Biomass distribution in marine planktonic communities

Abstract

Patterns in primary production and carbon export from the cuphotic zone suggest that the relative contribution of planktonic heterotrophs to community biomass should decline along gradients of phytoplankton biomass and primary production. Here, we use an extensive literature data survey to test the hypothesis that the ratio of total heterotrophic (bacteria + protozoa + mesozooplankton) biomass to total autotrophic biomass (H : A ratio) is not constant in marine plankton communities but rather tends to decline with increasing phytoplankton biomass and primary production. Our results show that the plankton of unproductive regions are characterized by very high relative heterotrophic biomasses resulting in inverted biomass pyramids, whereas the plankton of productive areas are characterized by a smaller contribution of heterotrophs to community biomass and a normal biomass pyramid with a broad autotrophic base. Moreover, open-ocean communities support significantly more heterotrophic biomass in the upper layers than do coastal communities for a given autotrophic biomass. These differences in the biomass structure of the community could be explained by the changes in the biomass-specific rates of phytoplankton production that seem to occur from ultraoligotrophic to eutrophic marine regions, but other factors could also generate them. The patterns described suggest a rather systematic shift from consumer control of primary production and phytoplankton biomass in open ocean to resource control in upwelling and coastal areas.

Variability and control of carbon consumption, export, and accumulation in marine communities

“…I expressed all variables in gC m Ϫ2 d Ϫ1 by dividing the cumulative values (i.e., values integrated over the duration of the study) by the duration of the study and using standard conversion factors (Wiebe 1988;Gasol et al 1997). Owing to the nonnormal nature of the data compiled, the overall variability in primary production, consumption by herbivores, decomposition, export and refractory accumulation Table 1.…”

Efectos microbiológicos producidos por un evento de surgencia costera en Chile central

“…En los sistemas improductivos la biomasa heterotrófica es más alta que la autotrófica; en cambio, como en el caso de la surgencia, cuando los niveles de nutrientes se incrementan, se produce un cambio progresivo hacia un predominio de los organismos autótrofos sobre los heterótrofos (Gasol et al 1997, Vargas et al 2007, situación coherente con lo que hemos observado, las bacterias aumentan 6 veces y los eucariontes autótrofos, 24 veces (Tabla 1).…”

Partitioning particulate light absorption: A budget for a Mediterranean bay

“…This role may be even more important in oligotrophic systems where the biomass of the microheterotrophs often equals or exceeds that of autotrophs (Bird and Kalff 1984;Cole et al 1988;Fuhrman et al 1989;Cho and Azam 1990;Simon et al 1992;Gasol et al 1997). As a result, the dynamics of the community of microplankton is imprinted in the optical properties of seawater (Spinrad et al 1989;Stramski et al 1992).…”

“…Monaco et al 1990;Dauby et al 1995), where the biomass of heterotrophic organisms often exceeds that of autotrophs (e.g. Gasol et al 1997). Hence, light absorption by inorganic particles and heterotrophic microplankton can equal (or exceed) that by photosynthetic plankton, particularly at the blue end of the visible spectra (cf.…”