Stable Isotopes Reveal Nitrogen Loading to Lake Tanganyika from Remote Shoreline Villages

TitleStable Isotopes Reveal Nitrogen Loading to Lake Tanganyika from Remote Shoreline Villages
Publication TypeJournal Article
Year of Publication2017
AuthorsKelly, B., Mtiti E., McIntyre P. B., and Vadeboncoeur Y.
JournalEnvironmental Management
Number of Pages264-273
Date PublishedFeb
Type of ArticleArticle
Reprint Number0364-152X
LTER Accession NumberWOS:000394257700007
Keywordscontamination; geochemistry; streams; carbon; zones, delta N-15; Anthropogenic nutrient loading; Oligotrophic; Lake, east-africa; food webs; productivity; indicators; eutrophication;, Environmental Sciences & Ecology, Tanganyika

Access to safe water is an ongoing challenge in rural areas in Tanzania where communities often lack access to improved sanitation. Methods to detect contamination of surface water bodies, such as monitoring nutrient concentrations and bacterial counts, are time consuming and results can be highly variable in space and time. On the northeast shore of Lake Tanganyika, Tanzania, the low population density coupled with the high potential for dilution in the lake necessitates the development of a sensitive method for detecting contamination in order to avoid human health concerns. We investigated the potential use of nitrogen and carbon stable isotopes of snail tissues to detect anthropogenic nutrient loading along the northeast shore of Lake Tanganyika. delta N-15 of snails was positively related to human population size in the nearest village, but only for villages with >4000 inhabitants. The areal footprint of villages within their watershed was also significantly correlated with snail delta N-15, while agricultural land use and natural vegetation were not. Dissolved nutrient concentrations were not significantly different between village and reference sites. Our results indicate that nitrogen isotopes provide a sensitive index of local nutrient loading that can be used to monitor contamination of oligotrophic aquatic environments with low surrounding population densities.

Print Copy LocationEnviron. Manage.