title: Lake restoration: Does sediment capping have post-application effects on zooplankton and phytoplankton?

authors: Özkundakci, Deniz

subjects: Eutrophication

abstract: Although in situ sediment capping is frequently used to reduce internal loading of contaminants and nutrients, post-application assessment rarely includes the potential undesirable short-term effects on plankton species composition. We hypothesised  that a modified zeolite (Z2G1) application as a sediment capping agent in Lake Okaro, New Zealand, could cause significant undesirable shifts in species composition of both zooplankton and phytoplankton due to burial of resting stages or interference with feeding for the zooplankton. Alternatively, we predicted that the capping agent might have no effect due to, for example, the coarse grain size of the material (1–3 mm). We used multidimensional scaling (MDS) and analysis of similarity (ANOSIM) to identify any adverse effects of Z2G1 on zooplankton and phytoplankton species composition (i.e. shifts in community structure, including species loss) by comparing the community structure before and after the Z2G1 application. We found no significant differences in species composition before and after the Z2G1 application at the depths investigated (surface and 9 m). However, all of the analyses showed statistically significant differences among seasons, indicating seasonal variations in plankton composition far outweigh those that may have resulted from the Z2G1 application. Coarse particle size, low dose rate and a restricted area where the sediment capping agent was applied were considered to be the factors limiting potential adverse effects on plankton species. Considerations of finer-grained material to increase coverage and efficacy of phosphorus adsorption require assessment for their effects on zooplankton, however, and a direct mode of application into the hypolimnion is recommended to minimise effects on zooplankton and phytoplankton communities.

text: Lake restoration: Does sediment capping have post-application effects on zooplankton and phytoplankton? Although in situ sediment capping is frequently used to reduce internal loading of contaminants and nutrients, post-application assessment rarely includes the potential undesirable short-term effects on plankton species composition. We hypothesised  that a modified zeolite (Z2G1) application as a sediment capping agent in Lake Okaro, New Zealand, could cause significant undesirable shifts in species composition of both zooplankton and phytoplankton due to burial of resting stages or interference with feeding for the zooplankton. Alternatively, we predicted that the capping agent might have no effect due to, for example, the coarse grain size of the material (1–3 mm). We used multidimensional scaling (MDS) and analysis of similarity (ANOSIM) to identify any adverse effects of Z2G1 on zooplankton and phytoplankton species composition (i.e. shifts in community structure, including species loss) by comparing the community structure before and after the Z2G1 application. We found no significant differences in species composition before and after the Z2G1 application at the depths investigated (surface and 9 m). However, all of the analyses showed statistically significant differences among seasons, indicating seasonal variations in plankton composition far outweigh those that may have resulted from the Z2G1 application. Coarse particle size, low dose rate and a restricted area where the sediment capping agent was applied were considered to be the factors limiting potential adverse effects on plankton species. Considerations of finer-grained material to increase coverage and efficacy of phosphorus adsorption require assessment for their effects on zooplankton, however, and a direct mode of application into the hypolimnion is recommended to minimise effects on zooplankton and phytoplankton communities.

year: 2011

title: Book review: The Colli Albani volcano

authors: Pittari, Adrian

abstract: This article reviews the book: “Adventure education: An introduction”,  edited by M, Berry & C. Hodgson.

text: Book review: The Colli Albani volcano This article reviews the book: “Adventure education: An introduction”,  edited by M, Berry & C. Hodgson.

year: 2012

title: Maori children and death: Views from parents

authors: Jacob, Juanita

subjects: Maori

abstract: Research about Maori children's experiences and perceptions of death and tangi (Maori death rituals) is sparse. What is available tends to be generalised and stems from Western paradigms of knowledge. In this study we explore Maori children's experiences of death and tangi through the eyes of Maori parents. Through semi-structured interviews with 17 Maori parents, five areas were explored: a) the childhood experiences of parents and how they learned about death and an afterlife; b) what their adult beliefs about these matters are; c) how they have communicated the death concept to their children; and d) whether their children are likely to do the same in the future. From this study we learn that death was not hidden from children, that parents talked with their children in very open and age relevant ways, and considered their children's participation in tangi an important way to grieve and ensure continuity with kinship networks and support. This study suggests that the challenge now is to ensure that these practices continue to persist between parents and their children, and future generations.

text: Maori children and death: Views from parents Research about Maori children's experiences and perceptions of death and tangi (Maori death rituals) is sparse. What is available tends to be generalised and stems from Western paradigms of knowledge. In this study we explore Maori children's experiences of death and tangi through the eyes of Maori parents. Through semi-structured interviews with 17 Maori parents, five areas were explored: a) the childhood experiences of parents and how they learned about death and an afterlife; b) what their adult beliefs about these matters are; c) how they have communicated the death concept to their children; and d) whether their children are likely to do the same in the future. From this study we learn that death was not hidden from children, that parents talked with their children in very open and age relevant ways, and considered their children's participation in tangi an important way to grieve and ensure continuity with kinship networks and support. This study suggests that the challenge now is to ensure that these practices continue to persist between parents and their children, and future generations.

year: 2011-12