Mudanças climáticas: efeitos deletérios da temperatura no desenvolvimento embrionário do ouriço-do-mar Echinometra lucunter (LINNAEUS, 1758)

Abstract

The climate it’s a physical component of Earth, with extreme complexity. It has origin from internal and external agents who interact to form a dynamic system, which results in patterns with great variability in spatial and temporal ranges around the globe. In view of the fact of intensification of these processes, understand the negative effects of the climate changes and the temperature warming over the organisms take a crucial role. In our work, we investigate experimentally the influence of temperature in the initial developmental stages of the sea urchin Echinometra lucunter, from Seixas beach in João Pessoa/PB. In our tests, embryos were exposed in different experimental temperature ranges (20 ºC – 36 ºC, degree per degree), where it’s was evaluated the synchronicity showed between the embryos from different experimental groups, characterized mainly for the distribution of the embryos in the different embryonic stages. In our results, we can confirm that E. lucunter responds to temperature changes in some low ranges, about ± 2 ºC in relation to the optimal temperature for development (28ºC). The embryos presented significant differences in the development rate, and additionally manifesting patterns, which corroborates with results in other organisms groups, on which we can see two patterns: a) increase in development rate in response to warming. b) Delaying of development in lower temperatures. We were able to confirm that specie response stronger to low temperatures than high temperatures, although, tolerates low range over the optimal range. We can still assume that upper limit to development, around 36 ºC, its an absolute superior limit, making it impossible the development in the early moments after the fertilization. The lower limit (20 ºC) aren’t capable to completely stop the development. Additionally, the climatic data bring evidences to relations between the environmental temperatures, from the occurrence areas for these animals, reproduction seasons and optimal developmental temperatures, allowing infer yet that environmental temperature can have high influence over the dynamics population for this specie. The possible climate changes scenarios and the future possibilities to increase of 2 ºC and 4 ºC until 2100, can change the regional climatic component with real possibilities to affect the development of the specie in Brazilian coast, resulting in spatial and temporal changes of animals parameters to adequate temperature ranges. With important involvement in traits, with changes on the range shift and existence of this specie in Brazilian ecosystems. The results presented here contribute to understanding the dynamics of interactions between the embryonic stages of the specie Echinometra lucunter in face of temperature variations, and actual and future conditions in the Brazil coast, and contribute to the understanding of current risks in the future climate change scenarios and its results on marine biological components, mainly from tropical origin.