Pseudodiaptomus binghami Sewell,
1912
was first described from the Rangoon River (now Yangon River) estuary, Myanmar. Pseudodiaptomus malayalus Wellershaus,
1969
previously known as P. binghami ...malayalus, is a typical brackish-water calanoid copepod from Cochin Estuary, Kerala. Morphological examination of P. malayalus and P. binghami collected from Cochin Estuary and the Nambur canal in Andhra Pradesh revealed crucial differences between the two congeners. Female specimens of P. malayalus exhibited marked differences from those described by Wellershaus. They are (1) the number of terminal spines on P5, (2) ornamentation of GS, (3) ornamentation of Ur1-4, (4) length ratio of the Ur and CR segments and (5) length:width ratio of the CR setae. Furthermore, significant and discrete morphological differences were observed between the two Indian species in their P5 and urosome. But the male specimens of P. malayalus did not show any major differences from the original description. In addition, distance matrix data revealed 22% interspecific divergence values which in turn confirmed the status of P. malayalus and P. binghami as two distinct species.
The proportion of blue carbon contribution by benthic fauna with regard to climate change issue is a relevant topic recent times. The present study is focusing on the carbon potential and blue carbon ...contribution of meiobenthic nematodes in the intermediate zone of Arctic Kongsfjord during 2015–2017 and the study is the first of its kind from this region. Foraminifera and Nematoda were the dominant fauna in 2015; whereas it was Foraminifera in 2016 and Tintinnida and Nematoda in 2017. Significant difference was noticed in the community structure of meiofauna in this three consecutive years. Twenty six nematodes were identified from the intermediate zone and their individual carbon potential and total blue carbon during the above-mentioned period is estimated.
Parasphaerolaimus paradoxus
(7.14 ± 0.05 μg/mg) recorded the highest carbon potential and the lowest value was recorded in
Terschellingia longicaudata
(0.11 ± 0.3 μg/mg). The sediment factors such as sediment granulometric composition, salinity, pH, Eh and total organic carbon (TOC) were the leading factors influencing the meiofaunal distribution as well as the distribution of nematodes based on carbon potential in the intermediate zone. Investigation of blue carbon deposition by nematodes turned out to be relevant in mitigating the climatic change as the fjord has a tranquil nature.
Mangrove ecosystems have high carbon storage and sequestration rates and become substantial sources of greenhouse gases when disturbed by land-use change. Thus, they are extremely valuable for ...inclusion in climate change mitigation and adaptation strategies. However in Kerala, a west coast state of India, has lost 95% of its mangroves in the last three decades, posing a serious threat to global climate. The regional carbon stock data of mangroves that are at risk of depletion are rarely reported, despite the fact that they are crucial for mitigating and managing climate change impacts. In response, the study estimated the ecosystem carbon stocks and soil organic carbon sources of three different estuarine mangrove habitats of Kerala. The mean total ecosystem carbon stock of Kerala mangroves was estimated to be 218.98 ± 169.86 Mg C ha
− 1
which is equivalent to 803.66 ± 621.47 Mg CO
2
ha
− 1
, contributing a substantial amount of carbon to the global ecosystem carbon. Further 88% of the estimated ecosystem carbon stock was represented by vegetation biomass and 22% by the soil carbon stock. The stable isotopic signatures revealed that the accumulated autochthonous mangrove source attributed to the organic carbon in the soils of site 1 (Munroe island) and site 3 (Vypin) while the suspended organic matter in tidal water contributed to the soil organic carbon of site 2 (Ayiramthengu) mangroves. Mangrove structure, salinity, soil pH and bulk density were found to be the correlating factors for the carbon stock variations across the study sites. Hence, the understanding of the amount of carbon stocks in the mangroves of Kerala coupled with other ecosystem services they offer highlights their importance in the creation of conservation, restoration and climate change mitigation plans in the country.
