NWAS 2001

15th NorthWest Algal Symposium Abstracts
  May 11-13, 2001 Camp Casey, Whidbey Island, Washington

(T= Talk, P= Poster)

T	MONITORING OF INTERTIDAL SEAWEED DIVERSITY IN THE OUTER BAY OF FUNDY (NEW BRUNSWICK, CANADA) REVEALS SYMPTOMS OF ENVIRONMENTAL STRESS
	Colin R. Bates^1, Thierry Chopin^1,2 & Gary W. Saunders^1. ^1Centre for Environmental & Molecular Algal Research, Department of Biology, University of New Brunswick, Fredericton, NB, Canada, E3B 6E1;^2Centre for Coastal Studies and Aquaculture, University of New Brunswick, Saint John, NB, Canada, E2L 4L5
	As a coastal environment, the Bay of Fundy presents many opportunities for use by humans. Along with these opportunities, pressure on the marine environment is inevitable, yet the resultant effects on coastal biotic communities can go unnoticed if not monitored. One way to monitor for such effects is to use biotic indicators, such as intertidal seaweeds. We have monitored seaweed community structure and indicator species in the outer Bay of Fundy throughout the year 2000 to evaluate for symptoms consistent with published indicators of stress. Our methods and results will be presented to confirm that pressures on the Bay of Fundy are indeed being reflected in intertidal seaweed communities. Specifically, we will indicate that certain sites within the Bay of Fundy are showing: low red algal diversity and abundance; blooms of opportunistic filamentous algae; increased abundance of benthic filter feeders and detritus feeders; and lower overall algal diversity..

T	Recruitment patterns onto natural substrata of the intertidal kelp Hedophyllumsessile (C. Ag.) Setchell in Barkley Sound, British Columbia
	Sophie Boizard, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
	Recruitment patterns onto natural substrata of the intertidal kelp Hedophyllum sessile (C. Ag.) Setchell were studied in Barkley Sound, BC. The most common substrata types found were articulated coralline algae, encrusting algae, bare rock and kelp holdfasts.Previous investigators have suggested that topographically complex substrata such as articulated coralli nes and kelp holdfasts might provide spatial refugia to juvenile H. sessile sporophytes.We hypothesized that substratum complexity would influence recruitment success and early survivorship of young H. sessile sporophytes, particularly in high energy environments.The recruitment and survivorship of young H. sessile sporophytes was monitored in permanent quadrats located on a wave-sheltered and on a wave-exposed shores over a period of one year.Recruits were found more frequently growing on articulated corallines than on anyother substratum.Substrata that were more or less flat such as encrusting algae and bare rock were rarely colonized by young sporophytes.H. sessile recruits were uncommon on adult  holdfasts despite their topographical complexity. These patterns were similar between wave-sheltered and wave-exposed shores. Following recruitment, survivorship was always greater for recruits that had settled onto articulated coralline algae.

P	A NEW CANDIDATE OF CERAMIUM (CERAMIACEAE, RHODOPHYTA) FROM THE NORTHWEST PACIFIC
	Tae Oh Cho & Sung Min Boo. Department of Biology, Chungnam National University, Daejon 305-764, Korea
	A new candidate of Ceramium (Ceramiaceae, Rhodophyta) is found in Kampo and Kuryongpo, on the east coast of Korea in February, April, August, September, and November, 1999 to 2001. Thalli are pseudodichotomously branched, corticated only in the nodes, and their apices are strongly rolled and have spines. Carpogonial branches occur singly per node, abaxially and unilaterally, and cystocarps are spherical and surrounded by five to six involucral branches. Male thalli are not found. Tetrasporangia are formed in an opposite sequence. Two tetrasporangia per each periaxial cell are produced and emergent on cortical nodes. Development of cystocarps and tetrasporangia conforms to that described in previous reports of the genus. Of 16 members known in the northwest Pacific, C. paniculatum Okamura and C. tenerrimum (Martens) Okamura are very similar to our alga. However, C. paniculatum has alternate branches that are repeated every four to five axial cells and a curved apex. Ceramium tenerrimum has only acropetal growth of cortical filaments. Our alga is mixed with C. paniculatum on cliffs, while C. tenerrimum occurs in flat areas. The nrDNA 18S gene sequences determined in this study strongly support that our alga should be described as a new member of Ceramium.

