Volume 44, Issue 2

Laurencia venusta Yamada, originally described from the western Pacific Ocean, is recorded for the first time from the Atlantic Ocean. It occurs in Quintana Roo State, Mexico, which is located on the eastern portion of Yucatan Peninsula, Caribbean Sea. The present species belongs to the subgenus Laurencia by nature of possessing four pericentral cells per vegetative axial segment, secondary pit-connections between superficial cortical cells, and parallel-type arrangement of the tetrasporangia. The principal characteristics for species identification are: pale green color, soft and flaccid thalli, verticillate branching, and the presence of lenticular thickenings in the walls of medullary cells.

This paper describes the large-scale geographical distribution, population structure, and reproductive season of the brown algae Fucus serratus L. in the Baltic proper. We have also experimentally tested fertilisation success and germination of F. serratus zygotes in a salinity gradient with the aim of finding out whether an adaptation to reduced salinity has occurred. Fucus serratus was found to be belt-forming along the shores of southeastern Sweden and scattered populations were found up to the middle of the Baltic proper. The ratio of non-reproductive (juvenile) plants per reproductive (adult) plant decreased significantly from 37 ± 8 S. E. in the south to 0.4 ± 0.2 in the north. Fucus serratus was reproductive during October to November on the mainland coast, while the populations on the southeast coast of Öland were reproductive during June to July. Laboratory experiments showed that successful fertilisation of Baltic F. serratus zygotes decreased drastically from 86.9 ± 1.0% S. E. at 9 psu to 5.5 ± 0.5% S. E. at 6 psu. Fucus serratus zygotes from the western coast of Sweden needed a significantly higher salinity for successful fertilisation than the Baltic gametes did, and at 8 psu, only a few eggs were fertilised (5.5 ± 0.5% S. E.). Since a relatively high proportion (35 %) of the Baltic F. serratus zygotes germinated in 7 psu, (the salinity at the northernmost populations) we discuss other factors such as ice-scraping and eutrophication as possible factors limiting the geographical and vertical distribution of the species in the Baltic Sea.

The ceramiaceous red alga Griffithsia tomo-yamadae was described from the Pacific side of Honshu, Japan by Okamura in 1936, based on vegetative and tetrasporangial material. Unreported since its original description, the species has recently been found growing in abundance at 1–2 m depths below lowest tide levels at Geojedo Island off the southeastern coast of Korea. Our detailed observations confirm the validity of G. tomo-yamadae as a species characterized by complanate, flabellate thalli; pseudodi-/trichotomous branching; nodal tetrasporangial fascicles that form an inner ring of bearing cells surrounded by 8–9 involucral branches, consisting of single basal cell and two terminal cells; naked spermatangial fascicles; and cystocarps surrounded by five involucral branches that originate from the hypogenous cell. Sexual reproductive structures are described for the first time and conform to previous reports of the genus.

A cellulose acetate electrophoresis method was used to examine allozyme variation both within and between three members of the genus Fucus : F. spiralis , F. vesiculosus and F. serratus and Ascophyllum nodosum . Samples of algae were collected from two rocky shores, one sheltered and one exposed, 11 km apart and screened for allozyme variation at eight loci . Patterns of allozyme variation at five polymorphic loci were successfully resolved. There was significant heterogeneity in allele frequencies between both the F. serratus and F. spiralis populations from the two shores but not between the two F. vesiculosus populations. In the fucoids, there was an overall heterozygote deficiency within populations relative to Hardy Weinberg proportions and FIT values were high. There was little genetic differentiation between the populations of each species, however Fucus serratus showed the greatest ( F ST = 0.0261) and F. vesiculosus the least amount ( F ST = 0.0058) of genetic differentiation between shores. Based upon UPGMA clustering of Nei's genetic identities, F. spiralis was the most genetically distinct and F. serratus clustered with F. vesiculosus. Ascophyllum nodosum joined the main Fucus cluster as an outgroup confirming that it is genetically quite distinct from the members of the genus Fucus . Based on our results we suggest that cellulose acetate electrophoresis is a suitable tool for the elucidation of population genetic patterns in the brown algae.

Photosynthetic activities of submerged seaweeds before and after drying were measured in eighteen species collected from different vertical positions from a Pacific shore at Shimoda City in Japan. The seaweeds were desiccated until the cellular water levels equilibrated with the air in the chamber under various humidities at 10 °C. Relative water contents of all species drastically decreased as the cellular water potentials were reduced from 0 to −14MPa and gradually decreased in the range from −14 to −158MPa. Porphyra dentata , which is an upper intertidal species, recovered photosynthetic activity from the lowermost water potential of −158MPa, while the plants collected from the lower intertidal and subtidal zones reduced their photosynthetic activities after desiccation to comparatively higher water potentials from 0 to −14MPa. Other species collected from the middle intertidal zone reduced their photosynthetic activities following desiccation to water potentials in the range from −14 to −158MPa. It is concluded that the cellular abilities of desiccation tolerance in intertidal seaweeds varied between the species examined and correlated with their vertical position within the tidal zone.

A method to determine the proportion of both enantiomers of 2,6-di- O -alkylgalactose in a permethylated/perethylated polysaccharide is described. It involves conversion of the monosaccharides, obtained by hydrolysis of the sample, to the corresponding diastereomeric acetylated 1-deoxy-1-(1-phenylethylamino)alditols, followed by gas chromatographic analysis. This procedure has been applied to a polysaccharide isolated from Pterocladiella capillacea .

