1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Microbial remineralization of the dissolved organic carbon(DOC)derived from the benthic producers of Gulf of Mannar(GoM) reef ecosystem(Academy of Climate Change Education and Research, Vellanikkara, 2020-07-01) Alen Mariyam Thomas; Manikandan, BCoral reefs are one of the most productive ecosystems with primary production rates compared to the tropical rain forest. Carbon dioxide is fixed as organic matter through photosynthesis and contributes to the temporary or permanent storage of carbon in the ocean. This is achieved by the sedimentation of particulate organic matter (POM) and transport of dissolved organic matter (DOM) to deeper environments through the movement of water masses. Almost, 10-15% of the gross organic production by reef benthic producers is released into the external environment and act as a main source of DOC in the reef environment. DOC represents one of the largest reservoirs of CO2 in the ocean equivalent to the atmospheric CO2 and acts as a source of carbon and energy for many organisms that depend on organic carbon for nutritional sources. DOC released by macroalgae enters into the food web through the microbial loop and plays a vital role in trophic energy transfer, however, not all DOC enters the microbial loop where some amount remains resistant to microbial action representing the recalcitrant DOC. Our results show that the organic matter released by different macroalgae accelerated the growth of bacterioplankton, and differed in their effect on bacterial community composition. All the macroalgae studied in this experiment released a significant amount of DOC into the reef with T. ornata the maximum DOC and H. tuna the least DOC with 72.1 μM C/g/h (dry weight) and 1.9 μM C/g/h (dry weight) respectively. The amount of DOC released by different macroalgae remained recalcitrant to microbial action by the 100th day ranged from 9.2% to 32.2% among different macroalgae. Green macroalgae possessed a weak shift in bacterial community composition whereas the brown macroalgae altered the bacterial community composition. The brown macroalgae contributed to a slight decrease in the dominant bacterial groups thereby enhancing the dormant bacterial groups. However, in this study, the existing bacterial population was able to utilize maximum DOC resulting in a weak shift in the bacterial composition among the green macroalgae giving no chance for the dormant bacterial communities. The type of macroalgae and the composition of DOC they produce are considered critical in determining the effect of DOC on the bacterial community. These comprehensive data provide an important basis for understanding the influence of DOC over coral-associated bacterial communities and the dynamics of carbon cycling in algal dominated reefs.Item Impact of convection over the equatorial through on Indian summer monsoon activity(Academy of Climate Change Education and Research, Vellanikkara, 2015) Gopika, S; Kurien, E KThe existence or nonexistence of break and active cycle of rainfall over the Indian subcontinent during the mid-monsoon months of July and August decides the success and failure of Indian monsoon rainfall. Effect of active or break cycle, convective systems and convection over the equatorial trough (ET) on Indian summer monsoon rainfall (ISMR) were studied. An increased number of convective systems in the west Pacific showed high negative correlation with rainfall over equatorial trough regions. During active monsoon years, cyclones are focused between 10° - 25° N and 110° - 140° E whereas the cyclones were widely distributed during the break monsoon years. The co-occurrence of active or break spells and convective activity have considerable influence on ISMR. During an active spell, enhanced convection was observed over North Indian Ocean (NIO) while during break spell it was over ET regions. Strong, widespread and short duration cyclonic activity over North West Pacific (NWP) resulted in a break spell in ISMR. The relative influence of El-Niño Southern oscillation and Indian Ocean Dipole (IOD) events on ISMR have been further studied for the period 1950-2010. In order to look into the role of El-Niño on the monsoon, the SST data over five regions (REG-I to REG-IV) were studied. SSTs in the central Pacific (Niño 3.4; REG- II) and eastern Pacific (Niño 3; REG- III) regions were more correlated with ISMR during the observation period. Decadal analysis showed that the temperature of central Pacific region indicated rapid cooling in the recent decades and increased the temperature gradient between western and eastern Pacific Ocean. This cooling in the central Pacific could create La-Niña type conditions. During El-Niño (La-Niña) years, the weakened (strengthened) Walker circulation influence the summer monsoon rainfall over the Indian subcontinent. The newly created Walker circulation index is a promising tool to examine the strengthening (weakening) of