Abstract
Photosynthetic organisms show a number of photoadaptations which enable them to acclimate to the light regime in which they grow. In the case of invertebrate-algal symbioses, the responses can occur in both the algae and the invertebrate. Colonies of the colonial ascidian-cyanophyte symbiosis Trididemnum solidum at Galeta, panama, show morphological variation relative to the light regime in which they live. Colonies growing in full sunlight are white, thicker, more heavily calcified, and distribute their cyanophytes more uniformly throughout the depth of the colony than do colonies in lower light regimes. Shaded colonies are purple, thinner, have fewer spicules at the colony surface, concentrate their algae near the surface, and have a greater amount of phycoerythrin relative to phycocyanin in their symbiotic algae. The purple coloration of low light colonies appears to be due primarily to the phycobilin pigment of the algae. Experimental shading of colonies in the lowest light areas in which they are found at Galeta, resulted in significantly higher mortality than colonies beneath clear control roofs. The ascidian host appears to be physiologically dependent upon its symbionts and capable of changing its morphology in response to ambient light levels.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.