This study, performed over the years 1999–2003, analyzed the species composition, spatial distribution and ecological aspects of macroalgal assemblages on Atol das Rocas reef, located 266 km off northeastern Brazil. It is the sole atoll in the South Atlantic and is almost completely built of coralline algae. Forty-seven new occurrences of macroalgae were recorded. Adding these to the previous studies, 143 taxa are now known for the local marine flora, with the Rhodophyta as the dominant group. New finds were mainly on the fore reef and in reef pools. The inner habitats (the reef flat, internal ridge and inner pools) harbored fewer macroalgal species than the outer habitats (the reef front, reef crest crevices and outer pools). Inner habitats are subject to prolonged desiccation and solar irradiation stress together with abrupt changes in temperature and salinity controlled by the water oscillations of the mesotidal regime within the atoll; the outer habitats are less affected by these short temporal impacts and are mainly governed by oceanic forcing. Atol das Rocas harbors some species unknown in other Brazilian waters, but these are common in Caribbean reef waters.
Major depressive disorder (MDD) is a highly prevalent and disabling condition for which the currently available treatments are not fully effective. Existing unmet needs include rapid onset of action and optimal management of concurrent agitation. Dexmedetomidine (DEX) is a selective and potent α2-adrenergic receptor (α2-AR) agonist, with unique pharmacokinetic and pharmacodynamic properties. In this review, we discuss pre-clinical and clinical studies which focused on DEX in the context of its putative antidepressant effects for the management of MDD. Preliminary data support DEX as an antidepressant with fast onset of action, which would be especially helpful for patients experiencing treatment resistant depression, and agitation. We further explore the mechanistic and clinical implications of considering DEX as a putative antidepressant agent, and the next steps to explore the efficacy of low dose DEX infusion among patients with treatment resistant depression.