P	Phylogenetic relationships of Polysiphonia (Rhodomelaceae, Rhodophyta) and its relatives based on anatomical and nuclear small-subunit rDNA sequence data
	Han-Gu Choi^1, Myung-Sook Kim^2, Michael D. Guiry^2 & Gary W. Saunders^1. ^1Centre for Environmental and Molecular Algal Research, Department of Biology, University of New Brunswick, Fredericton, N.B., Canada & ^2Department of Biology and The Martin Ryan Marine Science Institute, University College Galway, The National University of Ireland, Galway, Ireland
	The aim of this study was to assess monophyly of the genus Polysiphonia and determine the phylogenetic affinities of its component lineages among related Rhodomelaceae.Our ‘total-evidence’ approach, combining 28 anatomical characters and SSU sequence data for 28 ceramialean algae including 11 species of Polysiphonia sensu lato (including two species of the newly described Neosiphonia) and 15 related Rhodomelaceae, indicates that Polysiphonia consists of three strongly supported clades – Polysiphonia-group, Neosiphonia-group and the multipericentral Polysiphonia species.The type species of the genus, P. stricta from the North Atlantic, formed a distinct clade with P. morrowii from the Northwest Pacific and P. pacifica from the Northeast Pacific.Neosiphonia included N. japonica and N. savatieri from the Northwest Pacific as originally proposed, and additionally includes P. elongata and P. harveyi from the North Atlantic and P. sp. from South Africa, which share diagnostic features with this genus.The two genera Boergeseniella and Enelittosiphonia associated solidly with the multipericentral Polysiphonia spp., P. fucoides, P. lanosa and P. nigra from the North Atlantic.The implications for the taxonomy of Polysiphonia sensu lato and related genera within the Rhodomelaceae will be discussed.

T	MORPHOLOGICAL AND MOLECULAR ASSESSMENTS OF HYBRIDIZATION IN 7 KELP GENERA
	Julie Collens & Louis Druehl, Simon Fraser University, Vancouver, Canada, at the Bamfield Marine
	Controlled in-lab reciprocal crossing experiments were performed using 7 NE Pacific kelp species from Barkley Sound, Vancouver Island, Canada, representing 7 genera and 3 families.Putative hybrid sporophytes were produced in practically every situation.In addition, parthenosporophytes were very common.To eliminate potential non-viable hybrids and parthenosporophytes, individuals reaching a size of at least 5cm in length are being assessed through morphological development and molecular methods.

P	TAXONOMIC AFFINITIES OF SPECIES IN THE GENUS LEPTOFAUCHEA (RHODYMENIALES; RHODOPHYTA).
	Jennifer Dalen & Gary W. Saunders.Centre for Environmental and Molecular Algal Research, Department of Biology, University of New Brunswick, Fredericton, N.B., Canada, E3B 6E1.
	The genus Leptofauchea was established based on an Australian type, Leptofauchea nitophylloides (J.Agardh) Kylin and currently includes five recognized species.Collections are rare, and in some instances species are known only from the type material.Details of vegetative and reproductive anatomy are not well documented and, as recognized by other researchers, the genus Leptofauchea is in serious need of systematic re-evaluation.Molecular and anatomical studies of a new species from Chile have resolved the taxonomic affinities of Leptofauchea within the Rhodymeniales.However, a number of taxonomic concerns regarding other Leptofauchea species have surfaced.We, therefore, provide anatomical details of several species currently included in the genus Leptofauchea, with the objective of clarifying their taxonomic status and redefining the features that make this genus unique.

T	BIOMECHANICAL PROPERTIES OF COEXISTING SEAWEEDS – CONFORMATION TO FLOW, POINTS OF FAILURE, AND REGENERATION
	Robert E. DeWreede.Department of Botany, The University of British Columbia, Vancouver, B.C. Canada
	Algae of different morphologies exist in similar habitats; here I examine species of coexisting of algae (using representatives of the Rhodophyta, Phaseophyceae, and Chlorophyta) for several of their biomechanical properties.Characteristics examined include Coefficient of Drag, Force to Break, Location of Break, and likelihood of removal from the habitat based on generated drag.In addition, I examine the relationship between location of break and the ability of the species to regenerate both vegetative and reproductive tissue.In a more general sense, the extent to which these characteristics appear to govern the distribution and abundance of each of these species is examined.A number of studies have been published which report on one or more of the above properties, but a more general picture has yet to emerge (if indeed such a picture exists).Here I attempt to broaden the current picture by adding to the species examined and repeating experiments on some species.The data presented include the results of personal research projects, class studies done at the Bamfield Marine Station, Bamfield, B.C., and results from Graduate Student research.

