BIOGEOGRAPHY OF BATRACHOSPERMUM HELMENTOSUM (BATRACHOSPERMALES, RHODOPHYTA) IN NORTH AMERICA USING MOLECULAR AND MORPHOLOGICAL DATA

Over the course of 3 years (1997–1999), 72 stream sites were sampled for epilithic diatom communities. The analysis of these samples has led to the identification of over 325 species of diatoms. In addition to sampling the diatom community, selected physical and chemical parameters were recorded from each stream reach. These parameters included pH, specific conductance, current velocity, SRP, nitrate, silica, and total alkalinity. Canonical Correspondence Analysis (CCA) was used to identify influential environmental parameters and to assess the response of the diatom community to prominent anthropogenic inputs in the region (i.e. coal mine drainage, eutrophication). The initial analyses indicate that pH was the most influential environmental parameter along the first CCA axis. This shift was not unexpected, as acid mine drainage (AMD) in the region leads to a wide range of pH values (2.8–7.93). The highly acidic sites were characterized by species of the genus Eunotia (specifically E. exigua and E. steineckei ), Frustulia rhomboides , and Pinnularia subcapitata. Furthermore, Achnanthidium minutissimum was the most widely distributed of the diatom species encountered, being found at 94% of the sites sampled. Streams that fluctuated between acidic and circumneutral pH (termed "teeter-totter") had greater abundances of Brachysira vitrea than other streams in this survey. Further implications for the use of these diatom communities as biomonitoring tools and the distribution of assemblages within the Western Allegheny Plateau will be discussed.     

BIOGEOGRAPHYOF BATRACHOSPERMUM GELATINOSUM (BATRACHOSPERMALES,RHODOPHYTA) IN NORTH AMERICA BASED ON MOLECULAR AND MORPHOLOGICAL DATA1

Fifteen populations of the widespread fieshwater red alga Batrachospermum gelatinosum (L.) De Candolle were sampled throughout the geographic range in North America from central Alabama, U.S.A. (33° N), to Ellesmere Island, Northwest Territories (NWT), Canada (80° N). Analysis of ribosomal DNA internal transcribed spacer (ITS) 1 and 2 sequences yielded a parsimony tree with a large polytomy consisting of most populations plus a branch with one Nova Scotia and two NWT populations. The nucleotide variation, both within the polytomy and within the branch, was small (< 1%). The sequence divergence between the branch and polytomy was 3%. The lengths of the ITS 1 and 2 sequences of B. gelatinosum, 216–229 and 448–458 base pairs, respectively, fall within the very broad ranges reported for other red algae. The cluster analysis of 11 morphometric characteristics revealed three groupings of populations, partly based on geographic distribution. All tundra, eastern boreal forest, and mid-western hemlock-hardwood populations were in one grouping, whereas the deciduous forest, coastal plain, and eastern hemlock-hardwood populations were in a second. How ever, one deciduous forest population from Rhode Island, U.S.A. was unassociated. There was considerable overlap in morphometric characteristics among the three groupings. Based on this fact and the relatively small nucleotade variation in ITS sequences, we conclude that B. gelatinosum is a morphologically variable and geographically widespread species that is a valid taxonomic entity.     

