Hummel, H. G. K., Van Houcke, J., Nadolski, R. J., Van der Hiele, T., Kurvers, H., & Löhr, A. (20... more Hummel, H. G. K., Van Houcke, J., Nadolski, R. J., Van der Hiele, T., Kurvers, H., & Löhr, A. (2011). Scripted collaboration in gaming for complex learning: Effects of multiple perspectives when acquiring water management skills. British Journal of Educational Technology, 42(6), 1029-1041. doi:10.1111/j.1467-8535.2010.01122.x
We used Global NEWS to analyze the effects of dams in large rivers on nitrogen (N) and phosphorus... more We used Global NEWS to analyze the effects of dams in large rivers on nitrogen (N) and phosphorus (P) inputs to the coastal waters of Indonesia for the period 1970-2050. We model N and P export by rivers, taking into account nutrient retention on land, during river transport and in dammed reservoirs. Our results indicate that N and P export by rivers to coastal seas may increase over time. In the past the N and P inputs to coastal waters of Indonesia were low and have increased relatively fast since 1970 as a result of human activities. For the coming decades we calculate that P inputs to coastal waters in Indonesia may double while N inputs may increase by up to 20%. Damming may slow down these increases to some extent. Our study illustrates that it is important in river nutrient export models to appropriately account for nutrient retention in dam waters.
In Europe, the use of biodiesel may increase rapidly in the coming decades as a result of policie... more In Europe, the use of biodiesel may increase rapidly in the coming decades as a result of policies aiming to increase the use of renewable fuels. Therefore, the production of biofuels from energy crops is expected to increase as well as the use of fertilisers to grow these crops. Since fertilisers are an important cause of eutrophication, the use of biodiesel may have an effect on the water quality in rivers and coastal seas. In this study we explored the possible effects of increased biodiesel use on coastal eutrophication in European seas in the year 2050. To this end, we defined a number of illustrative scenarios in which the biodiesel production increases to about 10-30% of the current diesel use. The scenarios differ with respect to the assumptions on where the energy crops are cultivated: either on land that is currently used for agriculture, or on land used for other purposes. We analysed these scenarios with the Global NEWS (Nutrient Export from WaterSheds) model. We used an existing Millennium Ecosystem Assessment Scenario for 2050, Global Orchestration (GO2050), as a baseline. In this baseline scenario the amount of nitrogen (N) and phosphorus (P) exported by European rivers to coastal seas decreases between 2000 and 2050 as a result of environmental and agricultural policies. In our scenarios with increased biodiesel production the river export of N and P increases between 2000 and 2050, indicating that energy crop production may more than counterbalance this decrease. Largest increases in nutrient export were calculated for the Mediterranean Sea and the Black Sea. Differences in nutrient export among river basins are large.
A first study was made on the microbial community composition of the Indonesian crater lake Kawah... more A first study was made on the microbial community composition of the Indonesian crater lake Kawah Ijen (pH G 0.3) and the Banyupahit-Banyuputih river (pH 0.4-3.5) originating from it. Culture-independent, rRNA gene-based denaturing gradient gel electrophoresis was used to profile microbial communities in this natural and ancient, extremely acidic environment. Similarity in community profiles of the different sampling locations was low, indicating heterogeneity in community composition. Archaea were present at all sampling locations; archaeal diversity was low at the most acidic locations and increased at pH 92.6. Bacteria were not detected in the water column of the crater lake, but were found at all locations along the acidic river. Bacterial diversity increased with increasing pH. Eukarya were only present at pH 92.6. Retrieved rRNA gene sequences of Bacteria and Archaea were not closely related to known acidophilic species. It is concluded that tolerance to extreme acidity in this system is developed most extensively among Archaea. The acidity gradient of the Banyupahit-Banyuputih river has a clear effect on microbial community composition and biodiversity. ble for the bulk of acid generation . The acidity of AMD is, in general, caused by sulfuric acid, which is formed when sulfide minerals, associated with coal or metal (iron, zinc, lead, or copper), such as pyrite, are oxidized during contact with oxygen-rich water near the surface. Acidophilic chemolithotrophs, especially Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, accelerate the rate of pyrite oxidation . Compared to anthropogenic acidic systems, the microbial ecology of natural acidic systems has been less studied. Natural acidic aquatic systems are often of volcanogenic origin and can cause environmental problems similar to AMD, especially because of high metal concentrations. Examples are Agrio River (pH 0.37) and Lake Caviahue (pH 2.5) originating from Copahue Volcano in Argentina [37], Whangaehu River (pH 1.4-7.0) from the crater lake of Mt. Ruapehu in New Zealand, and Rio Agrio (pH 2-3) from Volcan Poas in Costa Rica .
