Estuarine Macrophytes at Bakkhali, Cox’s Bazar, Bangladesh with Reference to Mangrove Diversity

The diversity and ecosystem significance of macrophyte communities was studied, with emphasis on the mangrove species in the Bakkhali estuary of Cox’s Bazar, Bangladesh. Macrophytes of the Bakkhali river estuary were mainly mangroves (Avicennia marina Forssk Vierh and A. alba Blume and Acanthus ilicifolius Linnaeus) of inundation Class-IV; i.e., the mangroves are inundated 2-20 times per month (Watson, 1928), a wild rice variety of salt marsh (Porteresia coarctata Tateoka), Congon grass (Imperata cylindrica P. Beauv.), seagrass (Halophila beccarii Ascherson), macro-algae (Ulva intestinalis Linnaeus, Catenella nipae Zanardini and Hypnea sp.) and mangrove associates Suaeda maritima Only two individual plants of mangrove, Sonneratia apetala and Aegialitis rotundifolia, were found growing in the inter-tidal area of this estuary. On the eastern side of the estuary, almost 100% of the intertidal area is covered by the salt marsh plant P. coarctata, with patches of seagrass Halophila beccarii. The western portion of the estuary is covered by mangroves, mixed with patchy salt marsh and seagrass in and sheltered by a sand bar. Salt marsh and seagrass grow in mangrove dominated sites as 2nd pioneer species in the newly accreted land at the mouth of Bakkhali estuary. These estuarine macrophytes are of both economic and ecological significance and the macrophyte community plays a principal role directly or indirectly in supporting the local communities as source of food, cash and energy

Sediment and carbon accumulation in sub-tropical salt marsh and mangrove habitats of north-eastern coast of Bay of Bengal, Indian Ocean

Researches on salt marsh mangrove habitats as global carbon sink are increasing worldwide. However, uncertainties in measuring carbon sequestration capacity of the vulnerable subtropical South Asian coastal habitat thus obstructing the mapping sediment and carbon accumulation rate of their importance.The present investigation was carried out to assess the sedimentation and carbon accumulation rate in salt marsh and mangrove habitats in the vicinity of Sitakunda coast, Chittagong, Bangladesh. The data indicate that sedimentation rate was 22.76±2.56 mg/cm2/day in mangrove area, 63.52±7.42 mg/cm2/day in lower mangrove area, 97.02±6.64 mg/cm2/day in higher marsh area, 5.91±1.16 mg/cm 2/day in lower marsh area and 9.81±0.03 mg/cm2/day in muddy area. The average sedimentation rate was found 39.82±6.72 mg/cm2/day during the study period. Soil organic matter in the newly deposited sediment was 3.89±1.28%, while 3.57±0.77% in accumulated peat sediment.Organic carbon of the newly deposited sediment was 2.05±0.93% and 1.89±0.55% in accumulated peat sediment. Usually, the organic materials were found higher in the peat soil in the wetland habitat, while lower amount of organic materials are found in the present peat soil. Lower amount of organic materials in peat soil in the study area could probably due to higher utilization of organic materials by aquatic plants. Further, uncertainties remain about sediment and carbon accumulation changes with tidal range, latitude and elevation in study area require long-term spatio-temporal investigation

Distribution of aquatic macrophytes in the coastal area of Salimpur, Chittagong, Bangladesh.

This preliminary study was conducted to investigate the distribution pattern of the aquatic macrophytes in the inter-tidal coastal belt of Salimpur, Chittagong. During this study, 3 species of mangrove, i.e., Sonaratia apetala, Avicennia marina and Acanthus ilicifolius, 1 species of wild rice related to salt marsh grass, i.e., Porteresia coarctata, 3 species of macro-algae, i.e., Ulva intestinalis, Catenella nipae and Dictyota dichotoma and 1 species of poison lily Crinum defixum were identified from this coast. The dominant macrophyte was planted Sonaratia apetala, followed by Porteresia coarctata in the coast line of Salimpur. Considering from the ecological and economic view, especially Catenella nipae, could be an important living resource for cultivation and sea ranching in this area. Besides, the importance of these aquatic inter-tidal macrophytes for fishery resources and overall ecosystem processes should not be over looked in this coastal area

Distribution of trace metals in channel sediment: a case study in South Atlantic coast of Spain