The members of the family Arcidae are the most abundantly occurring species in tropical and subtropical regions and have very high economic value in the Indo-Pacific Region super(1-4). Some species ...such as Scapharca subcrenata, S. broughtonii and Tegillarca granosa have been cultured in China, Japan and Vietnam and others will certainly be cultured in the future. Hence, species identification and knowledge about distribution of this family will become important for choosing suitable species super(5). They are also ecologically important in recycling of organic matter super(6). Most species of Arcidae are intertidal or marginally sub-tidal in their distribution and settle on muddy shores between mean high water of neap tides (MHWN) and mean low water of neap tides (MLWN). They do not generally extend into the area above mean high tide level, which is usually dominated by mangrove swamp forests. Peak densities are usually encountered around mid-tide level super(1). Mass occurrence of the genera of the family Arcidae, such as Scapharca, Anadara and Arca, was reported from the South East Asian countries super(7-13) and their key role in the development of ecological processes has also been pointed out super(14,15). The results of the present study on the occurrence of Scapharca cornea are informative both for the Lakshadweep Islands and for other Indian coastal waters.
A fragment of the mtCOI gene was successfully PCR-amplified from two species (Oncaea venusta and Oncaea media; Family Oncaeidae; Cyclopoida) (534 to 640 base pairs) which represents the first ...molecular data. Objectives of this pioneering study were to derive their preliminary molecular phylogeny of based on mitochondrial (mtCOI) sequences; test if morpho-species are supported by molecular data. Reconstructed phylogeny postulated the Polyphyly of the genus Oncaea and paraphyly of its closely related genus Dioithona; Concluded the allopatric speciation and extended sovereign evolutionary history of O. venusta typica and O. venusta; Hypothesized the convergent evolution and homoplastic condition of the character (the absence of aberrant spine number in the distal segment of P1 endopod) in O. venusta; Re-confirmed the subspecies status of O. venusta typica to O. venusta through molecular study ; Hypothesized to retain the current genetic status of Oncaea sp. 7, O. parabathyalis, O. shmelevi and O. prendeli ; Recommended a detailed imminent morpho-molecular evaluation about the position of O. curta as the interspecific divergence values between O. waldemari and O. curta was found to be 2%.
The forest structure and its relation to environmental parameters of Sundarbans, largest mangrove habitat in India, are presented. Quadrat method was used to analyze the vegetation-environment ...interaction and structural maturity of mangroves. Floristic studies revealed twenty-seven mangrove species including the critically endangered Sonneratia griffithii and endangered Heritiera fomes. Based on Importance Value Index, Avicennia marina, Excoecaria agallocha, Avicennia officinalis and Avicennia alba were designated as the most important species. Higher diversity indices were observed (Shannon index, ranged from 4.2-1.8; Pielou’s index, 0.96-0.91) revealing greater species diversity and even dispersion of mangroves in Sundarbans. Stem density varied from 133 to 19333 ha−1 and individual basal area 0.4 to 13.4m2ha−1. A very low Maturity Index Value was recorded indicating a low degree of structural maturity. Most of the vegetation parameters (density, species diversity index, β diversity) and few of the edaphic parameters (pH, grain size, total carbon) were found to be in better condition; however, salinity showed significant negative correlations with vegetation characteristics. The study revealed a mixed species composition with intermediate structural development indicating a growing forest in Sundarbans. The data evolved in the study would be fundamental in site-specific management and conservation efforts of mangroves in this world heritage site.