Journal of Integrative Environmental Sciences, 2013
ABSTRACT This article analyzes past and future trends in nutrient export of dissolved and particu... more ABSTRACT This article analyzes past and future trends in nutrient export of dissolved and particulate nitrogen and phosphorus by rivers into the coastal waters of Indonesia. The focus is on 19 rivers included in the Global Nutrients Export from WaterSheds model. In the past, export of dissolved inorganic nitrogen by rivers doubled, while export of other forms of nitrogen and phosphorus by rivers did not change largely. For future trends of four Millennium Ecosystem Assessment scenarios, the largest increases are calculated for river export of dissolved inorganic phosphorus by rivers caused by increased inputs from sewage systems. The export of other nutrient forms is relatively constant in time, which is surprising, given the growing population and the associated increasing inputs of nitrogen and phosphorus to the land. Changes in export by rivers are the net effect of human activities and changes in hydrology. The results indicate that future increases in nitrogen and phosphorus inputs on land are partly counterbalanced by decreases in basin discharge as a result of climate change and consumptive water use. These results differ from other Asian regions, for which large increases in nitrogen and phosphorus inputs to coastal waters are calculated. This can be explained by population growth, gross domestic product increase, and sewage system development.
International Journal of Innovation and Sustainable Development, 2012
ABSTRACT Future climate change may critically affect natural resources that are essential for bas... more ABSTRACT Future climate change may critically affect natural resources that are essential for basic human needs. Water resources are undoubtedly among the most important resources in this respect. Moreover, water plays an important role in the climate system. These examples illustrate why it is important to pay considerable attention to natural resources in climate change education. The expertise associated with natural resource sectors is inherently multidisciplinary, focusing on real-world problems. Water expertise for example incorporates social, economic, environmental, health, political, institutional, technological and other aspects. In this article, the authors explore the potential contribution of expertise on water issues to climate change education at the Masters level, and the competences with which it is associated. This exploration is framed within a larger European Union Erasmus project 'The lived experience of climate change: interdisciplinary e-module development and virtual mobility'.
Functional processes in freshwater ecosystems are highly influenced by acidic conditions. Foodweb... more Functional processes in freshwater ecosystems are highly influenced by acidic conditions. Foodwebs are affected and macroinvertebrate species diversity is decreased. This study aims to investigate leaf decomposition at very low pH in the acidic Banyupahit-Banyuputih river originating from the acidic crater lake Kawah Ijen in Indonesia. Leaf decomposition experiments were carried out for 200 days in the acidic river at pHs of approximately 0.7, 2.3 and 3.0 and in the neutral Kali Sengon river, using leaves from teak, Tectona grandis, and bamboo, Bambusa sp. Two different types of leaf packs were used: fine mesh size packs were used to exclude macroinvertebrates and coarse mesh size packs allowed macroinvertebrate colonization. Clear differences in decomposition rate were observed between the neutral Kali Sengon and the acidic Banyupahit-Banyuputih river with decomposition in the Kali Sengon river proceeding significantly faster for both leaf types. In the Kali Sengon k values (d )1 ) over 46 days were 0.0202 for fine teak, 0.0236 for coarse teak, 0.0114 for fine bamboo and 0.0151 for coarse bamboo. No significant differences were observed between the three sites in the acidic Banyupahit-Banyuputih river with k values of 0.0034-0.0066 for fine teak, 0.0002-0.0057 for coarse teak, 0.0029-0.0054 for fine bamboo and 0.0000-0.0068 for coarse bamboo. Moreover, no clear adaptation of macroinvertebrates or microbes to low pH conditions could be detected. The coarse mesh leaf packs in the neutral Kali Sengon river revealed that macroinvertebrates are important in the breakdown process. Fine mesh packs revealed that microbial activity is depressed under acidic conditions. Based on this evidence, we conclude that the toxicity at low pH conditions, and probably also the precipitation of metals on the leaf material, seriously affects leaf decomposition.
