Linking chlorophyll-nutrient dynamics to the RedÞeld N:C ratio with a model of optimal phytoplankton growth

Pahlow, Markus

doi:10.3354/meps287033

Cited by 124 publications

(164 citation statements)

References 46 publications

Supporting

Mentioning

156

Contrasting

Unclassified

Order By: Relevance

“…Several authors argue that phytoplankton nutrient uptake should be modeled using "optimal uptake kinetics" (OU) (Pahlow et al, 2005;Smith and Yamanaka, 2007;Smith et al, 2009) rather than as the Michaelis-Menten (MM) function used in this study. Replacing MM with OU alters the control simulation and the concentrations of non-limiting nutrients.…”

Section: Discussionmentioning

confidence: 99%

Response of ocean phytoplankton community structure to climate change over the 21st century: partitioning the effects of nutrients, temperature and light

2010

View full text Add to dashboard Cite

Abstract. The response of ocean phytoplankton community structure to climate change depends, among other factors, upon species competition for nutrients and light, as well as the increase in surface ocean temperature. We propose an analytical framework linking changes in nutrients, temperature and light with changes in phytoplankton growth rates, and we assess our theoretical considerations against model projections (1980-2100) from a global Earth System model. Our proposed "critical nutrient hypothesis" stipulates the existence of a critical nutrient threshold below (above) which a nutrient change will affect small phytoplankton biomass more (less) than diatom biomass, i.e. the phytoplankton with lower half-saturation coefficient K are influenced more strongly in low nutrient environments. This nutrient threshold broadly corresponds to 45 • S and 45 • N, poleward of which high vertical mixing and inefficient biology maintain higher surface nutrient concentrations and equatorward of which reduced vertical mixing and more efficient biology maintain lower surface nutrients. In the 45 • S-45 • N low nutrient region, decreases in limiting nutrientsassociated with increased stratification under climate change -are predicted analytically to decrease more strongly the specific growth of small phytoplankton than the growth of diatoms. In high latitudes, the impact of nutrient decrease on phytoplankton biomass is more significant for diatoms than small phytoplankton, and contributes to diatom declines in the northern marginal sea ice and subpolar biomes. In the context of our model, climate driven increases in surCorrespondence to: I. Marinov (imarinov@sas.upenn.edu) face temperature and changes in light are predicted to have a stronger impact on small phytoplankton than on diatom biomass in all ocean domains. Our analytical predictions explain reasonably well the shifts in community structure under a modeled climate-warming scenario. Climate driven changes in nutrients, temperature and light have regionally varying and sometimes counterbalancing impacts on phytoplankton biomass and structure, with nutrients and temperature dominant in the 45 • S-45 • N band and light-temperature effects dominant in the marginal sea-ice and subpolar regions. As predicted, decreases in nutrients inside the 45 • S-45 • N "critical nutrient" band result in diatom biomass decreasing more than small phytoplankton biomass. Further stratification from global warming could result in geographical shifts in the "critical nutrient" threshold and additional changes in ecology.

show abstract

Section: Discussionmentioning

confidence: 99%

Response of ocean phytoplankton community structure to climate change over the 21st century: partitioning the effects of nutrients, temperature and light

2010

View full text Add to dashboard Cite

show abstract

“…Cellular biomass and metabolic energy are interconvertible, and thus metabolic energy can be accounted for as carbon (or biomass) equivalents (Pahlow 2005). 2.…”

Section: Methodsmentioning

confidence: 99%

“…One method for theoretically addressing this problem is via optimality models. Optimality models that examine how organisms allocate intracellular resources to optimize growth have helped to explain observed changes in cellular stoichiometry and physiology that occur because of changes in the environment (Shuter 1979;Klausmeier et al 2004;Pahlow 2005). Yet, some aspects of photoacclimation cannot be explained by simple optimality arguments.…”

