FORAMINIFERAL ASSEMBLEDGE IN SUNDARBAN MANGROVE ECOSYSTEM

Wetlands
DOI 10.1007/s13157-012-0312-x

Intra-Annual Variation of Modern ForaminiferalAssemblage in a Tropical Mangrove Ecosystem in India

 Mitali Dey & Dipnarayan Ganguly &Chumki Chowdhury & Natasha Majumder & Tapan Kumar Jana

Abstract This study relates the abundance of foraminifera with the fluctuations in hydrobiological characteristics gener- ated by the monsoonal cycle in a tropical mangrove ecosys-tem. Monthly variation of physicochemical properties of water and sediment, phytoplankton production, foraminifera assemblages were measured in the littoral zone of the Sundar- bans mangrove forest. Intra-annual variation of foraminifera exhibited a maximum abundance during the post-monsoon period and out of the 25 genera, numbers of calcareous and agglutinated forms were 16 and 9, respectively. Live benthic foraminifera were found to inhabit a wide range of sedimen depths and inhabiting a high energy environment their abun- dance was not restricted to the uppermost centimeter. Owing to mechanical damage (due to high energy system), chemical dissolution and intense bioturbation, the taphonomic process- es in this mangrove swamp could result in the destruction of the small size fraction of foraminifera, including agglutinatedtests. The low numbers of agglutinated foram could be due to silty clay substrate. Abundance of more calcareous dead specimens over live ones could be attributed to predation and transportation of dead marine species.Most of the marine species could not survive in this freshwater dominated system.Anthropogenic nutrient input and diatombloomin association with enhanced food to benthos are important controlling fac- tors on foraminiferal abundance and composition. 

Keywords:  Intertidal foraminifera . Phytoplankton . Mangrove . Indian Sundarban

CARBON SEQUESTRATION IN SUNDARBAN MANGROVE ECOSYSTEM

Carbohydrate Polymers , Elsevier                                                                               

Doi.org/10.1016/j.carbpol.2012.05.001

Wood chemistry & density: an analog for response to the change of carbon sequestration in mangroves

• R. Ray,
• N. Majumdar,
• C.Chowdhury,
• T.K. Jana

• Department of Marine Science, University of Calcutta, 35, B. C. Road, Kolkata-700019, India

• Received 21 February 2012. Revised 2 April 2012. Accepted 1 May 2012. Available online 8 May 2012.

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Abstract

This study aimed to resolve the variations of physical and chemical properties of wood records measured in different mangroves with their annual carbon sequestration. The methods of investigation used were to examine growth rate by monitoring breast height diameter, wood chemistry and density, FTIR spectroscopy and thermogravimetry. Carbon sequestration rate showing an increase with density varied between 0.088 and 0.171 μg C kg⁻¹ (AGB) s⁻¹, and Avicennia marina showed the maximum value and Bruguiera gymnorrhiza, the minimum. The changes in FTIR bands at 4000-2500 cm⁻¹ and 1700-800 cm⁻¹ were correlated to the variations in cellulose in mangrove woods and lignin to cellulose ratio ranged between 0.21 and 1.75. Thermal analyses of mangrove wood suggested that the fuel value index (985-3922) exhibited an increase with the decrease in maximum decomposition temperature and density. The seasonal variation of temperature and CO₂ were likely to affect chemical properties through changes in wood density.

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Highlights

► This study aimed to resolve the variations of wood properties and carbon stock. ► FTIR suggested lignin to cellulose ratio ranged b/w 0.32 & 1.72 in mangrove woods. ► Wood density increased with increase in cellulose & decrease in lignin. ► Mangrove showed an increase in C stock with increase wood density. ► FVI of mangroves exhibited an increase with decrease in T_m & increase in density. ► Primary energy can be derived from mangrove wood.

PHYTOPLANKTON AND ZOOPLANKTON PREY PREDATOR RELATIOSHIP IN SUNDARBAN MANGROVE ECOSYSYTEM

Biodiversity and conservation,Springer


DOI 10.1007/s10531-012-0295-1

Inter-annual abundance variation in some genera of diatom and zooplankton in a mangrove 

ecosystem

 Chumki Chowdhury • Natasha Majumder • Raghab Ray •

 Tapan Kumar Jana

This study presents data for the abundance of phytoplankton and zooplankton and related habitat parameters for Lothian Island mangrove ecosystem located at the coastal boundary of the Ganges River delta. Over the 3 study years, total abundance of phytoplankton and zooplankton was lowest during the monsoon period. In 2008, the most common diatom genera (by % relative abundance) were Skeletonema cf. costatum (14.2), Thalassiothrix (9.36), Nitzschia sigma (8.16), Coscinodiscus radiatus (7.65), Chaetoceros (6.64), Pleurosigma (3.05), Thalassionema (1.77), Dytilum brightweli (1.71), and Cyclo- tella (1.0), whereas in 2010 they were Skeletonema cf. costatum (41.7), Chaetoceros(11.1), Thalassiothrix (6.04), Nitzschia sigma (4.49), Coscinodiscus radiatus (3.96),Cyclotella (2.61), Thalassionema (2.11), Pleurosigma (1.22) and, Dytilum brightwellii(1.01). Relative abundance of the zooplankton size classes typically followed the order meso[micro[macro and Copepods were the most abundant taxa (54.6 % of total zooplankton abundance). Total abundance of both phyto and zooplankton almost doubled in 2010 relative to 2008 although the ratio of the two remained constant (Zooplankton: phytoplankton = 0.002). The N:P ratio of water did not change much over the study anddid not seem to be responsible for phytoplankton abundance changes; rather interannualvariations in phytoplankton abundance could be explained by a simple predator–prey- relationship with zooplankton.

PHYTOPLANKTON AND COMMUNITY METABOLISM , NUTRIENT BUDGET IN MAHANADI ESTUARY

Marine Ecology, Wiley


doi:10.1111/j.1439-0485.2012.00519.x

Comparison of Monsoonal change of water quality parameters between 1983 and 2008 in a tropical estuary in Northeastern India: role of phytoplankton and community metabolism

Mitali Dey, Chumki Chowdhury, Asim A. Pattnaik, Dipnarayan Ganguly, Sandip K. Mukhopadhyay, Tarun K. De & Tapan K. Jana.

Ongoing climate change and anthropogenic activities are introducing stressors that affect the structure and function of coastal ecosystems. This paper focuses on the fluvial fluxes and estuarine transport of nutrients from a tropical river (Mahanadi River) in Northeastern India and compares select nutrient and water quality parameters between 1983 and 2008. This estuary acts as a peren- nial source of CO2 with a net annual flux to the atmosphere of about 135 tons. The non-conservative fluxes showed a net annual removal of 650 and 140 tons of phosphorus and nitrogen from the water column, respectively. Negative bio- geochemical feedbacks that decreased the availability of N and P in 2008 rela- tive to 1983 levels indicate major changes in biogeochemical responses towards fluvial fluxes of nutrient.