... Ansje J. Löhr*, Rutger Sluik1, Mary M. Olaveson2, Núria Ivorra3, Cornelis AM Van Gestel1 and ... more ... Ansje J. Löhr*, Rutger Sluik1, Mary M. Olaveson2, Núria Ivorra3, Cornelis AM Van Gestel1 and Nico M. Van Straalen1 ... and attached algal fraction, were collected in April 2002 at the crater lake Kawah Ijen (only phytoplankton), at the sites Paltuding, Bla-wan, Waterfall, Liwung in ...
Environmental Science and Pollution Research - International, 2005
use of Al containing acidic irrigation water. Increased levels of metals (especially Cd, Co, Ni a... more use of Al containing acidic irrigation water. Increased levels of metals (especially Cd, Co, Ni and Mn) are found in different foodstuffs, but still remain within acceptable ranges. Considering local residents' diets, Cd levels may lead to an increased risk for the human health. Fluoride exposure is of highest concern, with levels in drinking water exceeding guideline values and a lot of local residents suffering from dental fluorosis.
ABSTRACT Abstract Nutrient export by rivers may cause coastal eutrophication. Some river basins, ... more ABSTRACT Abstract Nutrient export by rivers may cause coastal eutrophication. Some river basins, however, export more nutrients than others. We model the Basin-Wide Nutrient Export (BWNE) Index, defined as nutrient export by rivers as percentage of external nutrient inputs in the basins. We present results for rivers worldwide for the period 1970–2050. The results indicate that nutrient retentions differ largely among basins. They indicate that BWNE increases with nutrient inputs to the land, indicating that the percentage of, for instance, fertilizers exported to sea increases with fertilization rate. We argue that a better understanding of the BWNE Index might help to identify where measures and technologies to reduce nutrient inputs to coastal waters are most effective. Keywords: Coastal eutrophication; Nitrogen; Phosphorus; River pollution; Nutrient transport efficiency
Current Opinion in Environmental Sustainability, 2011
Human activities on land have increased the N inputs to rivers and coastal waters worldwide. This... more Human activities on land have increased the N inputs to rivers and coastal waters worldwide. This increased aquatic emissions of nitrous oxide (N2O). Global, spatially explicit modeling of N flows from land to sea and associated N2O emissions have been developed for a number of decades. During the 1990s, global N2O studies focused to a large extent on closing the
Current Opinion in Environmental Sustainability, 2013
ABSTRACT The natural cycles of carbon (C), nitrogen (N), phosphorus (P) and water have been distu... more ABSTRACT The natural cycles of carbon (C), nitrogen (N), phosphorus (P) and water have been disturbed substantially by human activities. Urbanizing coastal drainage basins and large river deltas are located at the interface of freshwater and coastal components of the larger earth system and the process of urbanization is increasingly affecting these cycles. We take coastal water pollution as an example to illustrate this. To ensure sustainable development of urban-dominated water systems, future research challenges must include studies of the effects of the urbanization process on biogeochemical cycles that firstly, account for feedbacks and tipping points at the global scale; secondly, link to the Sustainability Development Goals; and finally, link to other forms of pollution. Urban coastal systems are of particular interest when exploring human–water–nutrient cycle interactions, and effective solutions for environmental and health problems associated with these interactions.