Recently, Sancti Petri channel on the southwestern (SW) part of Iberian Peninsula has been experiencing urban, industrial, and vehicular expansion. Until recently, there have been only few published reports documenting the pattern of metal accumulation in this estuarine sediment. In the present study, trace metals such as Cu, Zn, Ni, Mn, Pb, Co, Cd, As, and Hg concentrations were analyzed from 69 sediment samples collected from 23 sampling sites of the Santi Petri channel. The magnitude of trace metal accumulation found as the following trend: Mn > Zn > Cu > Pb > Ni > Co > As > Cd > Hg. Spatial distribution pattern demonstrated overall decreasing trend of trace metal from Cadiz Bay mouth to the open ocean mouth, clearly correlative to the presence of anthropogenic inputs. Results of the principle component analysis (PCA) revealed that sediment metal chemistry of Sancti Petri channel is mainly regulated by the concentrations of Pb, Cu, Zn, and Ni; possible sources of those were from vehicular-related emissions. Pollution load index (PLI) and geo-accumulation index (I geo ) indicated overall low values. The study will stimulate improvement of our understanding regarding the pattern of accumulation of metals in the coastal sediments, and the recorded values of metals in the present study can be used as suitable reference for future studies

Litterfall production in a tropical mangrove of Sarawak, Malaysia

Assessment of litterfall production is essential to ascertain the status of nutrient cycling and forest health. Sarawak, Malaysia, is endowed with numerous pristine and estuarine mangroves; however, research on primary productivity of these forests is scanty. Therefore, litterfall production in a pristine Sibuti mangrove of Sarawak was estimated using litter traps for one year (January–December 2013), and forest structure was studied through tree census. The forest was dominated by Rhizophora apiculata (relative density [RD] was 77.11%), followed by Xylocarpus granatum (RD was 16.92%) and other species (RD was only 5.97%). The annual dry weight of litterfalls was estimated to be 1640.82 g m−2, of which R. apiculata contributed 92.94%, followed by X. granatum (4.01%) and other species (3.05%). Leaves were the most abundant (57.21%) contributory component of litters, followed by propagules (11.89%), flowers (10.85%), twigs (8.56%), and stipules (8.45%). No significant correlations were found for total litterfall and its major components with climatic variables and forest structure. Total litterfall of R. apiculata and X. granatum did not show any seasonal variations. However, leaf litter of R. apiculata showed a significant seasonal variation between intermediate (January–April) and wet (September–December) seasons. The litterfall production of Sibuti mangrove forest is higher in comparison to other tropical mangroves of the world. The higher productivity of the forest could be due to nutrient availability, pristine nature, and stand maturity of the forest rather than climatic influences. The findings of the study suggest that litterfall production of the pristine Sibuti mangrove is not influenced by the variability of climatic factors

ABUNDANCE AND COMPOSITION OF BENTHIC FAUNA IN PENAEUS MONODONFABRICIUS CULTURE POND ON THE WEST COAST OF MALAYSIA PENINSULAR

ABSTRACT: This Paper reports a study on the benthic faunal abundance and diversity of tiger shrimp P. monodon culture ponds in Perak, west coast of Malaysia Peninsular. Sampling was carried out at three weeks interval throughout the 116 days culture period. In addition, water temperature, dissolved oxygen, salinity, transparency, pH and organic matter of soil were also measured. Results showed that the major groups of macrobenthos comprised of gastropod, foraminifera, polychaetes, bivalve and insects; whereas the meio-benthos comprised of harpacticoid copepods, ostracods, nematods, gastropods, foraminifera, bivalve, insects, crustacean nauplii and polychaetes. In macro-benthos, the abundance of different sizes of Gastropods increased throughout the culture duration. This consisted of 37 -98.20% for <1 cm length, 1.80 -61.50% for 1-2 cm length and 1.18 -1.30% for >2 cm length. Other macro and meio-benthic organisms decreased linearly with the culture period. The depletion symptom indicates that the culture species may have intensively preyed upon the consumable (<0.5 cm in size) benthic fauna together with detritus and artificial diet; or could have been caused by pond bottom deterioration via uneaten feed, faces and toxic gases

Photosynthesis of seagrass <i style="">Cymodocea serrulata</i> (Magnoliophyta/ Potamogetonales/Cymodoceaceae) in field and laboratory

