Vertical attenuation coefficient of photosynthetically active radiation as a function of chlorophyll concentration and depth in case 1 waters.
Based on empirical relations found in the literature, relatively simple mathematical models of the average of the total absorption of seawater [a(T(z,Chl))], the chlorophyll-specific absorption coefficient of phytoplankton [a*(ph(z,Chl))], and the backscattering coefficient [b(b(Chl))], weighted by the in situ spectral distribution of photosynthetically active scalar irradiance (PAR), as functions of chlorophyll concentration and depth, were developed. The models for a(T(z,Chl)) and b(b(Chl)) can be used to calculate the coefficient of vertical attenuation of PAR [K(o(z,Chl))] and therefore to estimate the vertical profile of PAR as an input to algorithms for primary production. One application of a*(ph(z,Chl)) may be in the correction of the initial slope of the photosynthesis-irradiance curve [alpha*((z))] for the in situ spectral distribution of PAR and the package effect. Also, a*(ph(z,Chl)) may be used to calculate phi((z)), the in situ quantum yield of photosynthesis, from phi(max) and irradiance.
Giles-Guzmán
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División de Oceanología, Centro de Investigación Científica y de Educación Superior de Ensenada, BC, Ensenada, Baja California, Mexico. vfernan@cicese.mx
Alvarez-Borrego
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