A Systematic Study of Chondracanthus Kutzing (Rhodophyceae) with a Contribution to the Marine Flora of Tomales Bay, California

Purpose of the Study: Chondracanthus Kutzing is a common genus of the red algal family Gigartinaceae. Seven species are currently recognized to occur along the northeastern Pacific. Systematists have in the past and present held conflicting viewpoints as to the appropriate classification of these species. The purpose of this study was to verify the taxonomic treatments that have occurred in the recent literature and to delineate three species of Chondracanthus that occur within Tomales Bay, California. A survey of the seaweeds in Tomales Bay is long overdue. The only study to date was completed almost 25 years ago. A search for unique algae, including introductions, range extensions, and rare morphological forms of different species was the goal of this study. Procedure: Through field observations of a morphological cline of Chondracanthus californicus J. Agardh; C. exasperatus Harvey et Bailey; and C. spinosus (KUtz.) Guiry in Tomales Bay, transplantation of these three species to the exposed coast and to the inner portion of Tomales Bay, and analysis of restriction endonuclease patterns from the amplified internally transcribed spacers (ITS 1 and 2) of nuclear encoded rONA (5.85 region), answers to the interspecific classification of members of the Gigartinaceae can be adequately addressed. The algal flora of Tomales Bay was determined by temporal and spatial field studies at selected sites along the b~y. The . taxonomy of Egregia is studied using the same techniques applied to the Chondracanthus project. Findings: . . A cline was found in Tomales Bay between three allopatrically distributed and morphologically distinct species: Chondracanthus californicus; C. exasperatus; and C. spinosus. The populations along ~he bay ~howed a gradual change in the shape of the thallus, with intermediate forms between the three species. Transplants of Chondracanthus californicus, C. exasperatus, and C. spinosus to the exposed coast developed hemispherical papillae, a dark red color, and continuous margins. Plants transplanted to the inner portion of Tomales Bay developed spines on the margins, a dichotomously branching apophysis, and changed color to greenish olive. In addition, transplanted thalli to the bay that were covered with a light filtration mesh, showed that excess light was responsible for the color change that was observed in the three taxa from Tomales Bay. DNA was successfully extracted and amplified from fourteen populations of Gigartinaceae. The PCR product of all samples was approximately 770 bp long. Following amplification, it was digested with the four restriction endonucleases, Hinf 1 , Alu 1, Taq 1, and Rsa 1. The fourteen populations fell into six groups with respect to fragment patterns and the number of sites that were recognized by each enzyme. These groups are: Group 1 Chondracanthus binghamiae, C. californicus, C. exasperatus, and C. spinosus from Tomales Bay; Group 2 Chondracanthus spinosus and C. asperifoliuS; Group 3 Chondracanthus canalicu/atus and C. serratus; Group 4 Chondracanthus harveyanus; Group 5 Chondracanthus armatus; and Group 6 Chondracanthus corymbiferus. A total of 126 species of Macro-algae were found in Tomales Bay, including 15 Chlorophyceae, 20 Phaeophyceae, and 91 Rhodophyceae. New distribution limits are set for four species of algae from Tomales Bay, Centroceras clavulatum (C. Ag.) Montagne, Fucus spiralis L., Gastroclonium compressum (Hollenb.) Chang et Xia, and Gelidium vagum Okamura. In addition, Pogonophorella californica (J. Ag.) Silva was found growing in abundance at Marshall Beach as an epilithic alga. The siphonaceaous, green, and weedy alga, Codium fragile subsp. tomentosoides (van Goor) Silva is first reported for the bay. Egregia laevigata was found at the type locality growing sympatrically with E. menziesii. Restriction patterns produced from the endonucleases Hinf 1 and 1 were identical for two samples of E. menziesii but differed from one sample of E. laevigata. Transplants of E. laevigata to Bodega Head, Calif. after four months of growth did not change morphologically. Conclusions: A presence of a cline and results from transplants indicate that a single taxon is represented from the three species Chondracanthus californicus, C. exasperatus, and C. spinosus from Tomales Bay. Analysis of the ITS 1 and 2, and the S.8S region using restriction endonuclease patterns support the recognition of a single species in Tomales bay, and delineate selected Gigartinaceae into groups that are interpreted as species. Six species of Chondracanthus are verified to occur in the Pacific North American flora, including C. spinosus, C. canaliculatus, C. harveyanus; C. corymbiferus and two comb. nov., C. exasperatus (Synonyms: C. californicus and C. binghamiae) and C. armatus. The potential for interesting algal findings, as well as studying environmental thallus variation in the Tomales Bay, is apparent. Preliminary work including field studies, observations, and molecular DNA analysis on the genus Egregia (Phaeophyceae) support the recognition of the two species E. laevigata and E. menziesii.