salinity intrusion
Recently Published Documents


TOTAL DOCUMENTS

226
(FIVE YEARS 73)

H-INDEX

16
(FIVE YEARS 4)

Author(s):  
Nguyen Phuc Khoa ◽  
Nguyen Thanh Dien ◽  
Nguyen Huu Ngu ◽  
Hoang Dinh Trung

Background: Several coastal regions in Vietnam have been suffered from salinity intrusion as a consequence of global climate change. However, there are limited studies on saline intrusion in Vietnam. This paper aimed to investigate the salinity intrusion of water and soil samples in paddy fields along Tam Giang lagoon, Thua Thien Hue province and clarify the factors affecting the salinity level. Methods: We measured the salinity concentrations (EC, Electrical conductivity) of water and soil samples in paddy fields at different distances (400, 600, 800, 1000 and 1200 m) from Tam Giang lagoon. The multiple regression analysis was performed to figure out the factors affecting the salinity concentrations. Result: The salinity concentrations of water were assessed as 48% high saline (10-25 dS m-1), 34% moderately saline (2-10 dS m-1), 2% slightly saline (0.7-2 dS m-1) and 15% non-saline ( less than 0.7 dS m-1). As for surface soil in paddy field, 14.3% moderately saline (4-8 dS m-1), 35.4% slightly saline (2-4 dS m-1) and 50.3% non-saline (0-2 dS m-1) were measured. A significantly positive correlation was found between salinity concentrations of water and soil (n = 175, r = 0.886, p less than 0.01). The distances from salinity sources, Tam Giang lagoon and shrimp pond, were major factors affecting the salinity concentrations. The paddy fields near Tam Giang lagoon and shrimp pond have higher salinity concentrations compared to those areas close to the residential area. The surface water in the paddy field within 1000 m from the salinity source was assessed as saline that might harm the paddy soil and rice production. The results of this study provide highly useful information for local policymakers and farmers about the status of salinity intrusion in paddy land.


2021 ◽  
Vol 8 ◽  
Author(s):  
Farzana Hossain ◽  
S. M. Majharul Islam ◽  
Mohammad Ashaf-Ud-Doulah ◽  
Md Shaha Ali ◽  
Md Sadiqul Islam ◽  
...  

Salinity intrusion in coastal areas due to climate change is alarming. In this study, the effects of salinity on embryonic and larval development of striped catfish (Pangasianodon hypophthalmus) were studied experimentally. Embryos and larvae were exposed to seven salinity treatments (0, 2, 4, 6, 8, 10, and 12 ppt), each with three replications. Considerable survivability of embryos was recorded up to 6 ppt salinity. Mortality of embryos significantly increased at 8 and 10 ppt salinity, and 100% mortality was displayed within 12 h of exposure at 12 ppt salinity. The rate of hatching was significantly reduced at 8 and 10 ppt salinity. The 24 h lethal concentration (LC50) value of salinity for embryo was 11.24 ppt. Different types of deformities, such as undeveloped yolk sac, elongated gastrula yolk sac, and yolk sac bud, were highest at 10 ppt salinity. Similar to the embryo, considerable survivability of larvae was recorded up to 6 ppt salinity, and 100% mortalities were found within 24 h of exposure at 12 ppt salinity. The 24 and 48 h LC50 values of salinity for larvae were 10.63 and 8.48 ppt, respectively. Several types of deformities, including yolk sac ulceration, spine scoliosis, tail bent, yolk sac edema, and compromised swim bladder inflation, were highest at 10 ppt salinity after 48 h of exposure. Within 24 h of exposure, about 80% yolk sac of the larvae was absorbed at 8 and 10 ppt salinity, while 30%–50% yolk sac was absorbed at 0–6 ppt salinity. Growth rates in terms of length and weight were higher at 0, 2, and 4 ppt salinity and moderate at 6 and 8 ppt salinity. Overall, the current findings define the limits to optimize hatchery procedures for the culture of this species in low saline brackish water.


