The Role of Substrate Type on Benthic Diatom Assemblages in the Daly and Roper Rivers of the Australian Wet/Dry Tropics

Hydrobiologia ◽  
2005 ◽  
Vol 548 (1) ◽  
pp. 101-115 ◽  
Author(s):  
Simon A. Townsend ◽  
Peter A. Gell
Keyword(s):  
Benthic Diatom ◽  
Substrate Type ◽  
Diatom Assemblages ◽  
Dry Tropics

The role of plant substrate type in shaping the composition and diversity of epiphytic diatom assemblages in a eutrophic reservoir

2017 ◽  
Vol 189 (2) ◽  
pp. 117-135 ◽  
Author(s):  
Markéta Fránková ◽  
Kateřina Šumberová ◽  
Jan Potužák ◽  
Ondřej Vild
Keyword(s):  
Substrate Type ◽  
Diatom Assemblages ◽  
Eutrophic Reservoir

scholarly journals Diatom Biodiversity in Karst Springs of Mediterranean Geographic Areas with Contrasting Characteristics: Islands vs Mainland

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2602 ◽  
Author(s):  
Giuseppina G. Lai ◽  
Sara Burato ◽  
Bachisio M. Padedda ◽  
Raffaella Zorza ◽  
Elisabetta Pizzul ◽  
...  
Keyword(s):  
Anthropogenic Impact ◽  
Multivariate Analyses ◽  
Winter Season ◽  
Global Scale ◽  
Diatom Assemblages ◽  
Karst Springs ◽  
Karst Ecosystems ◽  
Structural Indices ◽  
Epilithic Diatom

Karst ecosystems are considered as priority environments for the protection of biodiversity on a global scale. This study provides a first comparative analysis of epilithic diatom flora from karst springs in two Mediterranean geographic areas (Spain and Italy) with contrasting characteristics (islands vs mainland). We investigated twenty-three springs with different anthropogenic impact levels once in the winter season between 2007 and 2017 (N = 23). A total of 176 diatom taxa (56 genera) were found of which 101 (44 genera) were observed in single sites. A general good biotic integrity was revealed by structural indices (species richness, diversity and evenness). However, crenophilous species were generally present and abundant in less impacted springs. Comparing islands and mainland, significant differences were found in species composition and diversity (H’) based on multivariate analyses (global R = 0.610; p = 0.001) and t-test (t = 2.304; p = 0.031). Discharge and Cl− were the most significant variables in determining diatom assemblages. Our results confirm the role of springs as multiple ecotones and refuges for rare species and suggest that the geographic insularity may be an important factor in maintaining diatom biodiversity.

Paleodepth determination from Antarctic benthic diatom assemblages

1997 ◽  
Vol 29 (3-4) ◽  
pp. 301-318 ◽  
Author(s):  
Jason M. Whitehead ◽  
Andrew McMinn
Keyword(s):  
Benthic Diatom ◽  
Diatom Assemblages

Effects of Didymosphenia geminata blooms on benthic diatom assemblages in the Restigouche River Watershed, eastern Canada

Botany ◽  
2015 ◽  
Vol 93 (5) ◽  
pp. 317-323 ◽  
Author(s):  
Branaavan Sivarajah ◽  
Joshua Kurek ◽  
Kathleen M. Rühland ◽  
John P. Smol
Keyword(s):  
Benthic Diatom ◽  
Diatom Assemblage ◽  
Diatom Assemblages ◽  
Eastern Canada ◽  
Didymosphenia Geminata ◽  
Assemblage Composition ◽  
River Watershed ◽  
And Function ◽  
Riverine Systems ◽  
The Impact

Nuisance Didymosphenia geminata (Lyngbye) M. Schmidt (didymo) blooms were first reported in 2006 from the Restigouche River Watershed (RRW), eastern Canada. Although government agencies and recreational users are concerned about these blooms, little is known about the impact on biota and (or) the structure and function of the relatively pristine riverine systems of the RRW. Here, we assess whether didymo blooms affect overall benthic diatom assemblage composition by examining epilithic samples from middle stretches of the Patapedia and Upsalquitch rivers. Significant (albeit minor) differences (P < 0.05) in diatom assemblage composition between sites, with and without didymo blooms, were only observed from the Patapedia River. Rarefied diatom species diversity (Hill’s N2) and rarefied richness did not differ significantly among sites, regardless of the presence or absence of blooms. Our data show that didymo blooms have minimal effect on benthic diatom assemblage composition in the RRW.

