Although the quality of the spermatozoa is a key factor for reproductive success, there is few information describing the sperm quality for most marine invertebrates, especially corals. Given the high mortality rates and several threats currently faced by coral reefs, ways of assessing coral spermatozoa viability are needed. Thus, in this study we proposed a morphological classification for coral spermatozoa using Mussismilia harttii as model. In addition, we evaluated the relationship of morphology with the percentage and duration of motility. Spermatozoa were first classified into two main morphological categories: normal and abnormal. Then, we classified morphological abnormalities in the head and flagellum together with proposing subcategories that better described it. In general, 68.77 ± 6.50

Bleaching events are becoming more frequent and intense worldwide. Southwestern Atlantic corals are considered stress-tolerant species that suffer less during bleaching episodes. Therefore, we investigated if the reef-building corals Mussismilia hispida and M. harttii are capable of spawning while fully bleached. We compared spermatozoa concentration and motility, egg diameter and embryo viability between seemingly healthy and bleached colonies for both species. Findings show that both species spawned viable gametes. Concentration and motility of newly-released spermatozoa were similar between healthy and bleached colonies for both species. Unlike M. hispida, a 10% reduction in size was found in egg diameter for M. harttii. Embryo viability for bleached M. hispida colonies did not decrease; for bleached M. harttii there was a reduction from 14.7 to 6.3%, but fertilization and larval development still took place. These findings describe the unprecedented episode of corals spawning viable gametes when entirely bleached, supporting the suggestion of greater resilience for Southwestern Atlantic corals.

O presente ensaio levanta algumas reflexões pontuais sobre o tempo corrente. Para tanto, toma-se, aqui, como mola propulsora os registros imagéticos e discursivos que compõem a série “Bucólico Marginal” (2020), dos artistas Esther Almeida e Luis Maria – que vieram à público recentemente através da exposição virtual “Do escuro do nosso tempo”.