Nitrogen pollution promotes changes in the niche space of fish communities

Historically, anthropogenic fixed nitrogen has been purposely increased to benefit food production and global development. One consequence of this increase has been to raise concentrations of nitrogen in aquatic ecosystems. To evaluate whether nitrogen pollution promotes changes in the estimates of...

Full description

Saved in:
Bibliographic Details
Published in:Oecologia 2021-10, Vol.197 (2), p.485-500
Main Authors: de Carvalho, Débora Reis, Sparks, Jed P., Flecker, Alexander S., Alves, Carlos Bernardo Mascarenhas, Moreira, Marcelo Zacharias, Pompeu, Paulo Santos
Format: Article
Language:English
Subjects:
Air pollution
Allochthonous deposits
Ammonium
Ammonium compounds
Analysis
Animal tissues
Anthropogenic factors
Aquatic ecosystems
Biomedical and Life Sciences
Community Ecology–Original Research
Detritivores
Detritus feeders
Ecology
Estimates
Evaluation
Fish
Fishes
Food chains
Food production
Food resources
Food supply
Food webs
Human influences
Hydrology/Water Resources
Industrial wastes
Isotope ratios
Isotopes
Life Sciences
Niches
Nitrogen
Organic matter
Particulate organic matter
Periphyton
Plant Sciences
Pollution
Rainy season
River basins
Seasonal variations
Seasonality
Sewage
Turnover rate
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Historically, anthropogenic fixed nitrogen has been purposely increased to benefit food production and global development. One consequence of this increase has been to raise concentrations of nitrogen in aquatic ecosystems. To evaluate whether nitrogen pollution promotes changes in the estimates of niche space of fish communities, we examined 16 sites along a Brazilian river basin highly impacted by anthropogenic activities, especially discharge of domestic and industrial sewage from a region with more than 5 million inhabitants. We analysed the carbon (δ 13 C) and nitrogen (δ 15 N) isotope ratios of fish species and both autochthonous (periphyton) and allochthonous (course and fine particulate organic matter) basal food resources. To estimate the magnitude of nitrogen pollution, we measured the nitrate and ammonium concentrations at each site. Sampling was conducted in the dry and wet seasons to evaluate the influence of seasonality. Nitrogen pollution generally increased estimates of niche space, and seasonality influenced only the niche estimates of fish communities from polluted sites. In addition, isotopic analyses of nitrogen polluted sites yielded unrealistic estimates of trophic positioning (detritivores at the top of the food web). We conclude that changes in niche space estimates reflect both alterations in baseline isotopic values and differential trophic behaviour among fishes. Our study suggests that under conditions of high pollution, other factors appear to influence isotopic estimates of niche, such as isotopically distinct sources that have not been sampled, and/or differences in δ 15 N turnover rates between fish tissue and basal resources, creating isotopic baselines that are challenging to interpret.
ISSN:0029-8549
1432-1939
DOI:10.1007/s00442-021-05029-z