01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0377 |
| Title of Abstract | Potential of optical and ecological proxies to quantify phytoplankton carbon in oligotrophic waters |
| Authors | David Antoine, Chandanlal Parida*, Camille Grimaldi |
| Organisation | Curtin University, Perth, Australia |
| Address | Marine Observations
Leibniz Institute for Baltic Sea Research Warnemünde (IOW)
Seestraße 15 Rostock, Rostock, Germany Pincode: D-18119 E-mail: chandanlal.parida@gmail.com |
| Country | Germany |
| Presentation | Oral |
| Abstract | Satellite ocean color observations provide two proxies to estimate the phytoplankton carbon concentration, Cphyto, then used as input to models quantifying growth rates and primary production, namely the phytoplankton chlorophyll-a concentration, Chl-a, and the particulate backscattering coefficient, bbp. Variability in phytoplankton community composition, pigment assemblages and contribution of non-algal material all interplay in the relation between these proxies and Cphyto, so that no ubiquitous relationship exists between them. It is accordingly still unclear which of Chl-a or bbp is best suited to quantify Cphyto, or whether they both are yet each in specific trophic conditions, especially for low-productivity oligotrophic waters. Here we use a data set from the eastern Indian Ocean that includes phytoplankton cell counts, phytoplankton pigments, particulate organic carbon (POC) and inherent optical properties (IOPs) to perform a comparative assessment of Cphyto derived from either Chl-a or bbp or cell counts combined with allometric relationships. We found significant correlations (r2 > ~0.5-0.6) between the three Cphyto estimates and IOPs, Chl-a or POC when samples from all depths down to 150 m are included. When only the top 25 m are included (amenable to ocean color remote sensing), no significant relationships were found, except between the cytometry-derived Cphyto and both Chl and POC. The bbp-derived Cphyto showed the smallest variability across the entire data set. These results warn about applying to satellite ocean color observations relationships derived from data collected throughout the euphotic layer. |
| Are you part of IIOE-2 endorsed project | yes |
| Endorsed Project Number | IIOE2-EP06 |
| Keywords | Phytoplankton carbon; Particulate organic carbon; Inherent optical properties; Indian Ocean; IIOE2 |
| For Awards | no |