Cascading influences of grassland degradation on nutrient limitation in a high mountain lake and its inflow streams

Ren, Ze; Niu, Decao; Ma, Panpan; Wang, Ying; Fu, Hua; Elser, James J.

doi:10.1002/ecy.2755

Cited by 28 publications

(12 citation statements)

References 89 publications

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“…The third objective of this study was to examine spatial variation in, and identify controls of, the degree of periphyton nutrient limitation. Our results agree with other studies of freshwater periphyton (Cooper et al., 2016; Fork et al., 2020; Ren et al., 2019) and support our hypothesis that limitation strength is inversely proportional to site trophic status. Periphyton at oligotrophic sites showed a larger increase in biomass (both as Chl‐ a and AFDW) in response to combined N + P enrichment than periphyton at eutrophic sites.…”

Section: Discussionsupporting

confidence: 93%

Factors regulating lake periphyton biomass and nutrient limitation status across a large trophic gradient

Ozersky

Camilleri

2021

Freshwater Biology

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Because of the historical focus of limnology on pelagic processes, the factors controlling lake periphyton growth and nutrient limitation are understudied compared to the phytoplankton. We deployed nutrient‐diffusing substrata at 28 sites spanning a wide trophic status gradient in Lakes Superior and Michigan to assess periphyton biomass accrual on control substrata and the response of periphyton to single and combined phosphorus (P) and nitrogen (N) additions. Periphyton growth was unimodally related to a composite metric of site trophic status, with highest biomass at mesotrophic sites and lower growth at oligotrophic and highly eutrophic sites. Contrary to expectations, P limitation was rare. Instead, several lines of evidence pointed to primary N or N + P co‐limitation of periphyton. Limitation extent was negatively related to site trophic status, with stronger nutrient limitation at oligotrophic sites. Our results support the hypothesis that phytoplankton and periphyton biomass respond differently to nutrient enrichment and suggest that different nutrients may limit pelagic and benthic primary production, even in the same system. Our findings also support the use of periphyton as an early warning indicator of nutrient pollution and help explain why large, oligotrophic lakes may be especially susceptible to localised benthic algal blooms.

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Section: Discussionsupporting

confidence: 93%

Factors regulating lake periphyton biomass and nutrient limitation status across a large trophic gradient

Ozersky

Camilleri

2021

Freshwater Biology

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“…The equation is represented as NDVI = (NIR − RED)/(NIR + RED), where NIR is near infrared reflectance and RED is visible red reflectance. It has been demonstrated that NDVI exhibits close relationships with above-ground vegetation biomass and coverage (Carlson & Ripley, 1997; Eastwood et al, 1997; Ren et al, 2019). For each stream site, the average NDVI of its sub-catchment (the upstream area of the stream site) was calculated as the mean NDVI of each pixel in the sub-catchment.…”

Section: Methodsmentioning

confidence: 99%

Ecological networks reveal contrasting patterns of bacterial and fungal communities in glacier-fed streams in Central Asia

Ren

Gao

2019

PeerJ

Self Cite

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Bacterial and fungal communities in biofilms are important components in driving biogeochemical processes in stream ecosystems. Previous studies have well documented the patterns of bacterial alpha diversity in stream biofilms in glacier-fed streams, where, however, beta diversity of the microbial communities has received much less attention especially considering both bacterial and fungal communities. A focus on beta diversity can provide insights into the mechanisms driving community changes associated to large environmental fluctuations and disturbances, such as in glacier-fed streams. Moreover, modularity of co-occurrence networks can reveal more ecological and evolutionary properties of microbial communities beyond taxonomic groups. Here, integrating beta diversity and co-occurrence approach, we explored the network topology and modularity of the bacterial and fungal communities with consideration of environmental variation in glacier-fed streams in Central Asia. Combining results from hydrological modeling and normalized difference of vegetation index, this study highlighted that hydrological variables and vegetation status are major variables determining the environmental heterogeneity of glacier-fed streams. Bacterial communities formed a more complex and connected network, while the fungal communities formed a more clustered network. Moreover, the strong interrelations among the taxonomic dissimilarities of bacterial community (BC) and modules suggest they had common processes in driving diversity and taxonomic compositions across the heterogeneous environment. In contrast, fungal community (FC) and modules generally showed distinct driving processes to each other. Moreover, bacterial and fungal communities also had different driving processes. Furthermore, the variation of BC and modules were strongly correlated with hydrological properties and vegetation status but not with nutrients, while FC and modules (except one module) were not associated with environmental variation. Our results suggest that bacterial and fungal communities had distinct mechanisms in structuring microbial networks, and environmental variation had strong influences on bacterial communities but not on fungal communities. The fungal communities have unique assembly mechanisms and physiological properties which might lead to their insensitive responses to environmental variations compared to bacterial communities. Overall, beyond alpha diversity in previous studies, these results add our knowledge that bacterial and fungal communities have contrasting assembly mechanisms and respond differently to environmental variation in glacier-fed streams.

