Premium
Patterns of phosphorus supply and utilization in Lake Washington and Findley Lake 1, 2
Author(s) -
Richey Jeffrey E.
Publication year - 1979
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1979.24.5.0906
Subject(s) - bloom , phosphate , zooplankton , phosphorus , photic zone , zoology , nutrient , phytoplankton , algae , photosynthesis , chemistry , environmental chemistry , ecology , biology , botany , organic chemistry
Patterns of phosphorus supply and utilization were investigated for 2 years. In Lake Washington, the phytoplankton bloom began in February or early March, reaching peaks of 2,165 (1974) and 1,885 mg C·m −2 ·d −1 (1975). Most of the P utilized was from phosphate accumulated in the water, resulting in depletions of soluble reactive phosphorus in the euphotic zone of 260‐12 mg PO 4 ‐P·m −2 . Zooplankton excretion supplied phosphate during the later stages of the bloom and in summer. In Findley Lake, the blooms were of shorter duration and reached maxima of 400–711 mg C·m −2 ·d −1 . Phosphate was supplied from fluvial inputs and zooplankton excretion, with little accumulation (10–50 mg PO 4 ‐P·m −2 ). Comparison of the measured rate constants for turnover ( k i ) with the constants expected for photosynthesis ( k e ) showed P flux patterns. In Lake Washington, k i varied from <0.05·h −1 in winter to 5–10·h −1 during summer stratification, whereas k e was comparable during prebloom and early‐bloom periods and only about 0.1·h −1 in summer. In Findley Lake, k i (2.9–5.3·h −1 ) was always > k e (0.05·h −1 ). Only after phosphate depletion did the usual pattern of rapid uptake and release occur. Nutrient addition and isotope partitioning experiments suggested that the divergence of k i and k e reflected a stressed physiological condition of the algae that prevented incorporation and promoted compensatory rapid turnover of phosphate.