the Walker circulation to predict the Indian summer monsoon in future research.Item Modelling climate change impact on surface runoff and sediment yield in a watershed of Shivalik region(Academy of Climate Change Education and Research, Vellanikkara, 2020) Anu Raj, D; Mary Regina, FThe climate change refers to the seasonal changes over a long duration in relation to the increasing amount of greenhouse gasses in the atmosphere. Global warming leads to a more vigorous hydrological cycle, including higher amount rainfall and more frequent high-intensity rainfall events. The Himalayan region is suffering from a serious problem of soil erosion and rivers flowing through this region transport a massive load of sediment. Climate change has a significant contribution to soil erosion. It leads to loss of nutrient-rich top soil which in turn can affect the nation’s food security. The present study depicts modelling climate change impact on surface runoff and sediment yield in a watershed of Shivalik region of Himachal Pradesh using a process-based Agricultural Policy/ Environmental eXtender(APEX) model. Terrain characteristics were analysed with the aid of Cartosat DEM. Land use/land cover characteristics were extracted from Resourcesat-2 LISS-IV and ground observations. Soil samples were collected from the field were analysed to identify soil physical and chemical properties. Surface runoff and sediment yield data required for model calibration and validation were collected from the gauging station constructed in the field. The future climate scenarios (temperature and rainfall) namely A2 and B2 of the study area were downscaled using statistical downscaling model (SDSM). APEX model parameterization was done as per local conditions. The APEX model was calibrated on a daily basis for 2017 and 2018. For calibration and validation of the model used low to medium rainfall days. The model calibrated quite well for surface runoff (r2 - 0.92) and sediment yield (r2 - 0.88) with RMSE of 4.98 mm and 0.20 t/ ha for surface runoff and sediment yield, respectively. The model was validated well for surface runoff (r2 - 0.81) and sediment yield (r2 - 0.81) with RMSE of 2.6 mm and 0.11 t/ha for surface runoff and sediment yield respectively. The model performance was identified based on Nash- Sutcliffe efficiency (NSE). The model performed quite well for surface runoff and sediment 224 yield of NSE 0.71 and 0.70 respectively. The change in soil loss under A2 and B2 scenarios with respect to baseline period were predicted for the study area to recognize the effect of climate change on soil loss. The general trend in future climate shows there is an increase in rainfall under both A2 and B2 scenario. Under the A2 scenario, rainfall increases marginally higher than B2 scenario. A total of 41.35 per cent increase in rainfall during 2080, 20.14 per cent during 2050, and 27.27 per cent during 2020 were observed. But in B2 scenario due to lower emission, change in rainfall is relatively lower than A2 scenario. It was observed that 24.71 per cent, 29.13 per cent and 35.16 per cent increase during 2020, 2050 and 2080 respectively. Maximum temperature increases 3.7 oC during 2080 under A2, while under B2 scenario the increase is 2.6 oC. Similarly, minimum temperature also rising at 3.6 oC during 2080 under A2 scenario and 2.7 oC under B2 scenario. The increase in temperature under both scenarios is almost similar and a marginal difference was observed. Highest soil loss was estimated from scrub land (38.42 t/ha/yr) followed by agriculture (26.97 t/ha/yr) then open forest (21.69 t/ha/yr) and lowest in the dense forest cover (14.70 t/ha/yr) under baseline period. The average annual soil loss from the watershed is 25.45 t/ha/yr. It was observed that 64.61 per cent of the study area was under moderate (10-20 t/ha/yr) erosion risk class. 24.15 per cent area with severe (20-40 ton ha-1 yr-1) erosion and 11.23 per cent area contribute very severe (>40 ton ha-1 yr-1) erosion. Under A2 scenario the average soil loss during 2020s, 2050s and 2080s may increase 27.71, 21.84 and 46.94 per cent respectively. Similarly under B2 scenario average soil loss may increase 23.24, 30.71 and 38.80 per cent, respectively. The climate change impact on soil erosion under both scenarios suggests that there is an increasing soil erosion due to the increase in rainfall in Shivalik region of Himachal Pradesh. Due to the high intensity of rainfall and steep slopes of the study area the mechanical conservation measures are preferred. The agronomic, mechanical and biological measures can be also used to conserve the soil and water.Item Impact of heat and nutritional stress on the growth and reproductive performance of bucks(Academy of Climate Change Education and Research, Vellanikkara, 2015) Abdul Niyas, P A; Girish Varma, GItem Impact of climate change on water availability across western ghats(Academy of Climate Change Education and Research, Vellanikkara, 2015) Anjali