P	SILVETIA, A NEW FUCOID FOR THE NORTHEAST PACIFIC?

Louis Druehl, Simon Fraser University, Vancouver, Canada, at the Bamfield Marine Station

The distribution of Silvetia (previously known as Pelvetia) has been variously described as extending from Coos Bay, OR to Ensenada Mexico (Setchell and Gardner 1925), from Mexico to southern British Columbia (Scagel 1957), and most recently from Mexico to central California (Scagel et al. 1989).  This poster describes plants recently collected from Nanaimo, BC resembling Silvetia and speculates on their origin.

T	SURVIVORSHIP AND NEW BLADE PRODUCTION IN MAZZAELLA SPLENDENS: THEIR RELATIVE IMPORTANCE IN LIFE HISTORY PHASE
	Leonard J. Dyck & Robert E. De Wreede.Department of Botany, University of British Columbia, 3529 - 6270 University Boulevard, Vancouver, B.C., Canada, V6T 2B1.
	The evolutionary persistence of stable biphasic isomorphic life histories is an important topic in current life history theory. Models which successfully reproduce these cycles do so by incorporation of ecological differences between the phases. The most recent models have shown that these differences can be small. At Brockton Point, Vancouver, Mazzaella splendens (Rhodophyta, Gigartinales) was observed to alternate between gametophyte dominance in summer and tetrasporophyte dominance in winter. The pattern of these seasonal changes in density suggested that higher qrowth rates might be coupled with lower survivorship in haploids, while slower growth and greater survivorship were concurrent in diploids. This could be interpreted as divergence in ecological strategies between the two phases; the haploid being r-selected relative to a more K-selected diploid. A preliminary analysis of three years data on blade production and survivorship in M. splendens at Second Beach, Barkley Sound, Canada, has been completed. Results indicate that growth and survivorship are not necessarily coupled. Probability of loss fluctuates randomly for both phases, conferring no particular advantage on either. New blade production, however, contributes significantly to gametophyte dominance at this site. Continuing work will examine the interaction between changes in density, phase ratio, survivorship, growth, reproduction and morphology from November 1997 to January 2001.

T	Diel rhythm in oxygen evolution of Euglena gracilis
	Gabriela Hannach & Frieda B. Taub.School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington
	Many cellular processes follow diel patterns that are governed by a biological clock.The alternation of light and dark imposed by a recurring photoperiod is a major cue for the setting of the clock.We investigated the daily pattern of net oxygen evolution and consumption by autotrophic cultures of Euglena gracilis strain z, via continuos recording by in-line, flow-through microelectrodes.To assess whether an endogenous rhythm is – at least in part - responsible for observed diel variations in oxygen exchange, the cells were entrained to a 14:10 h LD photoperiod and then subjected to short, 1:1 h LD cycles for several weeks.Short LD cycles provide sufficient light for photosynthesis but cannot be perceived as a photoperiodic cue by the cells.Cells transferred to the 1:1 h LD cycle continued to exhibit the entrained pattern in oxygen exchange with a 24 h periodicity.The rhythm persisted for several weeks without significant dampening of the diel oscillations in oxygen evolution.This study was conducted as part of NASA-funded testing of a Cell Culture Unit for use on the International Space Station.

