Rhodolith bed: a newly discovered habitat in the North Pacific Ocean

Abstract

Rhodoliths are unattached calcareous red algae that form extensive beds. Although rhodolith beds are widely distributed in temperate and tropical areas, a recent discovery in the North Pacific Ocean represents a significant northward extension of known rhodolith distribution. This bed, located in Prince William Sound, Alaska, is composed of one rhodolith species, Phymatolithon calcareum, with two reproductive states, tetrasporangial and gametangial. A characteristic feature of this bed is that cryptofaunal chitons were the most abundant associated invertebrate species. Comparisons with P. calcareum populations in other regions showed that Prince William Sound thalli are smaller in many measurable anatomical features.