Ocean acidification reduces sperm flagellar motility in broadcast spawning reef invertebrates

Abstract

Ocean acidification is now recognized as a threat to marine ecosystems; however, the effect of ocean acidification on fertilization in marine organisms is still largely unknown. In this study, we focused on sperm flagellar motility in broadcast spawning reef invertebrates (a coral and a sea cucumber). Below pH 7.7, the pH predicted to occur within the next 100 years, sperm flagellar motility was seriously impaired in these organisms. Considering that sperm flagellar motility is indispensable for transporting the paternal haploid genome for fertilization, fertilization taking place in seawater may decline in the not too distant future. Urgent surveys are necessary for a better understanding of the physiological consequences of ocean acidification on sperm flagellar motility in a wide range of marine invertebrates.

Effects of Ocean Acidification and Warming on Sperm Activity and Early Life Stages of the Mediterranean Mussel (Mytilus galloprovincialis)

“…Reports for sea-urchins suggest sperm motility is negatively impacted by acidification [35,65]. Negative effects of OA on sperm motility have also been reported for corals and sea cucumbers [66,67], while positive effects have been reported in one species of sea urchin [39]. Reduced sperm swimming performance in marine broadcast spawners is likely to decrease fertilization in sperm limited low density populations [68][69][70][71][72][73].…”

“…This resulted in sperm being activated only at control pH and temperature, and lead to a variable time lag (1-4.5 h) between recording of sperm activity and activation of sperm. Although similar method has been used previously [67,73] in sperm studies, we have no way knowing to what degree, if any the pH shock affected sperm activity. Further studies are needed to judge whether this could cause a significant bias.…”

Sources, factors, mechanisms and possible solutions to pollutants in marine ecosystems

“…Ocean acidification would decrease the saturation states of carbonate minerals and subsequently change the calcification rates of some marine organisms, thereby affecting aquatic food chains (Barker and Elderfield, 2002;Fabry et al, 2008;Kurihara, 2008;Cohen et al, 2009;Cohen and Holcomb, 2009;Moy et al, 2009;Buck and Folger, 2010;Morita et al, 2010;Cooley et al, 2010;Hofmann et al, 2010;Kroeker et al, 2010;Beaufort et al, 2011;Albright, 2011).…”

“…delay the onset of calcification and alter crystal morphology and composition; increase juvenile mortality because of slower post-settlement growth; reduce effective population size and fecundity, and disrupt the generation of sturdy skeletons and the resilience of reef-building corals (Done, 1999;Langdon and Atkinson, 2005;Edmunds, 2007;Albright et al, 2008;Kuffner et al, 2008;Kurihara, 2008;Cohen et al, 2009;de Moel et al, 2009;Cohen and Holcomb, 2009;Buck and Folger, 2010;Morita et al, 2010;Albright, 2011;Albright and Langdon, 2011;Nakamura et al, 2011). Such effects have an impact on the overall growth and reproduction, and on populations of corals as a whole.…”

Transcriptomic Resilience of the Montipora digitata Holobiont to Low pH

“…Other observed physiological changes triggered by low pH include impaired reproduction, growth and metabolic functions, and anomalies in skeletal morphology (Albright et al, 2008(Albright et al, , 2010Morita et al, 2010;Suwa et al, 2010;Albright and Langdon, 2011;Nakamura et al, 2011). Symbiosis can also be affected as coral bleaching can be triggered by ocean acidification (Anthony et al, 2008).…”