Nair, B; Prasada Rao, G S L H VThe present study entitled “Impact of climate change on water availability across Western Ghats” was taken up at the Energy and Wetlands Research Group, Indian Institute of Science, Bangalore during 2014-‘15 with the objectives of analyzing the changes in surface air temperature and rainfall across the Western Ghats along the Coast, Ghat and Plain regions and visualizing the likely scenario in land use and water availability in two selected basins viz., Karamana Basin (Thiruvananthapuram, Kerala and Sita Basin, Udupi, Karnataka) under the projected climate change scenario. The data required for the study were obtained from the Directorate of Economics and Statistics, Government of Karnataka, website of NOAA, website of Hydrology Department, University of Princeton and from the publications of the Central Government Department and the concerned State Departments. The study revealed that the rainfall over the Western Ghats as a whole doesn’t reveal any trend from 1901-2010 while it is not so at the regional level. However, the maximum and minimum temperatures along the Western Ghats showed an increasing trend from 1948- 2010. The trend was similar at regional level except in the plains of the Northern Western Ghats which showed a marginal decrease in the mean maximum temperature. Both the representative river basins viz., Karamana in Thiruvananthapuram district and Sita in Udupi district have undergone changes in the land use pattern which altered the water balance of the basin along with the change in population since last two decades from 1990 to 2010. The Karamana Basin suffered a deficit in the available water owing to the low rainfall received in the basin in comparison to the huge demand of water and the situation tend to aggravate with an increase in water demand and decrease in rainfall over the basin. But, Sita basin receives abundant rainfall which caters to the needs of the basin which rules out the water deficit in the basin unless in case of occurrence of moderate to severe drought.Item Impact of heat and nutritional stress on adaptive capability of bucks(Academy of Climate Change Education and Research, Vellanikkara, 2015) Shilja Shaji; Girish Varma, GItem Effect of growing environment and climate change on physiyology of tomato ( Lycopersicon esculentum Mill. )(Acadamy of Climate Change Education and Research, Vellanikkara, 2015) Rajalakshmi Radhakrishnan; Sunil, K MThe present world production of tomato stands at 100 million tons fresh fruits produced on 3.7 million hectares. Even though productivity levels of tomato have increased, it will not be sufficient enough to the increasing population. Global climate change is any significant long term change in expected patterns of weather over a region which may be naturally induced or anthropogenic. The effect of climate change on crop and terrestrial food production are evident in several regions of the world. Negative impacts of climate trends have been more common than positive ones. Objectives of the study were to study the effect of different growing environment and climate change on the physiological traits of tomato development of crop weather relationships for the selected rice varieties and assessment of possible change in yield due to climate change. The studies were conducted during December 2014- March 15at the Central Nursery, Vellanikkara in the bacterial wilt resistant variety Anagha by providing three different growing environments namely polyhouse, rainshelter and open field conditions with four dates of transplanting. The results showed that the dates of transplanting and growing environment had a significant effect on the physiology of tomato. The crop transplanted inside the polyhouse took the longest duration. Maximum leaf area index (3.8) was observed in in the crop transplanted in open field, polyhouse and rain shelter on different dates on different dates (1 December 2014 and 20 January 2015 respectively). The highest values of leaf relative water content was observed in the first week following transplanting and the lowest values appeared prior to the last harvest regardless of the dates of transplanting and growing environment. The lycopene content was consistently highest in the crops inside the Polyhouse. The highest value for the same was 1.52 mg gm-1 was recorded in crops inside the polyhouse transplanted on 10 January 2015.The fruit ascorbic acid content (2.06 mg gm-1) was highest in the crop inside rain shelter transplanted on 10 December 2014. The highest mean length of style was documented in the flowers of the crop transplanted inside rain shelter (8.08 mm) on 1 December 2014 whereas, the highest mean stamen length was recorded in the flowers of the crop transplanted inside polyhouse (8.28 mm) on 1 December 135 2014). The difference in the length of the style and stamen and its relative position significantly affected the total yield obtained. A difference of more than -0.05 mm