The initial steps of host-pathogen interactions leading to successful colonization of Porphyra yezoensis thalli by zoospores of Pythium porphyrae were studied using epifluorescence and scanning electron microscopy. Biflagellated zoospores act as the infective agents for the red rot causing microbial pathogen Pythium porphyrae . These biflagellate zoospores were similar in morphology to primary and secondary zoospores of diplanetic Oomycetes. The flagella lie in a longitudinal groove on the ventral zoospore surface, with long, fine mastigonemes occurring on the anterior tinsel flagellum. There was no evidence of zoospore chemotaxis. The zoospores came into contact, attached and encysted onto the host thallus. The membrane-bound zoospores did not stain with calcofluor, which is specific for chitin and glucans, while the cell walled cysts and mycelia specifically stained with calcofluor when viewed by epifluorescence microscopy, allowing in situ identification of the encysted zoospores, the first stage of colonization on the host thallus. Cysts attached to the host thallus developed a cell wall, germinated, formed appressoria (an essential prelude of penetration), and penetrated the host surface near the site of cyst attachment. The cysts appeared to be adhering to the host thallus by forming a cementing matrix around encysted zoospores when observed with a scanning electron microscope. Absence of inward deformations at penetration sites suggested that enzymatic action rather than mechanical pressure was responsible for initial penetration of the host cell wall. The specific staining of spore walls with calcofluor fluorescent brightner is an inexpensive, easy and rapid technique for early identification of parasitized Porphyra thalli.

Juncus roemerianus is an important component of salt marshes of the United States east coast and the Gulf of Mexico. This plant supports a large biodiversity of decomposers, mostly ascomycetes and coelomycetes, unknown even a few years ago. Koorchaloma galateae sp. nov. is an obligate marine species from the base of culms; Pestalotiopsis juncestris sp. nov. is a facultative marine species and grows in the middle of culms and on involucral leaves; Tetranacriella papillata anam.-gen. et sp. nov. can be classified as a terrestrial but halotolerant species, occurring in the middle and upper part of leaves and on involucral leaves. All three species are known so far only from North Carolina.

Hypoglossum imperfectum is described as new to science. It is a minute repent species collected in relatively deep water off the South African south coast, in the Tsitsikamma Coastal National Park. It differs from all other species of the genus by the possession, in fertile blades only, of stunted proximal third-order cell rows, which thus do not reach the thallus margin. This is in violation of the generic definition that proclaims that in Hypoglossum (and the ‘ Hypoglossum group’) all third-order cell rows reach the thallus margin.

Stirnia prolifera gen. et sp. nov. is described from the southern region of the Sultanate of Oman on the northern Arabian Sea. This alga forms clumps of erect axes up to 21 cm in height and arising from a well-developed hold-fast system. In Oman it occurs on wave-impacted rocky shores from the lowest intertidal down to a depth of 8 m. It exhibits a distinctive combination of features, including the solid nature of its compressed, dichotomously branched axes and the production of special small fertile proliferations bearing terminal, tetrahedrally divided tetrasporangia in invaginated regions. Male thalli produce the spermatangia also on special small proliferations. Reasons are presented to assign it to the Lomentariaceae (Rhodymeniales).

A check-list of Moroccan marine Chlorophyceae, based on both literature records and some original data, is given. The distribution of each taxon for this region (13 Mediterranean and 25 Atlantic localities) is reported. Using present-day taxonomy, 102 species, infraspecific taxa and stadia are accepted for the Moroccan coasts. A new combination is proposed: Blidingia tuberculosa (P. Dangeard) Benhissoune, Boudouresque et Verlaque.

Chilean specimens identified as Laingia hookeri (Lyall) Kylin and serving as the basis for the first report of this genus from Chile have been examined. Because of their apical structure and the tristromatic structure of their blades and because the cystocarps are borne directly on the primary blade in a scattered arrangement, these specimens have been determined to be Pseudophycodrys phyllophora (J. Agardh) Skottsberg. This species was previously known for southern Chile and with a distribution including the Subantarctic (Falkland Islands, Macquarie Island, Tristan da Cunha, and southern Argentina). Therefore, Laingia is removed from the marine algal flora of Chile.

During 1993, quarterly systematic samplings were made at ten representative locations of the benthic environments of La Paz Bay. At each location we gathered algae in the subtidal and intertidal zones. We identified 126 species, of which 118 were previously reported. Eight are first records: Amphiroa beauvoisii, A. misakiensis, A. vanbosseae, A. valonioides, Dictyota cervicornis, Endoplura aurea, Hydrolithon reinboldii, and Liagora ceranoides f. leprosa . The greatest richness was at Calerita and the smallest at Isla Gaviota. The largest number of species was found in spring and the least in autumn. In La Paz Bay the phycofloristic similarity between locations was determined by the degree of exposure to surge, depth, and type of substrate. The association analysis allowed us to identify groups of species that included organisms with different morphological characteristics, from structurally simple to complex, but that share a common preference for the same type of substrate and environment. The morphology of the algae that constituted the associations was different, however the organisms had strategies to adapt, allowing coexistence in habitats with similar conditions. La Paz Bay has a great variety of environments, different types of substrates, and climatic and oceanographic conditions which change during the year. In this sense, seaweeds would be a quantitative and qualitative sign of certain environmental characteristics. If the conditions change, there will be a variation in the species expression, which can be in number or in external morphology. This will depend on their ability to adapt.