Deposition, burial and sequestration of carbon in an oligotrophic, tropical lake

• Published in: Journal of limnology Vol. 73; no. 2; pp. 223 - 235
• Main Authors: Alcocer, Javier, Ruiz-Fernández, Ana C., Escobar, Elva, Pérez-Bernal, Libia H., Oseguera, Luis A., Ardiles-Gloria, Vilma
• Format: Journal Article
• Language: English
• Published: Pavia PAGEPress Publications 01.01.2014
• Subjects: Alchichica; biogenic carbon; Carbon; Carbon sequestration; chlorophyll a; Diagenesis; Dry weight; Freshwater; Lake sediments; Mexico; Oligotrophic lakes; Particulate organic carbon; POC; Preservation; Sediment; Sediment samplers; Sediment samples; Sediments; Temporal variations; Tropical climate; tropical lake; Tropical lakes; Mexico, Puebla, Alchichica L
• ISSN: 1129-5767; 1723-8633
• DOI: 10.4081/jlimnol.2014.783

The amount of biogenic carbon that may be deposited, buried and eventually preserved (sequestered) in the sediments of a tropical, oligotrophic lake, was evaluated based on i) the temporal variation of the particulate organic carbon (POC) concentration in the superficial sediments in the deep zone of lake Alchichica, Puebla, Mexico; and ii) the POC accumulation and preservation in a 210Pb-dated sediment core from the lake. In lake Alchichica the POC concentration in the surficial sediments ranged between 12 and 60 mg POC g-1 (25 ± 12 mg POC g-1 dry weight). The magnitude of the sedimented POC in Alchichica was high and mostly of autochthonous origin. The POC concentrations recorded in the sediment core (16.6 to 31.6 mg g-1 dry weight) were comparable to the concentration range observed in the surface sediment samples collected during the study period, which signaled a high POC preservation capacity in the sedimentary column of lake Alchichica. The POC fluxes, estimated from the 210Pb-dated sediment core, varied between 14.9 and 35.3 g m-2 year-1 within the past century; and the maximum POC losses through diagenesis during this period were estimated to be lower than 25%. This study concludes that deep tropical lakes, exemplified by lake Alchichica, accumulate and preserve most of the POC deposited, playing an important role in regional carbon balances.