Harmful algal blooms (HABs) are increasingly attracting attention all over the world. A diverse s... more Harmful algal blooms (HABs) are increasingly attracting attention all over the world. A diverse set of algal species including diatoms, flagellates, chrysophytes and dinoflagellates can cause harmful blooms, and many produce toxins that harm other organisms and human health. Intensive cyanobacterial blooms, in particular, have been associated with high costs for society due to their potential toxicity. Algal blooms can produce different toxins. These toxins present a long-standing threat to human and environmental health. For example, the severe Karenia bloom of 2005 in the eastern Gulf of Mexico demonstrates the complexities and magnitude of the challenges of managing algal blooms for both environmental and public health. With increasing events and severe impacts of algal blooms on human health, it becomes necessary to monitor and manage toxic algal blooms. Hence this paper presents a review of causes, impacts and control of algal blooms.
There are several methods to assess bacterial adhesion to metal surfaces. Although these methods ... more There are several methods to assess bacterial adhesion to metal surfaces. Although these methods are sensitive, they are time consuming and need expensive chemicals and instruments. Hence, their use in assessing bacterial adhesion is limited. Therefore, a simple spectrophotometric method was developed to evaluate bacterial adhesion to metal surface. The method was calibrated using a bacterium Vibrio sp. and aluminium as a model organism and substratum, respectively. The method involves staining attached bacterial cells with crystal violet (0.5%). The crystal violet stain from the cells was eluted with an aqueous solution of sodium deoxycholate (2%). The absorbance of the crystal violet stain in deoxycholate was measured at 570 nm. The viable cell count of the attached bacterial cells was also measured using coventional plating technique. Relationship between the absorbance of crystal violet stained attached cells and the viable cell count of the attached bacteria was assessed using ...
Current fishing practices show a global trend of stock depletions. Overfishing was recognized as ... more Current fishing practices show a global trend of stock depletions. Overfishing was recognized as an international problem in the early 1900s and since then has drawn attention of a number of international programmes, especially directed at environmental managers and the governments of many nations. However, the common pool nature of fish resources poses constraints for management. In particular, multispecies fisheries, as found in South Asian waters, have complex dynamics and pose additional constraints for management. The use of closed season/areas to control fishing efforts is a basic management tool in fisheries. The breeding season varies for different species and, hence, the closed season (and/or area) must be targeted at certain critical time periods (and/or habitats) of importance to key species. Such regulations made by the legislature, executive, or, at times, by the judiciary give rise to conflicts between industrial and traditional fishers and between the different instit...
Khazan ecosystems are reclaimed wetlands, salt marshes and mangrove areas, where tidal influence ... more Khazan ecosystems are reclaimed wetlands, salt marshes and mangrove areas, where tidal influence is regulated by the construction of embankments and sluice gates. They are predominantly rice and fish fields. Khazan engineering system has a very simple architectural design made from locally available low-cost resources, which is self-operating using tidal, hydro and solar energy, and the one which integrates highly complex, eco-friendly agriculture, aquaculture, and salt panning systems that function for the last more than 3,500 years with very low running cost. This chapter illustrates khazan architecture and presents different types of khazan farms and the processes involved therein, cultural aspects and traditions associated with khazans, traditional ecological knowledge in khazans and ecological services provided by khazans.
