Abstract
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. δ15N 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 δ15N, 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.
Similar content being viewed by others
References
Bade DL, Carpenter SR, Cole JJ, Hanson PC, Hesslein RH (2004) Controls of δ13C-DIC in lakes: geochemistry, lake metabolism, and morphometry. Limnol Oceanogr 49:1160–1172
Bilby RE, Fransen BR, Bisson PA (1996) Incorporation of nitrogen and carbon from spawning coho salmon into the trophic system of small streams: evidence from stable isotopes. Can J Fish Aquat Sci 53:163–173
Campbell L, Verburg P, Dixon DG, Hecky RE (2008) Mercury biomagnification in the food web of Lake Tanganyika (Tanzania, East Africa). Sci Total Environ 402:184–191
Childress ES, Allan JD, McIntyre PB (2014) Nutrient subsidies from iteroparous fish migrations can enhance stream productivity. Ecosystems 17:522–534
Cloern JE (2001) Our evolving conceptual model of the coastal eutrophication problem. Mar Ecol-Prog Ser 210:223–253
Cole ML, Kroeger KD, McClelland JW, Valiela I. (2005) Macrophytes as indicators of land‐derived wastewater: application of a δ15N method in aquatic systems. Water Resour Res 41. doi:10.1029/2004WR003269
Corman JR, McIntyre PB, Kujoba B, Mbemba W, Fink D, Wheeler CW, Gans C, Michel E, Flecker AS (2010) Upwelling couples chemical and biological dynamics across the littoral and pelagic zones of Lake Tanganyika, East Africa. Limnol Oceanogr 55:214–234
Costanza SD, O’Donohue MJ, Dennison WC, Loneragan NR, Thomas M (2001) A new approach for detecting and mapping sewage impacts. Mar Pollut Bul 42:149–156
Devlin SP, Vander Zanden MJ, Vadeboncoeur Y (2013) Depth‐specific variation in carbon isotopes demonstrates resource partitioning among the littoral zoobenthos. Freshwater Biol 58:2389–2400
Diebel MW, Vander Zanden MJ (2009) Nitrogen stable isotopes in streams: effects of agricultural sources and transformations. Ecol Appl 19:1127–1134
Fry B (1991) Stable isotope diagrams of freshwater food webs. Ecology 72:2293–2297
Fry B, Gace A, McClelland JW (2003) Chemical indicators of anthropogenic nitrogen-loading in four Pacific estuaries. Pac Sci 57:77–101
Karube Z, Sakai Y, Takeyama T, Okuda N, Kohzu A, Yoshimizu C, Nagata T, Tayasu I (2010) Carbon and nitrogen stable isotope ratios of macroinvertebrates in the littoral zone of Lake Biwa as indicators of anthropogenic activities in the watershed. Ecol Res 25:847–855
Kilham P, Kilham SS (1990) Endless summer: internal loading processes dominate nutrient cycling in tropical lakes. Freshw Biol 23:79–89
Knappett PS, Escamilla V, Layton A, McKay LD, Emch M, Williams DE, Huq R, Alam J, Farhana L, Mailloux BJ, Ferguson A (2011) Impact of population and latrines on fecal contamination of ponds in rural Bangladesh. Sci Total Environ 409:3174–3182
Langenberg VT, Sarvala J, Roijackers R (2003a) Effect of wind induced water movements on nutrients, chlorophyll-a, and primary production in Lake Tanganyika. Aquat. Ecosyst Health 6:45–58
Langenberg VT, Nyamushashu S, Roijackers R, Koelmans A-A (2003b) External nutrient sources for Lake Tanganyika. J Great Lakes Res 29:169–180
Lapointe BE, Barile PJ, Littler MM, Littler DS (2005) Microalgal blooms on southeast Florida coral reefs II. Cross-shelf discrimination of nitrogen sources indicates widespread assimilation of sewage nitrogen. Harmful Algae 4:1106–1122
Lau DCP, Leung KMY, Dudgeon D (2009) What does stable isotope analysis reveal about trophic relationships and the relative importance of allochthonous resources in tropical stream? A synthetic study from Hong Kong. Freshw Biol 54:127–141
Mayo AW, Mubarak T (2015) Challenges of adoption of urine-diversion dry toilets technology as sanitation option by coastal communities of Mkuranga District in Tanzania. Afr. J Environ Sci Technol 9:482–492
McClelland JW, Valiela I, Michener RH (1997) Nitrogen stable isotope values in estuarine food webs: A record of increasing urbanization in coastal watersheds. Limnol Oceanogr 42:930–937
McLellan SL, Salmore AK (2003) Evidence for localized bacterial loading as the cause of chronic beach closings in a freshwater marina. Water Res 37:2700–2708
Michel E, Mcintyre PB, Chan J (2007) A snail’s space sets a snail’s pace: movement rates of Lavigeria gastropods in Lake Tanganyika, East Africa. J Molluscan Stud 73:195–198
Meyers PA, Ishiwatari R (1993) Lacustrine organic geochemistry–an overview of indicators of organic matter and diagenesis in lake sediments. Org Geochem 20:867–900
