title: Impact of elevated levels of CO2 on animal mediated ecosystem function: The modification of sediment nutrient fluxes by burrowing urchins

authors: Widdicombe, S.

subjects: Bioturbation

abstract: A mesocosm experiment was conducted to quantify the relationships between the presence and body size of two burrowing heart urchins (Brissopsis lyrifera and Echinocardium cordatum) and rates of sediment nutrient flux. Furthermore, the impact of seawater acidification on these relationships was determined during this 40-day exposure experiment. Using carbon dioxide (CO ₂) gas, seawater was acidified to pH NBS 7.6, 7.2 or 6.8. Control treatments were maintained in natural seawater (pH ≈ 8.0). Under normocapnic conditions, burrowing urchins were seen to reduce the sediment uptake of nitrite or nitrate whilst enhancing the release of silicate and phosphate. In acidified (hypercapnic) treatments, the biological control of biogeochemical cycles by urchins was significantly affected, probably through the combined impacts of high CO ₂ on nitrifying bacteria, benthic algae and urchin behaviour. This study highlights the importance of considering biological interactions when predicting the consequences of seawater acidification on ecosystem function.

text: Impact of elevated levels of CO2 on animal mediated ecosystem function: The modification of sediment nutrient fluxes by burrowing urchins A mesocosm experiment was conducted to quantify the relationships between the presence and body size of two burrowing heart urchins (Brissopsis lyrifera and Echinocardium cordatum) and rates of sediment nutrient flux. Furthermore, the impact of seawater acidification on these relationships was determined during this 40-day exposure experiment. Using carbon dioxide (CO ₂) gas, seawater was acidified to pH NBS 7.6, 7.2 or 6.8. Control treatments were maintained in natural seawater (pH ≈ 8.0). Under normocapnic conditions, burrowing urchins were seen to reduce the sediment uptake of nitrite or nitrate whilst enhancing the release of silicate and phosphate. In acidified (hypercapnic) treatments, the biological control of biogeochemical cycles by urchins was significantly affected, probably through the combined impacts of high CO ₂ on nitrifying bacteria, benthic algae and urchin behaviour. This study highlights the importance of considering biological interactions when predicting the consequences of seawater acidification on ecosystem function.

year: 2012

title: Biomedical Ti-Cu-Mn alloys with antibacterial capability

authors: Alqattan, M.

subjects: titanium alloys

abstract: This study aims to develop Ti–Cu–Mn alloys with antibacterial capability for reducing the possibility of bacterial infection during biomedical implant surgeries. Ternary alloys were designed to be manufactured via powder metallurgy, which has intrinsic manufacturing, economic, and environmental benefits. The amount of each of the alloying elements was limited to prevent the formation of brittle phases. It is found that the selected compositions of Cu (0.5-5 wt.%) plus Mn (0.25-2.5 Mn wt.%) can successfully be manufactured achieving microstructures, tensile properties and antibacterial capability performance comparable to those of other biomedical Ti alloys. Specifically, homogeneous compositions are achieved with the selected sintering parameters (1300 °C/120 min). The strength and hardness of the material increase proportionally with the addition rate of Cu and Mn, and antibacterial capability values were found to be above the 90% threshold required for antibacterial certification.

text: Biomedical Ti-Cu-Mn alloys with antibacterial capability This study aims to develop Ti–Cu–Mn alloys with antibacterial capability for reducing the possibility of bacterial infection during biomedical implant surgeries. Ternary alloys were designed to be manufactured via powder metallurgy, which has intrinsic manufacturing, economic, and environmental benefits. The amount of each of the alloying elements was limited to prevent the formation of brittle phases. It is found that the selected compositions of Cu (0.5-5 wt.%) plus Mn (0.25-2.5 Mn wt.%) can successfully be manufactured achieving microstructures, tensile properties and antibacterial capability performance comparable to those of other biomedical Ti alloys. Specifically, homogeneous compositions are achieved with the selected sintering parameters (1300 °C/120 min). The strength and hardness of the material increase proportionally with the addition rate of Cu and Mn, and antibacterial capability values were found to be above the 90% threshold required for antibacterial certification.

year: 2021

title: Kāinga tahi, kāinga rua: A kaupapa Māori response of Te Puea Memorial Marae.

authors: Lee-Morgan, Jenny Bol Jun

abstract: In the winter of 2016, Te Puea Memorial Marae (TPMM) initiated a kaupapa Māori marae-led response, opening their doors to vulnerable whānau seeking emergency housing. Following in the legacy of Te Puea Herangi,¹ the marae answered the call of homeless whānau in Auckland and in doing so disrupted the dominant Auckland housing narrative where the government had until that time refused to acknowledge homelessness as a serious issue. In the full view of the media, TPMM not only made the reality of homelessness visible by caring for 181 people (of all ethnicities and cultural backgrounds), but named the housing situation in Auckland as a ‘crisis’. ²

text: Kāinga tahi, kāinga rua: A kaupapa Māori response of Te Puea Memorial Marae. In the winter of 2016, Te Puea Memorial Marae (TPMM) initiated a kaupapa Māori marae-led response, opening their doors to vulnerable whānau seeking emergency housing. Following in the legacy of Te Puea Herangi,¹ the marae answered the call of homeless whānau in Auckland and in doing so disrupted the dominant Auckland housing narrative where the government had until that time refused to acknowledge homelessness as a serious issue. In the full view of the media, TPMM not only made the reality of homelessness visible by caring for 181 people (of all ethnicities and cultural backgrounds), but named the housing situation in Auckland as a ‘crisis’. ²

year: 2017