P	SURVVAL STRATEGIES OF GRACILARIA CORTICATA J.AG. IN PORT OKHA IN THE GULF OF KUTCH(GUJARAT), WEST COAST OF INDIA
	Manoj Kumar, Environment Biology Laboratory, Department of Botany, University of Delhi,Delhi-110007, India
	Gracilariacorticata, a hydrocolloid taxon of red algae, grows along the intertidal zone at Port Okha in the Gulf of Kutch (Gujarat), India. The intertidal zone that gently slopes towards the sea is exposed and gets flooded during low and high tides respectively. The presence of discoid holdfast with modified internal cellular arrangement is a specialized adaptation which enables the plants to anchor firmly and withstand tidal fluctuations. The alga is characterised by wavy outline, compact arrangement of cortex and medulla, wall ingrowths in the medullary cells at thallus-holdfast transition zone as well as sulphatedpolysaccharides in the intercellular mucilage. These features provide strength and flexibility to the thallus in addition to protection of this seaweed against physical damage and stringent environmental conditions.The plant is dioecious, with distinct season specific phases of diplobiontic life cycle.The tetrasporophyte plants are robust, heavily infested with epiphytes and survive throughout the year. The carposporophyte phase is concerned with amplification of the diploid stage, because fertilisation chances are meagre due to non-motile male gametes.

T	USING ADDITIONAL GENE SYSTEMS TO UNDERSTAND KELP (LAMINARIALES; PHAEOPHYCEAE) EVOLUTION
	Christopher E. Lane, Charlene Mayes & Gary W. Saunders. Center for Environmental and Molecular Algal Research, Department of Biology, University of New Brunswick, Fredericton, N.B., Canada, E3B 6E1
	While there has been a relatively large body of work published on kelp, the phylogenetic relationships within the Laminariales remain poorly defined. The contemporary system of classification for the "advanced" group of the Laminariales was established in 1925 by Setchell and Gardner. At that time, they acknowledged that their system had shortcomings. In the early 1990s, molecular investigations involving small subunit (SSU) and the internal transcribed spacer (ITS) regions of the ribosomal DNA were initiated. While both of these genes provided valuable insights into kelp evolution which challenged the morphological system in place, many key nodes within the Laminariales phylogeny remained weakly supported. The large subunit (LSU) gene was considered as a system that may be useful in resolving some of the remaining questions regarding Laminariales systematics because the LSU is not as conservative as the SSU, but not nearly so divergent as the ITS. Furthermore, it is equivalent in length to the SSU and ITS regions combined, thus having the potential to offer substantially more phylogenetically informative sites. In addition to data from the LSU, sequence from the large subunit of the Rubisco encoding chloroplast DNA (rbcL) have also been determined in an attempt to make the data set more comprehensive. Results from LSU, rbcL, conserved regions of the ITS, and combined analyses will be discussed.

P	MORPHOLOGICAL DIVERSITY AND MOLECULAR RELATEDNESS OF THE SPECIES OF THE RED ALGAL GENUS PLOCAMIUM (PLOCAMIALES, FLORIDEOPHYCEAE)
	K. Virginia Lehmkuhl & Gary W. Saunders.Centre for Environmental and Molecular Algal Research, Department of Biology, University of New Brunswick, Fredericton, N.B., Canada, E3B 6E1
	Morphological/anatomical and molecular data provide powerful tools to construct phylogenies.The recently established red algal order, Plocamiales, currently contains two genera and there are a number of questions concerning relatedness among the species within these genera that need to be addressed.A key issue concerns the delimitation of the type species, Plocamium cartilagineum (L.) Dixon.Though P. cartilagineum is reportedly cosmopolitan in its distribution, preliminary molecular investigations indicate that there is substantial genetic divergence among P. cartilagineum isolates from diverse geographic locations.A second issue concerns the number of, and the relationships among, Plocamium species.Upwards of 40 Plocamium species have been reported worldwide.The current knowledge of species diversity, however, remains insufficient to draw conclusions regarding the evolutionary relatedness and the historical biogeography of the genus.We will illustrate the morphological and anatomical diversity of species within the Plocamiales with focus on P. cartilagineum.We will also present preliminary molecular phylogenetic results for Plocamium species based on the LSU (large ribosomal subunit) gene system.

