Long-Term Hydrologic Fluctuations and Dynamics of Primary Producers in a Tropical Crater Lake
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Frontiers in Ecology and Evolution
Abstract
Aquatic ecosystems in tropical regions remain understudied and their long-term
dynamics poorly understood. In East Africa, a better understanding of how natural
communities of primary producers in small freshwater ecosystems respond to climatic
variability is needed to improve management and conservation of aquatic resources. This
study explored the response of algae and bacteria communities to marked hydrological
variation over the past 1,500 years in a small western Ugandan crater lake, Lake Nkuruba.
We analyzed sedimentary algal and bacterial pigments to evaluate the magnitude
and direction of change in the autotrophic community in response to severe climatic
perturbations in the region. The lithology of the Lake Nkuruba sediment core indicated
that external forcing in the form of a major drought, associated with the Medieval Climate
Anomaly, caused a heavy, short-lived detrital pulse to the basin that led to a brief but
substantial disruption of the lake system in the second half of the Thirteenth century. The
system appears to have recovered rapidly, and then transitioned to a more productive
state than the one preceding the drought. The considerable variation observed in the
sedimentary pigment biomarkers is likely linked with climatically-induced changes in
the water column structure of this small crater lake. Our results highlight the challenge
of defining appropriate baselines or reference conditions in climatically-sensitive East
African aquatic ecosystems and disentangling long-term anthropogenic impacts from
the strong regional hydrological flux at the decadal to centennial scale.
Description
Keywords
Drought, Lake levels, Paleolimnology, Sedimentary pigments
Citation
Saulnier-Talbot É, Chapman LJ, Efitre J, Simpson KG and Gregory-Eaves I (2018) Long-Term Hydrologic Fluctuations and Dynamics of Primary Producers in a Tropical Crater Lake. Front. Ecol. Evol. 6:223. doi: 10.3389/fevo.2018.00223