The study furnishes an insight into the ecology of meiofauna through an elaborate examination of the living Foraminifera in the Krossfjorden system of the Svalbard Archipelago. Samples collected ...during the Summer Phase Indian Arctic Expeditions of 2017 and 2018 were analyzed to reveal novel insights into the distribution, abundance and species composition of living Foraminifera in this less studied fjord system. The investigation uncovered a rich and diverse meiofaunal community consisting of ten taxonomic groups, among which living Foraminifera emerged as a prominent component. The spatial patterns of Foraminifera distribution were examined, revealing their preferences for specific habitats and environmental conditions within the Krossfjorden system. The Shannon diversity index (H’) indicates good overall diversity of foraminifera in the Krossfjord region, with H’ ranging from 4.49 to 4.891 in 2017 and from 3.885 to 4.984 in 2018. The research discovered noteworthy inequalities in the distribution of Foraminifera species amid inner and outer stations, as inferred by PERMANOVA analysis (p<0.05). The foraminiferan species Nonionellina labradorica was the dominant species in outer, middle and inner zones in the fjord, while species Lobatula lobatula, Quinqueloculina seminulum, Hormosinella sp., and Procerolagena sp. played significant roles in driving the dissimilarity between outer, middle, and inner zones. Environmental factors accounted for a substantial 83.1% of the variations observed in foraminiferan species distribution across four CCA axes. The fluctuations in potential temperature, sand fraction, chlorophyll-a, C:N ratio, organic matter, and salinity have had a noteworthy effect on the distribution of species. These findings underscore the susceptibility of Foraminifera and the broader meiofaunal community to the impacts of environmental variations in this rapidly changing Arctic ecosystem. The outcomes of this research provide a crucial baseline for understanding the ecological dynamics of meiofaunal communities in the Krossfjorden system, contributing to predicting future changes in benthic habitats, including the potential repercussions for meiobenthic productivity.
Benthic dinoflagellates contribute significantly to the primary production and thereby the sustenance of shallow marine environments. However, some of them are considered potentially toxic or harmful ...species posing a serious threat to this marine ecosystem. The paper describes an extensive bloom of the dinoflagellate Prorocentrum rhathymum for the first time from the Lakshadweep waters in the eastern Arabian Sea. The dinoflagellates were observed as an intense bloom in the Bangaram Lagoon of Lakshadweep archipelago. The cells of P. rhathymum (7.6 x105 cells L−1) were observed in mucilaginous aggregations with macroalgal debris and filaments of the cyanobacterium, Trichodesmium erythraeum. The bloom area was devoid of other microalgal species, and P. rhathymum was also observed to be attached to fresh macroalgal thalli in the nearshore areas (4.67 x104cells g−1 wet weight of macroalgae). These observations suggest that the debris of macroalgae washed into the water column act as a substrate for the transport of P. rhathymum towards the water column. Warm sea surface temperature (SST, 29.7 °C) and stable conditions of the water column favoured the bloom of P. rhathymum in the Bangaram Lagoon during the spring inter-monsoon season. Coral reef ecosystems along the Indian EEZ are the least surveyed regarding the prevalence of harmful or toxic species, and most of the harmful algal bloom (HAB) events in these systems remain overlooked. Routine monitoring and meticulous bloom physiology studies can provide insights into the prevalence of HAB and prediction of such events in these diverse ecosystems.
•First report of Prorocentrum rhathymum bloom from Bangaram lagoon, Lakshadweep.•P. rhathymum observed in the sediments and along the thalli of the macroalga.•Presence of Trichodesmium erythraeum filaments indicating a prior bloom in the lagoon.•Sediment-detritus-water column system supported the transport of the dinoflagellate.•High SST, salinity and stable waters supported existence of P. rhathymum bloom.
The neritic ctenophore Beroe ovata (Bruguière, 1789) is a Beroida species frequently found along the western coast of the Atlantic, from northeastern USA to central Argentina. Here we report the ...geographical range expansion of Beroe ovata and its blooming from the Arabian Sea. In ctenophore the use of molecular tools to support conventional (morphological) identification offers a new perspective in the field of biogeography. The identification of this species is critical for both monitoring future blooms in the area and gaining a better knowledge of the genus diversity on a global scale. The density of the reported blooming was 189 ± 9 ind. m−3. The reported places for this taxon show that it has a subtropical and tropical affinity.
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