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| author | Olivia N Blondheim |
| title | In situ observations of pyrosomes in the northern California Current during an anomalous bloom year |
| abstract |
Pyrosomes (Pyrosoma atlanticum) are pelagic colonial tunicates that are typically found in tropical ocean waters. Research surveys from 2014 to 2017 conducted by the
National Oceanic and Atmospheric Administration (NOAA) showed unusually high abundances of pyrosomes off the Oregon Coast, where they have not previously been observed,
with the largest coastal blooms occurring in spring and summer of 2017. While pyrosomes can migrate to depths of 700 m over diel cycles in their normal range, nothing
is known about their vertical distribution in the northern California Current. We made seven deployments of a stereo camera system equipped with a temperature data
logger over a diurnal period at an off-shore location off the central Oregon coast and analyzed the video footage for pyrosome abundance, length, orientation, and
density relative to temperature and depth. Results indicated that despite an observed temporal variation in pyrosome vertical distribution, across all deployments
pyrosomes tended to be mainly distributed between 25 m and 35 m, with 53.6% of all pyrosomes observed aggregating in this depth range. Pyrosomes distributed between
25 m and 30 m were significantly shorter than pyrosomes between 30 m and 50+ m and tended to have a smaller nearest neighbor distance. Temperature did not appear to
have an effect on pyrosome distribution. Pyrosomes oriented their bodies obliquely in the water column, which may provide additional insight into their swimming
behaviors. By characterizing the swimming behaviors and abundance of pyrosomes over various depths in the northern California Current, better predictions can be
made for how pyrosomes may impact the pelagic ecosystem of the North Pacific.
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| school | The College of Liberal Arts, Drew University |
| degree | B.A. (2018) |
| advisor | Tammy Windfelder |
| committee | Ric Brodeur (NOAA)
Sarah Abramowitz |
| full text | ONBlondheim.pdf |
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