CO2 induced seawater acidification impacts sea urchin larval development I: Elevated metabolic rates decrease scope for growth and induce developmental delay

Abstract

Anthropogenic CO(2) emissions are acidifying the world's oceans. A growing body of evidence is showing that ocean acidification impacts growth and developmental rates of marine invertebrates. Here we test the impact of elevated seawater pCO(2) (129 Pa, 1271 μatm) on early development, larval metabolic and feeding rates in a marine model organism, the sea urchin Strongylocentrotus purpuratus. Growth and development was assessed by measuring total body length, body rod length, postoral rod length and posterolateral rod length. Comparing these parameters between treatments suggests that larvae suffer from a developmental delay (by ca. 8%) rather than from the previously postulated reductions in size at comparable developmental stages. Further, we found maximum increases in respiration rates of +100% under elevated pCO(2), while body length corrected feeding rates did not differ between larvae from both treatments. Calculating scope for growth illustrates that larvae raised under high pCO(2) spent an average of 39 to 45% of the available energy for somatic growth, while control larvae could allocate between 78 and 80% of the available energy into growth processes. Our results highlight the importance of defining a standard frame of reference when comparing a given parameter between treatments, as observed differences can be easily due to comparison of different larval ages with their specific set of biological characters.

Tolerance of Hyas araneus zoea I larvae to elevated seawater PCO2 despite elevated metabolic costs

“…This has been revealed by former studies on sea urchin larvae with continuous development (Stumpp et al 2011;Martin et al 2011), but to our knowledge, the present study is the first one on a species with discrete development. Larval age had a strong effect on all measured parameters in comparison with CO 2 .…”

“…This may result in decreasing whole animal oxygen consumption (Pörtner et al 1998;Michaelidis et al 2005) or, if compensated for by the rise in energy demanding processes (e.g. calcification), an increase in whole organism oxygen demand (Thomsen andMelzner 2010, Lannig et al 2010;Stumpp et al 2011) and an associated shift in energy budgets. So far, it is not known to what extent these patterns also hold for early life stages of crustaceans, which have to allocate considerable amounts of energy to growth and morphological changes and may be the more sensitive life stages under ocean acidification (Walther et al 2010).…”

Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis

“…Recent studies have measured increased metabolic costs associated with experimentally elevated seawater pCO 2 (Wood et al 2008;Stumpp et al 2011), more particularly suggesting energetic trade-offs that impact growth rate -a situation similar to that encountered in many echinoderm larval stages (see Dupont et al 2010for a review, Stumpp et al 2011. Active compensation for acidosis and hypercapnia did not induce measureable additive costs in subadult S.…”

Temperature modulates the response of the thermophilous sea urchin Arbacia lixula early life stages to CO2-driven acidification

“…It was hypothesized that the lecithotrophic life-history strategy (production of few energy rich eggs) allowed an increased growth following an increased in metabolism. On the other hand, under limiting energy conditions, an increased metabolism is associated with a reduced scope for growth as demonstrated in sea urchin larvae exposed to ocean acidification conditions (Stumpp et al, 2011). We can also hypothesize that under extreme stress, larvae are unable to compensate for the environmental challenge through increased metabolism and experience metabolic depression (Pörtner and Farrell, 2008).…”

“…Both increased temperature (e.g. Peck and Prothero-Thomas, 2002) and pH (Stumpp et al, 2011(Stumpp et al, , 2012 induce an up-regulation of larval metabolism. An increased metabolism under non-limiting energy conditions can translate into an increased scope for growth.…”