mentioning

confidence: 99%

An optimality model of photoadaptation in contrasting aquatic light regimes

Talmy

Blackford

Hardman-Mountford

et al. 2013

Limnology & Oceanography

View full text Add to dashboard Cite

To investigate photoacclimation of phytoplankton adapted to different aquatic light regimes, a physiologically explicit phytoplankton optimality model was applied in two contrasting environments: constant irradiance vs. dynamic irradiance associated with oceanic mixed layers. Nitrogen was assumed to be partitioned between cellular components associated with light harvesting, carbon fixation, biosynthesis, and photoprotection. The model was used to predict how resources are (re)distributed to optimize growth in the different environments. Optimal intracellular nitrogen allocation in dynamic environments was associated with constitutive investment in Calvin cycle enzymes; in contrast, in the static environment Calvin cycle allocation was reduced at low light. Furthermore, reduced allocation to components associated with photoprotection in static environments led to heavily inhibited photosynthesis-irradiance response consistent with that of Prochlorococcus adapted to relatively stable oligotrophic gyres. In contrast, photosynthetic response in the diatom Skeletonema costatum was better explained by maintenance of photoprotection components across a range of integrated light doses. Limited range of chlorophyll : C in Thalassiosira pseudonana was consistent with optimization of resource allocation to light-harvesting components in dynamic environments, in contrast to the relatively wide range in allocation to light harvesting predicted by the model in static environments and chlorophyll cell 21 observed in high-light-adapted Prochlorococcus. The model was used to explain variability of the photosynthesis-irradiance response of samples from the Celtic and Irish Seas. Photoacclimation state is a consequence of optimization of resource allocation to the set of environmental parameters (e.g., surface irradiance, depth of mixing, and light attenuation) that influence light variability.

show abstract

“…Despite such species specificity, the end result of altering the photosynthetic apparatus is the same: to reach a new state that is optimal for growth (Pahlow, 2005). However, there is still uncertainty about the extent to which achieving an optimal solution involves the trade-off between maximising the rate of photosynthesis and minimising the rate of photooxidative stress or photoinhibitory damage.…”

mentioning

confidence: 99%

Responses ofEmiliania huxleyi(Prymnesiophyceae) to step changes in photon flux density

Harris

Scanlan

Geider

2009

European Journal of Phycology

View full text Add to dashboard Cite

A non-calcifying strain (Ply 92) of Emiliania huxleyi (Lohman) Hay et Mohler, was subjected to reciprocal step changes of photon flux density (PFD) between 50 and 800 mmol photons m À2 s À1 to establish the timescales of photoacclimation.Photoacclimation in E. huxleyi involved adjustment of cellular light harvesting pigment contents, but not cellular ribulose bisphosphate carboxylase-oxygenase (RuBisCO) or cellular RNA contents. There was considerable variability in both the magnitude and the rate of the response of physiological and biophysical variables to the step changes in PFD. The slowest response was observed in cellular chl a content, and the chl a/carbon ratio. Acclimation of these variables appeared to be due to dilution of pigment pools rather than to pigment turnover. Changes in the chl a-specific light absorption coefficient accompanied changes in cellular chl a content. Following the shifts in PFD, the efficiency of excitation energy transfer from the photosystem II antennae to reaction centres II (RCII), as assessed from F Changes in non-photochemical excitation energy quenching were correlated with the relative and absolute abundance of the xanthophyll cycle pigments diadinoxanthin and diatoxanthin, which appeared to be reversibly interconverted with fucoxanthin. Thus, acclimation to PFD involved co-ordinated adjustment of the quantum efficiency of RCII, the efficiency of excitation energy transfer from the light-harvesting pigment bed to RCII, and cellular light absorption on overlapping time scales.

show abstract

Linking chlorophyll-nutrient dynamics to the RedÞeld N:C ratio with a model of optimal phytoplankton growth

Cited by 124 publications

References 46 publications

Response of ocean phytoplankton community structure to climate change over the 21st century: partitioning the effects of nutrients, temperature and light

Response of ocean phytoplankton community structure to climate change over the 21st century: partitioning the effects of nutrients, temperature and light

An optimality model of photoadaptation in contrasting aquatic light regimes

Responses ofEmiliania huxleyi(Prymnesiophyceae) to step changes in photon flux density

Contact Info

Product

Resources

About