Influência de Estressores Associados às Mudanças Climáticas no Desenvolvimento Larval de Platynereis dumerilii (Annelida: Nereididae)

Abstract

Changes in oceanic patterns driven by global climate change have especially affected the early life stages of marine organisms. Considering the scarcity of knowledge regarding the early development of annelids under the effects of climate change and their susceptibility, the present study aims to evaluate the isolated and synergistic effects of temperature and salinity on early development, survival, and the occurrence of morphological abnormalities in Platynereis dumerilii larvae. Three laboratory experiments were conducted: (i) salinity, with treatments of 35 (control), 30, and 25 at 18 °C; (ii) temperature, with treatments of 18 °C (control), 25 °C, 30 °C, and 35 °C at a constant salinity of 35; and (iii) a synergistic experiment, with seven combinations between 18 °C and 35 °C and salinities of 35, 30, and 25. The larvae were obtained through spontaneous fertilizations synchronized with the lunar cycle. Larval development was monitored up to the nectochaete stage. The results indicated that moderate temperatures (25 °C and 30 °C) accelerate development, while reduced salinities (25) cause significant delays and an increase in the incidence of morphological abnormalities. Exposure to 35 °C resulted in total mortality, suggesting a thermal limit for the species. In the combined treatments, moderate conditions favored development, while extreme combinations (35 °C/25) were lethal. The findings contribute to advancing knowledge on the responses of soft-bodied marine invertebrates to climate change, particularly within the phylum Annelida, an area still underexplored compared to studies on calcifying organisms and may serve as a reference for future experimental studies.