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“…Additionally, the N 2 -fixing cyanobacteria, such as Anabaena , Aphanizomenon , Aphanothece , Cylindrospermopsis , and Gloeotrichia , exhibit great flexibility in the N sources to form blooms and N fixation, making N sufficient to allow biomass to be continuously produced [ 9 , 17 , 28 , 29 ]. Temperature and nutrients are also essential factors for phytoplankton growth in high-latitude lakes [ 30 , 31 ]. A nine-year study of a mountain lake in Austria demonstrated that long-term phytoplankton changes were mainly attributed to the increasing temperature, while nutrients acted as modulating factors regulating the short-term phytoplankton changes [ 30 ].…”

Section: Introductionmentioning

confidence: 99%

“…A nine-year study of a mountain lake in Austria demonstrated that long-term phytoplankton changes were mainly attributed to the increasing temperature, while nutrients acted as modulating factors regulating the short-term phytoplankton changes [ 30 ]. A study of Lake Qinghai suggested that the increase in P load under climate change and overgrazing favored the growth of P-limited phytoplankton [ 31 ]. Nevertheless, some environmental factors such as salinity may have been neglected in the previous study.…”

Section: Introductionmentioning

confidence: 99%

Phytoplankton Composition and Their Related Factors in Five Different Lakes in China: Implications for Lake Management

Jia

Chen

Ren

et al. 2022

IJERPH

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In this paper, two trophic lakes: Lake Taihu and Lake Yanghe, and three alpine lakes: Lake Qinghai, Lake Keluke, and Lake Tuosu, were investigated to discover the connections between environmental factors and the phytoplankton community in lakes with differences in trophic levels and climatic conditions. Three seasonal data, including water quality and phytoplankton, were collected from the five lakes. The results demonstrated clear differences in water parameters and phytoplankton compositions in different lakes. The phytoplankton was dominated by Bacillariophyta, followed by Cyanobacteria and Chlorophyta in Lake Qinghai, Lake Keluke, and Lake Tuosu. It was dominated by Cyanobacteria (followed by Chlorophyta and Bacillariophyta in Lake Yanghe) and Cyanobacteria (followed by Chlorophyta and Cryptophyta in Lake Taihu). The temperature was an essential factor favoring the growth of Cyanobacteria, Chlorophyta, and Bacillariophyta, especially Cyanobacteria and Chlorophyta. The pH had significantly negative relationships with Cyanobacteria, Chlorophyta, and Bacillariophyta. Particularly, a high pH might be a strong and negative factor for phytoplankton growth in alpine lakes. A high salinity was also an adverse factor for phytoplankton. Those results could provide fundamental information about the phytoplankton community and their correlated factors in the alpine lakes of the Tibetan Plateau, contributing to the protection and management of alpine lakes.

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Cascading influences of grassland degradation on nutrient limitation in a high mountain lake and its inflow streams

Cited by 28 publications

References 89 publications

Factors regulating lake periphyton biomass and nutrient limitation status across a large trophic gradient

Factors regulating lake periphyton biomass and nutrient limitation status across a large trophic gradient

Ecological networks reveal contrasting patterns of bacterial and fungal communities in glacier-fed streams in Central Asia

Phytoplankton Composition and Their Related Factors in Five Different Lakes in China: Implications for Lake Management

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