Date of Submission
6-2025
Document Type
Thesis
Degree Name
Master of Science in Environmental Science
Department
Biology and Environmental Sciences
Advisor
Amy L. Carlile, Ph.D.
Committee Member
Christian Conroy, PhD.
Committee Member
Sharon Kahara, PhD.
Keywords
Bloom-Forming Ulva, Spatiotemporal Shifts, New Haven Harbor, Climate Change, Environmental Factors Assessment
MeSH
Global Warming
LCSH
Ulva, New Haven Harbor (Conn.), Biodiversity--Climatic factors, Global warming, Environmental impact analysis
Abstract
The green macroalgal genus Ulva is known to form troublesome blooms globally, negatively affecting marine ecosystems by deteriorating water quality and smothering other organisms. This study investigated the biodiversity of bloom-forming Ulva around New Haven Harbor (NHH), its impacts on water quality, and physiological responses to environmental conditions expected with climate change. Phylogenetic analysis of the chloroplast gene rbcL from 100 samples identified at least eight Ulva species across four locations in NHH. Compared to a 2015 study from the same location, this represents an increase in the number of identified species, while Ulva compressa and Ulva rigida are identified as the dominant bloom-forming algae. Water quality analysis comparing bloom and non-bloom zones demonstrated that the ulvoid bloom significantly (p< 0.05) deteriorated water conditions by depleting dissolved oxygen concentration and lowering water nutrient concentrations, specifically (NO2 -), and phosphate (PO4 3-). The impact of rising seawater temperature and acidification on photosynthesis and growth of Ulva was examined using mesocosm experiments under four treatments: control, high temperature, low pH, and combined (high temperature and low pH). The combined treatment resulted in the highest electron transport rate (ETRmax), daily growth rate (DGR), and specific growth rate (SGR) for Ulva. These results indicate that acidic and warmer seawater conditions could lead to more severe and frequent ulvoid blooms.
Recommended Citation
Banik, Ujjal, "Spatiotemporal Shifts in Bloom-Forming Ulva in New Haven Harbor and Their Physiological Response to Climate Change" (2025). Master's Theses. 229.
https://digitalcommons.newhaven.edu/masterstheses/229