Phytoplankton dynamics in a eutrophying south Texas estuary

Simple item page
dc.contributor.advisorWetz, Michael s.
dc.contributor.advisorWetz, Michael S.
dc.contributor.authorCira, Emily K.
dc.contributor.authorCira, Emily K.
dc.contributor.committeeMemberFelix, Joseph D.
dc.contributor.committeeMemberGobler, Christopher J.
dc.contributor.committeeMemberSterba-Boatwright, Blair
dc.contributor.committeeMemberFelix, Joseph D.
dc.contributor.committeeMemberGobler, Christopher J.
dc.contributor.committeeMemberSterba-Boatwright, Blair
dc.contributor.committeeMemberGobler, Christopher J.
dc.contributor.committeeMemberSterba-Boatwright, Blair
dc.creator.orcidhttps://orcid.org/0000-0002-4148-1133
dc.creator.orcid0000-0002-4148-1133en_US
dc.date.accessioned2020-10-18T21:23:03Z
dc.date.accessioned2020-10-18T21:23:03Z
dc.date.available2020-10-18T21:23:03Z
dc.date.available2020-10-18T21:23:03Z
dc.date.issued2020-08
dc.date.issued2020-082020-08
dc.description.abstractLow freshwater inflow estuaries are common worldwide, yet data is lacking on phytoplankton dynamics in these systems. This dissertation advances our understanding of phytoplankton dynamics in low-inflow estuaries through analysis of field data collected at multiple temporal scales throughout Baffin Bay, Texas, an estuary that is frequently hypersaline and that has been experiencing symptoms of eutrophication. These symptoms include long-term increases in nutrients and chlorophyll as well as recurring blooms of the “brown tide” phytoplankton, Aureoumbra lagunensis. Variability in phytoplankton biomass and community composition were related to climatic/hydrologic shifts associated with El Niño-Southern Oscillation. During drought conditions, high chlorophyll concentrations were observed (25.7 ± 11.7 µg L-1) and the phytoplankton community consisted of a near monoculture of A. lagunensis (87% of phytoplankton biovolume). These results point to the importance of regenerated nutrients in supporting phytoplankton growth during this time. When El Niño conditions developed, high rainfall took place and corresponded with increased dissolved inorganic nitrogen concentrations (ammonium, nitrate + nitrite) in the bay, but chlorophyll concentrations were lower during this time (16.2 ± 14.3 µg L-1). This suggests that the potential stimulatory effects of nutrient pulses were counter balanced by decreased residence times associated with increased inflow. This study also identified sub-monthly variability as a dominant timescale of chlorophyll variability in Baffin Bay. Wind speed was found to be an important factor related to short-term (timescales of days) bloom events, often positively correlating with chlorophyll concentrations. Results additionally demonstrate that traditional monitoring frequencies are often are not adequate to capture short-term process and bloom events. Lastly, this study quantified the distribution of, and potential controls upon, A. lagunensis in Baffin Bay. Persistently high abundances of A. lagunensis were observed in Laguna Salada, indicating that this tertiary bay may serve as a reservoir for A. lagunensis in the system. High abundances of A. lagunensis (> 1×106 cells mL-1) were found at salinities as low as 20, indicating that hypersalinity is not a prerequisite for A. lagunensis blooms. Instead, results suggest a variety of physical, chemical and biological factors (top-down controls, nutrient concentrations and forms, salinity) drive A. lagunensis population dynamics in the bay. This research improves our ecological understanding of low-inflow estuaries, specifically pertaining to the ecology of phytoplankton in them. Results also suggest that as climate pressures increase, causing systems like Baffin Bay to become warmer and drier, they will be more conducive for harmful taxa such as A. lagunensis. The finding that Laguna Salada may be a reservoir for A. lagunensis presents an opportunity for targeted bloom mitigation efforts.en_US
dc.description.collegeCollege of Science and Engineeringen_US
dc.description.departmentPhysical and Environmental Sciencesen_US
dc.format.extent132 pagesen_US
dc.identifier.urihttps://hdl.handle.net/1969.6/89083
dc.identifier.urihttps://hdl.handle.net/1969.6/89083https://hdl.handle.net/1969.6/89083
dc.language.isoen_USen_US
dc.rightsThis material is made available for use in research, teaching, and private study, pursuant to U.S. Copyright law. The user assumes full responsibility for any use of the materials, including but not limited to, infringement of copyright and publication rights of reproduced materials. Any materials used should be fully credited with its source. All rights are reserved and retained regardless of current or future development or laws that may apply to fair use standards. Permission for publication of this material, in part or in full, must be secured with the author and/or publisher.en_US
dc.rights.holderCira, Emily K.
dc.rights.holderCira, Emily K.Cira, Emily K.
dc.subjectaureoumbra lagunensisen_US
dc.subjectestuaryen_US
dc.subjectfreshwater inflowen_US
dc.subjectnutrientsen_US
dc.subjectphytoplanktonen_US
dc.subjectsalinityen_US
dc.subject.lcshecologyen_US
dc.titlePhytoplankton dynamics in a eutrophying south Texas estuaryen_US
dc.typeTexten_US
dc.type.genreDissertationen_US
dcterms.typeText
thesis.degree.disciplineCoastal and Marine System Scienceen_US
thesis.degree.grantorTexas A & M University--Corpus Christien_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US

Files

Original bundle

Now showing 1 - 1 of 1
Thumbnail Image
Name:
Cira_Emily_dissertation.pdf
Size:
4.89 MB
Format:
Adobe Portable Document Format
Description:
Dissertation
Download

License bundle

Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.72 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections

Dissertations
College of Science Theses and Dissertations