Where is Noctiluca scintillans in the Arabian Sea: An evaluation of in situ multispectral fluorescent
signatures
Tricia Thibodeau, 2013
Coinciding with a shift in monsoon weather patterns over India, the phytoplankter Noctiluca scintillans
has been overtaking phytoplankton blooms in the Arabian Sea. Identifying N. scintillans distributions and
abundances during these blooms allows us to identify environmental conditions favoring this species. One way
to assess phytoplankton composition is to use an optical multi-excitation chlorophyll fluorometer (WETLabs
ECO 3X1M sensor – 3 wavelength eXcitation, 1 wavelength eMission) that measures the fluorescence or the
excess light from phytoplankton that has not been utilized for photosynthesis.
The broader scope of this research is to understand how indirect effects of climate may structure
phytoplankton composition in the Arabian Sea. The objectives are to quantify the distribution of N. scintillans
within the NE monsoonal bloom off the Indian coast in 2011 with respect to the hydrographic characteristics.
The approach of this study is to test whether a multispectral fluorescence method can be used to identify
populations of N. scintillans in the Arabian Sea and to distinguish them from other phytoplankton groups using
multispectral fluorescence profiles.
The study successfully evaluated the novel multispectral fluorescence approach and identified zones of
N. scintillans abundance (Figure 1). This approach can now provide continuous observation of any
phytoplankton with distinct pigment differences and can be applied to multiple oceanographic platforms
presenting instantaneous observations of any given environment.
Figure 1. Spatial distribution and dominance
of N. scintillans and other phytoplankton
groups as determined by fluorescence. Based
on the separation of these species, it is
evident that the offshore stations at the
beginning of the cruise had fundamentally
different phytoplankton composition
compared to the offshore stations at the end
of the cruise.
Faculty Mentor: Dr. Collin S. Roesler
Funded by the Peter J. Grua and Mary G. O'Connell Research Award
References:
Goes, J. I., P. G. Thoppil, H. D. R. Gomes, and J. T. Fasullo. 2005. Warming of the Eurasian landmass is
making the Arabian Sea more productive. Science 308: 345-347.
Gomes, H. D. R., J. I. Goes, P. Matondkar, S. G. Parab, A. R. N. Al-Azri, and P. G. Thoppil. 2008. Blooms of
Noctiluca miliaris in the Arabian Sea-An in situ and satellite study. Deep Sea Research I 55: 751-765.
Proctor, C. W., and C. S. Roesler. 2010. New insights on obtaining phytoplankton concentration and
composition from in situ multispectral chlorophyll fluorescence. Limnology and OceanographyMethods 8: 695-708.