the translation of these terms may cause some confusion - in fact, while technically 'lagoas' translate as 'ponds', in rio all lagoas are lagoons and even when the technical definition might be different, all these formations are referred simply as 'lagoas', no matter the size or characteristics.  

for visitors interested in a close-up look to amazing nature and perhaps even a glimpse at some alligators (jacarés) the company ecobalsas rio, based at avenida das américas, 700, barra da tijuca, specializes in taking visitors on the lagoas of barra, such as the lagoa da tijuca and lagoa de marapendi - the service can be contacted via email on this link, by calling 21 2132.8053, or via the website on this page. 

a great aerial video showing the system of lagoons in this western region or rio de janeiro can be seen on this page.