Growth inhibition of fouling bacteria and diatoms by extract of terrestrial plant, Derris scandens (Dicotyledonae:Leguminocae)
Methanol extract of terrestrial plant, Derris scandens Benth, was found to inhibit growth of four... more Methanol extract of terrestrial plant, Derris scandens Benth, was found to inhibit growth of four diatoms and 7 bacterial species of fouling community. The concentrations required to bring about 100% inhibition of growth of the diatoms ranged between 200 to 300 mg g.ml sup(-1), whereas, the bacterial inhibition zone around the disc containing about 600-800 mu g of extract ranged between 1-5 mm. The results suggest that the crude extract of the plant is nontoxic and possesses both antibacterial and antialgal properties. Therefore, the extract promises to be a potential source of natural biocide for fouling organisms
Issues of equity and justice are not very explicit and are not readily accepted in case of enviro... more Issues of equity and justice are not very explicit and are not readily accepted in case of environmental matters such as pollution by industries and its impacts on unempowered communities. An area of focus, which is currently debated, but less accepted is the export of pollutants from the developed to the developing and the least developed countries, which are neither well regulated, nor well informed and equipped. In this context, recently voiced protests against the entry of French aircraft carrier “Le Clemenceau” in the Indian waters at ship breaking yard in Alang ring an alarm in favor of a need for stricter regulations to prohibit export of possible environmental pollutants. This paper uses a case study of shipping industry and marine environment, the French aircraft carrier “Le Clemenceau”, which was transported to India at the shipyard in Alang, to illustrate inequity involved in these negotiations. An unknown amount of toxic waste i.e. asbestos was shipped to India for clean...
Advances in Asian Human-Environmental Research, 2014
ABSTRACT Goa is a small state on the West Coast of India. Goa was formed during the continental d... more ABSTRACT Goa is a small state on the West Coast of India. Goa was formed during the continental drift in the course of the northward movement of the Indian plate, before it collided with the mainland Asia. A repetitive sequence of events with slow emergence and dissection of land with intermittent phases of quiescence leading to erosional surfaces have shaped Goa’s topography. Geographical boundaries confer upon Goa a distinctive ecological status. Goa is replete with natural resources as well as rich heritage. It has fertile agricultural land. History of agriculture in Goa is very ancient and can be traced to the transition from food gathering to food growing. This chapter introduces Goa, portrays its climate and ecology and describes human migration and the beginning of agricultural operations in Goa leading to khazan ecosystems. It sets stage for the following chapters by providing sufficient knowledge about ecological and sociopolitical conditions in Goa.
Advances in Asian Human-Environmental Research, 2014
The series aims at fostering the discussion on the complex relationships between physical landsca... more The series aims at fostering the discussion on the complex relationships between physical landscapes, natural resources, and their modifi cation by human land use in various environments of Asia. It is widely acknowledged that human-environmentinteractions become increasingly important in area studies and development research, taking into account regional differences as well as bio-physical, socioeconomic and cultural particularities.
This book elaborates on the Khazan ecosystems of Goa, India. Khazans are human-managed agricultur... more This book elaborates on the Khazan ecosystems of Goa, India. Khazans are human-managed agricultural ecosystems, which are reclaimed from coastal wetlands, salt marshes and mangrove areas, where tidal influence is regulated through a highly structured system of dykes, canals, furrows, and sluice gates using resources that are amply available locally. Khazan ecosystems are marvels of tribal engineering. They are a simple architectural design, which operate at a very low running cost using tidal, hydro, and solar energy. The design contributes to a highly complex but eco-friendly ecosystem integrating agriculture, aquaculture and salt panning. . Khazan ecosystems have been functional for the last 3500 years. The history of Khazans is very ancient and can be traced to the transition from food gathering to food growing, which has been regarded as the biggest step in the history of human civilization. Khazan ecosystems thus have a high historical and world heritage value. They are also repositories of global biodiversity, with unique flora suitable to their unique and highly variable environment. They are endemic and heritage ecosystems of Goa and ultimately reservoirs of history and heritage.
Using the example of the Khazan lands, the book analyzes and comments on traditional ecological knowledge and indigenous technology. It presents the evolution of Khazan management institutions over a period of more than three thousand years, as well as factors that have contributed to its decline in recent years. It develops a conceptual framework for ecosystem performance and suggests strategies for conservation of Khazans as well as strategies to build on these indigenous adaptation mechanisms to cope with the global environmental change.
