Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)


Ocean, Coastal, and Earth Sciences

First Advisor

Dr. Carlos E. Cintra-Buenrostro

Second Advisor

Dr. Alejandro Fierro-Cabo

Third Advisor

Dr. Engil Pereira


Black mangrove (Avicennia germinans) in south Texas provide ecosystem services and benefits to humans including: habitat for wildlife, prevention of coastline erosion, and mitigation of natural disasters. One step to preserve their ecological functions is to identify and protect the source of their nitrogen (N). Nitrogen stable isotopes were sampled for one year beginning August 2018 and used as tracers to identify how mangroves obtain N. Total N in (A. germinans) and associated (Batis maritima) (plants) (2.1%) was more abundant than in cyanobacteria (0.6%) and sediment (0.1%). Plant d15N signatures (5.52‰) were more similar to sediment (5.21‰) than cyanobacteria (1.98‰), suggesting A. germinans obtain N from sediment and/or plants and sediment obtain N from sources other than cyanobacteria. Nutrient content indicates that seedlings growing in (B. maritima) vegetation patches are more similar to adult mangroves, suggesting vegetation is beneficial to young mangroves and should be considered in transplanting events.


Copyright 2019 Ashley Elizabeth Murphy. All Rights Reserved.