Date

Summer 2024

Document Type

Master's Thesis (Open Access)

Degree Name

Master of Science (M.S.)

Department

Moss Landing Marine Laboratories

Abstract

The red alga, Pyropia perforata, commonly referred to as nori, is ubiquitous in intertidal communities throughout coastal California and offers high nutritional value to marine herbivores. However, California rocky shores are dynamic ecosystems, with dramatic abiotic and biotic shifts resulting in environmental heterogeneity. Research has shown that seaweed nutrient physiology is impacted by environmental heterogeneity, yet there is sparse data on how internal nitrogen and total protein content change as a result of environmental heterogeneity. Here, I studied the impacts of seasonality, geography (spanning 4° of latitude from Northern to Southern California), and the onset of environmental heterogeneity on internal nitrogen percentages and total protein content in the nutrient rich, broadly distributed red alga P. perforata. Percent nitrogen and total protein in P. perforata were found to be higher in northern sites compared to southern sites, suggesting a spatial influence on nutrient physiology. Moreover, the winter and spring seasons had higher % nitrogen and total protein compared to summer and fall, further suggesting a temporal effect on nutrient physiology. Cultured P. perforata also exhibited an increase in % nitrogen and total protein as nutrient concentration increased, an effect that was consistent whether the nitrogen source provided was nitrate (NO3-) or ammonium (NH4+). There was little evidence, however, of a correlation between abiotic factors (including temperature, solar radiation, day length, chl ɑ , wind speed, Coastal Upwelling Transport Index, Biologically Effective Upwelling Transport Index , and estimated nitrate) with % nitrogen and total protein. However, solar radiation, daylength, and sea surface nitrogen concentration were significantly correlated with % nitrogen. Overall, there is evidence from this study that % nitrogen and total protein in P. perforata vary as a function of time and space. Furthermore, environmental nitrogen concentration can be used as a proxy for internal nitrogen content.

Download

Share

COinS