A dynamic regulatory model of phytoplanktonic acclimation to light, nutrients, and temperature

Abstract

A new regulatory model can describe acclimation of phytoplankton growth rate (p), chlorophyll a : carbon ratio and nitrogen: carbon ratio to irradiance, temperature and nutrient availability. The model uses three indices of phytoplankton biomass-phytoplankton carbon (C), phytoplankton nitrogen (N), and chlorophyll a (Chl). The model links the light-saturated rate of photosynthesis to N: C, requires that Chl a synthesis be coupled to nitrogen assimilation, and includes several regulatory features. These include feedback inhibition of the nitrogen assimilation rate by increases in the N: C ratio, as well as regulation of Chl a synthesis by the balance between light absorption and photosynthetic carbon fixation. The model treats respiration as the sum of the maintenance metabolic requirement and the cost of biosynthesis. In addition, the model can account for accumulation and mobilization of energy reserves (i.e. variability of N: C) and photoacclimation (i.e. variability of Chl : N and Chl : C) in response to variations in irradiance and nutrient availability. The assumptions of the model are shown to be in agreement with experimental observations and the model output compares favorably with data for cultures in balanced and unbalanced growth.

Primary production in a tropical large lake: The role of phytoplankton composition

“…As the effects of nutrient supply and phytoplankton taxonomic composition are confounded in our field study, we cannot distinguish their respective role in controlling P Bm . It was demonstrated that N limitation in microalgae limits the amount of Chla and RubisCO, the key enzyme involved in photosynthetic fixation of carbon dioxide (CO 2 ) (Geider and MacIntyre, 2002;Turpin, 1991) and that P Bm parallels N content in N-limited algae (Geider et al, 1998). Moreover, P starvation limited also P Bm and the contribution of RubisCO to cell protein in Dunaliella tertiolecta Butcher (Geider et al, 1998).…”

“…Main environmental factors influencing P Bm in cultures are temperature and nutrient availability (Geider and MacIntyre, 2002). A reduction of P Bm is observed in nutrient-limited algae (Geider et al, 1998;Greene et al, 1991). At the community level, it has occasionally been demonstrated that larger cells sustain higher P Bm than smaller cells (Cermeño et al, 2005;Peltomaa and Ojala, 2010), but field studies attempting to relate the compound photosynthetic response on the taxonomic composition of the phytoplankton assemblage are rare (Segura et al, 2013).…”

Numerical modelling of spatio-temporal variability of growth of Mytilus edulis (L.) and influence of its cultivation on ecosystem functioning

“…Since CChl changes due to the effects of photoacclimation, it is modelled according to the formulations given in Geider et al (1997) and Geider et al (1998).…”

An optimization‐based model of iron—light—ammonium colimitation of nitrate uptake and phytoplankton growth

“…The model is based on this optimality argument, and some physiological detail has been sacrificed to allow the optimality argument to be used. One important simplification is that carbon metabolism and nitrogen metabolism are treated as being independent, whereas recent empirically based model structures allow carbon acquisition to depend on cell nitrogen (Sciandra et al 1997;Geider et al 1998). Explicit modeling of physiological feedbacks between internal nitrogen stores and external ammonium and nitrate pools (Flynn et al 1997) has also been suppressed for biogeochemical clarity.…”