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Peyssonnelia conchicola Piccone and Grunow, Gymnothamnion elegans (Schousboe) J. Ag. (reds) and Spatoglossum schroederi (Mertens) Kütz. (brown) seaweeds as new records are described and reported here in the second part of studies in the St. Martin's Reef. This along with the eight seaweeds (with six new records) recorded and described in the first part earlier, the total taxa now are 11 (eleven). Again, all the eight samples were collected in a single day light period. Through extensive studies including sub-littoral zones of the two tiny Reefs having crystal clear water is expected to yield many seaweed species, including new ones. [ABSTRACT FROM AUTHOR]

St. Martin's Reef (SMR) about 14 km west of the St. Martin's Island, Teknaf, Cox's Bazar, Bangladesh was not known during last over 50 years of seaweed researches. Recent six collections made with the assistance of Bangladesh Navy revealed 8 seaweeds species which are Pterocladiella maribagoensis Boo and Geraldino, Hypnea spinella (C. Agardh) Kützing, Peyssonnelia polymorpha (Zanar.) Schmitz, Jania pumila Lam., J. ungulata f. brevior (Yendo) Yendo (Rhodophyta); Caulerpa racemosa var. clavifera (Turner) Bosse, Bryopsis plumosa (Huds.) C. Ag. and Halimeda tuna (Ellis & Solander) Lam. (Chlorophyta). Of these six seaweeds such as Pterocladiella maribagoensis Boo et Geraldino, Hypnea spinella (C. Agardh) Kützing, Jania pumila Lamx., J. ungulata f. brevior (Yendo) Yendo, Bryopsis plumosa (Huds.) C. Ag. and Halimeda tuna (Ellis & Solander) Lam. have been newly recorded and described from the SMR in Bay of Bengal (Bangladesh territory). Presence of Peyssonnelia polymorpha and Bryopsis plumosa in the collections and physical and chemical water environments recorded indicated it as a true newly forming reef. The present illustrated account is however may be considered as base-line information on seaweed flora of the new SMR in the North-east Bangladesh coast. A total of six seaweeds have been newly recorded making the total seaweeds to 216 mostly from the SMI and nearby SMR. [ABSTRACT FROM AUTHOR]

Substantial works carried out for over nearly fifty years contributed around 200 taxa under 84 genera along Bangladesh coast specially the St. Martin's Island (SMI) when only intertidal and knee to waist deep seaweeds were collected. Sublittoral seaweed diversity, their distribution and standing biomass along the coast of the SMI with the assistance of Bangladesh Navy using underwater gears, still photography and videography up to a depth of 15 m, were first studied during March and April 2013. It revealed a total of 40 seaweed taxa of which 16 were browns,12 reds and 12 greens including two new variety Caulerpa chemnitzia var. irregulare Aziz et Alfasane and C. sertularioides var. robusta Aziz et Alfasane. Total taxa were low compared to 1990's and early 2000's affected by human activities and that some smaller forms were washed away by current and waves during collections. Depth profile showed occurrence of a total of 31 (77%) taxa within 1 m and 34 (85%) in the next 1 m (within 2 m) have been considered as highly productive zone; 27 (67%) taxa in the next 1 m (3rd 1m) depth have been considered as the medium productive zone. The lower productivity in the 3rd m depth measured was due to low light (only 16% of surface light 1350 µEm-2s-1), high Secchi Depth and TDS, all indicating limited light intensity. The number of organisms at 10 m depth decreased to 17 (42%) taxa and at 15 m depth only 4 (10%) taxa were present. The 10 to 15 m depth studied have been considered as low productive zone for March and April environment. The 4 taxa at 15 m were represented by Peyssonnelia polymorpha, Caulerpa taxifolia, Halimeda discoidea and Dictyota atomaria and considered as highly adaptive seaweeds. Of these P. polymorpha in particular could grow on bare boulders of upper intertidal zone under direct sunlight during lowest tide. The average wet biomass in March and April was 55 g m-2 and 902 g m-2, respectively where browns had highest (291.00 g m-2) followed by greens (118.6 g m-2) and reds (45.10 g m-2). Highest average biomass was at location D (696 g m-2) followed by B (179.90 g m-2), A (175.70 g m-2) and C (74.20 g m-2). Total standing sublittoral wet biomass around the SMI was estimated to be 148.50 metric ton for each month based on collections from a total of 50 sites and contribute mostly by Caulerpa chemnitzia var. irregulare Aziz et Alfasane, C. sertularioides var, robusta Aziz et Alfasane, C. furgusonii, Caulerpa taxifolia and Asparagopsis taxiformis. Higher Shannon-Weiner Index of diversity (H') occurred in March at Zone C (3.152) followed by A (2.778), D (2.284), E (1.95) and a minimum at Zone B (1.53). In contrast, Shannon-Weiner Index of diversity (H') showed the higher values at Zone F (2.60) followed by C (1.87), B (1.47), D (1.21) and Zone A showed minimum value (<1). Green seaweed diversity was higher among the classes. The Jaccard similarity index showed slightly higher percentage between Zone A and C (28%) than between Zone C and D (27%) and their intersecting numbers were found to be eight. [ABSTRACT FROM AUTHOR]

