Impacts of climate change on water resources and agriculture in Sri Lanka: vulnerability hot spots and options for adaptation

Climate change, Adaptation, Water resources, Sri Lanka

Environmental journalists have important role to play in helping Sri Lanka’s water sector meet the coming challenges of climate change. Media release

Climate changeModelsWater storageWater management

Observed and projected climatic changes, their impacts and adaptation options for Sri Lanka: a review

Climate is changing world-wide, and the science community in Sri Lanka has come up with ample evidence to suggest that the country’s climate has already changed. During 1961-1990 the country’s mean air temperature increased by 0.016 0C per year, and the mean annual rainfall decreased by 144 mm (7 %) compared to the period 1931-1960. In addition, mean annual daytime maximum and mean annual night-time minimum air temperatures increased. However, the bigger question of national importance is what Sri Lanka’s climate will look like in 50 or 100 years and how prepared is the country to face it. Apart from the Intergovernmental Panel on Climate Change (IPCC) projections at the coarse global scale, few studies have attempted to project future climate scenarios for Sri Lanka and to identify climate change impacts on agriculture, water resources, the sea level, the plantation sector, the economy and health. Vulnerability and adaptation to climate change are the least studied areas. This paper reviews the status of climate change research and activities in Sri Lanka with respect to future climate projections, impacts, climate change mitigation and the country’s ability to adapt, and identifies existing knowledge gaps. Messages emerging from this review suggest that Sri Lanka’s mean temperature during the North-East (December-February) and South-West (May-September) monsoon seasons will increase by about 2.9 0C and 2.5 0C, respectively, over the baseline (1961-1990), by the year 2100 with accompanying changes in the quantity and spatial distribution of rainfall. Extreme climate events are expected to increase in frequency. These changes will bring about widespread impacts on the country’s agriculture and economy For example, an increase of 0.5 0C in temperature can reduce rice yield by approximately 6%; extended dry spells and excessive cloudiness during the wet season can reduce coconut yield resulting in annual losses between $32 and$73 million to the economy. Pilot studies in the Galle District suggest that sea level rise could inundate about 20 % of the land area of Galle’s coastal District Secretariat Divisions. Adaptation measures already undertaken in the agriculture sector include the development of low water consuming rice varieties and the use of micro-irrigation technologies. Tools have been developed for predicting seasonal water availability within the Mahaweli Scheme and annual national coconut production. However, Sri Lanka is yet to undertake a comprehensive national study on the vulnerability of her water resources and agriculture to climate change. The formulation of detailed and reliable future climate scenarios for the country is therefore, urgently required.Length: pp.99-117Climate changeImpact assessmentWater resourcesAgricultureAdaptation

NON-CHROMATOGRAPHIC OLIGONUCLEOTIDE PURIFICATION AND AUTOMATED POLYETHYLENEGLYCOL SYNTHESIS

Synthetic oligodeoxynucleotides (ODN) have various applications in many areas such as, synthetic biology, chemical biology, antisense drug development, and data storage. As a result, there is a high demand for synthetic ODNs. Many advances have been made with ODN synthesis the purification still remains a bottleneck. The non-chromatographic purification method is developed to address this problem. Similarly, polyethylene glycols (PEGs) have been used in many areas including pharmaceutical applications, surface science, and nanomedicine due to its unique properties. However, monodispersed PEG synthesis is expensive with existing methods. A novel automated solid phase synthesis method is developed to obtain monodispersed PEGs. The first two chapters are an introduction to synthetic oligodeoxynucleotide purification. These chapters describe oligonucleotides and applications, chemical synthesis of oligodeoxynucleotides, impurities in synthetic oligonucleotides, and current purification methods. Even though many chromatographic purification methods are available for synthetic ODN purification, there is no method that is capable of high throughput purification, large scale ODN purification, and long ODN purification. To address this problem, we developed two non-chromatographic purification methods which are based on polymerization, to purify synthetic ODNs. One is catching failure sequences by polymerization, and the second method is catching full-length sequences by polymerization. The second method is less expensive for large-scale and long ODN purification compared to the first method. It is demonstrated that this new non-chromatographic method is suitable for high throughput, large scale, and long ODN purification. The final chapters describe applications of polyethylene glycol and current PEG synthesis methods. For many applications monodispersed PEGs are preferred. However, PEGs synthesized using current synthesis methods are polydispersed and excessive purification is required to obtain monodispersed PEGs. Therefore, it is expensive to obtain monodispersed PEGs using these existing methods. An automated solid-phase stepwise synthesis method is developed for monodispersed PEG synthesis. This solid-phase xxii synthesis method is cost effective because the purification is not required to obtain monodispersed PEGs using this method. Monodispersed PEGs with eight, twelve, and sixteen ethylene glycol units and their derivatives were synthesized using automated stepwise addition of tetra ethylene glycol monomer without chromatographic purification. The monomer consists of a 4,4′ dimethoxy trityl group at one end and the tosyl group at the other hydroxyl group. Wang resin was used as the solid support for the automated synthesis. The automated synthesis cycle consists of three steps, deprotonation, coupling, and detritylation. PEGs were cleaved off from the solid support and analyzed with ESI-MS. After PEG12 synthesis, the coupling step with DMTr monomer had some complications and therefore a new monomer with a smaller protecting group was designed. Using this new monomer monodispersed PEGs with ten, fifteen, and twenty ethylene glycol units were synthesized. The synthesis was done using automated solid-phase stepwise addition of penta ethylene glycol units without chromatographic purification. The penta ethylene glycol monomer consists of a 2-phenethyl group at one end, and the tosyl group at the other hydroxyl group was used for the synthesis. The first step is deprotection and deprotonation, and the second step is coupling. These two steps were performed alternatively until the PEG with the desired length was obtained. After the synthesis, PEGs were cleaved from the solid support and analyzed using ESI-MS

