Beginning today, Dr. Al Dove of Deep Type Flow will be floating somewhere of the coast of Brazil exploring the Abrolhos reef platform. They will be using the Johnson Sea Link, the tragically mothballed US submersible once described as “a shining legacy of deep sea research“, which has been granted a second life under long-term contract with CEPEMAR Environmental Services. Follow along with the adventure at Deep Type Flow or under the twitter hashtag #Abrolhos2011.
The Abrolhos are completely unique reefs: they’re the largest and southernmost in the South Atlantic and biologically very different from perhaps more familiar Pacific or Caribbean Reefs. You’d think they might show some similarity to Caribbean reefs, but not so, possibly because unfavourable currents and the influence of the Amazon pouring into the ocean between the two may serve as an important barrier to animal dispersal (more on that in future posts). There’s tremendously high endemicity there, which is to say that many of the resident critters are found nowhere else in the world. Of key importance is the main reef-forming coral Mussismilia braziliensis, a massive species that forms an unusual bommie-like reef structure called a mushroom reef; we’ll meet this species in more detail later too.
The main aim of the expedition is actually to go a bit deeper than the known parts of the Abrolhos, and look at the depths where light starts to get dim: the mesophotic zone. These parts of many reef platforms are poorly known and nowhere moreso than at Abrolhos, where these areas are completely unexplored. That’s because mesophotic reefs are beyond comfortable SCUBA diving range and therefore hard to get to. To study them between 300 and 3,000ft in depth, we’ll be using the Johnson Sea Link, a submersible that operates from the R/V Seward Johnson, which is on a 5 year assignment from it’s home at Harbor Branch Oceanographic Insitute to CEPEMAR, a Brazilian environmental services company.