Determinants of Benthic Diatom Community Structurein Boreal Streams: the Role of Environmental and Spatial Factors at Different Scales

The ecological characteristics of benthic diatom genera from lakes and tarns in mountainous areas of Tasmania (76 lakes) and the South Island (65 lakes) and Stewart Island (6 lakes) of New Zealand were investigated. Community composition and diversity were mainly governed by gradients in calcium, pH and the monovalent/divalent ionic (M/D) ratio, with typical acidophilous and calciphilous communities present in both regions. Highest genus diversity occurred in the pH range between 5.5 and 7.5. Marked interregional differences were present in both calciphilous and acidophilous diatom community assemblages, which were at least partially related to variations in the concentration of the chloride, sodium, potassium and humic substances. Acidophilous communities in New Zealand were typically dominated by Frustulia, Brachysira and Kobayasiella, whereas Eunotia and Actinella dominated in Tasmania. Calciphilous communities in New Zealand were characterised by higher relative abundances of the genera Hantzschia, Diploneis, Nupela, Stauroneis and Synedra, whereas their Tasmanian counterparts were typified by the genera Amphora (subgenus Psammamphora), Biremis, Navicula and Psammothidium. The provinciality of the floras underscores the need for continued protection and conservation of high latitude aquatic ecosystems worldwide and in the Australasian region in particular.

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Identifying environmental drivers of benthic diatom diversity: the case of Mediterranean mountain ponds

PeerJ ◽

10.7717/peerj.8825 ◽

2020 ◽

Vol 8 ◽

pp. e8825 ◽

Cited By ~ 1

Author(s):

Saúl Blanco ◽

Adriana Olenici ◽

Fernando Ortega ◽

Francisco Jiménez-Gómez ◽

Francisco Guerrero

Keyword(s):

Diversity Index ◽

Abiotic Factors ◽

Floristic Composition ◽

Dispersal Limitation ◽

High Elevation ◽

Benthic Diatom ◽

Temporary Ponds ◽

Environmental Drivers ◽

Significant Distance

This study aims at elucidating the environmental factors controlling benthic diatom diversity and uniqueness in Mediterranean mountain ponds. Samples of periphytic diatoms were collected in 45 ponds in Andalusia, south of Spain, and analysed by standard methods. Data analysis reveals that diatom diversity is mainly controlled by elevation and hydroperiod. Contrary to the usual findings in the literature, the highest scores on Shannon’s diversity index were found in high-elevation temporary ponds, but this effect is hidden by lake clustering in the analysed dataset. Significant distance-decay similarity (DDS) trends were detected in the analysis of floristic composition among the samples, stressing the importance of spatial factors that may override the effect of other abiotic factors. These findings highlight the role of isolation and dispersal limitation in the configuration of the biogeographical patterns of benthic diatoms.

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Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands

Biogeosciences Discussions ◽

10.5194/bgd-9-2823-2012 ◽

2012 ◽

Vol 9 (3) ◽

pp. 2823-2849 ◽

Cited By ~ 2

Author(s):

F. Lidman ◽

C. M. Mörth ◽

H. Laudon

Keyword(s):

Boreal Forest ◽

Gamma Spectrometry ◽

Spatiotemporal Variability ◽

Forest Landscape ◽

Spatiotemporal Variations ◽

Forest Region ◽

Boreal Streams ◽

Landscape Control ◽

Boreal Forest Region

Abstract. The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. Considerable spatiotemporal variations were observed, with little or no correlation between streams. The export of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, but could not explain the variability in the export. Instead, the extent of lakes and mires within each subcatchment was found to be a stronger predictor for the transport of uranium and thorium. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal mires. Approximately 65–80 % of uranium and 55–65 % of thorium entering a mire is estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands is estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30–40 %. The atmospheric deposition of uranium and thorium was also quantified and its contribution to boreal streams was found to be low compared to weathering.

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Benthic diatom community response to metal contamination from an abandoned Cu mine: Case study of the Gromolo Torrent (Italy)

Journal of Environmental Sciences ◽

10.1016/j.jes.2018.03.034 ◽

2019 ◽

Vol 75 ◽

pp. 233-246 ◽

Cited By ~ 10

Author(s):

Raffaella Tolotti ◽

Sirio Consani ◽

Cristina Carbone ◽

Greta Vagge ◽

Marco Capello ◽

...

Keyword(s):

Metal Contamination ◽

Community Response ◽

Benthic Diatom ◽

Diatom Community

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Intra-annual fluctuations dominating temporal dynamics of benthic diatom assemblages in a Chinese mountainous river

Annales de Limnologie - International Journal of Limnology ◽

10.1051/limn/2020020 ◽

2020 ◽

Vol 56 ◽

pp. 22

Author(s):

Shuhan Guo ◽

Fengzhi He ◽

Tao Tang ◽

Lu Tan ◽

Qinghua Cai

Keyword(s):

Community Dynamics ◽

Environmental Changes ◽

Temporal Dynamics ◽

Multivariate Time Series ◽

Multiple Scale ◽

Benthic Diatom ◽

Diatom Community ◽

Diatom Communities ◽

Mountainous River

Understanding temporal dynamics of community may provide insights on biological responses under environmental changes. However, our knowledge on temporal dynamics of river organisms is still limited. In the present study, we employed a multivariate time-series modeling approach with a long-term dataset (i.e. 72 consecutive months) to investigate temporal dynamics of benthic diatom communities in four sites located in a Chinese mountainous river network. We hypothesized that: (1) there are multi-scale temporal dynamics within the diatom community; (2) intra-annual fluctuations dominate the community dynamics; (3) diatom species composing the community respond distinctly to environmental changes. We found that intra-annual fluctuations with periodicities <12 months explained 8.1–16.1% of community variation. In contrast, fluctuations with periodicities of 13–36 months and 37–72 months only accounted for 1.1–5.9% and 2.8–9.7% of variance in diatom community dynamics, respectively. Taxa correlating significantly to each significant RDA axis (namely, RDA taxa group) displayed distinct temporal dynamics. Conductivity, total nitrogen, and pH were important to most RDA taxa groups across the four sites while their effects were group-specific. We concluded that intra-annual dynamics dominated temporal variation in diatom communities due to community responses to local environmental fluctuations. We suggest that long-term monitoring data are valuable for identifying multiple-scale temporal dynamics within biological communities.

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