considerably reduced the yield. The highest yield (111.5 tons ha-1) was recorded inside the polyhouse in the crops transplanted on 1 December 2014. The net photosynthesis rate was highest in the rain shelter crops regardless of the dates of transplanting. The highest values recorded was 19.7 in the rain shelter and poly house for the crops transplanted on 10 and 20 January 2015. The temperature prevalent was the most crucial factor determining the rate of photosynthesis followed by Carbon dioxide. Under the projected climate change scenarios i.e. RCP 2.6, 4.5, 6.5 and 8.0, the ascorbic acid content increased in the fruit owing to higher temperature and lower soil moisture availability. The lycopene content remained unaffected as the UV radiation concentration is will be changing negligibly for the region where the study is conducted. The duration of the crop will be reduced drastically from 2030 to 2080 under all the scenarios. The results also showed that the effect of minimum temperature would drastically reduce the yield. The increasing atmospheric CO2 concentration is likely to have some positive effect on yield, but the effect is not significant compared to the negative impact of rise in temperature.Item Changing global climatic scenario on environmental processes across India: its possible causes and impacts(Academy of Climate Change Education and Research, Vellanikkara, 2016) Lekshmi Mudra, B; Prasada Rao, G S L H VItem Phenology of medicinal snake gourd (Trichosanthes cucumerina L.) under different seasons(Academy of Climate Change Education and Research, Vellanikkara, 2015) Harsha Satheesh; Kanakamany, M TThe present study entitled “Phenology of medicinal snake gourd (Trichosanthes cucumerina L.) under different seasons” was carried out at Academy of Climate Change Education and Research (ACCER), Vellanikkara during the period 2014-2015. Field experiments were conducted at All India Coordinated Research Project on Medicinal, Aromatic Plants and Betel Vine (AICRP on MAP & B), College of Horticulture, Vellanikkara. The objective of the study was to assess the influence of weather parameters on yield and yield attributing characters of medicinal snake gourd (Trichosanthes cucumerina L.) under open and rain shelter during winter, summer and rainy seasons. The experiment was laid out in a randomized block design with six treatments and four replications each in open and rain shelter during winter, summer and rainy seasons. Observations on meteorological, growth characters, floral biology, yield and quality parameters were recorded under open and rain shelter in all the three seasons. Significant difference was observed in number of flowers, number of fruits produced, pollen fertility, fruit yield per plant, herbage yield per plant, total yield per plant and per plant cucurbitacin content for plants grown under rain shelter as well as in open condition during the three seasons. During winter, summer and rainy seasons crops grown under rain shelter recorded highest vine length, number of branches, maximum leaf area and number of male and female flowers produced, herbage yield per plant and dry yield per plant than open condition. Whereas pollen fertility, pollen viability and fruit weight were found to be highest in open condition than in rain shelter during summer season and found more in rain shelter during winter and rainy seasons. Earlier anthesis of both male and female flower was recorded during summer season under open condition. Highest herbage yield per plant, fruit yield per plant and total yield per plant were recorded under open condition during summer season. But during rainy season it is higher under rain shelter when compared to open field.Per plant cucurbitacin content was highest for the plants that grown under open environment than in rain shelter. It was found to be maximum during summer season followed by winter and rainy season. Weather parameters such as canopy air temperature, daily minimum and maximum temperature were high under rain shelter during the three cropping seasons. Relative humidity and soil moisture were high under rain shelter during winter and summer and low during rainy season. Correlation analysis with the weather parameters and crop was studied. Relative humidity and soil moisture had a significant negative correlation with the number of male flowers produced, pollen fertility, herbage yield per plant, total yield per plant and per plant cucurbitacin content. Canopy air temperature, minimum and maximum temperature showed positive correlation with the number of male flowers, produced pollen fertility, number of fruits, fruit yield per plant, herbage yield per plant, total yield per plant and per plant cucurbitacin content whereas rainfall had a negative correlation.Item Impact of heat and nutritional stress on rumen fermentation characteristics and metabolic activity Bucks(Academy of Climate Change Education and Research, Vellanikkara, 2015) Chaidanya, K; Girish Varma