Hyperspectral Distinction of Two Caribbean Shallow-Water Corals Based on Their Pigments and Corresponding Reflectance

The coloration of tropical reef corals is mainly due to their association with photosynthetic dinoflagellates commonly known as zooxanthellae. Combining High Performance Liquid Chromatography (HPLC), spectroscopy and derivative analysis we provide a novel approach to discriminate between the Caribbean shallow-water corals Acropora cervicornis and Porites porites based on their associated pigments. To the best of our knowledge, this is the first time that the total array of pigments found within the coral holobiont is reported. A total of 20 different pigments were identified including chlorophylls, carotenes and xanthophylls. Of these, eleven pigments were common to both species, eight were present only in A. cervicornis, and three were present only in P. porites. Given that these corals are living in similar physical conditions, we hypothesize that this pigment composition difference is likely a consequence of harboring different zooxanthellae clades with a possible influence of endolithic green or brown algae. We tested the effect of this difference in pigments on the reflectance spectra of both species. An important outcome was the correlation of total pigment concentration with coral reflectance spectra up to a 97% confidence level. Derivative analysis of the reflectance curves showed particular differences between species at wavelengths where several chlorophylls, carotenes and xanthophylls absorb. Within species variability of spectral features was not significant while interspecies variability was highly significant. We recognize that the detection of such differences with actual airborne or satellite remote sensors is extremely difficult. Nonetheless, based on our results, the combination of these techniques (HPLC, spectroscopy and derivative analysis) can be used as a robust approach for the development of a site specific spectral library for the identification of shallow-water coral species. Studies (Torres-Perez, NASA Postdoctoral Program) are currently underway to further apply this approach to other Caribbean benthic coral reef features. The data will be used with planned and future airborne and satellite studies of the site and for algorithm development to advance the use of future airborne and satellite instrument capabilities (NASA PRISM and HyspIRI) for discrimination of coral reef benthic composition.

[1]  R. Rowan,et al.  REVIEW—DIVERSITY AND ECOLOGY OF ZOOXANTHELLAE ON CORAL REEFS , 1998 .

[2]  S. Phinn,et al.  Spectral unmixing of coral reef benthos under ideal conditions , 2004, Coral Reefs.

[3]  Serge Andréfouët,et al.  Spectral reflectance of coral reef bottom-types worldwide and implications for coral reef remote sensing , 2003 .

[4]  Serge Andréfouët,et al.  Airborne hyperspectral detection of microbial mat pigmentation in Rangiroa atoll (French Polynesia) , 2003 .

[5]  M. Zapata,et al.  Microalgal classes and their signature pigments , 2011 .

[6]  Eric J. Hochberg,et al.  Capabilities of remote sensors to classify coral, algae, and sand as pure and mixed spectra , 2003 .

[7]  D. Powers,et al.  Molecular genetic identification of symbiotic dinoflagellates (zooxanthellae) , 1991 .

[8]  Mar Ecol Prog,et al.  Improved HPLC method for the analysis of chlorophylls and carotenoids from marine phytoplankton , 2022 .

[9]  Randall S. Alberte,et al.  Characterization of in vivo absorption features of chlorophyte, phaeophyte and rhodophyte algal species , 1994 .

[10]  Geir Johnsen,et al.  Phytoplankton pigments : characterization, chemotaxonomy and applications in oceanography , 2011 .

[11]  A. Savitzky,et al.  Smoothing and Differentiation of Data by Simplified Least Squares Procedures. , 1964 .

[12]  G. F. Humphrey,et al.  New spectrophotometric equations for determining chlorophylls a, b, c1 and c2 in higher plants, algae and natural phytoplankton , 1975 .

[13]  A. Banaszak,et al.  SCRIPPSIELLA VELELLAE SP. NOV. (PERIDINIALES) AND GLOEOKINIUM VISCUM SP. NOV. (PHYTODINIALES), DINOFLAGELLATE SYMBIONTS OF TWO HYDROZOANS (CNIDIARIA) 1, 2 , 1993 .

[14]  J. Marsh,et al.  Primary productivity of reef-building calcareous red algae , 1970 .

[15]  S. Liaaen-Jensen,et al.  Carotenoids of the dinophyceae , 1974 .

[16]  R. Armstrong,et al.  Physiological Responses of Acropora cervicornis to Increased Solar Irradiance † , 2007, Photochemistry and photobiology.

[17]  Peter J Mumby,et al.  Biological and remote sensing perspectives of pigmentation in coral reef organisms. , 2002, Advances in marine biology.