PHYLOGEOGRAPHY OF BATRACHOSPERMUM MACROSPORUM (BATRACHOSPERMALES,RHODOPHYTA) FROM NORTH AND SOUTH AMERICA1

Phylogeographic trends in Batrachospermum macrosporum Mont. were investigated using the mitochondrial intergenic spacer between the cytochrome oxidase subunit 2 and 3 genes (cox2‐3). A total of 11 stream segments were sampled with seven in the coastal plain of North America and four in tropical areas of South America. Fifteen thalli were sampled from seven streams, 14 thalli from two streams, and eight thalli from two streams. There were 16 haplotypes detected using 149 individuals. Of the eight haplotypes from locations in North America, all were 334 base pairs (bp) in length, and of those from South America, five were 344 bp, and three were 348 bp. Two individual networks were produced: one for the haplotypes from North America and another for those from South America, and these could not be joined due to the large number of base pair differences. This split between haplotypes from North and South America was confirmed with sequence data of the rbcL gene. There was very little genetic variation among the haplotypes from the North American locations, leading us to hypothesize that these are fairly recent colonization events along the coastal plain. In contrast, there was high variation among haplotypes from South America, and it would appear that the Amazon serves as a center of diversity. We detected considerable variation in haplotypes among streams, but frequently, a single haplotype in an individual stream segment, which is consistent with data from previous studies of other batrachospermalean taxa, may suggest a single colonization event per stream.     

BIOGEOGRAPHY AND TAXONOMY OF BATRACHOSPERMUM HELMINTHOSUM (BATRACHOSPERMALES,RHODOPHYTA) IN JAPAN INFERRED FROM RBCL GENE SEQUENCES1

Twenty‐seven individuals of Batrachospermum helminthosum Bory were collected from various sites in Japan, from temperate Iwate Prefecture to subtropical Okinawa Prefecture. The chloroplast‐encoded rbcL gene was sequenced from each sample. Phylogenetic analyses were performed using these and previously published sequences of 12 samples from North America. There were five haplotypes among the Japanese samples. Haplotype 1 was collected throughout a large geographical area corresponding to most of the sampling range in this study and was represented by most individuals (21 individuals). The other haplotypes were represented by one to three individuals, respectively. These distributions of haplotypes suggest the occurrence of one large metapopulation and/or recent colonization over a wide geographical area in Japan. Phylogenetic analysis showed two well‐supported clades within B. helminthosum, one clade containing four haplotypes (1–4) from Japan and the other clade comprising five North American haplotypes. Such differences between Japanese and North American haplotypes might be a result of continental drift and subsequent isolation in the Mesozoic era. The position of haplotype 5 from Okinawa in Japan is poorly resolved, but it is not closely related to the other four Japanese haplotypes. It is suggested that several taxonomic characteristics (sexuality, point of origin of carpogonium‐bearing branches, and trichogynes with or without basal knobs or branching) is not fixed genetically but is affected by environmental conditions. Based on the results of the present study, B. coerulescens Sirodot and B. elegans Sirodot should be placed in synonymy with B. helminthosum.     

DISTRIBUTION AND SYSTEMATICS OF BATRACHOSPERMUM (BATRACHOSPERMALES,RHODOPHYTA) IN NORTH AMERICA. 3. SECTION SETACEA1

Six populations of Batirachospermum section Setacea from North America were compared to eight type specimens using multivariate morphometrics and image analysis. From this analysis, four species in this section were distinguished worldwide: B. atrum (Hudson) Hartley [syn. B. gallaei Sirodot]; B. orrthostichum Skuja, B. sertularina (Bory) Bory]; B. diatyches Entwisle; B. androinvolucrum sp. nov.; and B. puiggarianum Grunow in Wittrock et Nordstedt (syn. B. angolense Welwitsch ex West et West, B. nigrescens Welwitsch ex West et West). Two of these species were found in North America: B. atrum in California and Texas and B. androinvolucrum in British Columbia, Washington State, and Alabama. The new species, B. androinvolucrum, is distinguished by having spermatangia restricted to one-celled involucral bracts of the carpogonial branch.     