Determination of Optical Density (OD) of Oligodeoxynucleotide from HPLC Peak Area

Oligodeoxynucleotides (ODNs) are typically purified and analysed with HPLC equipped with a UV-Vis detector. Quantities of ODNs are usually determined using a UV-Vis spectrometer separately after HPLC, and are reported as optical density at 260 nm (OD260). Here, we describe a method for direct determination of OD260 of ODNs using the area of the peaks in HPLC profiles

Observed and Projected Climatic Changes, Their Impacts and Adaptation Options for Sri Lanka: A Review

Abstract Climate is changing world-wide, and the science community in Sri Lanka has come up with ample evidence to suggest that the country's climate has already changed. During 1961-1990 the country's mean air temperature increased by 0.016 0 C per year, and the mean annual rainfall decreased by 144 mm (7 %) compared to the period 1931-1960. In addition, mean annual daytime maximum and mean annual night-time minimum air temperatures increased. However, the bigger question of national importance is what Sri Lanka's climate will look like in 50 or 100 years and how prepared is the country to face it. Apart from the Intergovernmental Panel on Climate Change (IPCC) projections at the coarse global scale, few studies have attempted to project future climate scenarios for Sri Lanka and to identify climate change impacts on agriculture, water resources, the sea level, the plantation sector, the economy and health. Vulnerability and adaptation to climate change are the least studied areas. This paper reviews the status of climate change research and activities in Sri Lanka with respect to future climate projections, impacts, climate change mitigation and the country's ability to adapt, and identifies existing knowledge gaps. Messages emerging from this review suggest that Sri Lanka's mean temperature during the North-East (December-February) and South-West (May-September) monsoon seasons will increase by about 2.9 0 C and 2.5 0 C, respectively, over the baseline , by the year 2100 with accompanying changes in the quantity and spatial distribution of rainfall. Extreme climate events are expected to increase in frequency. These changes will bring about widespread impacts on the country's agriculture and economy. For example, an increase of 0.5 0 C in temperature can reduce rice yield by approximately 6 %; extended dry spells and excessive cloudiness during the wet season can reduce coconut yield resulting in annual losses between $32 and$73 million to the economy. Pilot studies in the Galle District suggest that sea level rise could inundate about 20 % of the land area of Galle's coastal District Secretariat Divisions. Adaptation measures already undertaken in the agriculture sector include the development of low water consuming rice varieties and the use of micro-irrigation technologies. Tools have been developed for predicting seasonal water availability within the Mahaweli Scheme and annual national coconut production. However, Sri Lanka is yet to undertake a comprehensive national study on the vulnerability of her water resources and agriculture to climate change. The formulation of detailed and reliable future climate scenarios for the country is therefore, urgently required. 100 Nishadi Eriyagama and Vladimir Smakhti

Lysine Crosslinked Polyacrylamide─A Novel Green Polymer Gel for Preferential Flow Control

