Effect of phytoplankton growth on air bubble residence time in seawater
Effect of phytoplankton growth on air bubble residence time in seawater
Laboratory experiments were carried out in a seawater mesocosm tank to investigate the influence of marine phytoplankton growth on air bubble residence time (BRT). Air bubbles of 10–1000 ?m in diameter were injected by flushing a water jet into the top of the tank and BRT was determined acoustically. The tank was filled with seawater containing a natural phytoplankton population and growth stimulated by irradiating with artificial fluorescent light. A second experiment was conducted using a monoculture of the diatom Cylindrotheca closterium. BRT and several phytoplankton growth-related parameters (chlorophyll concentration, dissolved inorganic nutrients, dissolved organic carbon (DOC), oxygen saturation and bacteria numbers) as well as the water viscosity were monitored over periods of up to 24 days. BRT showed a statistically significant covariation with oxygen saturation (r = 0.69, ? = 0.01 for natural phytoplankton; r = 0.93, ? = 0.01 for the Cylindrotheca closterium) and chlorophyll concentration (r = 0.69, ? = 0.05 natural phytoplankton; r = 0.76, ? = 0.01 Cylindrotheca closterium) during phytoplankton growth periods. Increases in BRT of a factor >2 were found during the chlorophyll maximum, when the water was sufficiently supersaturated with oxygen (?>110%). No clear relationship was evident between BRT and measurements of DOC or water viscosity. Model experiments with highly oxygen-supersaturated water and artificial polysaccharide compounds indicated that oxygen supersaturation alone is not the main factor causing increased BRT during phytoplankton growth, but it is most likely a combination of the degree of gas saturation and the composition of the organic exudates derived from the microalgal population.
Phytoplankton, bubbles, residence time
C06009-[17pp]
Kuhnhenn-Dauben, V.
4c45c389-0399-4b3b-aa57-fffcc614dae0
Purdie, D.A.
18820b32-185a-467a-8019-01f245191cd8
Knispel, U.
a86aa646-812e-4cde-95cb-a403e438db13
Voss, H.
423b4060-ef6a-4d3f-abf4-ad148296657c
Horstmann, U.
ec63b28c-5465-4c35-b6be-393aa45a19ef
2008
Kuhnhenn-Dauben, V.
4c45c389-0399-4b3b-aa57-fffcc614dae0
Purdie, D.A.
18820b32-185a-467a-8019-01f245191cd8
Knispel, U.
a86aa646-812e-4cde-95cb-a403e438db13
Voss, H.
423b4060-ef6a-4d3f-abf4-ad148296657c
Horstmann, U.
ec63b28c-5465-4c35-b6be-393aa45a19ef
Kuhnhenn-Dauben, V., Purdie, D.A., Knispel, U., Voss, H. and Horstmann, U.
(2008)
Effect of phytoplankton growth on air bubble residence time in seawater.
Journal of Geophysical Research, 113, .
(doi:10.1029/2007JC004232).
Abstract
Laboratory experiments were carried out in a seawater mesocosm tank to investigate the influence of marine phytoplankton growth on air bubble residence time (BRT). Air bubbles of 10–1000 ?m in diameter were injected by flushing a water jet into the top of the tank and BRT was determined acoustically. The tank was filled with seawater containing a natural phytoplankton population and growth stimulated by irradiating with artificial fluorescent light. A second experiment was conducted using a monoculture of the diatom Cylindrotheca closterium. BRT and several phytoplankton growth-related parameters (chlorophyll concentration, dissolved inorganic nutrients, dissolved organic carbon (DOC), oxygen saturation and bacteria numbers) as well as the water viscosity were monitored over periods of up to 24 days. BRT showed a statistically significant covariation with oxygen saturation (r = 0.69, ? = 0.01 for natural phytoplankton; r = 0.93, ? = 0.01 for the Cylindrotheca closterium) and chlorophyll concentration (r = 0.69, ? = 0.05 natural phytoplankton; r = 0.76, ? = 0.01 Cylindrotheca closterium) during phytoplankton growth periods. Increases in BRT of a factor >2 were found during the chlorophyll maximum, when the water was sufficiently supersaturated with oxygen (?>110%). No clear relationship was evident between BRT and measurements of DOC or water viscosity. Model experiments with highly oxygen-supersaturated water and artificial polysaccharide compounds indicated that oxygen supersaturation alone is not the main factor causing increased BRT during phytoplankton growth, but it is most likely a combination of the degree of gas saturation and the composition of the organic exudates derived from the microalgal population.
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Published date: 2008
Keywords:
Phytoplankton, bubbles, residence time
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Local EPrints ID: 52065
URI: http://eprints.soton.ac.uk/id/eprint/52065
ISSN: 0148-0227
PURE UUID: 4f81ec74-b6ee-4924-9c42-9b1ef4d98c16
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Date deposited: 13 Jun 2008
Last modified: 16 Mar 2024 02:32
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Author:
V. Kuhnhenn-Dauben
Author:
U. Knispel
Author:
H. Voss
Author:
U. Horstmann
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