This paper examines how learning outcomes from playing serious games can be enhanced by including... more This paper examines how learning outcomes from playing serious games can be enhanced by including scripted collaboration in the game play. We compared the quality of advisory reports, that students in the domain of water management had to draw up for an authentic case problem, both before and after collaborating on the problem with (virtual) peer students. Peers studied the case from either an ecological or governance perspective, and during collaboration both perspectives had to be confronted and reflected upon. This paper argues why such type of workplace-based learning scenarios are important for professional development, describes how serious gaming scenarios can be designed to support such complex learning, and reports data on student satisfaction and learning effects of including scripted collaboration. Preliminary results from a pilot study with 12 students show that including scripted collaboration significantly enhances the quality of learning outcomes.
A river ecosystem in East Java, Indonesia, fed by a volcanic lake with high concentrations of dis... more A river ecosystem in East Java, Indonesia, fed by a volcanic lake with high concentrations of dissolved metals and a low pH, was found to support only few macroinvertebrates. To unravel the causes of toxicity and to determine the level of dilution necessary to obtain non-toxic water, a bioassay was conducted with the fairy shrimp Thamnocephalus platyurus. A partial toxicity identification evaluation (TIE) approach was used with EDTA as a chelating agent to relate toxicity to pH and metal concentrations. Three water samples were tested, with pHs ranging from 0.72 to 4.5, and diluted with water from a neutral river to different degrees. The dilution factor necessary to achieve no more than 50% mortality in the Thamnotox test (Ldf 50 ) varied from N 300 at the most acidic site, to 7 for water of pH 2.6 and 1.5 for water of pH 4.5. Toxicity was best explained from both low pH and high concentrations of metals, especially Al and Fe. The key role of Al and Fe in the toxicity was confirmed by relating concentrations of the different compounds in the river water to toxicity data from the literature. EDTA addition did not significantly influence Ldf 50 or the lethal pH 50% (LpH 50 ), suggesting a large effect, besides cationic components and pH, of anions (F, SO 4 and Cl).
Hummel, H. G. K., Van Houcke, J., Nadolski, R. J., Van der Hiele, T., Kurvers, H., & Löhr, A. (20... more Hummel, H. G. K., Van Houcke, J., Nadolski, R. J., Van der Hiele, T., Kurvers, H., & Löhr, A. (2011). Scripted collaboration in gaming for complex learning: Effects of multiple perspectives when acquiring water management skills. British Journal of Educational Technology, 42(6), 1029-1041. doi:10.1111/j.1467-8535.2010.01122.x
We used Global NEWS to analyze the effects of dams in large rivers on nitrogen (N) and phosphorus... more We used Global NEWS to analyze the effects of dams in large rivers on nitrogen (N) and phosphorus (P) inputs to the coastal waters of Indonesia for the period 1970-2050. We model N and P export by rivers, taking into account nutrient retention on land, during river transport and in dammed reservoirs. Our results indicate that N and P export by rivers to coastal seas may increase over time. In the past the N and P inputs to coastal waters of Indonesia were low and have increased relatively fast since 1970 as a result of human activities. For the coming decades we calculate that P inputs to coastal waters in Indonesia may double while N inputs may increase by up to 20%. Damming may slow down these increases to some extent. Our study illustrates that it is important in river nutrient export models to appropriately account for nutrient retention in dam waters.
