Table 1.
Index of the studies from which the size-fractionated chlorophyll a and temperature measurements were taken.
All data were compiled by [4].
Fig 1.
Relative errors of the temperature-independent model, plotted as a function of temperature.
The three coloured lines in each plot represent linear (blue), quadratic (green) and exponential (red) functions that were fit to the residuals as a function of temperature (Table 2). The dashed black lines indicate the fit of the exponential function, with the exclusion of all observations taken below either 15 or 40 m depth. Data were generously made available by E. Marañón [4].
Table 2.
Coefficients and goodness-of-fit statistics for the functions fit to the temperature-independent model residuals (ϵs), as shown in Fig 1.
Goodness-of-fit metrics: SSE = Sum of Squared Errors; r2 = coefficient of determination (significant at p = 0.01); RMSE = Root Mean Squared Error.
Fig 2.
Absolute (left) and relative (right) chlorophyll a biomass in (a,d) picoplankton, (b,e) nanoplankton and (c,f) microplankton size-classes, as a function of total chlorophyll a (x-axis) and temperature (colours).
The thick black lines represent the best-fit temperature-independent functions (Eq 1). The coloured lines represent the best-fit temperature-dependent functions (Eq 2) at discrete temperatures (see legend).
Table 3.
Coefficients and goodness-of-fit statistics for the temperature-independent (Eq 1) and temperature-dependent (Eq 2) functions.
pSSE = predictive SSE from cross-validation experiment; AIC = Akaike Information Criterion. Coefficients of determination are significant at p = 0.01.
Fig 3.
Relative error of the temperature-dependent and temperature-independent functions when used to predict size-class biomasses for independent, unassimilated observations.
Dots represent the mean temperature and geometric mean relative error for each data subset, with error bars showing ±1 standard deviation for temperature, and 1 geometric standard deviation for the relative error.
Fig 4.
Satellite-derived estimates of annual mean surface chlorophyll a biomass in three phytoplankton size classes.
Panels (a-c): Temperature-independent functions (Eq 1). Panels (d-f): Temperature-dependent functions (Eq 2). Panels (g-i): Relative change in biomass attributable to temperature, calculated by removing the two chlorophyll-dependent terms from Eq 2.
Fig 5.
Satellite-derived estimates of the fractional contribution of the three phytoplankton size classes to annual mean total surface chlorophyll a biomass.
Panels (a-c): Temperature-independent functions (Eq 1). Panels (d-f): Temperature-dependent functions (Eq 2).
Fig 6.
Four satellite-derived estimates for the zonal geometric mean surface chlorophyll a biomass (1 geometric standard deviation) in (a) picoplankton, (b) nanoplankton, and (c) microplankton size classes.