Meeting Abstract
71.4 Sunday, Jan. 6 The rainbow in the dark: absorptive and fluorescent pigments of deep-sea plankton SWEENEY, AM*; BECK, N; HADDOCK, SHD; Duke Univ., UC Berkeley; Univ. of Penn.; MBARI alison.sweeney@berkeley.edu
Many deep-sea organisms contain red, black, or other pigments. While their ability to mask and absorb light has been well documented (e.g., Herring 1972; Johnsen 2005), the full variety of colors and their inferred functions are not well understood. Several of the pigments are autofluorescent, and one related function of luminescence may be to excite an overlying fluorescent tissue (Haddock et al. 2005), thereby generating more signaling color possibilities than typical blues and greens. In order to explore the possible functions of vivid pigmentation in deep-sea organisms and generate candidates for further study of the ecological functions of fluorescence, we extracted these pigments from more than 60 species in a variety of phyla. Using a range of organic solvents, we measured their absorbance and fluorescence characteristics, and explored correlations of these parameters with taxonomy and depth. We observed that many mesopelagic organisms contain regions of orange, yellow, blue and magenta coloration, and that many of these pigments were fluorescent. Our analyses revealed three major pigmentation categories: (1) non-polar, orange, carotenoid-like pigments; (2) highly polar red and magenta pigments; and (3) detergent-soluble porphyrin-based pigments. Crustaceans, chaetognaths and nemerteans contained carotenoid-like pigments, while all three pigment classes were found in cnidarians. Ctenophores at all depths possessed two separate pigments: one dark red and fluorescent, and the other bright magenta and non-fluorescent. This technique holds promise for tracing food-chain linkages through color measurements. Interestingly, we found that below the immediate ocean surface, there was no correlation between depth and pigment-type, supporting the idea that the functions of these pigments are related to bioluminescence-based visual ecology.
