Lake Rerewhakaaitu ‐ an apparently phosphate‐free lake

Lake Rerewhakaaitu, near the Bay of Plenty, New Zealand, is a warm, third‐class lake. From a 1972–74 limnological survey, its annual heat budget (50 J.crrT 1 ) was similar to those of comparable mixed lakes in the area, but its biological production (mean particulate chlorophyll a 12.9 g•m −3 , and mean dry weight of bottom fauna 1.82 g•m −2 ) was comparatively low, although its catchment is extensively farmed. Dissolved phosphate concentrations in its water remained too low for detection at all times, probably because of rapid sorption by colloidal allophanic clays.