Penicillin-mediated changes in viable benthic diatom assemblages – insights about the relevance of bacteria across spatial and seasonal scales

2014 ◽  
Vol 65 (5) ◽  
pp. 437 ◽  
Author(s):  
Priya M. D'Costa ◽  
Arga C. Anil
Keyword(s):  
Ecological Study ◽  
Benthic Diatom ◽  
Diatom Assemblages ◽  
Total Inhibition ◽  
Mesocosm Experiments ◽  
Lactam Antibiotic ◽  
Intertidal Sandflat ◽  
Penicillin Treatment ◽  
Conditioning Film ◽  
Limited Diffusion

Penicillin, a β-lactam antibiotic, cannot affect diatoms directly but does so through bacteria. Its effects on viable benthic diatom assemblages in a tropical environment were evaluated across spatial (intertidal sandflat, mangrove site, port environment) and seasonal (post-monsoon, pre-monsoon, monsoon) scales. Penicillin treatment resulted in bacterial suppression and a reduction in diatoms at the intertidal and mangrove sites having stable pennate-dominated assemblages. Diatom response at the port site, dominated by transient centric diatoms, ranged from total inhibition to enhancement. The monsoon diatom assemblages, which differed in composition from those in other seasons, showed reduced susceptibility to penicillin. These observations highlight the bacterial influence on diatom assemblages and the significance of species composition of diatom assemblages in these interactions. Epipsammic diatoms (Cocconeis, Grammatophora and Thalassionema) were more sensitive to penicillin than epipelic forms, probably due to: (1) their inability to escape unfavourable bacterial metabolites because of limited diffusion in benthic environments; and (2) the interference of penicillin with the bacterial ‘conditioning’ film required for their attachment. Overall, the observations from the present, preliminary, ecological study provide insights into the relevance of bacteria in influencing viable benthic diatom assemblages across spatial and seasonal scales and emphasise the need for future mesocosm experiments on these aspects.

How do abiotic environmental variables shape benthic diatom assemblages in subtropical streams?

2017 ◽  
Vol 68 (5) ◽  
pp. 863 ◽  
Author(s):  
Wing Ying Tsoi ◽  
Wade L. Hadwen ◽  
F. Sheldon
Keyword(s):  
Environmental Gradients ◽  
Critical Role ◽  
Benthic Diatom ◽  
Base Flow ◽  
Diatom Assemblage ◽  
Environmental Drivers ◽  
Diatom Assemblages ◽  
Physical And Chemical Variables ◽  
Ecological Importance ◽  
Physical And Chemical

Diatoms (Division Bacillariophyta) commonly dominate benthic algal communities in upland streams and are the major primary producers that sit at the base of food webs. Given their ecological importance, the aim of the present study was to investigate the spatial patterns of freshwater biofilm biomass and diatom assemblage composition in response to differences in physical and chemical variables in the Bremer, Logan and Albert catchments in south-east Queensland. Patterns in benthic diatom assemblage structure were examined during base flow conditions and the focus was on relating the spatial hierarchical interrelationships among ultimate (i.e. catchments and geology) and proximate (i.e. flow, nutrients, light, conductivity, pH and turbidity) environmental drivers. The spatial difference observed in the benthic diatom assemblages was predominantly driven by proximate environmental drivers, which, in turn, were affected by ultimate drivers. Flow played a critical role in controlling both biofilm biomass and affecting the occurrence of diatom taxa. Nutrients and light also played roles as limiting resources structuring biofilm biomass and the relative abundance of diatoms. Diatom growth form, cell size and attachment mode can be used to create a more quantitative and predictive approach to establishing relationships between diatoms and environmental gradients.

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