Combined Effects of Dissolved Oxygen and Temperature On Aerobic Respiration and Respiratory Recovery Responses of the Spioniform Polychaete, <i>Streblospio gynobranchiata</i>, In Relation to Body Size

<p>Elevated surface temperatures exacerbate the threat of hypoxia within coastal ecosystems. These two primary stressors likely interact as they elicit opposing physiological responses from marine organisms. Metabolic depression is typically associated with hypoxia, while metabolic rates increase with temperature. Moreover, physiological effects of combined stressors may not be additive. In light of increasing pressures from hypoxia, elevated ocean temperatures, and other stressors within coastal regions, studies need to examine effects of multiple stressors on physiology of coastal organisms.</p> <p>Mass-specific aerobic respiration (V_O2) was characterized as a proxy for metabolic cost of <em>Streblospio gynobranchiata</em>, at combined levels of dissolved oxygen and temperature relative to body size. Also, changes in V_O2 during acclimation to hypoxia and respiratory recovery following hypoxia exposure were examined. Overall, oxyregulatory abilities were maintained with decreasing dissolved oxygen levels and increasing temperatures except at the highest temperature treatment, indicating the critical temperature was reached within the treatment range. Over a 12 hour period of hypoxia exposure, this species showed an initial acclimation period, followed by a decreased V_O2for the remainder of the exposure. After returning to aerated conditions following acclimation to hypoxia, V_O2 appeared to increase and decrease in two cycles over a 12 hour period, possibly reflecting energy cycling in terms of ATP usage. V_O2peaked at 10 hours, overshooting reference normoxia readings, perhaps indicating an oxygen debt. <em>Streblospio gynobranchiata</em> exhibited a high tolerance to these combined stressors, however, further challenges by decreasing oxygen and increasing temperatures may surpass this species’ ability to meet energy demands.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Discipline thesis:degree_discipline

Ocean Science and Technology

Year dc:date.available

2017

Author dc:creator

• Bennett, Alyssa

Contributors dc:contributor

• Chester F. Rakocinski
• Robert J. Griffitt
• Kelly M. Dorgan

• hypoxia
• climate change
• polychaete
• oxygen consumption
• respiration rate
• physiology
• Environmental Indicators and Impact Assessment
• Environmental Sciences
• Life Sciences
• Marine Biology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/336

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1353