DISTRIBUTION AND SYSTEMATICS OF BATRACHOSPERMUM(BATRACHOSPERMALES,RHODOPHYTA) IN NORTH AMERICA. 6. SECTION TURFOSA1

Twenty-one populations of Batrachospermum section Turfosa from North America were compared to nine type and two historically important specimens using multivariate morphometrics and image analysis. The protologues of six other infrageneric taxa were also compared. From this analysis, six species are recognized worldwide: B, de-sikacharyi Sankaran, B. gombakense Kumano et Ratnasabapathy, B. keratophytum Bory de Saint-Vincent [syn. B. vagum var. keratophytum (Bory de Saint-Vincent) Sirodot, B. gulbenkianum Reis, and B. suevorum Kützing nom. Meg.], B. sinense Jao, B. turfosum Bory de Saint-Vincent [syn. B. vagum (Roth) C. Agardh and B. vagum var. undulato-pedicellatum Kumano et Watanabe], and B. vogesiacum F. G. Schultz ex Skuja [syn. B. vagum var. flagelliforme Sirodot, B. flagelliforme (Sirodot) Necchi], These species are distinguished on the basis of carposporophyte-bearing branch cortication, secondary fascicle development, monoecy or dioecy, presence of spermatangia on involucral filaments and monosporangia, and dimensions of trichogynes and carposporangia. Peripheral cortication has been previously used to separate species in this section, but we observed that this feature is quite widespread in the section. Presence of indeterminate gonimoblast filaments has been reported for some taxa in section Turfosa, but no such structures were seen in any of the specimens examined. Only B. keratophytum has been collected in North America, ranging from southwestern Greenland (64°N) to Louisiana (30° N).     

SEXUAL AND APOMICTIC REPRODUCTION IN CALAMAGROSTIS (GRAMINEAE) FROM EASTERN NORTH AMERICA

Reproductive mode and chromosome numbers were determined for populations of several species of Calamagrostis from eastern North America. Calamagrostis pickeringii (2n = 28), C. perplexa (2n = 70), C. porteri subsp. porteri (2n = ca. 88–100) and C. porteri subsp. insperata (2n = 56) all have a sexual pattern of megagametophyte formation; the basal megaspore of a tetrad develops into a Polygonum-type embryo sac with proliferating antipodal cells characteristic of the Gramineae. In these four taxa self-incompatability, population structure and infrequent flowering limit seed production; they persist primarily by rhizomes and occupy relatively stable, late-successional habitats. Calamagrostis stricta subsp. inexpansa includes apomictic variants (2n = ca. 104–123)that produce megagametophytes by diplospory; the single archesporial cell divides mitotically to produce an embryo sac appearing identical to those formed by sexual species. The embryo and endosperm develop autonomously from egg cell and polar nuclei, respectively. Some apomictic individuals occasionally produce some pollen and may have the potential for reproducing sexually. Their seed set insured by apomixis, variants of subsp. inexpansa colonize disturbed, open habitats and have achieved wide distributions in glaciated regions of North America. Reinterpretation of relationships among taxa I examined necessitates the following new nomenclatural combinations; C. porteri subsp. insperata (Swallen) comb. nov. is based on C. insperata Swallen; C. stricta subsp. inexpansa (A. Gray) comb. nov. is based on C. inexpansa A. Gray and includes C. lacustris (Kearney) Nash and C. fernaldii Louis-Marie.     

INCORPORATION OF FRESHWATER RHODOPHYTA INTO THE CASES OF CADDISFLIES (TRICHOPTERA) FROM NORTH AMERICA

Cases of larvae and pupae from six caddisfly (Insecta, Trichoptera) genera in three families from North America were observed to contain pieces of freshwater rhodophyte thalli. Seven genera of Rhodophyta, representing 13 species and 35 populations, were observed in this association. Four of the 25 species of Batrachospermum were incorporated into cases of Ochrotrichia ( Hydroptilidae) and Agrypnia ( Phryganeidae). Two of the three freshwater species of Bostrychia were used by Ochrotrichia larvae. Both Compsopogon coeruleus ( Balbis) Mont. and C. prolificus Yadava et Kumano were present in the cases of Hydroptial ( Hydroptilidae) and Ochrotrichia; Compsopogonopsis leptocladus ( Mont.) Krishnamur-thy was observed in the cases of Hydroptila. The more cartilaginous thalli of Lemanea fluviatilis ( L.) C. Ag. and Tuomeya americana ( Kütz.) Papenfuss were used by the brachycentrid larvae of Brachycentrus and Mi-crasema. Lemanea and Paralemanea spp. were also in the cases of Dibusa angata Ross (Hydroptilidae). The architecture of each caddisfly case was studied with light and scanning electron microscopy. Strips of algae were fit together in a transverse, concentric, or spiralled fashion. Based on transmission electron micrographs, cortical cells of Lemanea and Tuomeya in the cases of Brachycentrus and Micrasema appeared to be healthy with intact chloroplasts and typical batrachospermalean pit plugs. Geographic distributions of each rhodophyte-caddisfly association are given .     

