Responses of primary production, leaf litter decomposition and associated communities to stream eutrophication

Dunck, Bárbara; Lima-Fernandes, Eva; Cássio, Fernanda; Cunha, Ana; Rodrigues, Liliana; Pascoal, Cláudia

doi:10.1016/j.envpol.2015.03.014

Cited by 57 publications

(34 citation statements)

References 52 publications

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“…Among all results, the lack of a spatial effect is the most expected to occur, since microorganisms have high dispersal abilities and thus a low rate of distance decay in similarity is expected (Nekola & White, 1999; but see Wetzel et al, 2012). On the other hand, the relevance of environmental heterogeneity in shaping the structure of communities of microorganisms has been shown for various aquatic environments (De Bie et al, 2012;Algarte et al, 2014;Padial et al, 2014;Dunck et al, 2015). Environmental filters may restrict the occurrence of species to the environmental conditions of the habitats, and higher variety of environmental conditions provides more variety of niches, leading to variation in species composition among localities (Chase & Leibold, 2003;Leibold et al, 2004).…”

Section: Discussionmentioning

confidence: 86%

Patterns in species and functional dissimilarity: insights from periphytic algae in subtropical floodplain lakes

2015

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Understanding spatial and temporal changes in species composition has long demanded the attention of ecologists. However, only recently questions related to changes in species functional traits have been investigated. We explored patterns of species and functional dissimilarity of periphytic algae at six lakes sampled over a year across a subtropical floodplain. We evaluated the importance of turnover and nestedness components across space and time; the influence of environmental dissimilarity, spatial distance, and time on species and functional dissimilarity; and whether functional dissimilarity results from nonstochastic assembly processes. We used six functional traits to describe 155 species. Functional dissimilarity was estimated by functional dendrograms, and stochasticity was evaluated using null models. The turnover component was greater than nestedness for species and functional dissimilarity. Environmental dissimilarity, spatial distance, or time did not significantly explain species or functional dissimilarity. However, functional dissimilarity was significantly greater than expected given the observed species dissimilarity. The main finding of this study is that community assembly was deterministic with respect to traits. Further, each lake contributed similarly to the overall species and traits pool. These results highlight the importance of comparing species and functional dissimilarities to reach a better understanding of the organization of periphytic algal communities.

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Section: Discussionmentioning

confidence: 86%

Patterns in species and functional dissimilarity: insights from periphytic algae in subtropical floodplain lakes

2015

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“…Furthermore, many diatoms have specialized structures for attachment to the substrate, such as mucilaginous peduncles in the Gomphonema species and the production of mucilaginous matrices as in Frustulia and Navicula (Round 1991). The highest values for density and richness of diatoms in the lentic system is partly related to their specialized structures that pollution (Bes & Torgan 2010) and may also have wide distribution, including lakes (Bes & Torgan 2010), rivers (Rusanov et al 2009), streams (Dunck et al 2015), and floodplains (Weilhoefer & Pan 2006). In lotic environments, M. varians was the most abundant species.…”

Section: Discussionmentioning

confidence: 99%

“…A. minutissimum is among the diatoms more often recorded in periphytic samples worldwide (Krammer & Lange-Bertalot 1991, Round 2004). This species can occur in acidic to alkaline environments (Round 2004) and is oligotrophic to eutrophic (Leandrini et al 2013, Dunck et al 2015. N. palea is generally considered tolerant to organic Supplement 1.…”

