As usual, the answer is both "yes and no".

Yes, there are such relationships but they are highly variable dependend on the species and photoadapation.

The following papers can give you an impression -- and estimates for the conversion ratios of your model.

Hope it helps

Thomas

Geider, R.J., MacIntyre, H.L., Kana, T.M., 1998. A dynamic regulatory model of phytoplankton acclimation to light, nutrients, and temperature. Limnol. Oceanogr. 43 (4), 679–694.

Baumert, H.Z. & Petzoldt, T., 2008. The role of temperature, cellular quota and nutrient concentrations for photosynthesis, growth and light-dark acclimation in phytoplankton. Limnologica 38(3-4): 424-426. http://dx.doi.org/10.1016/j.limno.2008.06.002

Peter Kasprzak, Judit Padisák, Rainer Koschel, Lothar Krienitz, Frank Gervais, 2008. Chlorophyll a concentration across a trophic gradient of lakes: An estimator of phytoplankton biomass? Limnologica 38(3–4), 327-338. http://dx.doi.org/10.1016/j.limno.2008.07.002.

One additional comment:

A first approximation for the Chl:C range may be derived from Figure 1 in Cloern et al. (1995) to be 0 ... 0.06 (mg CHLa) / (mg C). It is up to you to derive a point estimate as a default from this.

Thomas

Cloern, J. E., Grenz, C. and Videgar-Lucas, L., 1995. An empirical model of the phytoplankton chlorophyll: carbon ratio -- the conversion factor between productivity and growth rate. Limnol. Oceanogr. 40, 1313-1321.

Hi Mouhamadou,

In addition to the literature provided by Thomas, let me offer one more paper where this question is given in details:

Paul G. Falkowski, Zvy Dubinsky, and Kevin Wyman. Growth-irradiance relationships in phytoplankton. Limnol. Oceanogr., 30(2), 311-321 (1985).

Hope it may help you.

The ratio chla/carbon is more or less dependent of the trophic conditions ; however the ratio indicated in several papers can be used, although t it should be taken in your mind that it is only an approximative value being largely having 10% of "standard deviation" !!!

Hi Mr Jeanjean, thank you for being so direct in your answer. Please would you give me some references where the order of magnitude you are talking about are given?

Thank you so much Mister Petzoldt for your help

The admissible ratio carbone/chla is 40.

(1) For phytoplankton, you can use a carbon:chlorophyll a ratio of 40 g/g

Reference: LORENZEN C. J.  (1968) CARBON/CHLOROPHYLL RELATIONSHIPS IN AN UPWELLING AREA, Limnology and Oceanography, 13, doi:10.4319/lo.1968.13.1.0202.

(2) You can also use the empirical model of Cloern et al. (1995) where the carbon:chlorophyll a ratio change  as a function of temperature, daily irradiance, and nutrient-limited growth rate.

Reference: Cloern et al. (1995) An empirical model of the phytoplankton chlorophyll : carbon ratio—the conversion factor between productivity and growth rate. Limnology and Oceanography 40, 1313–1321.