BIOGEOGRAPHY OF STREAM MACROALGAE IN NORTH AMERICA1

In a survey of 1000 20-m long stream segments in North America from 73°N to 10° N, 259 infrageneric taxa were identified, composed of 35% Chlorophyta, 24% Cyanophyta, 21% Chrysophyta, 20% Rhodophyta, and one species of Phaeophyta. The most common morphological forms were mats (42%), gelatinous colonies (23%), and gelatinous filaments (13%); the majority of taxa were vegetative (78%). The frequency of reproductive states varied among the biomes examined, with the highest values observed as follows: vegetative (85%) in the tundra, sexual (35%) in the deciduous forest, and asexual (21%) in the tropical rainforest. In terms of total species, the tundra had the lowest number (54), the boreal forest had the greatest number (100), and other well-sampled biomes had 84 to 87. The Chlorophyta had the greatest species numbers in all biomes, and the relative contribution of this division did not vary significantly throughout the continent. With regard to similarity of species composition, the two closest associations were the boreal forest with the western coniferous forest and the eastern hemlock–hardwood forest with the deciduous forest. Species numbers per stream segment ranged from 0 to 11 (X?= 3.1), cover ranged from 0 to 100% (X?= 15%), and there was no significant difference in these values among the biomes. The cyanophyte Phormidium retzii (C. Ag.) Gom. was the most widespread species (in 172 segments and all biomes). The majority of species were found in moderate current velocities (X?= 40 cm X? s^?1), neutral to slightly alkaline pH (X?= 7.5), and moderately low ion waters (X?= 261 μS · cm^?1). On both tropical and Arctic islands, there was no significant increase in total species or species numbers per stream segment with increasing surface area.     

DISTRIBUTION AND SYSTEMATICS OF FRESHWATER CERAMIALES (RHODOPHYTA) IN NORTH AMERICA1

Twenty-five freshwater populations of Ceramiales were collected in North America, 24 of which were from the tropical rainforest region of Central America and the Caribbean. The streams tended to be moderate in mean current velocity (X?= 23.3 cm·S^?1) and maximum width (X?= 6.3 m) but high in temperature (X?= 23.1°C), pH (X?= 7.9), and specific conductance (X?= 320 μS·cm^?1). Three Bostrychia species were restricted to the Caribbean islands: B. moritziana (Sonder ex Kütz.) J. Ag. (syn. B. cornigera Mont. and B. radicans f. moliforme Post), with ecorticate indeterminate axes, monosiphonous ultimate branches, and cladohaptera; B. radicans (Mont.) Mont. (syn. B. leprieurii Mont and B. rivularis Harv.), with ecorticate and polysiphonous axes throughout and cladophaptera; and B. tenella (Lamour.) J. Ag., with corticate indeterminate axes, monosiphonous ultimate branches, and peripherohaptera. Ballia prieurii Kütz. was found in Belize and Costa Rica and was characterized by rebranched determinate laterals, opposite branching, and long apical cells (X?= 61 μm) and axial cells (X?= 43 μm). Caloglossa leprieurii (Mont.) J. Ag. was localized in Puerto Rico while. C. ogasawaerensis Okam. was collected only in Costa Rica. The two species were separated by site of branching (midrib vs. margin) and blade width (X?= 384 vs. 861 μm). Polysiphonia subtilissima Mont. from Florida and Jamaica had four pericentral cells, no cortication, rhizoids arising from pericentral cells, and branches initiated at trichoblast scars.     

