Consistent diversity loss but divergent functional responses of freshwater biofilms to salinity and nutrient enrichment across climatic regions.
4 affiliations
- 1The University of Sydney , New South Wales, Australia.
- 2University of New South Wales , Sydney, New South Wales, Australia.
- 3Sydney Institute of Marine Science , Mosman, New South Wales, Australia.
- 4Museo Nacional de Ciencias Naturales Madrid, Community of Madrid, Spain.
Abstract
Freshwater salinization and nutrient enrichment are intensifying globally. Despite their widespread co-occurrence, the generality of their combined effects across regions remains unclear, limiting identification of appropriate policy scales. Using outdoor freshwater ponds established >10 years ago, replicated across inland, coastal and mountain regions, we examined independent and interactive effects of elevated salinity (0, +5 and +15 g NaCl l⁻¹) and nutrient enrichment (10 : 1 N : P additions) on benthic biofilms. Salinity was the dominant driver of community structure and function. Nutrient enrichment increased green algae abundances after 30 days but did not affect biofilm function or bacterial structure. Across all regions, bacterial richness and Shannon's diversity index declined consistently with increasing salinity after 30 days and bacterial community structures differed among all salinity levels by 60 days. Responses of phototrophic groups and biofilm functions, however, were region-specific. In the inland region, high salinity increased biofilm biomass, gross primary productivity (GPP), net primary productivity (NPP) and abundances of diatoms and cyanobacteria; in the coastal region, GPP and NPP declined under high salinity with no change to phototroph abundances; while neither was affected in the mountain region. In sum, taxonomic changes in biofilm bacterial communities under salinization were consistent across regions, while functional changes varied.
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BibTeX
@article{fuggle2026consistent,
title = {{Consistent diversity loss but divergent functional responses of freshwater biofilms to salinity and nutrient enrichment across climatic regions.}},
author = {Rose Fuggle and Mariana Mayer-Pinto and Miguel G Matias and Ezequiel M Marzinelli},
journal = {Proceedings. Biological sciences},
year = {2026},
month = oct,
doi = {10.1098/rspb.2026.1161},
url = {https://europepmc.org/article/MED/42901527},
note = {CC BY},
}
RIS
TY - JOUR
TI - Consistent diversity loss but divergent functional responses of freshwater biofilms to salinity and nutrient enrichment across climatic regions.
AU - Rose Fuggle
AU - Mariana Mayer-Pinto
AU - Miguel G Matias
AU - Ezequiel M Marzinelli
PY - 2026
DA - 2026/10/01
JO - Proceedings. Biological sciences
DO - 10.1098/rspb.2026.1161
UR - https://europepmc.org/article/MED/42901527
AB - Freshwater salinization and nutrient enrichment are intensifying globally. Despite their widespread co-occurrence, the generality of their combined effects across regions remains unclear, limiting identification of appropriate policy scales. Using outdoor freshwater ponds established >10 years ago, replicated across inland, coastal and mountain regions, we examined independent and interactive effects of elevated salinity (0, +5 and +15 g NaCl l⁻¹) and nutrient enrichment (10 : 1 N : P additions) on benthic biofilms. Salinity was the dominant driver of community structure and function. Nutrient enrichment increased green algae abundances after 30 days but did not affect biofilm function or bacterial structure. Across all regions, bacterial richness and Shannon's diversity index declined consistently with increasing salinity after 30 days and bacterial community structures differed among all salinity levels by 60 days. Responses of phototrophic groups and biofilm functions, however, were region-specific. In the inland region, high salinity increased biofilm biomass, gross primary productivity (GPP), net primary productivity (NPP) and abundances of diatoms and cyanobacteria; in the coastal region, GPP and NPP declined under high salinity with no change to phototroph abundances; while neither was affected in the mountain region. In sum, taxonomic changes in biofilm bacterial communities under salinization were consistent across regions, while functional changes varied.
SN - 0962-8452
SN - 1471-2954
ER -