The sea urchin Lytechinus variegatus is a known grazer of the seagrass Thalassia testudinum, and has been known to denude vast stands of seagrass beds at high densities. Outside of these denudation events, the effects of sea urchins on seagrass are poorly understood. This study examines the effects of L. variegatus on T. testudinum in situ, to understand how sea urchins are affecting seagrasses in situ. Results indicate that urchins were found in the offshore portion of the seagrass bed at densities up to 4 urchins/m2. Changes in temperature and sediment size in the bay indicate that there is a greater exchange rate bay water in the offshore portion of the seagrass bed, and bay water may act as a temperature buffer for urchins in that part of the bed. Urchin movement experiments and dispersion patterns indicate that urchins move more where seagrass cover is low. Field surveys and lab choice experiments indicate that urchins tend to be detrital consumers of seagrass blades rather than herbivores on live seagrass tissue. Together, these results suggest that L. varieagtus densities observed in this study do not appear to have strong negative affects on seagrass beds as has been previously seen in field enclosure experiments and denudation events.
","abstract_html":"<p>The sea urchin<em> Lytechinus variegatus </em>is a known grazer of the seagrass <em>Thalassia testudinum</em>, and has been known to denude vast stands of seagrass beds at high densities. Outside of these denudation events, the effects of sea urchins on seagrass are poorly understood. This study examines the effects of <em>L. variegatus</em> on <em>T. testudinum</em> in situ, to understand how sea urchins are affecting seagrasses <em>in situ</em>. Results indicate that urchins were found in the offshore portion of the seagrass bed at densities up to 4 urchins/m<sup>2</sup>. Changes in temperature and sediment size in the bay indicate that there is a greater exchange rate bay water in the offshore portion of the seagrass bed, and bay water may act as a temperature buffer for urchins in that part of the bed. Urchin movement experiments and dispersion patterns indicate that urchins move more where seagrass cover is low. Field surveys and lab choice experiments indicate that urchins tend to be detrital consumers of seagrass blades rather than herbivores on live seagrass tissue. Together, these results suggest that <em>L. varieagtus</em> densities observed in this study do not appear to have strong negative affects on seagrass beds as has been previously seen in field enclosure experiments and denudation events.</p>","abstract_has_math":false,"creators":["Parson, Adrianna"],"institution":null,"degree_name":"Master of Science in Integrative Biology (MSIB)","degree_level":"Thesis","degree_discipline":"Biology","degree_department":null,"school":null,"contributors":["Dr. Troy Mutchler","Dr. William Ensign","Dr. Jared Taglialatela"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2018,"date_issued":"2018-05-01T07:00:00Z","date_published":"2018-05-01T07:00:00Z","updated_at":"2026-07-24T02:43:26Z","subjects":["Lytechinus Variegatus","Thalassia Testudinum","grazing","seagrass","sea urchin","in situ","Animal Studies","Behavior and Ethology","Biology","Integrative Biology","Marine Biology","Population Biology","Terrestrial and Aquatic Ecology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.kennesaw.edu/integrbiol_etd/27","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dr. Troy Mutchler","Dr. William Ensign","Dr. Jared Taglialatela"]},{"key":"dc:creator","label":"Author","values":["Parson, Adrianna"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2019-05-07T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Integrative Biology (MSIB)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Lytechinus Variegatus","Thalassia Testudinum","grazing","seagrass","sea urchin","in situ","Animal Studies","Behavior and Ethology","Biology","Integrative Biology","Marine Biology","Population Biology","Terrestrial and Aquatic Ecology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.kennesaw.edu/integrbiol_etd/27"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The sea urchin Lytechinus variegatus is a known grazer of the seagrass Thalassia testudinum, and has been known to denude vast stands of seagrass beds at high densities. Outside of these denudation events, the effects of sea urchins on seagrass are poorly understood. This study examines the effects of L. variegatus on T. testudinum in situ, to understand how sea urchins are affecting seagrasses in situ. Results indicate that urchins were found in the offshore portion of the seagrass bed at densities up to 4 urchins/m2. Changes in temperature and sediment size in the bay indicate that there is a greater exchange rate bay water in the offshore portion of the seagrass bed, and bay water may act as a temperature buffer for urchins in that part of the bed. Urchin movement experiments and dispersion patterns indicate that urchins move more where seagrass cover is low. Field surveys and lab choice experiments indicate that urchins tend to be detrital consumers of seagrass blades rather than herbivores on live seagrass tissue. Together, these results suggest that L. varieagtus densities observed in this study do not appear to have strong negative affects on seagrass beds as has been previously seen in field enclosure experiments and denudation events.
"]},{"key":"dc:title","label":"Title","values":["Evaluating in situ Grazing Patterns of Lytechinus variegatus and their Effects on Seagrass Beds of Thalassia testudinum"]}]}],"canonical_facts":{"dc:contributor":["Dr. Troy Mutchler","Dr. William Ensign","Dr. Jared Taglialatela"],"dc:creator":["Parson, Adrianna"],"dc:date.available":["2019-05-07T07:00:00Z"],"dc:description.abstract":["The sea urchin Lytechinus variegatus is a known grazer of the seagrass Thalassia testudinum, and has been known to denude vast stands of seagrass beds at high densities. Outside of these denudation events, the effects of sea urchins on seagrass are poorly understood. This study examines the effects of L. variegatus on T. testudinum in situ, to understand how sea urchins are affecting seagrasses in situ. Results indicate that urchins were found in the offshore portion of the seagrass bed at densities up to 4 urchins/m2. Changes in temperature and sediment size in the bay indicate that there is a greater exchange rate bay water in the offshore portion of the seagrass bed, and bay water may act as a temperature buffer for urchins in that part of the bed. Urchin movement experiments and dispersion patterns indicate that urchins move more where seagrass cover is low. Field surveys and lab choice experiments indicate that urchins tend to be detrital consumers of seagrass blades rather than herbivores on live seagrass tissue. Together, these results suggest that L. varieagtus densities observed in this study do not appear to have strong negative affects on seagrass beds as has been previously seen in field enclosure experiments and denudation events.
"],"dc:identifier":["https://digitalcommons.kennesaw.edu/integrbiol_etd/27"],"dc:subject":["Lytechinus Variegatus","Thalassia Testudinum","grazing","seagrass","sea urchin","in situ","Animal Studies","Behavior and Ethology","Biology","Integrative Biology","Marine Biology","Population Biology","Terrestrial and Aquatic Ecology"],"dc:title":["Evaluating in situ Grazing Patterns of Lytechinus variegatus and their Effects on Seagrass Beds of Thalassia testudinum"],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science in Integrative Biology (MSIB)"]},"updated_at":"2026-07-24T02:43:26Z"}