253-256In situ photosynthetic study for seagrass Cymodocea serrulata at two depths (0.5 m, 2.0 m) at Port Dickson, Negeri Sembilan was conducted. The photosynthetic rate at 0.5 m was comparatively higher (0.476±0.080 mg O2/hr/g fr wt or 0.571±0.182 mg O2/hr/cm2) than at 2.0 m depth (0.292±0.030 mg O2/hr/g fr wt or 0.426±0.135 mg O2/hr/cm2). Respiration rate was not significantly difference at the two depths. Laboratory study showed that the rate of photosynthesis varied with light intensity, exhibiting saturation at 200-800 mmol/m2/sec with a light compensation point at 20-40 mmol/m2/sec. The in situ light measurement recorded at 2.0 m depth was 108.33±9.18 mmol/m2/sec, which is comparatively higher than those at compensation light point, which suggests that this seagrass may inhabit the depth more than 2.0 m. However, based on field observation, this seagrass was only found at depth of 1.5-2.0 m HWL

Salt marsh and seagrass communities of Bakkhali Estuary, Cox’s Bazar, Bangladesh

The species identification, distribution pattern, density and biomass of salt marsh and seagrass plants with some of the ecological parameters were studied in the Bakkhali river estuary, Cox\u27s Bazar, Bangladesh during the first half of 2006. Two salt marsh species (Spartina sp. and Imperata cylindrica) and one seagrass species (Halophila beccarii) were identified during this investigation, providing the first reports of Spartina sp. and H. beccarii in coastal Bangladesh. Seagrass H. beccarii was found in an accreted area and co-existing with salt marsh, and scattered sparsely in the salt marsh habitat and macroalgae Ulva intestinalis. Flowering and fruiting were recorded from the seagrass H. beccarri during January and February. No flowers and fruits were observed for the salt marsh Spartina sp. during the study period. Results showed that the shoot density of Spartina ranged from 400 to 2875 shoots m−2 with the highest total biomass (165.80 g dry weight (DW) m−2) in March. Shoot density of H. beccarii ranged from 2716 to 14320 shoots m−2 in this estuarine coastal environment. The total biomass of seagrass was higher (17.56 g DW m−2) in March compared to the other months. The highest H. beccarii above ground (AG) biomass and below ground (BG) biomass were 9.59 g DW m−2 and 9.42 g DW m−2, respectively. These parameters are comparable with those generally observed for the salt marsh and seagrass species in the other places of the world

Temporal variation in community structure of Dragnet (Pukat Tarik) fishery in relation to ecological variables in an inshore area of Sarawak, Malaysia

Inshore waters are crucial for fisheries since such areas show a wide range of variations in ecology, mostly consideredto shape biotic ecosystems. Despite major fishing activities off Bintulu coast located along the South China Sea operating in theinshore areas and significantly contributing to local fisheriesโ economy by Pukat Tarik (dragnet), temporal exchange of fisheriescomposition in terms of ecological parameters has been little studied. Therefore, temporal changes in pull net fisheriescomposition and assemblages in relation to the ecological parameters in the inshore waters of Bintulu coast, Sarawak, wereobserved from May 2016 to April 2017. A total of 63 species belonging to 15 orders of 40 families were recorded, and 11 speciesfound ubiquitous. Species diversity (Hยด) was recorded higher (2.61) in northeast monsoon, and lower (0.51) in inter-monsoonseason, yet the species richness and diversity did not show temporal differences (p>0.05). Among the species Kurtus indicus wasrecorded the most abundant (58% of the total catch) followed by Photopectoralis bindus (15%) and Opisthopterus tardoore(7%); and the species abundance showed significant temporal differences (p<0.05). However, temperature, salinity, pH,dissolved oxygen (DO) and rainfall showed classical temporal differences (p<0.05), and no significant difference was found inchlorophyll a and water nutrients. ANOSIM indicated that the significant difference of assemblages among season was moreapparent than within season (Global R=0.65, p<0.001). The canonical correspondence analysis indicated total suspended solids,dissolved oxygen (DO), transparency, rainfall and salinity as the most important ecological factors affecting fish assemblagestructure. The inshore fisheries of Bintulu coast were found immensely rich and profoundly related to ecological factors, whichwill eventually help manage this fishery resource in the future in tropical coastal waters of the South China Sea