Isometric size-scaling of metabolic rate and the size abundance distribution of phytoplankton

Abstract

The relationship between phytoplankton cell size and abundance has long been known to follow regular, predictable patterns in near steady-state ecosystems, but its origin has remained elusive. To explore the linkage between the size-scaling of metabolic rate and the size abundance distribution of natural phytoplankton communities, we determined simultaneously phytoplankton carbon fixation rates and cell abundance across a cell volume range of over six orders of magnitude in tropical and subtropical waters of the Atlantic Ocean. We found an approximately isometric relationship between carbon fixation rate and cell size (mean slope value: 1.16; range: 1.03-1.32), negating the idea that Kleiber's law is applicable to unicellular autotrophic protists. On the basis of the scaling of individual resource use with cell size, we predicted a reciprocal relationship between the size-scalings of phytoplankton metabolic rate and abundance. This prediction was confirmed by the observed slopes of the relationship between phytoplankton abundance and cell size, which have a mean value of 21.15 (range: 21.29 to 20.97), indicating that the size abundance distribution largely results from the size-scaling of metabolic rate. Our results imply that the total energy processed by carbon fixation is constant along the phytoplankton size spectrum in near steady-state marine ecosystems.

Scaling of growth rate and mortality with size and its consequence on size spectra of natural microphytoplankton assemblages in the East China Sea

“…This value is comparable with the reported values of individual-specific metabolic rates observed in other studies, which ranged from 0.9 to 1.2 (Marañón, 2008;Marañón et al, 2007). Moreover, the 95 % confidence interval of the individual-specific scaling exponent we calculated (1.056 to 1.123) is comparable to those in Huete-Ortega et al (2012), where the individualspecific carbon fixation rate is reported to range from 1.03 to 1.32. Together with the results of other studies showing isometric scaling between individual respiration and body size in other photosynthetic plants (Reich et al, 2006), Table 2) and the environmental factors (blue arrows; N: nitrite + nitrate concentration; PAR: photosynthesis active radiation; P: phosphate concentration; S: salinity; Si: silicate concentration; T : temperature).…”

“…According to MTE, the temperature-corrected size-specific population growth rate scales allometrically with its body size, with an exponent of −1/4 (Brown et al, 2004). Although this −1/4 scaling exponent has been observed in compiled data from freshwater and marine phytoplankton (Edwards et al, 2012;Litchman et al, 2007), other studies using natural assemblages from open ocean and coastal regions have showed that the phytoplankton growth rate scales isometrically with body size (Marañón, 2008;Marañón et al, 2007;Huete-Ortega et al, 2012) or exhibits a parabolic relationship with body size . However, reviews suggest that the scaling exponents vary from −1/3 to 0 (Glazier, 2005(Glazier, , 2010.…”

“…Nutrient limitation may not be a concern because our incubations all received artificial nutrient amendments and our scaling analyses used only the growth rates measured with a nutrient amendment (µ). For the issue of light limitation, our samples were taken from surface water (10 m depth) and incubated on deck to avoid light limitation, as was done in other studies (Marañón et al, 2007;Marañón, 2008;Huete-Ortega et al, 2012;McManus et al, 2007). Thus, light limitation effects on phytoplankton growth should not be a problem.…”

Dependency of Microalgal Production on Biomass and the Relationship to Yield and Bioreactor Scale-up for Biofuels: a Statistical Analysis of 60+ Years of Algal Bioreactor Data

“…Biomass from bioreactors was compared to maximum cell concentrations from laboratory cultures [213] after converting concentration to biomass using Strathmann's equation. Biomass was also compared to phytoplankton in temperate [214] and tropical [215] oceans after converting biomass per cell to g L −1 dry weight.…”

“…8b), though the trend had a lower correlation coefficient (r 2 = 0.0484, df = 265, F = 4.73, P = 0.030). There was a significant difference in production Table 6 b Cells L −1 from Agusti and Kalff [213] converted to biomass, in g L −1 , using g cell −1 from Strathmann [207] c Biomass from Rodríguez and Mullin [214] converted to g L −1 from Strathmann [207] d Cells L −1 from Huete-Ortega et al [215] converted to biomass, in g L −1 , using g cell −1 from Strathmann [207] for open systems and three of the closed bioreactors (VTR, HTR, and FP) with the flat plates having the highest production rates (Table 10). Bioreactor volume and illuminated surface area (SA) are physical variables that depend on the design of the culture system.…”