title: Effect of nutrient enrichment and turbidity on interactions between Microphytobenthos and a key bivalve: implications for higher trophic levels

authors: Hope, Julie A.

subjects: Science & Technology

abstract: Benthic diatoms are a high-quality food resource providing essential fatty acids to benthic grazers. Different stressors may alter the proportion of diatoms and other microalgae and thus can affect the quality as well as quantity of food available to benthic consumers. Microphytobenthos (MPB) lipid biomarkers were assessed in a field experiment to elucidate changes to the biosynthesis of fatty acids (FA) under nitrogen (N) enrichment (three levels) at eight intertidal sites that spanned a turbidity gradient. Influences on the flow of carbon and energy were determined using FA biomarkers of a functionally important deposit-feeding tellinid bivalve (Macomona liliana). Site-specific effects of N enrichment were detected in MPB quantity and quality measurements. Enrichment generally increased MPB biomass (chl a) across all sites, while the proportion of diatom associated fatty acid biomarkers was more variable at some sites. Analysis of sediment FA biomarkers and environmental variables suggested that changes to the microbial community composition and quality were related to water clarity and mud content of the bed. The ability of the MPB to utilize the increased nitrogen, as indicated by the resource use efficiency index, was also important. Despite the increase in MPB biomass, lipid reserves in the tissue of M. liliana, a primary consumer of MPB, were reduced (by up to 6 orders of magnitude) in medium and high N addition plots compared to control plots. Further, the nutritional quality of the bivalves to higher trophic levels [indicated by a lower ratio of essential FAs (ω3:ω6)] was reduced in high treatment plots compared to control plots suggesting the bivalves were adversely affected by nutrient enrichment but not due to a reduction in food availability. This study suggests anthropogenic nutrient enrichment and turbidity may indirectly alter the structure and function of the benthic food web, in terms of carbon flow and ecosystem productivity. This may indirectly change the interactions between MPB and key bivalves as suspended sediment concentrations and nutrient enrichment continue to increase globally. This has implications for various ecosystem functions that are mediated by these interactions, such as nutrient cycling as well as primary and secondary production.

text: Effect of nutrient enrichment and turbidity on interactions between Microphytobenthos and a key bivalve: implications for higher trophic levels Benthic diatoms are a high-quality food resource providing essential fatty acids to benthic grazers. Different stressors may alter the proportion of diatoms and other microalgae and thus can affect the quality as well as quantity of food available to benthic consumers. Microphytobenthos (MPB) lipid biomarkers were assessed in a field experiment to elucidate changes to the biosynthesis of fatty acids (FA) under nitrogen (N) enrichment (three levels) at eight intertidal sites that spanned a turbidity gradient. Influences on the flow of carbon and energy were determined using FA biomarkers of a functionally important deposit-feeding tellinid bivalve (Macomona liliana). Site-specific effects of N enrichment were detected in MPB quantity and quality measurements. Enrichment generally increased MPB biomass (chl a) across all sites, while the proportion of diatom associated fatty acid biomarkers was more variable at some sites. Analysis of sediment FA biomarkers and environmental variables suggested that changes to the microbial community composition and quality were related to water clarity and mud content of the bed. The ability of the MPB to utilize the increased nitrogen, as indicated by the resource use efficiency index, was also important. Despite the increase in MPB biomass, lipid reserves in the tissue of M. liliana, a primary consumer of MPB, were reduced (by up to 6 orders of magnitude) in medium and high N addition plots compared to control plots. Further, the nutritional quality of the bivalves to higher trophic levels [indicated by a lower ratio of essential FAs (ω3:ω6)] was reduced in high treatment plots compared to control plots suggesting the bivalves were adversely affected by nutrient enrichment but not due to a reduction in food availability. This study suggests anthropogenic nutrient enrichment and turbidity may indirectly alter the structure and function of the benthic food web, in terms of carbon flow and ecosystem productivity. This may indirectly change the interactions between MPB and key bivalves as suspended sediment concentrations and nutrient enrichment continue to increase globally. This has implications for various ecosystem functions that are mediated by these interactions, such as nutrient cycling as well as primary and secondary production.

year: 2020

title: The importance of employment protection for skill development in coordinated market economies

authors: Harcourt, Mark

subjects: employment protection

abstract: During the heyday of neoliberalism, employment protection was widely believed to be one of the main causes of Europe's poor economic performance and high unemployment. We challenge this view and instead argue that employment protection is crucial to preserving Europe's export success in higher value-added industries. In particular, we explore the relationship between employment protection and skills development.

text: The importance of employment protection for skill development in coordinated market economies During the heyday of neoliberalism, employment protection was widely believed to be one of the main causes of Europe's poor economic performance and high unemployment. We challenge this view and instead argue that employment protection is crucial to preserving Europe's export success in higher value-added industries. In particular, we explore the relationship between employment protection and skills development.

year: 2007

title: Māori and community news constructions of Meningococcal B: the promotion of a moral obligation to vaccinate

authors: Groot, Shiloh Ann Maree

subjects: psychology

abstract: News media communicate various risks of disease, showcase medical breakthroughs and disseminate texts that both reflect and renegotiate shared cultural understandings of health and illness. Little is known about the role of Māori and community news media in the social negotiation of health and illness in Aotearoa. To address this gap in the literature, this paper reports findings from a study of news reporting on Meningococcal B by the Māori Television Service and two community newspapers serving Māori communities. Findings document how news works to position vaccination as a ‘common sense’ practice that whānau have a moral obligation to undergo. Neglected are wider socio-structural considerations that impact the prevalence of illness among Māori.

text: Māori and community news constructions of Meningococcal B: the promotion of a moral obligation to vaccinate News media communicate various risks of disease, showcase medical breakthroughs and disseminate texts that both reflect and renegotiate shared cultural understandings of health and illness. Little is known about the role of Māori and community news media in the social negotiation of health and illness in Aotearoa. To address this gap in the literature, this paper reports findings from a study of news reporting on Meningococcal B by the Māori Television Service and two community newspapers serving Māori communities. Findings document how news works to position vaccination as a ‘common sense’ practice that whānau have a moral obligation to undergo. Neglected are wider socio-structural considerations that impact the prevalence of illness among Māori.

year: 2007