Type
Text
Type
Dissertation
Advisor
Aller, Robert | Lonsdale, Darcy J. | Cerrato, Robert | Warren, Joseph | Costello, John.
Date
2013-12-01
Keywords
Ecology | ciliates, ctenophore, gelatinous zooplankton, microplankton, Mnemiopsis, trophic cascade
Department
Department of Marine and Atmospheric Science.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76198
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
This dissertation investigated the ecology of the ctenophore Mnemiopsis leidyi in Great South Bay, New York via field and laboratory studies. The research focused on the role of M. leidyi in controlling plankton community structure and the influence of the plankton community in regulating seasonal population blooms of M. leidyi. First, this study documented top-down control of microplankton by larval M. leidyi in Great South Bay. A relationship between high adult M. leidyi/low mesozooplankton with high microplankton abundance was also identified, and preceded an increase in larval ctenophores, suggesting that intense feeding on mesozooplankton by adult M. leidyi enhances prey conditions for their larvae. Secondly, this study found significant interannual differences in M. leidyi abundance, fecundity and recruitment. Ctenophores contained nearly three times as many prey items and produced twice as many eggs in 2008 during a brown tide (Aureococcus anophagefferens) than in 2009, a non-bloom year, implying bottom-up regulation of the ctenophore population. However, M. leidyi abundance was five times lower in 2008 than in 2009 and field data identified a mismatch between maximum ctenophore egg production and microplankton abundance in 2008, whereas the two coincided in 2009, further demonstrating the importance of microplankton for larval M. leidyi. Thirdly, field-based mesocosm experiments examined the individual and interactive roles of M. leidyi predation and eutrophication (i.e. | nutrient loading) on the microplankton community. Ciliates, an important prey item for larval M. leidyi, exhibited an order of magnitude increase in tanks receiving nutrients and in those containing M. leidyi, but increased by two orders of magnitude in treatments receiving both ctenophore and nutrient additions, which may help explain recently documented shifts in M. leidyi population dynamics in coastal estuaries. Mnemiopsis populations interact with estuarine nutrient distributions in multiple ways, including biomass production, excretion, and decomposition. The elemental composition (carbon, nitrogen, and phosphorous) of M. leidyi demonstrated a significant dependence on ctenophore size and zooplankton prey abundance; percentages of C, N, and P declined 30-60% from the onset of the M. leidyi population bloom to their collapse, when prey were fewer. This study documented in situ seasonal patterns in ctenophore elemental stoichiometry and suggests that previous estimates of nutrients remineralized during population crashes are likely over-estimated. | 121 pages
Recommended Citation
McNamara, Marianne E., "Population dynamics of the ctenophore Mnemiopsis leidyi and implications for bottom-up and top-down controls of the plankton community" (2013). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2135.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2135