chronic additions of liquid fertilizer with amounts of micro- and macro-nutrients adjusted annually to match tree nutritional requirements. We used a short-term (maintained since 2007) and a long-term (maintained since 1987) fertilization experiment in northern Sweden, in order to understand nutrient optimization effects on soil microbiota and mesofauna, and to explore the relationships between plant litter and microbial elemental stoichiometry. Soil microbes, soil fauna, and aboveground litter were collected from the control plots, and short- and long-term nutrient optimization plots. Correlation analyses revealed no relationships between microbial biomass and litter nutrient ratios. Litter C:N, C:P and N:P ratios declined in response to both optimization treatments; while only microbial C:P ratios declined in response to long-term nutrient optimization. Further, we found that both short- and long-term optimization treatments decreased total microbial, fungal, and bacterial PLFA biomass and shifted the microbial community structure towards a lower fungi:bacterial ratio. In contrast, abundances of most fungal- and bacterial-feeding soil biota were little affected by the nutrient optimization treatments. However, abundance of hemi-edaphic Collembola declined in response to the long-term nutrient optimization treatment. The relative abundances (%) of fungal-feeding and plant-feeding nematodes, respectively, declined and increased in response to both short-term and long-term treatments; bacterial-feeding nematodes increased relative to fungal feeders. Overall, our results demonstrate that long-term nutrient optimization aiming to increase forest production decreases litter C:N, C:P and N:P ratios, microbial C:P ratios and fungal biomass, whereas higher trophic levels are less affected.

  • 18.
    Meunier, Cedric L.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gundale, Michael J.
    Sanchez, Irene S.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Impact of nitrogen deposition on forest and lake food webs in nitrogen-limited environments2016In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 22, no 1, p. 164-179Article, review/survey (Refereed)
    Abstract [en]

    Increased reactive nitrogen (N-r) deposition has raised the amount of N available to organisms and has greatly altered the transfer of energy through food webs, with major consequences for trophic dynamics. The aim of this review was to: (i) clarify the direct and indirect effects of N-r deposition on forest and lake food webs in N-limited biomes, (ii) compare and contrast how aquatic and terrestrial systems respond to increased N-r deposition, and (iii) identify how the nutrient pathways within and between ecosystems change in response to N-r deposition. We present that N-r deposition releases primary producers from N limitation in both forest and lake ecosystems and raises plants' N content which in turn benefits herbivores with high N requirements. Such trophic effects are coupled with a general decrease in biodiversity caused by different N-use efficiencies; slow-growing species with low rates of N turnover are replaced by fast-growing species with high rates of N turnover. In contrast, N-r deposition diminishes below-ground production in forests, due to a range of mechanisms that reduce microbial biomass, and decreases lake benthic productivity by switching herbivore growth from N to phosphorus (P) limitation, and by intensifying P limitation of benthic fish. The flow of nutrients between ecosystems is expected to change with increasing N-r deposition. Due to higher litter production and more intense precipitation, more terrestrial matter will enter lakes. This will benefit bacteria and will in turn boost the microbial food web. Additionally, N-r deposition promotes emergent insects, which subsidize the terrestrial food web as prey for insectivores or by dying and decomposing on land. So far, most studies have examined N-r-deposition effects on the food web base, whereas our review highlights that changes at the base of food webs substantially impact higher trophic levels and therefore food web structure and functioning.

  • 19.
    Meunier, Cédric L.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Rydberg Laboratory of Applied Science, School of Business, Science and Engineering, Halmstad University, Halmstad, Sweden.
    Andersson, Agneta
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Brugel, Sonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Paczkowska, Joanna
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Rahman, Habib
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Skoglund, Björn
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rowe, Owen F.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF).
    Allochthonous carbon is a major driver of the microbial food web: a mesocosm study simulating elevated terrestrial matter runoff2017In: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 129, p. 236-244Article in journal (Refereed)
    Abstract [en]

    Climate change predictions indicate that coastal and estuarine environments will receive increased terrestrial runoff via increased river discharge. This discharge transports allochthonous material, containing bioavailable nutrients and light attenuating matter. Since light and nutrients are important drivers of basal production, their relative and absolute availability have important consequences for the base of the aquatic food web, with potential ramifications for higher trophic levels. Here, we investigated the effects of shifts in terrestrial organic matter and light availability on basal producers and their grazers. In twelve Baltic Sea mesocosms, we simulated the effects of increased river runoff alone and in combination. We manipulated light (clear/shade) and carbon (added/not added) in a fully factorial design, with three replicates. We assessed microzooplankton grazing preferences in each treatment to assess whether increased terrestrial organic matter input would: (1) decrease the phytoplankton to bacterial biomass ratio, (2) shift microzooplanlcton diet from phytoplankton to bacteria, and (3) affect microzooplankton biomass. We found that carbon addition, but not reduced light levels per se resulted in lower phytoplanlcton to bacteria biomass ratios. Microzooplankton generally showed a strong feeding preference for phytoplanlcton over bacteria, but, in carbon-amended mesocosms which favored bacteria, microzooplankton shifted their diet towards bacteria. Furthermore, low total prey availability corresponded with low microzooplankton biomass and the highest bacteria/phytoplankton ratio. Overall our results suggest that in shallow coastal waters, modified with allochthonous matter from river discharge, light attenuation may be inconsequential for the basal producer balance, whereas increased allochthonous carbon, especially if readily bioavailable, favors bacteria over phytoplankton. We conclude that climate change induced shifts at the base of the food web may alter energy mobilization to and the biomass of microzooplankton grazers.

