NOPR Collection:

Impact of climate change on marine plankton with special reference to Indian Seas

2018-02-12T10:36:40Z

Title: Impact of climate change on marine plankton with special reference to Indian Seas Authors: Sahu, Biraja Kumar; Pati, Premalata; Panigrahy, R. C. Abstract: The seas surrounding India, namely Arabian Sea (AS) and Bay of Bengal (BoB) with their associated coastal embayments form one of the highly productive areas and biodiversity hotspots in the tropics contributing profusely to the socio-economic front of the region. Therefore, acquiring knowledge on the climate change scenario of this region and its impacts on marine ecosystems in general and planktons, in particular, is considered crucial for better resilience. In fact, several attempts have been made of late to understand the climate change impacts on plankton, corals and mangroves of this region. In this article, we tried to update the climate change scenario of Indian seas and its impact on plankton communities based on the information gathered from the peer reviewed publications and scientific reports. Results of this review have shown that the global warming generated SST (Sea Surface Temperature) rise and sea water acidification related pH fall have affected the species composition, abundance, phenology and metabolic pathways of plankton populations in this region. Page(s): 259-268

Development pattern and reservoir-formation mechanism of reef-bank complex in Late Ordovician Lianglitage Formation, Tazhong area, Tarim Basin, China

2018-02-12T10:34:58Z

Title: Development pattern and reservoir-formation mechanism of reef-bank complex in Late Ordovician Lianglitage Formation, Tazhong area, Tarim Basin, China Authors: Zheng, Jian; Wang, Zhenyu; Zhong, Zhiqi; Zhai, Na; Liu, Yang Abstract: Present study consists the development pattern of reef-bank complex and its reservoir formation mechanism. The earliest Ordovician coral-stromatoporoids reef-building organisms are found in Lianglitage Formation, which fills the blank of Late Ordovician organic reef in China. Type of sedimentary microfacies, combination form and scale differentiation of reef-bank complex in Lianglitage Formation are controlled by high-frequency sea-level change and multi-stage tectonic evolution. In vertical direction, four or five periods of reef-back motivated inside out of platform margin of Lianglitage Formation. Besides that, reef-bank complex is linear and clumped distributed along Tazhong NO.1 fault belt on horizontal direction. High-energy reef-bank in platform margin controlled distribution of favourable reservoir lithofacies. Karstification in syngenetic-supergene stage is the key factor for the development of high-quality vuggy reservoir. Hercynian deep fluid that migrating along the faults, fractures and previous vuggy layers greatly improve the reservoir property of reef-bank carbonates during the buried process. Page(s): 269-280

Distribution, ecology and paleoenvironments of Benthic foraminifera - A case study off Manora, Palk Strait, Tamil Nadu

2018-02-12T10:32:41Z

Title: Distribution, ecology and paleoenvironments of Benthic foraminifera - A case study off Manora, Palk Strait, Tamil Nadu Authors: Gandhi, M.Suresh; Rao, N.Rajeswara; Kasilingam, K.; Raja, M. Abstract: A total of 21 benthic foraminiferal species and varieties belonging to 12 genera, 9 families, 6 superfamilies, and 3 suborder have been identified. From the total number of species, Ammonia beccarri, A.tepida, P.calcar, P. nipponica shows a higher abundance in this region. The following species are found only in few core samples, namely Elphidium incertum, Spiroloculina communis, Spiroloculina orbis and T. agglutinans,. Size of the foraminifera in this region is very small. It may due to the finer nature of sediments and high rate of sedimentation in this region observed by earlier workers. The OM values ranges from 0.54 to 1.37 %. CaCO₃ value ranges from 1 to 6%. Based on the sand-silt-clay ratio, the study area was predominated with silty sand and sand in majority of the region. From the coastal geomorphological studies it is observed that, the distribution of landforms between near Manora displays a paleo micro deltaic characteristic the beach ridges have width of 200m around Manora. The sediments of beach ridges lie directly above the mudflats suggesting that the beach ridges were deposited later to the formation of mudflats i.e. mudflats are older to beach ridges. Page(s): 281-290

The influence of reservoir filling on a preexisting bank landslide stability

2018-02-12T10:28:26Z

Title: The influence of reservoir filling on a preexisting bank landslide stability Authors: Song, Danqing; Liang, Shouyun; Wang, Zhiqiang Abstract: A new monitoring instrument (automatic GPS) was used to understand the relationship between the stability of landslide and the hydrological triggering factors in the process of reservoir filling. These factors were drawn from a study that reported on the relationship between surface movement and hydrological triggers of a typical reservoir landslide (Yanziping landslide) in Jiudian Gorge Reservoir (JGR). A Fast Moving Zone (FMZ) can be spatially identified from the Main Deformation Zone (MDZ), and the temporal evolution of the landslide consists of a progression in time with short periods of Fast Movement (FM) and longer periods of slower movement. The results indicate that three FMs could be identified, which are triggered by different factors. The continuous rapid water rise will definitely trigger FMs with the rainfall being the secondary role and the longer duration of rapid water rise is not conducive to the stability of landslide in the phase of 70～100 m. Rapid drawdown of reservoir water level also triggers FMs from 100 to 130 m. Besides, there is a lag time of approximately 5 days between FMs and rapid water rise. A most dangerous water level for the landslide movement also can be identified approximately 80 m. The sliding mode was changed by reservoir water storage. Near-real-time monitoring by GPS can provide more reliable and timely data, which is significantly important for disaster prevention and mitigation. Page(s): 291-300