Background. Increases in oceanic temperatures are expected to affect the cellular function of ecologically important organisms, such as sponges. Sponges are important to biodiversity, coral reef systems, benthic and spongiverous organisms, and the biomedical industry. Sponges can repair wounds (regeneration) and rebuild their body from separated cells (reaggregation). The rates of regeneration and reaggregation can serve as a proxy for cellular functions. These processes are important to sponge physiology, growth and competition in reef systems. This study will examine how temperature affects the regeneration and reaggregation of Haliclona reniera.
Methods. This study considered the effects of temperature on growth and reaggregation. Percent of reaggregation was measured in a range of temperatures (4-34˚C) for 15 minutes and analyzed using imageJ software. Regeneration rates of wounded sponges were measured in fluctuating (28-32˚C & 28-34˚C) and non-fluctuating (28˚C and 32˚C) oceanic temperatures. The depth and size of H. reniera was measured with transects.
Results. Through observing growth and aggregation rates in a variety of temperatures, this study showed that sponges exposed to average fluctuations at 1m (28-32˚C) had higher regeneration rates than those exposed to high fluctuations (28-34˚C) at 0.5m. Wounded sponges regenerated faster in higher temperatures (32˚C) than in lower temperatures (28˚C). Aggregation cells fit a temperature performance curve with a peak at 29.5˚C, or just above average oceanic temperatures (29˚C). H. reniera was most commonly found at depths of 1m.
Discussion. Although coral and other organisms may be greatly affected by oceanic warming, sponges may persist, depending on how oceanic temperature will fluctuate in the future. H. reniera repaired wounds faster in average temperature with normally occurring fluctuations and aggregated most frequently at temperatures slightly above average (29.5˚C). With IPCC predictions of increased oceanic temperatures and fluctuations, H. reniera may not have ideal oceanic conditions, but will still endure these conditions. With coral reefs affected by climate change conditions, many organisms may die off, perhaps transitioning coral reefs into sponge reefs.