Lake trophic status can be determined by the depth distribution of sediment phosphorus

Cayelan C. Carey and Emil Rydin

Limnol. Oceanogr., 56(6), 2011, 2051-2063 | DOI: 10.4319/lo.2011.56.6.2051

ABSTRACT: In this meta-analysis, we examine how sediment phosphorus (P) burial pattern may be related to trophic state. We present sediment P profiles from 94 lakes that demonstrate fundamental differences in P burial between oligotrophic and eutrophic systems. In sediments of eutrophic (≥ 30 µg water column total P (TP) L-1) lakes, P concentrations are elevated in the surficial sediments in comparison with deeper layers, representing a large P pool that can be recycled. This pattern directly contrasts with sediment P profiles in oligotrophic lakes (< 10 µg water column TP L-1), which exhibit increasing concentrations of permanently buried P with depth. Sediment processes regulating P burial may be important regulators of internal P recycling and consequently lake trophic status. Thus, mesotrophic lakes (10 to 30 µg water column TP L-1), which exhibit consistent P concentrations with depth, are more vulnerable to external P inputs than oligotrophic lakes because they are at their maximal sediment P burial flux. Our data suggest that thresholds in sediment P pattern may correlate with thresholds in sediment P burial processes and consequently may indicate whether deposited P will be released to the water column.

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