2021 ◽  
Vol 22 (2) ◽  
Author(s):  
Sourabh Kumar Dubey ◽  
Raman Kumar Trivedi ◽  
Bimal Kinkar Chand

Salinity intrusion into coastal mainland or freshwater habitat because of recent climatic changes is exacerbating production risks and challenging the coping capacity of freshwater fish farmers of Sundarban coastal delta in India. Hence, an experiment was conducted to evaluate the survival and growth performance of certain commercially important brackish water species in freshwater, and subsequent low salinities (5 g l−1 and 10 g l−1). Species like Scatophagus argus, Chelon parsia, Terapon jarbua, Etroplus suratensis, and Penaeus monodon showed the highest specific growth rate (SGR) at 10 g l-1 salinity. However, the growth rates were not differed significantly (P>0.05) compared to freshwater. Chelon planiceps and Mystus gulio exhibited the highest SGR at 5 g l-1 salinity, although growth rates of the fish were not differed significantly (P>0.05) with freshwater treatments. Comparable survival and growth of all species in the freshwater condition indicated their ability of healthy acclimation at freshwater ponds. Therefore, these euryhaline fish species can be promoted in the Indian Sundarban for culture in freshwater ponds as climate-resilient adaptation strategies. This study could be useful in decision making during species and farm site selection which eventually will minimize the risks from total crop loss during saltwater inundation.


Author(s):  
Md. Anowarul Islam

The main objective of this study is to explore the major impacts of salinity intrusion on coastal agriculture and farmer’s livelihoods in Bangladesh. The study has attempted to identify some effective measures for the sustainability of coastal agriculture. The study was conducted based on both primary and secondary data during 2010-2020. To collect primary data, a total of 150 respondents out of 240 households were randomly interviewed and samples are drawn proportionately from study sites. Descriptive and inferential statistics have been done to analyze data. The ArcGIS mapping tool was adopted to represent the spatio-temporal change of saline area. It reveals that due to high salinity intrusion the coastal agriculture has already experienced noticeable adverse impacts especially in increasing rate of salinity, loss in cultivable land and production. Shrimp farming with brackish water and tidal inundation are explored as the main causes for salinity intrusion. In study sites, the level of salinity in 2020 is much stronger than in 2010. It reveals that due to strong salinity in agricultural land the farmer's are suffering from low income, unemployment, scarcity in irrigation and freshwater. It was identified that the planned shrimp culture, management of the embankment, cultivation of saline tolerant crops and raising public awareness will be the possible measures to control the intrusion of salinity. Therefore, it is expected that the evaluation of the revealed impacts of salinity intrusions and the explored measures will be effective to ensure the sustainability of coastal agriculture in Bangladesh. 


Author(s):  
Umma Habiba ◽  
Md. Anwarul Abedin

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Natural Hazard Science. Please check back later for the full article. Bangladesh scored seventh in a ranking of countries most affected by climatic calamities in the second decade of the 21st century. Climate change poses a great threat to Bangladesh’s economy due to its effect on the agricultural system. The agriculture sector employs about 40.6% of the country’s labor force and contributes 14.1% of the gross domestic product (GDP). Various climatic factors such as changes in precipitation, temperature, sea level rise, salinity intrusion, drought, and natural disasters (storm surges, cyclones, etc.) impact the agriculture sector. These factors ultimately affect crop production and increase food insecurity. The coastal zone frequently suffers the impacts of climate change through coastal flooding, cyclones, storm surges, drought, salinity intrusion, water-logging, and so forth. These crises not only affect agricultural productivity but also lead to degradation of soil productivity and lower agricultural production/yield. To cope with the impacts on coastal agriculture, government, nongovernmental organizations, and communities have practiced a number of adaptation measures. They have adopted several measures such as using stress-tolerant rice varieties; crops that consume less water; short-duration crops; crop diversification; crop rotation; mix cropping/intercropping; efficient use of irrigation, fertilizer, and pesticides; soil conservation; floating gardens; sorjan cultivation; homestead vegetable gardening; and the re-excavation of canals. However, these adaptive practices are responsive and timely immediately after the occurrence of the effects of climate change. Taking this into consideration, it is imperative to scale up these adaptation measures and to synchronize efforts at various levels for their successful implementation by coastal communities in order to cope with climate change in a sustainable manner.


Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2139
Author(s):  
Paul H. Hutton ◽  
David M. Meko ◽  
Sujoy B. Roy

This work presents updated reconstructions of watershed runoff to San Francisco Estuary from tree-ring data to AD 903, coupled with models relating runoff to freshwater flow to the estuary and salinity intrusion. We characterize pre-development freshwater flow and salinity conditions in the estuary over the past millennium and compare this characterization with contemporary conditions to better understand the magnitude and seasonality of changes over this time. This work shows that the instrumented flow record spans the range of runoff patterns over the past millennium (averaged over 5, 10, 20 and 100 years), and thus serves as a reasonable basis for planning-level evaluations of historical hydrologic conditions in the estuary. Over annual timescales we show that, although median freshwater flow to the estuary has not changed significantly, it has been more variable over the past century compared to pre-development flow conditions. We further show that the contemporary period is generally associated with greater spring salinity intrusion and lesser summer–fall salinity intrusion relative to the pre-development period. Thus, salinity intrusion in summer and fall months was a common occurrence under pre-development conditions and has been moderated in the contemporary period due to the operations of upstream reservoirs, which were designed to hold winter and spring runoff for release in summer and fall. This work also confirms a dramatic decadal-scale hydrologic shift in the watershed from very wet to very dry conditions during the late 19th and early 20th centuries; while not unprecedented, these shifts have been seen only a few times in the past millennium. This shift resulted in an increase in salinity intrusion in the first three decades of the 20th century, as documented through early records. Population growth and extensive watershed modification during this period exacerbated this underlying hydrologic shift. Putting this shift in the context of other anthropogenic drivers is important in understanding the historical response of the estuary and in setting salinity targets for estuarine restoration. By characterizing the long-term behavior of San Francisco Estuary, this work supports decision-making in the State of California related to flow and salinity management for restoration of the estuarine ecosystem.


2021 ◽  
pp. e00424
Author(s):  
Tien Giang Nguyen ◽  
Ngoc Anh Tran ◽  
Phuong Lan Vu ◽  
Quoc-Huy Nguyen ◽  
Huu Duy Nguyen ◽  
...  

Author(s):  
Paul H Hutton ◽  
David M Meko ◽  
Sujoy B Roy

This work presents updated reconstructions of watershed runoff to San Francisco Estuary from tree-ring data to AD 903, coupled with models relating runoff to freshwater flow to the estuary and salinity intrusion. We characterize pre-development freshwater flow and salinity conditions in the estuary over the past millennium and compare this characterization with contemporary conditions to better understand the magnitude and seasonality of changes over this time. This work shows that the instrumented flow record spans the range of runoff patterns over the past millennium (averaged over five, ten, twenty and one hundred years), and thus serves as a reasonable basis for planning-level evaluations of historical hydrologic conditions in the estuary. Over annual timescales we show that, although median freshwater flow to the estuary has not changed significantly, it has been more variable over the past century compared to pre-development flow conditions. We further show that the contemporary period is generally associated with greater spring salinity intrusion and lesser summer-fall salinity intrusion relative to the pre-development period. Thus, salinity intrusion in summer and fall months was a common occurrence under pre-development conditions and has been moderated in the contemporary period due to the operations of upstream reservoirs, which were designed to hold winter and spring runoff for release in summer and fall. This work also confirms a dramatic decadal-scale hydrologic shift in the watershed from very wet to very dry conditions during the late 19th and early 20th centuries; while not unprecedented, these shifts have been seen only a few times in the past millennium. This shift resulted in an increase in salinity intrusion in the first three decades of the 20th century, as documented through early records. Population growth and extensive watershed modification during this period exacerbated this underlying hydrologic shift. Putting this shift in the context of other anthropogenic drivers is important in understanding the historical response of the estuary and in setting salinity targets for estuarine restoration. By characterizing the long-term behavior of San Francisco Estuary, this work supports decision-making in the State of California related to flow and salinity management for restoration of the estuarine ecosystem.


Sign in / Sign up

Export Citation Format

Share Document