Harmful algal blooms (HABs) are increasingly attracting attention all over the world. A diverse s... more Harmful algal blooms (HABs) are increasingly attracting attention all over the world. A diverse set of algal species including diatoms, flagellates, chrysophytes and dinoflagellates can cause harmful blooms, and many produce toxins that harm other organisms and human health. Intensive cyanobacterial blooms, in particular, have been associated with high costs for society due to their potential toxicity. Algal blooms can produce different toxins. These toxins present a long-standing threat to human and environmental health. For example, the severe Karenia bloom of 2005 in the eastern Gulf of Mexico demonstrates the complexities and magnitude of the challenges of managing algal blooms for both environmental and public health. With increasing events and severe impacts of algal blooms on human health, it becomes necessary to monitor and manage toxic algal blooms. Hence this paper presents a review of causes, impacts and control of algal blooms.
There are several methods to assess bacterial adhesion to metal surfaces. Although these methods ... more There are several methods to assess bacterial adhesion to metal surfaces. Although these methods are sensitive, they are time consuming and need expensive chemicals and instruments. Hence, their use in assessing bacterial adhesion is limited. Therefore, a simple spectrophotometric method was developed to evaluate bacterial adhesion to metal surface. The method was calibrated using a bacterium Vibrio sp. and aluminium as a model organism and substratum, respectively. The method involves staining attached bacterial cells with crystal violet (0.5%). The crystal violet stain from the cells was eluted with an aqueous solution of sodium deoxycholate (2%). The absorbance of the crystal violet stain in deoxycholate was measured at 570 nm. The viable cell count of the attached bacterial cells was also measured using coventional plating technique. Relationship between the absorbance of crystal violet stained attached cells and the viable cell count of the attached bacteria was assessed using ...
Current fishing practices show a global trend of stock depletions. Overfishing was recognized as ... more Current fishing practices show a global trend of stock depletions. Overfishing was recognized as an international problem in the early 1900s and since then has drawn attention of a number of international programmes, especially directed at environmental managers and the governments of many nations. However, the common pool nature of fish resources poses constraints for management. In particular, multispecies fisheries, as found in South Asian waters, have complex dynamics and pose additional constraints for management. The use of closed season/areas to control fishing efforts is a basic management tool in fisheries. The breeding season varies for different species and, hence, the closed season (and/or area) must be targeted at certain critical time periods (and/or habitats) of importance to key species. Such regulations made by the legislature, executive, or, at times, by the judiciary give rise to conflicts between industrial and traditional fishers and between the different instit...
Khazan ecosystems are reclaimed wetlands, salt marshes and mangrove areas, where tidal influence ... more Khazan ecosystems are reclaimed wetlands, salt marshes and mangrove areas, where tidal influence is regulated by the construction of embankments and sluice gates. They are predominantly rice and fish fields. Khazan engineering system has a very simple architectural design made from locally available low-cost resources, which is self-operating using tidal, hydro and solar energy, and the one which integrates highly complex, eco-friendly agriculture, aquaculture, and salt panning systems that function for the last more than 3,500 years with very low running cost. This chapter illustrates khazan architecture and presents different types of khazan farms and the processes involved therein, cultural aspects and traditions associated with khazans, traditional ecological knowledge in khazans and ecological services provided by khazans.
Growth inhibition of fouling bacteria and diatoms by extract of terrestrial plant, Derris scandens (Dicotyledonae:Leguminocae)
Methanol extract of terrestrial plant, Derris scandens Benth, was found to inhibit growth of four... more Methanol extract of terrestrial plant, Derris scandens Benth, was found to inhibit growth of four diatoms and 7 bacterial species of fouling community. The concentrations required to bring about 100% inhibition of growth of the diatoms ranged between 200 to 300 mg g.ml sup(-1), whereas, the bacterial inhibition zone around the disc containing about 600-800 mu g of extract ranged between 1-5 mm. The results suggest that the crude extract of the plant is nontoxic and possesses both antibacterial and antialgal properties. Therefore, the extract promises to be a potential source of natural biocide for fouling organisms
Issues of equity and justice are not very explicit and are not readily accepted in case of enviro... more Issues of equity and justice are not very explicit and are not readily accepted in case of environmental matters such as pollution by industries and its impacts on unempowered communities. An area of focus, which is currently debated, but less accepted is the export of pollutants from the developed to the developing and the least developed countries, which are neither well regulated, nor well informed and equipped. In this context, recently voiced protests against the entry of French aircraft carrier “Le Clemenceau” in the Indian waters at ship breaking yard in Alang ring an alarm in favor of a need for stricter regulations to prohibit export of possible environmental pollutants. This paper uses a case study of shipping industry and marine environment, the French aircraft carrier “Le Clemenceau”, which was transported to India at the shipyard in Alang, to illustrate inequity involved in these negotiations. An unknown amount of toxic waste i.e. asbestos was shipped to India for clean...
