title: Is there a link between deep-sea biodiversity and ecosystem function?

authors: Leduc, Daniel

subjects: Challenger Plateau

abstract: Studying the diversity-ecosystem function relationship in the deep sea is of primary importance in the face of biodiversity loss and for our understanding of how the deep sea functions. Results from the first study of diversity-ecosystem function relationships in the deep sea (Danovaro et al. 2008; Current Biology, 18, 1–8) are unexpected and show an exponential relationship between deep-sea nematode diversity and ecosystem function and efficiency, although this relationship appears largely restricted to relatively low diversities [ES(51) <25]. Here, we investigate the relationship between nematode diversity and several independent measures/proxies of ecosystem function (sediment community oxygen consumption, bacterial biomass, bacterial extracellular enzyme activity) and efficiency (ratio of bacterial/nematode carbon to organic C content of the sediment) on the New Zealand continental slope. Nematode diversity at our study sites was relatively high [ES(51) = 30–42], and there was no relationship between species/functional diversity and ecosystem function/efficiency after accounting for the effects of water depth and food availability. Our results are consistent with a breakdown of the exponential diversity-function relationship at high levels of diversity, which may be due to increased competition or greater functional redundancy. Future studies need to take into account as many environmental factors and as wide a range of diversities as possible to provide further insights into the diversity-ecosystem function relationship in the largest ecosystem on Earth.

text: Is there a link between deep-sea biodiversity and ecosystem function? Studying the diversity-ecosystem function relationship in the deep sea is of primary importance in the face of biodiversity loss and for our understanding of how the deep sea functions. Results from the first study of diversity-ecosystem function relationships in the deep sea (Danovaro et al. 2008; Current Biology, 18, 1–8) are unexpected and show an exponential relationship between deep-sea nematode diversity and ecosystem function and efficiency, although this relationship appears largely restricted to relatively low diversities [ES(51) <25]. Here, we investigate the relationship between nematode diversity and several independent measures/proxies of ecosystem function (sediment community oxygen consumption, bacterial biomass, bacterial extracellular enzyme activity) and efficiency (ratio of bacterial/nematode carbon to organic C content of the sediment) on the New Zealand continental slope. Nematode diversity at our study sites was relatively high [ES(51) = 30–42], and there was no relationship between species/functional diversity and ecosystem function/efficiency after accounting for the effects of water depth and food availability. Our results are consistent with a breakdown of the exponential diversity-function relationship at high levels of diversity, which may be due to increased competition or greater functional redundancy. Future studies need to take into account as many environmental factors and as wide a range of diversities as possible to provide further insights into the diversity-ecosystem function relationship in the largest ecosystem on Earth.

year: 2013

title: A cell-associated oligo-1,6-alpha-glucosidase from an extremely thermophilic anaerobic bacterium, Thermoanaerobium Tok6-B1.

authors: Plant, Adrian R.

subjects: biology

abstract: Cell-associated oligo-1,6-alpha-glucosidase (EC 3.2.1.10) was isolated from Thermoanaerobium Tok6-B1 grown on starch-containing medium. Activity was purified 11.4-fold by salt precipitation, gel filtration, hydroxyapatite and anion-exchange chromatography. Molecular mass was determined as 30,000 by SDS/polyacrylamide-gel electrophoresis and 33,000 by analytical gel filtration. The probable order of specificity was p-nitrophenyl-alpha D-glucose greater than-isomaltose greater than-isomaltotriose greater than-panose greater than-nigerose and no activity was shown against malto-oligosaccharides, melezitose, melibiose, raffinose, cellobiose, sophorose, gentiobiose, lactose, pullulan, dextran or amylose. The optima for activity and stability were between pH 5.6 and 7.0 and the half-life at pH 6.5 was 1000 min at 70 degrees C and 20 min at 76 degrees C. Activity was stabilized by substrate, Mg2+, Mn2+ and Ca2+, but was destabilized by Zn2+ and EDTA. N-Ethylmaleimide, glucose and 1-O-methyl-alpha D-glucose were inhibitory but 1-O-methyl-beta D-glucose stimulated activity. The activation energy (Ea) was 109 kJ/mol.

text: A cell-associated oligo-1,6-alpha-glucosidase from an extremely thermophilic anaerobic bacterium, Thermoanaerobium Tok6-B1. Cell-associated oligo-1,6-alpha-glucosidase (EC 3.2.1.10) was isolated from Thermoanaerobium Tok6-B1 grown on starch-containing medium. Activity was purified 11.4-fold by salt precipitation, gel filtration, hydroxyapatite and anion-exchange chromatography. Molecular mass was determined as 30,000 by SDS/polyacrylamide-gel electrophoresis and 33,000 by analytical gel filtration. The probable order of specificity was p-nitrophenyl-alpha D-glucose greater than-isomaltose greater than-isomaltotriose greater than-panose greater than-nigerose and no activity was shown against malto-oligosaccharides, melezitose, melibiose, raffinose, cellobiose, sophorose, gentiobiose, lactose, pullulan, dextran or amylose. The optima for activity and stability were between pH 5.6 and 7.0 and the half-life at pH 6.5 was 1000 min at 70 degrees C and 20 min at 76 degrees C. Activity was stabilized by substrate, Mg2+, Mn2+ and Ca2+, but was destabilized by Zn2+ and EDTA. N-Ethylmaleimide, glucose and 1-O-methyl-alpha D-glucose were inhibitory but 1-O-methyl-beta D-glucose stimulated activity. The activation energy (Ea) was 109 kJ/mol.