Acrylamide-based polymer gels have been applied to control the preferential flow in the subsurface for decades. However, some commonly used crosslinkers, such as Cr (III) and phenol-formaldehyde, are highly toxic and are being phased out because of stringent environmental regulations. This work uses l-lysine as the green crosslinker to produce acrylamide-based polymer gels. This article systematically studied the effect of lysine and polymer concentration, salinity, pH, and temperature on gelation behavior and thermal stability. Besides, the gelation mechanism and crosslinking density were elucidated in this work. A high-permeability sandstone core was used to test the plugging efficiency of this novel green gel system. This polyacrylamide/lysine system has a controllable gelation time. It can form gels at temperatures higher than 80 °C, with the gelation time from hours to days, and the elastic modulus of the gel can reach over 400 Pa. In addition, the crosslinked gels have been stable at 80 to 130 °C for over 200 days. This novel gel system could decrease rock permeability by over 1000 times. Besides, the Frrw is two times higher than the Frro, confirming that the current gel system can reduce the permeability to water more than that to oil. As a green gel system, this novel polymer gel system could replace the current toxic gel systems for the preferential fluid control for water management projects in oil and gas reservoirs, enhanced geothermal systems, and carbon capture and sequestration projects

Electrophilic oligodeoxynucleotide synthesis using dM-Dmoc for amino protection

Solid-phase synthesis of electrophilic oligodeoxynucleotides (ODNs) was achieved using dimethyl-Dmoc (dM-Dmoc) as amino protecting group. Due to the high steric hindrance of the 2-(propan-2-ylidene)-1,3-dithiane side product from deprotection, the use of excess nucleophilic scavengers such as aniline to prevent Michael addition of the side product to the deprotected ODN during ODN cleavage and deprotection was no longer needed. The improved technology was demonstrated by the synthesis and characterization of five ODNs including three modified ones. The modified ODNs contained the electrophilic groups ethyl ester, α-chloroamide, and thioester. Using the technology, the sensitive groups can be installed at any location within the ODN sequences without using any sequence- or functionality-specific conditions and procedures

Global Environmental Flow Information for the Sustainable Development Goals

Environmental flows (EF) are an important component of Goal 6 (the ‘water goal’) of the Sustainable Development Goals (SDGs). Yet, many countries still do not have well-defined criteria on how to define EF. In this study, we bring together the International Water Management Institute’s (IWMI’s) expertise and previous research in this area to develop a new methodology to quantify EF at a global scale. EF are developed for grids (0.1 degree spatial resolution) for different levels of health (defined as environmental management classes [EMCs]) of river sections. Additionally, EF have been separated into surface water and groundwater components, which also helps in developing sustainable groundwater abstraction (SGWA) limits. An online tool has been developed to calculate EF and SGWA in any area of interest

Laboratory Evaluation of a Novel Self-Healable Polymer Gel for CO2 Leakage Remediation during CO2 Storage and CO2 Flooding

For CO2 storage in subsurface reservoirs, one of the most crucial requirements is the ability to remediate the leakage caused by the natural fractures or newly generated fractures due to the increasing pore pressure associated with CO2 injection. For CO2 Enhanced Oil Recovery (EOR), high conductivity features such as fractures and void space conduits can severely restrict the CO2 sweep efficiency. Polymer gels have been developed to plug the leakage and improve the sweep efficiency. This work evaluated a CO2 resistant branched self-healable preformed particle gel (CO2-BRPPG) for CO2 plugging purpose. This novel CO2-BRPPG can reform a mechanical robust adhesive bulk gel after being placed in the reservoir and efficiently seal fractures. In this work, the swelling kinetics, self-healing behavior, thermal stability, CO2 stability, rheology, adhesion property and plugging performance of this novel CO2-BRPPG were studied in the laboratory. Results showed that this CO2-BRPPG has good self-healing abilities, and the self-healed bulk gel has excellent mechanical and adhesion strength. Gel with a swelling ratio of ten has an elastic modulus of over 2000 Pa, and the adhesion strength to sandstone is 1.16 psi. The CO2-BRPPG has good CO2 phase stability at 65 °C, and no dehydration was observed after 60 days of exposure to 2900 psi CO2 at 65 °C. Core flooding test proved that the swelled particles could reform a bulk gel after being placed in the fractures, and the reformed bulky gel has excellent CO2 plugging efficiency. The supercritical CO2 breakthrough pressure gradient was 265 psi/feet (5.48 MPa/m). This work could offer the experimental basis for the field application of this CO2-BRPPG in CO2 storage and CO2 enhanced oil recovery