T	PHOTOSYNTHETIC COMPETENCE OF SYMBIOTIC ALGAE (ZOOXANTHELLAE) EXPELLED AND RETAINED BY STRESSED CORALS
	Gisele Muller-Parker.Shannon Point Marine Center and Dept. of Biology, Western Washington University, Bellingham, WA 98225-9160, USA
	Coral “bleach” (lose their symbiotic algae) in response to environmental stresses.Although this phenomenon is well described, no one has collected the expelled algae to determine their physiological state.The photosynthetic parameters of expelled zooxanthellae were compared with those of algae retained by the host coral Montastraea faveolata after exposure to elevated temperature (+2^oC) and enhanced PAR and UV-B irradiance.Zooxanthellae were obtained from coral plugs collected in the Bahamas (15-m depth; July 1998 and 1999) and subjected to different experimental treatments, including seawater ammonium enrichment.Photosynthesis-irradiance curves were used to derive photosynthetic capacity (Pmax) and photosynthetic efficiency (alpha) of zooxanthellae.Photosynthetic parameters indicate that zooxanthellae remaining in the host are protected from moderate UV-B stress and do not respond to increased ammonium availability.In contrast, expelled zooxanthellae are damaged by UV-B exposure and utilize increased ammonium enrichments to increase both alpha and Pmax.Detrimental effects of high temperature are more pronounced under high PAR and UV-B.The host provides adequate photoprotection for resident zooxanthellae.Expelled zooxanthellae lose this advantage but gain the ability to utilize seawater nutrient enrichments and enhance their productivity.Although both populations are damaged by high temperature, our study shows that zooxanthellae remain photosynthetically competent after expulsion.These results offer hope for coral recovery following a bleaching event.Whether expelled zooxanthellae can re-infect bleached corals awaits investigation.

T	KINETICS OF HALOGENATED MONOTERPENE BIOSYNTHESIS BY MICROPLANTLET SUSPENSION CULTURES OF THE RED ALGA OCHTODES SECUNDIRAMEA WITHIN AN AIRLIFT PERFUSION PHOTOBIOREACTOR
	Gregory L. Rorrer & Jason P. Polzin.Department of Chemical Engineering, Oregon State University, Corvallis, Oregon, USA
	Three genera of macrophytic red algae (Ochtodes, Plocamium, Portieria) contain novel halogenated monoterpenes that are potential candidates for pharmaceutical compound development.In order to study halogenated monoterpene biosynthesis, a microplantet suspension culture was established from the tropical red alga Ochtodes secundiramea.O. secundiramea microplantlets produced seven halogenated monoterpenes derived from the halogenation of myrcene, including bromomyrcene, chloromyrcene, bromochloromyrcene, and dibromomyrcene.The kinetics of myrcene and halogenated monoterpene formation were followed as a function of time during cultivation of O. secundiramea microplantlets within an airlift photobioreactor under batch and liquid medium perfusion modes of operation.Under batch cultivation, myrcene levels increased 10-fold during late exponential phase.Cultivation under high nutrient perfusion rates (20% per day medium replacement rate, 3.5 mM nitrate, N:P of 19:1) at 400 mE m^-2s^-1 light intensity provided growth rates exceeding 20% per day and plantlet mass densities exceeding 10 g dry mass per liter.These conditions also stimulated the formation of myrcene and bromomyrcene to levels exceeding 3.0 mg bromomyrcene per g dry cell mass.However, di-halogenated monoterepene formation was not influenced by high-nutrient growth conditions.A biosynthetic pathway proposed for halogenated monoterpene formation suggests that although growth conditions may control monoterpene production, other factors may determine the rates for subsequent halogenation of these monoterpenes.

P	PHOTOPERIOD GROWTH MODEL FOR AGARDHIELLA SUBULATA MICROPLANTLETS
	Gregory L. Rorrer & Bryan Huang.Department of Chemical Engineering, Oregon State University, Corvallis, Oregon, USA
	A model was developed to describe the effect of photoperiod on the phototrophic growth of microplantlets derived from the macrophytic marine red alga Agardhiella subulata.The effects of photoperiod (h light: h dark within 24 h cycle) on the biomass growth curve were studied within a bubble-column photobioreactor.Photobioreactor cultivation of A. subulata microplantlets was carried out at saturation conditions with respect to light flux intensity (76 mmol photons m^-2 s^-1), nutrient medium delivery (20% nutrient replacement per day), and CO2 delivery (0.35 mmol CO2 L^-1 h^-1),so that the cumulative effects of photodamage on the cell density vs. time curve at photoperiods approaching continuous light could be observed.Biomass production was maximized at 16:8 LD, where plantlet mass densities exceeding 3.6 g dry cell L^-1 were achieved after 60 days in culture.Biomass production was proportional to photoperiod at low fractional photoperiods (< 10:14 LD), but high fractional photoperiods approaching continuous light (> 20:4 LD) shut down biomass production.Cell density vs. time profiles under resource-saturated cultivation conditions were adequately described by a cumulative photodamage growth model, which incorporated irreversible photodamage, photoperiod, and light saturation processes into the specific growth rate.Cell density vs. time data was fitted to the model.The maximum specific growth rate in the absence of photodamage was 0.078 day^-1, whereas the apparent rate constant for photodamage ranged from 0.018 day^-1 (10:14 LD) to 0.26 day^-1 (24:0 LD), suggesting that photodamage was the limiting factor to biomass production at photoperiods approaching continuous light.

