Alpine lake sediment records of the impact of glaciation and climate change on the biogeochemical cycling of soil nutrients

• Published in: Quaternary Research
• Main Authors: Filippelli, Gabriel M., Souch, Catherine, Menounos, Brian, Slater-Atwater, Sara, Timothy Jull, A.J., Slaymaker, Olav
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2006
• Subjects: Alpine Lake; North Atlantic
• Online Access: http://dx.doi.org/10.1016/j.yqres.2006.03.009; http://api.elsevier.com/content/article/PII:S0033589406000500?httpAccept=text/xml; http://api.elsevier.com/content/article/PII:S0033589406000500?httpAccept=text/plain; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400004300

Abstract Lake sediment cores from the Coast Mountains of British Columbia were analyzed using chemical sequential extractions to partition the dominant geochemical fractions of phosphorus (P). The P fractions include mineral P (the original source of bioavailable P), occluded P (bound to soil oxides), and organic P (remains of organic matter). By comparing P fractions of soil and recent lake sediment samples, these fractions are shown to be a valid proxy for landscape-scale nutrient status. Changes in soil development for an alpine watershed (Lower Joffre Lake) are inferred from the P fractions in the basin's outlet lake sediments. Glacially sourced mineral P dominates at the base of the core, but several rapid shifts in P geochemistry are evident in the first ∼3000 yr of the record. The latter indicates an interval of early and rapid soil nutrient maturation from ∼9600 to 8500 cal yr BP and a significant influx of slope-derived material into Lower Joffre Lake. A substantial increase in mineral P occurs at ca. 8200 cal yr BP, consistent with the cold event in the vicinity of the North Atlantic at that time. The more recent record reveals a continual increase in the proportion of mineral P from glacial sources to the lake, indicating a trend toward cooler conditions in the Coast Mountains.