中国串珠藻属新记录

记述了我国串珠藻属的6个新记录种,即灌丛串珠藻(Batrachospermum lochmodes Skuja),内卷串珠藻(B. involutum Vis et Sheath),博雷串珠藻(B. boryanum Sirodot),下位串珠藻(B. hypogynum Kumano et Ratnasabapathy),阿比串珠藻(B. abilii Reis)和茶溪串珠藻(B. theaquum Skuja ex Entwisle et Foard)     

STICTYOSIPHON SORIFERUS (PHAEOPHYTA,DICTYOSIPHONALES) FROM EASTERN NORTH AMERICA1

Although earlier North American records of Stictyosiphon soriferus (Reinke) Rosenvinge cannot he substantiated, the species is shown to be common in Newfoundland and is also reported from Nova Scotia. Plants are summer annuals and a component of ephemeral subtidal communities characteristic of suitable inlets and harbors. Only plurilocular reproductive organs are produced. In culture the life history of populations from both sides of the North Atlantic consists of a direct replication by asexual zoospores. A microscopic stage might occur in the field, and is presently known only from European cultures. In eastern Canada S. soriferus is readily distinguishable from S. tortilis (Rupr.) Reinke, S. subsimplex Holden and S. griffithsianus (Le Jol.) Holmes & Batters.     

INCORPORATION OF FRESHWATER RHODOPHYTA INTO THE CASES OF CHIRONOMID LARVAE (CHIRONOMIDAE,DIPTERA) FROM NORTH AMERICA1

Chironomid larvae incorporate pieces of freshwater red algae into their cases from a wide geographic range in North America, extending from southern Canada to central Mexico. The Rhodophyta used in this process represent two orders (Acrochaetiales and Batrachospermales), five genera (Audouinella, Batrachospermum, Lemanea, Paralemanea, and Sirodotia), and 14 species from 21 locations. Three genera from the chironomid subfamily Orthocladiinae make these cases: Cardiocladius, Eukiefferiella, and Orthocladius. The Eukiefferiella claripennis group was the most frequently observed infrageneric taxon using red algae in its cases. The cases were tubular in shape with longitudinally oriented strips of algae held together by silken threads. Some of the cases constructed with Batrachospermum and Sirodotia also had several lateral branches of the alga radiating from the tube.     

A STARCH GRAIN-MITOCHONDRION-DICTYOSOME ASSOCIATION IN BATRACHOSPERMUM(RHODOPHYTA)1

In Batrachospermum sirodotii Skuja the dictyosome-mitochondrion association, commonly reported in other red algae, includes a floridean starch grain during periods of intense dictyosomal activity. Such an organellar assemblage may serve to provide the most efficient means of energy flow during periods of peak dictyosomal activity.     

A SYSTEMATIC STUDY OF GIGAR-TINACEAE FROM PACIFIC NORTH AMERICA BASED ON MOLECULAR AND MORPHOLOGICAL EVIDENCE

Frequent episodes of algal-related tastes and odors (T & O) in drinking waters in metropolitan Phoenix, Arizona prompted initiation of a three-year project in July 1999 to investigate the occurrence of T & O metabolites and to develop a comprehensive management strategy to reduce the problems in drinking water supplies in arid environments. Two metabolites, 2-methylisoborneol (MIB) and geosmin, have been identified as compounds responsible for the earthy-musty tastes and odors in water supplies. Both were detected in the water supply system, including source rivers, reservoirs, canal delivery system and water treatment plants. Higher concentrations of MIB and geosmin occurred in distribution canals than in the upstream reservoirs indicating that significant production of the T & O compounds occurs within the canal system. A baseline-monitoring program has been established for the complex water supply system, with special emphasis on the canal system. Efforts are underway to investigate possible correlations between physical/chemical parameters, algal composition and biomass, with the occurrence of MIB and geosmin. In addition, several physical and chemical treatments are planned for the canal system to reduce algal growth and related MIB and geosmin concentrations.