T	HYDROGEN PEROXIDE PRODUCTION IN CYANOBACTERIA
	JohnRueter^1, Mike Houston^2 & Eric Henry^2. ^1Environmental Sciences Department, Portland State University, Portland, Oregon, USA. & ^2Puriponics, Portland, Oregon, USA.
	Many different strains of algae have been observed to produce hydrogen peroxide (H2O2) as a natural side product of the light reactions in photosynthesis. This production can be followed with fluorescence methods or estimated using transient measurements of O2 during light to dark transitions. The production was not a function of ambient O2 concentrations but did increase with light- dark oscillations. If held in the light, cells eventually reach steady state between the H2O2 production rate and breakdown. The transient O2 concentration after the lights are turned off can be modeleld as a increase due to the action of catalase on H2O2 superimposed on a decrease in O2 from cell respiration. These results are discussed in the context of the roles that H2O2 and reactive oxygen species play in short term (minutes) regulation of photosynthesis.

P	VALVE MORPHOGENESIS IN THE MARINE ARAPHID DIATOM, GEPHYRIA MEDIA (BACILLARIOPHYCEAE)
	Mary A. Tiffany.Department of Biology and Center for Inland Waters, San Diego State University, San Diego, CA 92182, USA
	Gephyria media is an atypical marine araphid diatom, arcuate in general shape. It is heterovalvar, heavily silicified, with chambered valves and girdle bands. A study was made of the progression of valve morphogenesis of both types ofvalves, the concave valve with apical pore fields, the convex lacking these. Valves begin with a narrow sternum with virgae (pinnate lateral outgrowths).The apical pore fields and rimoportulae at each end of the concave valve are produced early in valve morphogenesis.The rimoportula of the convex valve is also formed early and the virgae are branched at the apex.Formation of the bi- to triseriate areolae begins at the sternum.Completion of the valves involves the development of an internal silica sheet beginning at the sternum.When the silica sheet is complete it forms a zigzag pattern of foramina at the edge of the interior of both kinds of valves and encloses the chambers.The rimoportulae lengthen internally and in the final process forms the labiate process upon a stalk.

T	PHYTOPLANKTON DYNAMICS IN THE SALTON SEA, CALIFORNIA, 1997-1999
	Mary A. Tiffany^1, Maria R. González^2 & Stuart H. Hurlbert^1.^1Department of Biology and Center for Inland Waters, San Diego State University, San Diego, CA, USA & ^2Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
	Phytoplankton dynamics of the Salton Sea, a large salt lake situated in southeastern California, were studied over a three-year interval 1997-1999. Chlorophyll a values ranged from 7-100 µg L^-1, indicating the eutrophic nature of this lake.Three algal groups dominated: dinoflagellates, diatoms and a raphidophyte.Cryptomonads, a coccolithophore, non-motile chlorophytes and a euglenoid were also important.Total phytoplankton abundance was highest in late winter, when it was dominated by dinoflagellates, especially Gyrodinium uncatenum, Heterocapsaniei and a species of Gymnodinium.A drop in phytoplankton density each April was likely caused by increased feeding by the planktivorous fish, tilapia, Oreochromis mossambicus, as the lake warmed.As the fish were forced into nearshore environments in summer by anoxia, the mid-lake phytoplankton rebounded and was dominated primarily by Chattonella marina, Thalassionema sp., scrippsielloid dinoflagellates, and Gonyaulaxgrindleyi.Overturn events occurring in late summer or early fall were associated with low oxygen and high sulfide concentrations in the water, and both phytoplankton and metazooplankton abundance declined abruptly by an order of magnitude or more. After the crashes, phytoplankton density showed a gradual increase throughout the fall and winter, mostly involving diatoms and dinoflagellates.These crashes in plankton did not occur in the 1950s.Species composition has also changed since the 1950s.We report a number of dinoflagellate and diatom species and one raphidophyte species that have not previously been documented, but some of which now dominate. A number of these are species new to science.