[18]  R. Bidigare,et al.  Visibly healthy corals exhibit variable pigment concentrations and symbiont phenotypes , 2007, Coral Reefs.

[19]  O. Hoegh‐Guldberg,et al.  Low symbiont diversity in southern Great Barrier Reef corals, relative to those of the Caribbean , 2003 .

[20]  Paul Stoodley,et al.  Modular Spectral Imaging System for Discrimination of Pigments in Cells and Microbial Communities , 2008, Applied and Environmental Microbiology.

[21]  Fuan Tsai,et al.  Derivative Analysis of Hyperspectral Data , 1998 .

[22]  M. Lesser,et al.  Depth-dependent responses to solar ultraviolet radiation and oxidative stress in the zooxanthellate coral Acropora microphthalma , 1995 .

[23]  P. Falkowski,et al.  � 2003, by the American Society of Limnology and Oceanography, Inc. Green-fluorescent proteins in Caribbean corals , 2022 .

[24]  UV-absorbing compounds in three species of Caribbean zooxanthellate corals : Depth distribution and spectral response , 2000 .

[25]  Heather Holden,et al.  Hyperspectral identification of coral reef features , 1999 .

[26]  S. Wright,et al.  Rapid extraction and high-performance liquid chromatography of chlorophylls and carotenoids from marine phytoplankton , 1984 .

[27]  Robert R. Bidigare,et al.  Bio-optical modeling of photosynthetic pigments in corals , 2006, Coral Reefs.

[28]  E. LeDrew,et al.  Application of principal components analysis to change detection , 1987 .

[29]  R. Trench,et al.  NOMENCLATURE OF ENDOSYMBIOTIC DINOFLAGELLATES , 1986 .

[30]  S. Wright,et al.  Phytoplankton Pigments in Oceanography: Guidelines to Modern Methods , 1997 .

[31]  M. Matz,et al.  Evolution of Coral Pigments Recreated , 2004, Science.

[32]  N. Knowlton,et al.  Intraspecific diversity and ecological zonation in coral-algal symbiosis. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[33]  R. Bidigare,et al.  Analysis of Algal Pigments by High-Performance Liquid Chromatography , 2005 .

[34]  R. Bidigare.  Analysis of algal chlorophylls and carotenoids , 2013 .

[35]  A. Baker,et al.  Diversity of symbiotic dinoflagellates (zooxanthellae) in scleractinian corals of the Caribbean and eastern Pacific , 1997 .

[36]  Agaricia tenuifolia,et al.  Diversity and community structure of symbiotic dinoflagellates from Caribbean coral reefs , 2002 .

[37]  Warren L. Butler,et al.  HIGHER DERIVATIVE ANALYSIS OF COMPLEX ABSORPTION SPECTRA , 1970 .

[38]  Daniel J. Repeta,et al.  Improved HPLC method for the analysis of chlorophylls and carotenoids from marine phytoplankton , 1991 .

[39]  Eugenio R. Mendez,et al.  Multiple scattering on coral skeletons enhances light absorption by symbiotic algae , 2005 .

[40]  Stuart R. Phinn,et al.  Environmental and Sensor Limitations in Optical Remote Sensing of Coral Reefs: Implications for Monitoring and Sensor Design , 2012, Remote. Sens..

[41]  Dale A. Kiefer,et al.  Derivative analysis of spectral absorption by photosynthetic pigments in the western Sargasso Sea , 1989 .

[42]  M. Warner,et al.  Differential xanthophyll cycling and photochemical activity in symbiotic dinoflagellates in multiple locations of three species of Caribbean coral , 2006 .

[43]  Effects of UV radiation on the growth, photosynthetic and photoprotective components, and reproduction of the Caribbean shallow-water coral Porites furcata , 2012, Coral Reefs.

[44]  Locally accelerated growth is part of the innate immune response and repair mechanisms in reef-building corals as detected by green fluorescent protein (GFP)-like pigments , 2012, Coral Reefs.

[45]  Wei Li,et al.  Spectral Signatures of Coral Reefs: Features from Space , 2001 .

[46]  r.drew C. 2zker.  SYMBIOSIS ECOLOGY OF TWO CARIBBEAN ACROPORID CORALS , 2004 .

[47]  Anya Salih,et al.  Contributions of host and symbiont pigments to the coloration of reef corals , 2007, The FEBS journal.

[48]  Serge Andréfouët,et al.  Spectral reflectance of coral , 2004, Coral Reefs.

[49]  Charles H. Maze.  Spectral measurements of fluorescence emission in Caribbean cnidarians , 2006 .