Advances in Asian Human-Environmental Research, 2014
ABSTRACT Goa is a small state on the West Coast of India. Goa was formed during the continental d... more ABSTRACT Goa is a small state on the West Coast of India. Goa was formed during the continental drift in the course of the northward movement of the Indian plate, before it collided with the mainland Asia. A repetitive sequence of events with slow emergence and dissection of land with intermittent phases of quiescence leading to erosional surfaces have shaped Goa’s topography. Geographical boundaries confer upon Goa a distinctive ecological status. Goa is replete with natural resources as well as rich heritage. It has fertile agricultural land. History of agriculture in Goa is very ancient and can be traced to the transition from food gathering to food growing. This chapter introduces Goa, portrays its climate and ecology and describes human migration and the beginning of agricultural operations in Goa leading to khazan ecosystems. It sets stage for the following chapters by providing sufficient knowledge about ecological and sociopolitical conditions in Goa.
Advances in Asian Human-Environmental Research, 2014
The series aims at fostering the discussion on the complex relationships between physical landsca... more The series aims at fostering the discussion on the complex relationships between physical landscapes, natural resources, and their modifi cation by human land use in various environments of Asia. It is widely acknowledged that human-environmentinteractions become increasingly important in area studies and development research, taking into account regional differences as well as bio-physical, socioeconomic and cultural particularities.
This book elaborates on the Khazan ecosystems of Goa, India. Khazans are human-managed agricultur... more This book elaborates on the Khazan ecosystems of Goa, India. Khazans are human-managed agricultural ecosystems, which are reclaimed from coastal wetlands, salt marshes and mangrove areas, where tidal influence is regulated through a highly structured system of dykes, canals, furrows, and sluice gates using resources that are amply available locally. Khazan ecosystems are marvels of tribal engineering. They are a simple architectural design, which operate at a very low running cost using tidal, hydro, and solar energy. The design contributes to a highly complex but eco-friendly ecosystem integrating agriculture, aquaculture and salt panning. . Khazan ecosystems have been functional for the last 3500 years. The history of Khazans is very ancient and can be traced to the transition from food gathering to food growing, which has been regarded as the biggest step in the history of human civilization. Khazan ecosystems thus have a high historical and world heritage value. They are also repositories of global biodiversity, with unique flora suitable to their unique and highly variable environment. They are endemic and heritage ecosystems of Goa and ultimately reservoirs of history and heritage.
Using the example of the Khazan lands, the book analyzes and comments on traditional ecological knowledge and indigenous technology. It presents the evolution of Khazan management institutions over a period of more than three thousand years, as well as factors that have contributed to its decline in recent years. It develops a conceptual framework for ecosystem performance and suggests strategies for conservation of Khazans as well as strategies to build on these indigenous adaptation mechanisms to cope with the global environmental change.
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Papers by Sangeeta Sonak
Using the example of the Khazan lands, the book analyzes and comments on traditional ecological knowledge and indigenous technology. It presents the evolution of Khazan management institutions over a period of more than three thousand years, as well as factors that have contributed to its decline in recent years. It develops a conceptual framework for ecosystem performance and suggests strategies for conservation of Khazans as well as strategies to build on these indigenous adaptation mechanisms to cope with the global environmental change.
Using the example of the Khazan lands, the book analyzes and comments on traditional ecological knowledge and indigenous technology. It presents the evolution of Khazan management institutions over a period of more than three thousand years, as well as factors that have contributed to its decline in recent years. It develops a conceptual framework for ecosystem performance and suggests strategies for conservation of Khazans as well as strategies to build on these indigenous adaptation mechanisms to cope with the global environmental change.