T	Coexistence of introduced and native congeneric algae:Codium fragile and C. tomentosum on Irish rocky intertidal shores
	Cynthia D. Trowbridge. Hatfield Marine Science Center, Oregon State University, Newport, Oregon 97365, USA
	The coexistence of three taxa of Codium (Chlorophyta: Codiaceae) was examined on wave-swept shores of western Ireland:the introduced macroalgae C. fragile (Sur.) Hariot ssp. atlanticum (Cotton) Silva and ssp. tomentosoides (van Goor) Silva and the native C. tomentosum Stackhouse. In spring 1999 and 2000, four sites were monitored to evaluate whether past predictions regarding temporal changes and species replacement occurred.Introduced and native species of dichotomously branching Codium occurred at four tidal levels:in tidepools in the (1) upper barnacle zone, (2) mid barnacle/fucoid zone, and (3) mussel zone, and on emergent substrata in the (4) red algal turf/kelp zone. In my survey, 4.8% of pools with Codium contained two species (C. tomentosum and C. fragile) and 11.9% of pools with C. fragile contained both subspecies; thus, local coexistence of native and introduced congeners did occur. Compared to 1971 censuses, C. fragile ssp. atlanticum increased in relative abundance at all tidal levels, and the dominance of C. fragile ssp. tomentosoides declined.The native C. tomentosum constituted the same percentage of the population as it did in 1971:predictions of the elimination of the native species were not met. Pool availability and primary rock surfaces were not limiting at most sites, indicating that inter-subspecific and inter-specific competition could not account for temporal changes in Codium distribution on Irish shores.Other ecological constraints may have contributed to the purported long-term changes in Codium abundance.

T	LOW PREFERENCE ULVOID GREEN ALGAE ARE CHEMICALLY DEFENDED
	Kathy Van Alstyne & Letise Houser.Shannon Point Marine Center, Western Washington University, 1900 Shannon Point Road, Anacortes, WA 98221, USA
	Green algae in the genera Ulva and Enteromorpha are often thought to be high preference foods for all herbivores. However, some herbivores such as the green sea urchin Strongylocentrotus droebachiensis preferentially avoid consuming Ulva fenestrata and Enteromorpha linza when offered a choice of macroalgal species. Like many green algae, Ulva and Enteromorpha produce high concentrations of dimethylsulfoniopropionate (DMSP). When these algae are physically damaged, DMSP is converted to dimethyl sulfide (DMS) and acrylic acid by the enzyme DMSP lyase. Both DMS and acrylic acid function as feeding deterrents towards urchins whereas DMSP is a feeding attractant. These results confirm that DMSP and DMS function as part of an herbivore activated defense system.They also suggest that chemical defenses may contribute to the persistence of green algal blooms because they make the algae unpalatable to some herbivores.

T	ANABAENA AND APHANIZOMENON: ENIGMATIC FILAMENTS
	Charles R. Williams & J.R. Waaland. Department of Botany, University of Washington, Seattle, Washington.
	Representatives of Pacific Northwest planktonic Anabaena and Aphanizomenon morphotypes were compared via direct filament PCR with representative strains from several culture collections.Phylogenetic relationships between Anabaena and Aphanizomenon were investigated using DNA sequence from cpcBA-IGS (cyanophycocyanin alpha and beta subunits with intergenic spacer) and rpoC1 (RNA Polymerase subunit C1) gene sequence.The results seriously question the current taxonomy of the Nostocaceae and in combination with other molecular phylogenetic studies strongly suggest that Aphanizomenon be subsumed within the genus Anabaena.The diversity of Anabaena genotypes in Puget Sound lowland lakes will also be discussed briefly.