Diversity, distribution and density of estuarine phytoplankton from nine sites under four Ranges of the Sundarban Mangrove Forests (SMF), Bangladesh have been studied. The phytoplankton communities represented by 36 species which belonged to Chlorophyceae (3), Euglenophyceae (2), Bacillariophyceae (30) and Xanthophyceae (1). Occurrence of taxa and their densities were highest near the confluence of Hangsha River (R) with the river Murdat at Patcosta. Shannon-Wiener diversity index was also highest (H = 3.494) in this area. Lowest density of phytoplankton and diversity indices (H = 1.661) were found in Bal R., Bisandri Khal and Kalabogi R. Oocystis pusilla, Coscinodiscus excentricus, C. lineatus and Navicula brekkeansis occurred abundantly, while Cyclotella comta, Thalassionema nitzschioides and Lioloma delicatula were common. Coscinodiscus lineatus was distributed in all the nine sites including high and low tides indicating its high capacity to tolerate habitat fluctuations. Chaetoceros socialis was found only in Passur R. with low salinity, conductivity and total dissolved solids. The total numbers of phytoplankton individuals per liter were generally higher during low tide than those of high one. Principal Component Analysis (PCA) showed the relationship between pH and some species of phytoplankton.

ABSTRACT

not availableJahangirnagar University J. Biol. Sci. 5(1): 87-93, 2016 (June)

No abstract

The present study dealt with the exploration and documentation of the floristic composition and phyto-diversity of Sitakunda Eco-park, Chittagong, Bangladesh. A total of 412 vascular plant species under 315 genera belonging to 94 plant families have been recorded from the study area during February, 2013 to April, 2015. Out of these recorded taxa, 330 were dicotyledons, 62 were monocotyledons, 5 were gymnosperms and 15 were pteridophytes. Among those, the maximum 144 species belonged to herbs followed by 138, 75 and 55 species as trees, shrubs and climbers, respectively. The species composition among the plant families varied in plant groups. In dicotyledonous group, Euphorbiaceae appeared to be the largest family with 35 species, whereas Poaceae showed the largest family containing 30 species among monocotyledonous group. The highest values of both Shannon-Weiner and Simpson diversity indices have been observed as 3.82 and 0.98, respectively to site D during monsoon season, whereas the lowest values 3.19 and 0.95, respectively of these indices were recorded in site A during summer season.