The sedimentary response to a rapid change in lake level in Lake Tanganyika

James McManus, Silke Severmann, Andrew Cohen, Jennifer L. McKay, Bo R. Montanye, Anne M. Hartwell, Rebecca L P Brucker, Robert Wheatcroft

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

We present records of sedimentary organic carbon, nitrogen, and carbonate, and stable isotope records of organic material and carbonate from a series of sediment cores that straddle the permanent chemocline in Lake Tanganyika. Sedimentation rates for these cores are consistent among the sites (~0.05-0.1cm y-1), and all records show an increase in sedimentary carbonate (aragonite) content centered at ~1879. The mid-19th century coincides with a major (~10m) lake level transgression. Throughout the period of lake level transgression and subsequent regression, the organic matter δ13C and δ15N records develop a prominent and coincident negative excursion followed by a return to values similar to those prior to the lake level transgression. This negative excursion in δ15N and δ13C is also coincident with an increase in carbonate-corrected organic carbon. We interpret the δ13C results as a decline in primary production during the transgression with the δ15N results signaling a concomitant increase in the reliance on nitrogen fixation as the nitrogen source. The coincident peak in organic carbon is interpreted as being a result of enhanced preservation driven by the precipitation and burial of aragonite.

Original languageEnglish (US)
Pages (from-to)647-658
Number of pages12
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume440
DOIs
Publication statusPublished - Dec 15 2015

    Fingerprint

Keywords

  • Geochemistry
  • Lake Tanganyika
  • Little Ice Age
  • Transgression
  • δC
  • δN

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Palaeontology
  • Earth-Surface Processes
  • Oceanography

Cite this

McManus, J., Severmann, S., Cohen, A., McKay, J. L., Montanye, B. R., Hartwell, A. M., ... Wheatcroft, R. (2015). The sedimentary response to a rapid change in lake level in Lake Tanganyika. Palaeogeography, Palaeoclimatology, Palaeoecology, 440, 647-658. https://doi.org/10.1016/j.palaeo.2015.09.035