Primary production models derived from chlorophyll-a fluorescence parameterized according to the phytoplankton community structure

• Grant number: 13/06282-8
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2013
• End date: August 31, 2016
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Biological Oceanography
• Principal Investigator: Aurea Maria Ciotti
• Grantee: Maria Fernanda Coló Giannini
• Host Institution: Centro de Biologia Marinha (CEBIMAR). Universidade de São Paulo (USP). São Sebastião , SP, Brazil

Abstract

Primary production estimates in the oceans are usually obtained through conventional methods involving oxygen production or inorganic carbon uptake. However, there are other techniques, such as the direct and less invasive method derived from the chlorophyll-a active fluorescence. The active fluorescence provides estimates of electron transfer rates (ETR) during photosynthesis in the autotrophic organisms. Measured ETRs are directly related to the oxygen production and carbon assimilation by phytoplankton. Variations in ETR occur due to different responses of the organism on the efficiency to capture light and effectively use it to photosynthesize, and those are called as photophysiological rates. The photophysiological rates may vary as function of nutrients concentration in the water, light and temperature conditions, as well as the acclimation level of the phytoplankton community to that condition. Due to the fast growth rates of phytoplankton cells, however, we expect that a measured photophysiological rates are mainly a function of phytoplankton community structure, either by their dominant cell sizes or by the presence of different accessory pigments. The hypothesis of this work is that the photophysiological parameters variability as a response of nutrients availability, important factor for the primary production models, are primarily driven by changes in the phytoplankton community structure. The main goal of the work is to improve models of primary production estimates derived from chlorophyll-a fluorescence in oligotrophic regions through parameterizations according to the community structure. In situ analysis and laboratory experiments will be carried out, from which we expect to find robust relationships between the community and the photophysiological rates in order to parameterize the proposed models. The current proposal is part of the thematic project Biota/FAPESP - Araça: "Biodiversidade e funcionamento de um ecossistema costeiro subtropical: subsídios para gestão integrada". (AU)

Scientific publications

(4)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

GIANNINI, F.; MENDES, C. R. B.; GARCIA, C. A. E.; CARVALHO, A. C. O.; CIOTTI, A. M.. Phytoplankton community and the fluorescence-derived photo-physiological parameters in the South Atlantic Ocean. JOURNAL OF MARINE SYSTEMS, v. 218, JUN 2021. (13/06282-8)

CIOTTI, AUREA M.; FERREIRA, AMABILE; GIANNINI, MARIA F. C.. Seasonal and event-driven changes in the phytoplankton communities in the Araca Bay and adjacent waters. OCEAN & COASTAL MANAGEMENT, v. 164, n. SI, p. 14-31, OCT 1 2018. (11/50317-5, 13/06282-8)

COLO GIANNINI, MARIA FERNANDA; CIOTTI, AUREA MARIA. Parameterization of natural phytoplankton photo-physiology: Effects of cell size and nutrient concentration. Limnology and Oceanography, v. 61, n. 4, p. 1495-1512, JUL 2016. (13/06282-8, 11/50317-5)

CIOTTI, AUREA M.; FERREIRA, AMABILE; GIANNINI, MARIA F. C.. Seasonal and event-driven changes in the phytoplankton communities in the Araca Bay and adjacent waters. OCEAN & COASTAL MANAGEMENT, v. 164, p. 18-pg., 2018-10-01. (11/50317-5, 13/06282-8)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

GIANNINI, Maria Fernanda Coló. The influence of phytoplankton pigments composition and dominant cell size on fluorescence-derived photophysiological parameters and implications for primary production rates. 2016. Doctoral Thesis - Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC) São Paulo.