Gracilaria tenuistipitata var. liui Zhang et Xia 1988 from sand-flat at Nuniachara, Cox's Bazar, Ulva linza Lin. from west coast of Naf R. at Noapara, Teknaf and Fishary Ghat in River Bakkhali, at Cox's Bazar, and Caulerpa fergusonii Murray from St. Martin's Island (SMI), have been newly recorded and illustrated from Bangladesh. C. chemnitzschi (Esper) Weber-van Bosse var. irregulare Aziz & Alfasane var. nov. and C. sertularioides (S.G. Gmelin) M. Howe var. robusta Aziz & Alfasane var. nov. from SMI, Cox's Bazar District, Bangladesh are new to science. Total number of marine algal taxa so far recorded from Bangladesh coasts is now 210. [ABSTRACT FROM AUTHOR]

Trichodesmium erythraeum Ehrenberg 1830 (Cyanobacteria) has been described and newly recorded from three km off the west coast of the St. Martin's Island (SMI), Cox's Bazar, Bangladesh. The Red Sea algal bloom was narrowly elliptical raft-like loose aggregates 20-40 cm long, 4-8 cm wide and 2-3 cm thick. Volume of small and large Sea sawdust were 160×10-6 to 960×10-6 m³ consisting of 25-153 millions flat tuft or spindlelike colonies measured 830-1500 µm long and 155-260 µm wide with 13-16 filaments laterally in the median region. Sheath was present around each trichome even covering the tip cell wall the feature has so far not been reported for the Trichodesmium spp. Because of most likely sticky nature of the sheath 300-600 µm long filaments of 195-450 formed compact colonies without colonial sheath around. In interior filaments cells were rectangular 7-10 µm long and 6.3-10 µm wide with abundant gas vacuoles, bluish-green red, no diazocytes developed and without calyptrae. Cells of peripheral filaments were without gas vacuoles, cytoplasm disorganized, appearing necrotic with glycogen granules, and produced convex to sickle-shaped four-layered calyptra consisting of outermost sheath followed by outer extra thick wall, tip cell wall and inner extra thick wall on the tip cell. Calyptra was also produced on tip cells of tapered filaments. Presence of sheath around each trichome binding all filaments into a colony without colonial sheath described here, and presence of nitrogenase containing diazocytes in interior filaments, both temporal and spatial segregation of N2 fixation and photosynthesis within the photoperiod described and discussed in literature made the authors to consider T. erythraeum Ehr. a distinct taxon under family Microcoleacece. [ABSTRACT FROM AUTHOR]