Bacterial extracellular enzyme activity in a future ocean
Heterotrophic bacteria are recognised as vital components in the cycling and regulation of inorganic and organic matter in the ocean. Research to date indicates that future changes in ocean conditions may influence bacterial extracellular enzyme hydrolysis rates, which could affect the strength of t...
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ftvuwellington:oai:researcharchive.vuw.ac.nz:10063/3771 2023-08-15T12:42:43+02:00 Bacterial extracellular enzyme activity in a future ocean Burrell, Timothy James Maas, Els Law, Cliff Teesdale-Spittle, Paul 2015 http://researcharchive.vuw.ac.nz/handle/10063/3771 en_NZ eng Victoria University of Wellington http://researcharchive.vuw.ac.nz/handle/10063/3771 Greenhouse Enzymes Bacteria Text Doctoral 2015 ftvuwellington 2023-07-25T17:24:34Z Heterotrophic bacteria are recognised as vital components in the cycling and regulation of inorganic and organic matter in the ocean. Research to date indicates that future changes in ocean conditions may influence bacterial extracellular enzyme hydrolysis rates, which could affect the strength of the microbial loop and consequently organic matter export. The aim of this thesis was to examine how changes in ocean acidification and warming predicted to occur by the end of the century will affect extracellular enzyme activities in the near-surface ocean and below the surface mixed layer in the South West Pacific. A series of small-scale seawater incubations were conducted under three different perturbed conditions: elevated temperature (ambient +3°C), low pH (pCO₂ 750 ppmv; pHт 7.8) and greenhouse conditions (elevated temperature and low pH), with responses compared to ambient control samples. In particular, the response of protease activity (leucine- and arginine-aminopeptidase) and glucosidase activity (β- and α-glucosidase) were examined, as these enzymes are known to degrade the two major components of organic matter in the ocean, namely proteins and carbohydrates. Bacterial secondary production rates (³H-TdR & ³H-Leu incorporation) were also examined as a proxy for carbon turnover. To investigate spatial variability, parameter responses from near-surface open ocean seawater consisting of different phytoplankton communities were compared with coastal seawater, as well as seawater collected from below the surface mixed layer. To determine temporal variability, both direct and indirect parameter responses were investigated. Finally, responses were determined from a shallow CO₂ vent that provided a natural low pH environment in coastal waters north of New Zealand. By comparing responses derived from vent water and artificially low pH water, vent plumes were also investigated for their utility as proxies for future low pH environments. Incubation results showed that protease activity increased in response to ... Doctoral or Postdoctoral Thesis Ocean acidification Victoria University of Wellington: ResearchArchive New Zealand Pacific |
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Open Polar |
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Victoria University of Wellington: ResearchArchive |
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ftvuwellington |
language |
English |
topic |
Greenhouse Enzymes Bacteria |
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Greenhouse Enzymes Bacteria Burrell, Timothy James Bacterial extracellular enzyme activity in a future ocean |
topic_facet |
Greenhouse Enzymes Bacteria |
description |
Heterotrophic bacteria are recognised as vital components in the cycling and regulation of inorganic and organic matter in the ocean. Research to date indicates that future changes in ocean conditions may influence bacterial extracellular enzyme hydrolysis rates, which could affect the strength of the microbial loop and consequently organic matter export. The aim of this thesis was to examine how changes in ocean acidification and warming predicted to occur by the end of the century will affect extracellular enzyme activities in the near-surface ocean and below the surface mixed layer in the South West Pacific. A series of small-scale seawater incubations were conducted under three different perturbed conditions: elevated temperature (ambient +3°C), low pH (pCO₂ 750 ppmv; pHт 7.8) and greenhouse conditions (elevated temperature and low pH), with responses compared to ambient control samples. In particular, the response of protease activity (leucine- and arginine-aminopeptidase) and glucosidase activity (β- and α-glucosidase) were examined, as these enzymes are known to degrade the two major components of organic matter in the ocean, namely proteins and carbohydrates. Bacterial secondary production rates (³H-TdR & ³H-Leu incorporation) were also examined as a proxy for carbon turnover. To investigate spatial variability, parameter responses from near-surface open ocean seawater consisting of different phytoplankton communities were compared with coastal seawater, as well as seawater collected from below the surface mixed layer. To determine temporal variability, both direct and indirect parameter responses were investigated. Finally, responses were determined from a shallow CO₂ vent that provided a natural low pH environment in coastal waters north of New Zealand. By comparing responses derived from vent water and artificially low pH water, vent plumes were also investigated for their utility as proxies for future low pH environments. Incubation results showed that protease activity increased in response to ... |
author2 |
Maas, Els Law, Cliff Teesdale-Spittle, Paul |
format |
Doctoral or Postdoctoral Thesis |
author |
Burrell, Timothy James |
author_facet |
Burrell, Timothy James |
author_sort |
Burrell, Timothy James |
title |
Bacterial extracellular enzyme activity in a future ocean |
title_short |
Bacterial extracellular enzyme activity in a future ocean |
title_full |
Bacterial extracellular enzyme activity in a future ocean |
title_fullStr |
Bacterial extracellular enzyme activity in a future ocean |
title_full_unstemmed |
Bacterial extracellular enzyme activity in a future ocean |
title_sort |
bacterial extracellular enzyme activity in a future ocean |
publisher |
Victoria University of Wellington |
publishDate |
2015 |
url |
http://researcharchive.vuw.ac.nz/handle/10063/3771 |
geographic |
New Zealand Pacific |
geographic_facet |
New Zealand Pacific |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
http://researcharchive.vuw.ac.nz/handle/10063/3771 |
_version_ |
1774297198924660736 |