In Europe, the use of biodiesel may increase rapidly in the coming decades as a result of policie... more In Europe, the use of biodiesel may increase rapidly in the coming decades as a result of policies aiming to increase the use of renewable fuels. Therefore, the production of biofuels from energy crops is expected to increase as well as the use of fertilisers to grow these crops. Since fertilisers are an important cause of eutrophication, the use of biodiesel may have an effect on the water quality in rivers and coastal seas. In this study we explored the possible effects of increased biodiesel use on coastal eutrophication in European seas in the year 2050. To this end, we defined a number of illustrative scenarios in which the biodiesel production increases to about 10-30% of the current diesel use. The scenarios differ with respect to the assumptions on where the energy crops are cultivated: either on land that is currently used for agriculture, or on land used for other purposes. We analysed these scenarios with the Global NEWS (Nutrient Export from WaterSheds) model. We used an existing Millennium Ecosystem Assessment Scenario for 2050, Global Orchestration (GO2050), as a baseline. In this baseline scenario the amount of nitrogen (N) and phosphorus (P) exported by European rivers to coastal seas decreases between 2000 and 2050 as a result of environmental and agricultural policies. In our scenarios with increased biodiesel production the river export of N and P increases between 2000 and 2050, indicating that energy crop production may more than counterbalance this decrease. Largest increases in nutrient export were calculated for the Mediterranean Sea and the Black Sea. Differences in nutrient export among river basins are large.
A first study was made on the microbial community composition of the Indonesian crater lake Kawah... more A first study was made on the microbial community composition of the Indonesian crater lake Kawah Ijen (pH G 0.3) and the Banyupahit-Banyuputih river (pH 0.4-3.5) originating from it. Culture-independent, rRNA gene-based denaturing gradient gel electrophoresis was used to profile microbial communities in this natural and ancient, extremely acidic environment. Similarity in community profiles of the different sampling locations was low, indicating heterogeneity in community composition. Archaea were present at all sampling locations; archaeal diversity was low at the most acidic locations and increased at pH 92.6. Bacteria were not detected in the water column of the crater lake, but were found at all locations along the acidic river. Bacterial diversity increased with increasing pH. Eukarya were only present at pH 92.6. Retrieved rRNA gene sequences of Bacteria and Archaea were not closely related to known acidophilic species. It is concluded that tolerance to extreme acidity in this system is developed most extensively among Archaea. The acidity gradient of the Banyupahit-Banyuputih river has a clear effect on microbial community composition and biodiversity. ble for the bulk of acid generation . The acidity of AMD is, in general, caused by sulfuric acid, which is formed when sulfide minerals, associated with coal or metal (iron, zinc, lead, or copper), such as pyrite, are oxidized during contact with oxygen-rich water near the surface. Acidophilic chemolithotrophs, especially Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, accelerate the rate of pyrite oxidation . Compared to anthropogenic acidic systems, the microbial ecology of natural acidic systems has been less studied. Natural acidic aquatic systems are often of volcanogenic origin and can cause environmental problems similar to AMD, especially because of high metal concentrations. Examples are Agrio River (pH 0.37) and Lake Caviahue (pH 2.5) originating from Copahue Volcano in Argentina [37], Whangaehu River (pH 1.4-7.0) from the crater lake of Mt. Ruapehu in New Zealand, and Rio Agrio (pH 2-3) from Volcan Poas in Costa Rica .
Journal of Integrative Environmental Sciences, 2013
ABSTRACT This article analyzes past and future trends in nutrient export of dissolved and particu... more ABSTRACT This article analyzes past and future trends in nutrient export of dissolved and particulate nitrogen and phosphorus by rivers into the coastal waters of Indonesia. The focus is on 19 rivers included in the Global Nutrients Export from WaterSheds model. In the past, export of dissolved inorganic nitrogen by rivers doubled, while export of other forms of nitrogen and phosphorus by rivers did not change largely. For future trends of four Millennium Ecosystem Assessment scenarios, the largest increases are calculated for river export of dissolved inorganic phosphorus by rivers caused by increased inputs from sewage systems. The export of other nutrient forms is relatively constant in time, which is surprising, given the growing population and the associated increasing inputs of nitrogen and phosphorus to the land. Changes in export by rivers are the net effect of human activities and changes in hydrology. The results indicate that future increases in nitrogen and phosphorus inputs on land are partly counterbalanced by decreases in basin discharge as a result of climate change and consumptive water use. These results differ from other Asian regions, for which large increases in nitrogen and phosphorus inputs to coastal waters are calculated. This can be explained by population growth, gross domestic product increase, and sewage system development.