Munda IM (1993) Changes and degradation of seaweed stands in the northern Adriatic. Hydrobiologia 260-261:239–253
O’Reilly CM, Hecky RE, Cohen AS, Plisnier PD (2002) Interpreting stable isotopes in food webs: recognizing the role of time averaging at different trophic levels. Limnol Oceanogr 47:306–309
O’Reilly CM, Dettman DL, Cohen AS (2005) Paleolimnological investigations of anthropogenic environmental change in Lake Tanganyika: VI. Geochemical indicators. J Paleolimnol 34:85–91
Peterson GS, Sierszen ME, Yurista PM, Kelly JR (2007) Stable nitrogen isotopes of plankton and benthos reflect a landscape-level influence on Great Lakes coastal ecosystems. J Great Lakes Res 33:27–41
Plisnier PD, Chitamwebwa D, Mwape L, Tshibangu K, Langenberg V, Coenen E (1999) Limnological annual cycle inferred from physical-chemical fluctuations at three stations of Lake Tanganyika. Hydrobiologia 407:45–58
Post DM (2002) Using stable isotopes to estimate trophic position: models, methods, and assumptions. Ecology 83:703–718
R Core Team (2014) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, http://www.R-project.org/
Rogers KM (1999) Effects of sewage contamination on macro-algae and shellfish at Moa Point, New Zealand using stable carbon and nitrogen isotopes. New Zeal J Mar Fresh 33:181–188
Savage C (2005) Tracing the influence of sewage nitrogen in a coastal ecosystem using stable nitrogen isotopes. Ambio 43:145–150
Savage C, Elmgren R (2004) Macroalgal (Fucus vesiculosus) δ15N values trace decrease in sewage influence. Ecol Appl 14:517–526
Taylor BW, Keep CF, Hall Jr RO, Koch BJ, Tronstad LM, Flecker AS, Ulseth AJ (2007) Improving the fluorometric ammonium method: matrix effects, background fluorescence, and standard additions. J N Am Benthol Soc 26:167–177
Tewfik A, Rasmussen JB, McCann KS (2005) Anthropogenic enrichment alters a marine benthic food web. Ecology 86:2726–2736
Vadeboncoeur Y, Jeppesen E, Vander Zanden JM, Schierup HH, Christoffersen K, Lodge DM (2003) From Greenland to green lakes: cultural eutrophication and the loss of benthic pathways in lakes. Limnol Oceanogr 48:1408–1418
Vadeboncoeur Y, Devlin SP, McIntyre PB, Vander Zanden MJ (2014) Is there light after depth? Distribution of periphyton chlorophyll and productivity in lake littoral zones. Freshw Sci 33:524–536
Vander Zanden MJ, Rasmussen JB (1999) Primary consumer δ13C and δ15N and the trophic position of aquatic consumers. Ecology 80:1395–1404
Vander Zanden MJ, Vadeboncoeur Y, Diebel MW, Jeppesen E (2005) Primary consumer stable nitrogen isotopes as indicators of nutrient source. Environ Sci Technol 39:7509–7515
Verburg P (2007) The need to correct for the Suess effect in the application of δ13C in sediment of autotrophic Lake Tanganyika, as a productivity proxy in the Anthropocene. J1 Paleolimnol 37:591–602
Vermuellen S, Sturaro N, Gobert S, Bouquegneau JM, Lepoint G (2011) Potential early indicators of anthropogenically derived nutrients: a multiscale stable isotope analysis. Mar Ecol-Prog Ser 422:9–22
Wagner CE, McIntyre PB, Smith K, Michel E, Gilbert D (2009) Diet predicts intestine length in Lake Tanganyika’s cichlid fishes. Funct Ecol 23:1122–1131
World Health Organization. (2013) Progress on sanitation and drinking-water 2013 update.
Xu J, Zhang M (2012) Primary consumers as bioindicator of nitrogen pollution in lake planktonic and benthic food webs. Ecol Indic 14:189–196
Zar JH (2010) Biostatistical analysis, 5th edn. Prentice Hall, Upper Saddle River, NJ
Acknowledgments
Funding for this research was provided by the National Science Foundation grants DEB-0842253 (YV) and DEB-1030242 (PBM) and the Department of Biology at Wright State University. We thank Ellen Hamann, Evan Childress, and Kim Sparks for assistance with chemical analyses, and members of the Lake Tanganyika Ecosystem Project team for help in the field. We thank the JGI and the Tanzania Fishery Research Institute for logistical assistance with field sampling, and Dr. Rashid Tamatamah and the University of Dar es Salaam for research clearance. We gratefully recognize The Nature Conservancy’s Africa Program for sharing watershed delineations. We thank two anonymous reviewers whose comments improved the manuscript.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no competing interests.
Rights and permissions
About this article
Cite this article
Kelly, B., Mtiti, E., McIntyre, P.B. et al. Stable Isotopes Reveal Nitrogen Loading to Lake Tanganyika from Remote Shoreline Villages. Environmental Management 59, 264–273 (2017). https://doi.org/10.1007/s00267-016-0787-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00267-016-0787-y