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RECRUITMENT STRATEGIES OF ULVA AND PORPHYRA IN CENTRAL CALIFORNIA by Rosemary Romero Ephemeral algae are early colonizers of the rocky intertidal zone after a disturbance, although the mechanism of early colonization (including benthic microscopic stages and waterborne propagules) is poorly known. Recruitment of the ephemeral Ulva spp. was studied in two types of disturbance manipulations (partial removal of all macroscopic organisms were removed vs. complete removal of all macroand microscopic organisms) and an un-manipulated control at two tidal heights (high

Enzyme-catalyzed preparation of polymers offers several potentially valuable advantages over the usual polymerization procedures. This paper summarizes our successful use of lipase-catalyzed polycondensations to prepare both a series of achiral [AA-BB]x polyesters from bis(2,2,2- trichloroethyl) alkanedioates and diols and of an optically active, epoxy-substituted polyester having a stereochemical purity estimated to be greater than 96%, from racemic bis(2,2,2-trichloroethyl) trans-3,4-epoxyhexanedioate and 1,4-butanediol. All of the reactions were carried out at ambient temperature in anhydrous, low to intermediate polarity, organic solvents such as ether, THF, 2-ethoxyethyl ether, dibenzyl ether, o-dichlorobenzene, or methylene choride, using porcine pancreatic lipase (PPL) as the catalyst. The molecular weight achieved by the polycondensation is limited by accumulation of the trihaloethanol that forms as the reaction progresses, probably because it frees enzyme-bound water permitting hydrolysis of the polymer to occur. This problem has been alleviated by using a high boiling solvent and removing the alcohol by placing the re'action mixture under vacuum.