International Journal of Innovation and Sustainable Development, 2012
ABSTRACT Future climate change may critically affect natural resources that are essential for bas... more ABSTRACT Future climate change may critically affect natural resources that are essential for basic human needs. Water resources are undoubtedly among the most important resources in this respect. Moreover, water plays an important role in the climate system. These examples illustrate why it is important to pay considerable attention to natural resources in climate change education. The expertise associated with natural resource sectors is inherently multidisciplinary, focusing on real-world problems. Water expertise for example incorporates social, economic, environmental, health, political, institutional, technological and other aspects. In this article, the authors explore the potential contribution of expertise on water issues to climate change education at the Masters level, and the competences with which it is associated. This exploration is framed within a larger European Union Erasmus project 'The lived experience of climate change: interdisciplinary e-module development and virtual mobility'.
Functional processes in freshwater ecosystems are highly influenced by acidic conditions. Foodweb... more Functional processes in freshwater ecosystems are highly influenced by acidic conditions. Foodwebs are affected and macroinvertebrate species diversity is decreased. This study aims to investigate leaf decomposition at very low pH in the acidic Banyupahit-Banyuputih river originating from the acidic crater lake Kawah Ijen in Indonesia. Leaf decomposition experiments were carried out for 200 days in the acidic river at pHs of approximately 0.7, 2.3 and 3.0 and in the neutral Kali Sengon river, using leaves from teak, Tectona grandis, and bamboo, Bambusa sp. Two different types of leaf packs were used: fine mesh size packs were used to exclude macroinvertebrates and coarse mesh size packs allowed macroinvertebrate colonization. Clear differences in decomposition rate were observed between the neutral Kali Sengon and the acidic Banyupahit-Banyuputih river with decomposition in the Kali Sengon river proceeding significantly faster for both leaf types. In the Kali Sengon k values (d )1 ) over 46 days were 0.0202 for fine teak, 0.0236 for coarse teak, 0.0114 for fine bamboo and 0.0151 for coarse bamboo. No significant differences were observed between the three sites in the acidic Banyupahit-Banyuputih river with k values of 0.0034-0.0066 for fine teak, 0.0002-0.0057 for coarse teak, 0.0029-0.0054 for fine bamboo and 0.0000-0.0068 for coarse bamboo. Moreover, no clear adaptation of macroinvertebrates or microbes to low pH conditions could be detected. The coarse mesh leaf packs in the neutral Kali Sengon river revealed that macroinvertebrates are important in the breakdown process. Fine mesh packs revealed that microbial activity is depressed under acidic conditions. Based on this evidence, we conclude that the toxicity at low pH conditions, and probably also the precipitation of metals on the leaf material, seriously affects leaf decomposition.
... Ansje J. Löhr*, Rutger Sluik1, Mary M. Olaveson2, Núria Ivorra3, Cornelis AM Van Gestel1 and ... more ... Ansje J. Löhr*, Rutger Sluik1, Mary M. Olaveson2, Núria Ivorra3, Cornelis AM Van Gestel1 and Nico M. Van Straalen1 ... and attached algal fraction, were collected in April 2002 at the crater lake Kawah Ijen (only phytoplankton), at the sites Paltuding, Bla-wan, Waterfall, Liwung in ...
Environmental Science and Pollution Research - International, 2005
use of Al containing acidic irrigation water. Increased levels of metals (especially Cd, Co, Ni a... more use of Al containing acidic irrigation water. Increased levels of metals (especially Cd, Co, Ni and Mn) are found in different foodstuffs, but still remain within acceptable ranges. Considering local residents' diets, Cd levels may lead to an increased risk for the human health. Fluoride exposure is of highest concern, with levels in drinking water exceeding guideline values and a lot of local residents suffering from dental fluorosis.
