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Description
The phytoplankton communities in the open oceans are dominated by picophytoplankton (0.7-2µm) and nanophytoplankton (3-5µm). Studying the community dynamics of these phytoplankton is important to learn about their role in the carbon cycle and food web of the oceans. Dilution experiments were used, along with microscopy and molecular techniques, to determine abundance, biomass and phytoplankton growth and grazing rates in the oligotrophic Sargasso Sea (western North Atlantic subtropical gyre) around the Bermuda Atlantic Time Series Station (BATS) in the summer of 2012. With low biomass and chlorophyll a, the Sargasso Sea appears to be unproductive at first glance, but I found that pico- and nanophytoplankton have high instantaneous growth rates that are balanced by the high grazing rates of microzooplankton.
Mesoscale eddies are important features in the Sargasso Sea that can increase or decrease the available nutrients in the euphotic zone. Two different mesoscale eddies were sampled: an anti-cyclonic eddy and the BATS station which was located at the edge of a cyclonic eddy. The results indicated that BATS had overall higher instantaneous growth (µ between 0.1 d-1 and 3.7 d-1) and grazing rates on pico- and nanophytoplankton, as well as diatoms, compared to the anti-cyclonic eddy (µ between 0.2 d-1 and 3 d-1). I also determined taxon-specific rates using quantitative polymerase chain reaction (qPCR) for the order Mamiellales, one of the smallest representatives of the abundant prasinophytes. This method yielded surprisingly high growth (9.7 d-1 ) and grazing rates (-8.2 d-1) at 80m for BATS. The euphotic zone (~100m) integrated biomass of all phytoplankton did not vary significantly between BATS (379 mg C m-2) and the anti-cyclonic eddy (408 mg C m-2) and the net growth rates at both locations were very close to zero for most of the groups. Although the biomass and net growth rates did not vary greatly between the two locations, the high instantaneous growth and grazing rates of pico- and nano-eukaryotic phytoplankton indicate an increase in the rate of the marine microbial food web, or microbial loop, compared to the anti-cyclonic eddy. This could have been due to the input of new nutrients in the edge of the cyclonic eddy at BATS. Thus, my study suggests that mesoscale variability is of considerable importance for the dynamics of the phytoplankton community and their role in the microbial loop. Much can be learned when using DNA based taxon-specific rates, especially to understand the relative importance and contribution of specific taxa.
More taxon-specific molecular studies will have to be carried out to quantify specific rates of more phytoplankton groups, which will supply a more complete knowledge of phytoplankton community dynamics in the Sargasso Sea. This will increase our understanding of the role of specific groups to the biological carbon dynamics in the euphotic zone into the deep ocean.
Mesoscale eddies are important features in the Sargasso Sea that can increase or decrease the available nutrients in the euphotic zone. Two different mesoscale eddies were sampled: an anti-cyclonic eddy and the BATS station which was located at the edge of a cyclonic eddy. The results indicated that BATS had overall higher instantaneous growth (µ between 0.1 d-1 and 3.7 d-1) and grazing rates on pico- and nanophytoplankton, as well as diatoms, compared to the anti-cyclonic eddy (µ between 0.2 d-1 and 3 d-1). I also determined taxon-specific rates using quantitative polymerase chain reaction (qPCR) for the order Mamiellales, one of the smallest representatives of the abundant prasinophytes. This method yielded surprisingly high growth (9.7 d-1 ) and grazing rates (-8.2 d-1) at 80m for BATS. The euphotic zone (~100m) integrated biomass of all phytoplankton did not vary significantly between BATS (379 mg C m-2) and the anti-cyclonic eddy (408 mg C m-2) and the net growth rates at both locations were very close to zero for most of the groups. Although the biomass and net growth rates did not vary greatly between the two locations, the high instantaneous growth and grazing rates of pico- and nano-eukaryotic phytoplankton indicate an increase in the rate of the marine microbial food web, or microbial loop, compared to the anti-cyclonic eddy. This could have been due to the input of new nutrients in the edge of the cyclonic eddy at BATS. Thus, my study suggests that mesoscale variability is of considerable importance for the dynamics of the phytoplankton community and their role in the microbial loop. Much can be learned when using DNA based taxon-specific rates, especially to understand the relative importance and contribution of specific taxa.
More taxon-specific molecular studies will have to be carried out to quantify specific rates of more phytoplankton groups, which will supply a more complete knowledge of phytoplankton community dynamics in the Sargasso Sea. This will increase our understanding of the role of specific groups to the biological carbon dynamics in the euphotic zone into the deep ocean.
ContributorsHamill, Demetra Scott (Author) / Neuer, Susanne (Thesis director) / Elser, Jim (Committee member) / De Martini, Francesca (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
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Description
Each year the United States' interstates and roadways become increasingly congested, with little development of useful mass transit. Elon Musk released a whitepaper titled Hyperloop Alpha in order to generate conversation around a potential "fifth mode of transportation" as an alternative to current high-speed rail technologies. This case study analyzes the implications of implementing the Hyperloop along the 120-mile Phoenix-Tucson route in terms of the State's geographic, economic, political, and environmental advantages for the Hyperloop design. This case study was not meant to investigate the engineering aspects of an untested technology, but rather to generate conversation and elicit enthusiasm in the State of Arizona in order to bring the project in-house. Through comparison of the California context of the Hyperloop and other megaregions this report proposes that given Arizona's solar power production potential, short, flat, undeveloped route, explosive population growth, urban density distribution, recognized need for HSR, and strong research institutions make it the ideal site and premiere candidate for initial Hyperloop testing and construction.
ContributorsMartin, Sean Joseph (Author) / Martin, Pasqualetti (Thesis director) / Basile, George (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / W. P. Carey School of Business (Contributor)
Created2014-05
DescriptionA creative project was made in the form of a movie. The video portrays the corruption of children through media and pop culture's influence. From this, we created the ideas of the Superhero Complex, Princess Complex, and Quasi-fairytale life.
ContributorsEvans, Chanel Nicole (Co-author) / Clayson, Danielle (Co-author) / Switzer, Heather (Thesis director) / Dove-Viebahn, Aviva (Committee member) / Katsulis, Yasmina (Committee member) / Barrett, The Honors College (Contributor)
Created2013-05