Exploring the controls on the cycle of carbon in the Ross Sea, Antarctica [microform]
- Bib ID:
- 4225107
- Format:
- Book and Microform
- Author:
- Tagliabue, Alessandro
- Online Version:
- http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3235361
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- Description:
- 230 p.
- ISBN:
- 9780542895982
- Summary:
-
Photosynthesis by surface-dwelling phytoplankton results in a disequilibrium in CO2 with respect to the atmosphere, facilitating the oceanic uptake of atmospheric CO2 (FCO2). Despite only accounting for 10% of the global ocean, the Southern Ocean is responsible for 25% of global FCO2. Moreover, this region is vulnerable to future changes in climate. The micronutrient iron is the predominant regulator of primary productivity (PP) across the modern Southern Ocean. Located on the Antarctic continental shelf, the southwestern Ross Sea (RS) sector of the Southern Ocean is typified by high rates of PP, multiple phytoplankton blooms, and spatially varying physiochemical characteristics. This makes the RS an ideal natural laboratory within which to examine the influence of biological, chemical, and physical factors on the oceanic carbon cycle.
In this thesis, I use a combination of ecosystem modeling and laboratory experiments to examine the role of zooplankton grazing, phytoplankton species composition, upper ocean physics, and iron cycling on rates of PP and FCO2. The exaggerated boom/bust cycle that typifies RS phytoplankton blooms decouples them from zooplankton grazing resulting in low zooplankton biomass. Phytoplankton species composition controls the relative rate of macronutrient removal, while iron availability constrains the absolute magnitude of utilization. Shifts in phytoplankton species composition significantly alters both PP and FCO2. Variability in wind speed, temperature, and sea-ice dynamics are also important in controlling FCO2.
Ultimately, PP and FCO 2 are limited by iron. Photoreduction governs the supply of bioavailable iron to the phytoplankton and is controlled by the degree of organic complexation. As the speciation and bioavailability of iron depends on physiochemical factors, it is highly sensitive to mixed layer conditions. The efficiency with which iron fuels PP is greater in seasonal ice zones than in permanently ice-free waters. In general, shallow mixed layers are characterized by a greater supply of iron to phytoplankton via photoreduction, which is relatively insensitive to temperature. Variability in mixed layer characteristics in the geologic past or future would therefore impact the supply of bioavailable iron to the phytoplankton community, and FCO2, independent of any change in exogenous iron inputs.
- Notes:
-
- (UMI)AAI3235361
- Adviser: Kevin R. Arrigo.
- Source: Dissertation Abstracts International, Volume: 67-09, Section: B, page: 4933.
- Thesis (Ph.D.)--Stanford University, 2006.
- Reproduction:
- Microfiche. Ann Arbor, Mich.: University Microfilms International
- Subject:
- Biogeochemistry
- Other authors/contributors:
- Stanford University
- Copyright:
-
In Copyright
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- Reason for copyright status:
- Until 2076 [Created/Published Date + 70 Years]
Copyright status was determined using the following information:
- Material type:
- Literary Dramatic Musical
- Published status:
- Unpublished
- Creation date:
- 2006
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