ABSTRACT Abstract Nutrient export by rivers may cause coastal eutrophication. Some river basins, ... more ABSTRACT Abstract Nutrient export by rivers may cause coastal eutrophication. Some river basins, however, export more nutrients than others. We model the Basin-Wide Nutrient Export (BWNE) Index, defined as nutrient export by rivers as percentage of external nutrient inputs in the basins. We present results for rivers worldwide for the period 1970–2050. The results indicate that nutrient retentions differ largely among basins. They indicate that BWNE increases with nutrient inputs to the land, indicating that the percentage of, for instance, fertilizers exported to sea increases with fertilization rate. We argue that a better understanding of the BWNE Index might help to identify where measures and technologies to reduce nutrient inputs to coastal waters are most effective. Keywords: Coastal eutrophication; Nitrogen; Phosphorus; River pollution; Nutrient transport efficiency
Current Opinion in Environmental Sustainability, 2011
Human activities on land have increased the N inputs to rivers and coastal waters worldwide. This... more Human activities on land have increased the N inputs to rivers and coastal waters worldwide. This increased aquatic emissions of nitrous oxide (N2O). Global, spatially explicit modeling of N flows from land to sea and associated N2O emissions have been developed for a number of decades. During the 1990s, global N2O studies focused to a large extent on closing the
Current Opinion in Environmental Sustainability, 2013
ABSTRACT The natural cycles of carbon (C), nitrogen (N), phosphorus (P) and water have been distu... more ABSTRACT The natural cycles of carbon (C), nitrogen (N), phosphorus (P) and water have been disturbed substantially by human activities. Urbanizing coastal drainage basins and large river deltas are located at the interface of freshwater and coastal components of the larger earth system and the process of urbanization is increasingly affecting these cycles. We take coastal water pollution as an example to illustrate this. To ensure sustainable development of urban-dominated water systems, future research challenges must include studies of the effects of the urbanization process on biogeochemical cycles that firstly, account for feedbacks and tipping points at the global scale; secondly, link to the Sustainability Development Goals; and finally, link to other forms of pollution. Urban coastal systems are of particular interest when exploring human–water–nutrient cycle interactions, and effective solutions for environmental and health problems associated with these interactions.
This paper examines how learning outcomes from playing serious games can be enhanced by including... more This paper examines how learning outcomes from playing serious games can be enhanced by including scripted collaboration in the game play. We compared the quality of advisory reports, that students in the domain of water management had to draw up for an authentic case problem, both before and after collaborating on the problem with (virtual) peer students. Peers studied the case from either an ecological or governance perspective, and during collaboration both perspectives had to be confronted and reflected upon. This paper argues why such type of workplace-based learning scenarios are important for professional development, describes how serious gaming scenarios can be designed to support such complex learning, and reports data on student satisfaction and learning effects of including scripted collaboration. Preliminary results from a pilot study with 12 students show that including scripted collaboration significantly enhances the quality of learning outcomes.
A river ecosystem in East Java, Indonesia, fed by a volcanic lake with high concentrations of dis... more A river ecosystem in East Java, Indonesia, fed by a volcanic lake with high concentrations of dissolved metals and a low pH, was found to support only few macroinvertebrates. To unravel the causes of toxicity and to determine the level of dilution necessary to obtain non-toxic water, a bioassay was conducted with the fairy shrimp Thamnocephalus platyurus. A partial toxicity identification evaluation (TIE) approach was used with EDTA as a chelating agent to relate toxicity to pH and metal concentrations. Three water samples were tested, with pHs ranging from 0.72 to 4.5, and diluted with water from a neutral river to different degrees. The dilution factor necessary to achieve no more than 50% mortality in the Thamnotox test (Ldf 50 ) varied from N 300 at the most acidic site, to 7 for water of pH 2.6 and 1.5 for water of pH 4.5. Toxicity was best explained from both low pH and high concentrations of metals, especially Al and Fe. The key role of Al and Fe in the toxicity was confirmed by relating concentrations of the different compounds in the river water to toxicity data from the literature. EDTA addition did not significantly influence Ldf 50 or the lethal pH 50% (LpH 50 ), suggesting a large effect, besides cationic components and pH, of anions (F, SO 4 and Cl).
Uploads
Papers by Ansje Löhr