  • 20.
    Thomsson, Gustaf
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Diehl, Sebastian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Kahlert, Maria
    Karlsson, Jan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Inverse relationship of benthic algae and pelagic phosphorus in unproductive lakes: roles of N2 fixers and lightManuscript (preprint) (Other academic)
  • 21. Vrede, Tobias
    et al.
    Drakare, Stina
    Eklöv, Peter
    Hein, Arne
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Olsson, Jens
    Persson, Jonas
    Quevedo, Mario
    Ragnarsson Stabo, Henrik
    Svanbäck, Richard
    Ecological stoichiometry of Eurasian perch: intraspecific variation due to size, habitat and diet2011In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 120, no 6, p. 886-896Article in journal (Refereed)
    Abstract [en]

    The turnover and distribution of energy and nutrients in food webs is influenced by consumer stoichiometry. Although the stoichiometry of heterotrophs is generally considered to vary only little, there may be intraspecific variation due to factors such as habitat, resources, ontogeny and size. We examined intraspecific variation in Eurasian perch Perca fluviatilis stoichiometry, a common species that exhibits habitat and resource specialization, ontogenetic niche shifts and a large size range. This study investigated the elemental stoichiometry of a wide size range of perch from littoral and pelagic habitats. The mean C:N:P stoichiometry of whole perch was 37:9:1 (molar ratios). However, %C, %P, C:N, C:P and N:P varied with size, morphology, habitat and diet category. These factors together explained 24–40% of the variation in C:N:P stoichiometry. In contrast, perch stoichiometry was not related to diet stoichiometry, suggesting that the former is homeostatically regulated. The results suggest that the high P content of perch may result in stoichiometric constraints on the growth of non-piscivorous perch, and that piscivory is an efficient strategy for acquiring P. Resource polymorphism, individual diet specialization and intraspecific size variation are widespread among animals. Thus changes in stoichiometry with size, habitat, morphology and resource use, and therefore also stoichiometric demands, are probably common.

  • 22. Wagenhoff, Annika
    et al.
    Liess, Antonia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Pastor, Ada
    Clapcott, Joanne E.
    Goodwin, Eric O.
    Young, Roger G.
    Thresholds in ecosystem structural and functional responses to agricultural stressors can inform limit setting in streams2017In: Freshwater Science, ISSN 2161-9549, E-ISSN 2161-9565, Vol. 36, no 1, p. 178-194Article in journal (Refereed)
    Abstract [en]

    Setting numeric in-stream objectives (limits, criteria) to inform limits on catchment loads for major land use stressors is a promising policy instrument to prevent ecosystem degradation. Management objectives can be informed by thresholds identified from stressor response shapes of ecological indicators based on field survey data. Use of multiple structural and functional indicators and different organism groups provides multiple lines of evidence to make objectives more robust. We measured a suite of ecological indicators during a regional field survey in New Zealand. We built flexible boosted regression tree (BRT) models with a predictor set consisting of nutrient, sediment, and environmental variables and investigated the fitted functions for different types of thresholds across each stressor gradient. Congruence of impact initiation (II) thresholds for N among macroinvertebrate metrics and 2 periphyton indicators provided multiple lines of evidence for ecosystem change with small increases in N concentrations above background levels. Impact cessation (IC) on macroinvertebrate metrics at total N = 0.5 mg/L (below N concentrations that saturate important ecosystem processes) highlighted sensitivity of macroinvertebrate communities to eutrophication. We found few stressor response relationships for sediment. We suggest use of sediment-specific macroinvertebrate metrics and a reliable measure of deposited fine sediment in the future. Few indicators responded to phosphorus (P) concentration. Limited information for setting P objectives highlights the need to develop alternative indicators of P loading. Statistical analysis based on single-stressor inferential threshold models suggested that these models carry high risk of identifying spurious thresholds and are less suitable for setting management objectives. II and IC thresholds of multiple ecological indicators can be used to set robust objectives aimed at different levels of protection of ecosystem health.

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