5.5 Wednesday, Jan. 4 The effects of temperature on the developmental energetics of a sea urchin with indirect larval development WHITEHILL, E.A.G.*; MORAN, A.L.; Clemson University; Clemson University email@example.com
The early life history stages of marine invertebrates are strongly affected by temperature, and these effects can carry over into juvenile and adult stages. Rearing temperature affects many physiological processes within the animal, which can lead to differences in growth and energetic efficiencies though the extent of this phenomenon - and the underlying mechanisms - are poorly understood. We assembled energy budgets for marine invertebrate larvae raised at different temperatures to determine if rearing temperature affects larval energetic efficiency and larval and juvenile quality. Larvae of the sea urchin Lytechinus variegatus were reared through metamorphosis at 23, 27, and 30°C (±1°C). Larvae grew faster when reared at higher temperatures but larvae reared at higher temperatures were smaller at comparable developmental stages. High-temperature larvae also contained less protein and lipid and had higher rates of oxygen consumption. Overall, when summed across development, larvae at high temperatures used more oxygen, excreted more ammonia, and consumed fewer algae during the larval phase than larvae at low temperatures. Juveniles resulting from larvae reared at higher temperatures were smaller and experienced greater mortality. The data suggest that higher rearing temperatures result in smaller larvae that contain fewer nutrient reserves and poorer-quality juveniles. These data also indicate that these larvae and juveniles may follow the temperature-size rule due to a combination of greater energy expenditures and lower energy intake at higher temperatures during the larval period.