Meeting Abstract
Increasing dissolution of carbon dioxide in the surface ocean, the process of ocean acidification, is expected to incur overall negative effects on various marine organisms. Often, these impacts are sublethal, e.g., reduction in growth, calcification, and elevated per unit size metabolic rates. These effects are well-documented for the vulnerable, yet crucial, life history stage of the planktonic larvae of the sea urchins. However, these responses, especially in terms of body growth, are not uniform within a single family, between parental lineages, between populations of the same species, and between species. Our earlier work also showed that some larval urchins Strongylocentrotus purpuratus and other echinoids release blastula-like particles when exposed to low pH. One hypothesis is that delay in growth and the process budding/tissue shredding reduce the overall size of the larva, and hence, the total metabolic demand. By applying blastomere separation techniques, we tested if embryos of S. purpuratus of reduced-size were less affected by acidification. Our observations suggested that the relatively smaller twins (~80% of the unmanipulated embryos) were relatively less impacted by ocean acidification: the increase in oxygen consumption was smaller between the embryos reared under control (pH 8.0) and acidified (pH 7.3) conditions. Our results reinforce the notion that some organismal response, e.g., reduced growth and budding, could provide short-term advantages for survival under stressful conditions. However, such phenotypically plastic responses observed likely come at long-term developmental cost.