Section: Discussionmentioning

confidence: 99%

Periphytic algae in a floodplain lake and river under low water conditions

et al. 2016

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Drought events will become more frequent due the climate change. In floodplains, periphytic algae are responsible for part of the primary production, are the principal source of organic carbon deposition, play an important role in mineralization and nutrient cycling, and are the base of the food web for many organisms. As algae distribution in aquatic environments is a strong indicator of physical and chemical conditions of the sites, we aimed to determine the structure of periphytic algae in lentic and lotic environments during drought conditions and to uncover the main local abiotic factors in community structuring. We hypothesized diatoms would be more frequent than green algae and desmids at both sites, due to their resistance characteristics, and that higher periphyton algal richness, density and diversity would occur in the lake due to the greater availability of nutrients and the absence of flow. The study was carried out in the Finado Raimundo lake and the Ivinhema river in the Upper Paraná river floodplain during the low water period of 2011. Petioles of the aquatic macrophyte Eichhornia azurea (Sw.) Kunth were used as a substrate for periphytic algae. We found a total of 171 species, 104 species in the lake and 80 in the river. Diatoms were predominant at both sites due to their strategic traits, and between sites, there were different patterns in the periphytic algal community structure, owing to the distinctive physical and chemical characteristics of the lake and the river. Achnanthidium minutissimum (Kützing) Czarnecki and Nitzschia palea (Kützing) W. Smith were the most abundant species in both environments. Our results showed patterns of periphytic algae in a floodplain during drought conditions, which will assist in understanding their structuring during future drought scenarios.

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“…Because fungal reproduction is highly sensitive to nutrients in stream water (Suberkropp and Chauvet, 1995;Duarte et al, 2009), we hypothesized that aquatic hyphomycete diversity would be more accurately assessed through molecular approaches, particularly in streams with high levels of eutrophication, in which fungal reproduction might be compromised (Duarte et al, 2015b;Dunck et al, 2015;Lima-Fernandes et al, 2015). However, successful species identification through pyrosequencing crucially depends on the availability of reference sequences in databases.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, we assessed aquatic hyphomycete diversity on Quercus robur leaves decomposing in 5 streams along a gradient of eutrophication in the Northwest Portugal (Duarte et al, 2015b;Dunck et al, 2015;Lima-Fernandes et al, 2015), in autumn 2012 and spring 2013, through microscopy-based techniques (identification of spores), and by molecular techniques (DGGE and 454 pyrosequencing) of the transcribed spacer 2 region (ITS2) of ribosomal RNA gene (rDNA). Because fungal reproduction is highly sensitive to nutrients in stream water (Suberkropp and Chauvet, 1995;Duarte et al, 2009), we hypothesized that aquatic hyphomycete diversity would be more accurately assessed through molecular approaches, particularly in streams with high levels of eutrophication, in which fungal reproduction might be compromised (Duarte et al, 2015b;Dunck et al, 2015;Lima-Fernandes et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Microscopy- or DNA-based analyses: Which methodology gives a truer picture of stream-dwelling decomposer fungal diversity?

et al. 2015

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a b s t r a c tWe assessed aquatic hyphomycete diversity in autumn and spring on oak leaves decomposing in five streams along a gradient of eutrophication in the Northwest of Portugal. Diversity was assessed through microscopy-based (identification by spore morphology) and DNA-based techniques (Denaturing Gradient Gel Electrophoresis and 454 pyrosequencing). Pyrosequencing revealed five times greater diversity than DGGE. About 21% of all aquatic hyphomycete species were exclusively detected by pyrosequencing and 26% exclusively by spore identification. In some streams, more than half of the recorded species would have remained undetected if we had relied only on spore identification. Nevertheless, in spring aquatic hyphomycete diversity was higher based on spore identification, probably because many species occurring in this season are not yet connected to ITS barcodes in genetic databases. Pyrosequencing was a powerful tool for revealing aquatic hyphomycete diversity on decomposing plant litter in streams and we strongly encourage researchers to continue the effort in barcoding fungal species.

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Responses of primary production, leaf litter decomposition and associated communities to stream eutrophication

Cited by 57 publications

References 52 publications

Patterns in species and functional dissimilarity: insights from periphytic algae in subtropical floodplain lakes

Patterns in species and functional dissimilarity: insights from periphytic algae in subtropical floodplain lakes

Periphytic algae in a floodplain lake and river under low water conditions

Microscopy- or DNA-based analyses: Which methodology gives a truer picture of stream-dwelling decomposer fungal diversity?

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