Analytical solution for the vertical profile of daily production in the ocean. Issue 5 (27th May 2016)

• Record Type: Journal Article
• Authors: Kovač, Žarko; Platt, Trevor; Sathyendranath, Shubha; Morović, Mira
• Is Part Of: Journal of geophysical research. Volume 121:Issue 5(2016:May)
• Page Start: 3532
• Page End: 3548
• Publication Date: 2016-05-27
• Subjects: primary production -- analytical solution -- photosynthesis parameters -- production estimation -- seasonal cycle; Oceanography -- Periodicals; 551.4605
• DOI: 10.1002/2015JC011293
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract: Photosynthesis parameters are routinely estimated from in vitro measurements of primary production under constant light reaching each incubation bottle, by fitting a photosynthesis‐irradiance function to the measurements. Here we take one such function and integrate it in time for variable light input, similar to natural conditions, to obtain the analytical solution for the vertical profile of daily phytoplankton production in the field. This solution is then fitted to in situ measurements of primary production profiles in the same manner as a photosynthesis‐irradiance function is fitted to in vitro measurements under controlled and constant light conditions to retrieve the photosynthesis‐irradiance parameters. The method is tested on the Hawaii Ocean Time‐series data set. The solution explained 97.88% of the variance in measured normalized production at individual depths. The recovered parameters were then used to model the normalized daily water‐column production. The model explained 99.21% of variance in normalized watercolumn production of the entire data set. The seasonal cycle of the photosynthesis parameters recovered with the analytical solution was further studied for the Hawaii Ocean Time‐series. With respect to the photosynthesis parameter determination, the solution bridges the gap between classical photosynthesis‐irradiance measurements under controlled light conditions and in situ measurements which are made under natural, variable light conditions. It presents a new tool for the estimation of photosynthesis parameters from in situ measurements of primary production. Key Points: Analytical solution for the profile of phytoplankton production derived from a nonlinear model. Procedure for estimating photosynthesis parameters from in‐situ production profiles established. Photosynthesis parameters estimated from Hawaii Ocean Time‐series in‐situ production profiles.