Effect of ocean acidification on swimming of larval green urchins in flow

• Main Authors: Chan, Kit Yu Karen LIFS, Garcia, E., Dupont, Sam T.
• Format: Conference Object
• Language: English
• Published: 2014
• Subjects: Ocean acidification
• Online Access: http://repository.ust.hk/ir/Record/1783.1-67471; http://lbdiscover.ust.hk/uresolver?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rfr_id=info:sid/HKUST:SPI&rft.genre=article&rft.issn=&rft.volume=&rft.issue=&rft.date=2014&rft.spage=&rft.aulast=Chan&rft.aufirst=&rft.atitle=Effect%20of%20ocean%20acidification%20on%20swimming%20of%20larval%20green%20urchins%20in%20flow&rft.title=2014%20Ocean%20Sciences%20Meeting,%20Honolulu,%20Hawaii,%20USA,%2023-28%20February%202014

Many marine invertebrates have benthic adults with limited mobility and rely on planktonic larvae for dispersal. However, these planktonic stages are vulnerable to various environmental stressors, including those associated with ocean acidification (OA). Larval urchins have calcified skeletons supporting long ciliated arms used for feeding and swimming and previous studies demonstrated that OA affects their survival, physiology, growth, and morphology. Larval morphology imposes biomechanical constraints on ecological functions. For instance, changes in arm length would affect weight distribution, and hence, larval ability to swim upright in moving water. Given their small size, larval urchins often experience turbulence as shear. We exposed larval green urchin Strongylocentrotus droebachiensis to three pH levels (pH 8.1, 7.7, and 7.3) and quantified the impact on movement in vertical shear. Larval growth and overall shape differed between pH levels. Video motion analysis suggests that OA affects larval swimming speed in still water and tilt in flow. Differences in larval orientation and movement in shear under OA conditions would have significant implication for larval distribution and transport, such that non-lethal impact OA would have population-level consequences.