year: 1988

title: He whiringa aroha: A mokopuna and a pare in the peabody essex museum

authors: Murray, Moana

abstract: Taonga, Māori ancestral treasures, embody the mana and knowledge of Māori ancestors. He Whiringa Aroha is one such treasure: a carved pare that affirms the mana of wāhine in the colonial archives, but whose whakapapa has been obscured. This thesis uses the name ‘He Whiringa Aroha’ and the te reo Māori pronoun ‘ia’ to refer to ‘E5501’, which is located in the 1806 Richardson collection in the Peabody Essex Museum. As He Whiringa Aroha travelled from Aotearoa New Zealand to Massachusetts, United States, ia became entangled in historical narratives that disembodied the taonga from hapū and iwi Māori. Taonga were not only physically removed from Aotearoa, but taonga and Māori creative practices were named, gendered, and displayed by colonisers. American sailors collected and displayed He Whiringa Aroha as an exotic ‘curiosity’ to showcase their triumph over Pacific waters. Yet, He Whiringa Aroha is a power portal—a potent braid to the past, the future, and to those Māori ways of being that defy the limiting archival language of colonialism. How do we relate to taonga Māori that have been fragmented by the colonial archive? What are alternatives to restory and reclaim taonga that remain in overseas museums? 

Using a creative methodology grounded in Mana Wahine and pūrākau, this thesis weaves a whiri (braid) of aroha (reverence) that attempts to restore he hononga mokopuna–the connection between taonga and their descendants. Through poetry, a decolonial map, interviews with ringatoi (Māori creatives), and archival research, I explore how the histories of taonga can be reclaimed in Māori worldviews. Interviews with pūkenga and tohunga toi reveal Māori understandings of taonga as expressions of toi, defying western taxonomies of ‘art’ and ‘curio’. Furthermore, archival research into the East India Marine Society and Peabody Essex Museum unmasks the American sailors and their provenance practices that
have marginalised Māori, and in particular, wāhine Māori. Finally, I use pūrākau of atua wāhine, Mana Wahine and takatāpui scholarship to restory and rename He Whiringa Aroha. This archival storytelling raises new ethical questions about ownership and kaitiakitanga (guardianship), which pose interventions for existing conversations about the place of taonga Māori in overseas museum collections. Reclaiming the histories of ancestors in museums is more than decolonizing colonial archives; on the contrary, restorying taonga is an act of Indigenous resurgence. This Masters research opens new possibilities to reclaiming takatāpui narratives and the mana of wahine in museum archives.

text: He whiringa aroha: A mokopuna and a pare in the peabody essex museum Taonga, Māori ancestral treasures, embody the mana and knowledge of Māori ancestors. He Whiringa Aroha is one such treasure: a carved pare that affirms the mana of wāhine in the colonial archives, but whose whakapapa has been obscured. This thesis uses the name ‘He Whiringa Aroha’ and the te reo Māori pronoun ‘ia’ to refer to ‘E5501’, which is located in the 1806 Richardson collection in the Peabody Essex Museum. As He Whiringa Aroha travelled from Aotearoa New Zealand to Massachusetts, United States, ia became entangled in historical narratives that disembodied the taonga from hapū and iwi Māori. Taonga were not only physically removed from Aotearoa, but taonga and Māori creative practices were named, gendered, and displayed by colonisers. American sailors collected and displayed He Whiringa Aroha as an exotic ‘curiosity’ to showcase their triumph over Pacific waters. Yet, He Whiringa Aroha is a power portal—a potent braid to the past, the future, and to those Māori ways of being that defy the limiting archival language of colonialism. How do we relate to taonga Māori that have been fragmented by the colonial archive? What are alternatives to restory and reclaim taonga that remain in overseas museums? 

Using a creative methodology grounded in Mana Wahine and pūrākau, this thesis weaves a whiri (braid) of aroha (reverence) that attempts to restore he hononga mokopuna–the connection between taonga and their descendants. Through poetry, a decolonial map, interviews with ringatoi (Māori creatives), and archival research, I explore how the histories of taonga can be reclaimed in Māori worldviews. Interviews with pūkenga and tohunga toi reveal Māori understandings of taonga as expressions of toi, defying western taxonomies of ‘art’ and ‘curio’. Furthermore, archival research into the East India Marine Society and Peabody Essex Museum unmasks the American sailors and their provenance practices that
have marginalised Māori, and in particular, wāhine Māori. Finally, I use pūrākau of atua wāhine, Mana Wahine and takatāpui scholarship to restory and rename He Whiringa Aroha. This archival storytelling raises new ethical questions about ownership and kaitiakitanga (guardianship), which pose interventions for existing conversations about the place of taonga Māori in overseas museum collections. Reclaiming the histories of ancestors in museums is more than decolonizing colonial archives; on the contrary, restorying taonga is an act of Indigenous resurgence. This Masters research opens new possibilities to reclaiming takatāpui narratives and the mana of wahine in museum archives.

year: 2024