Changes in the net heat flux (NHF) into the ocean have profound impacts on global climate. We analyse a long-term
plankton time-series and show that the NHF is a critical indicator of ecosystem dynamics. We show that phytoplankton
abundance and diversity patterns are tightly bounded by the switches between negative and positive NHF ...
Changes in the net heat flux (NHF) into the ocean have profound impacts on global climate. We analyse a long-term
plankton time-series and show that the NHF is a critical indicator of ecosystem dynamics. We show that phytoplankton
abundance and diversity patterns are tightly bounded by the switches between negative and positive NHF over an annual
cycle. Zooplankton increase before the transition to positive NHF in the spring but are constrained by the negative NHF
switch in autumn. By contrast bacterial diversity is decoupled from either NHF switch, but is inversely correlated (r = 20.920)
with the magnitude of the NHF. We show that the NHF is a robust mechanistic tool for predicting climate change indicators
such as spring phytoplankton bloom timing and length of the growing season.