Imagine a coastline where one of every ten of the species that live on the seabed may be new and totally unknown to science. A coast with such as yet unexplored wealth of benthonic fauna, the technical name given to mollusks, crustaceans, worms and other beings that inhabit the bed of the oceans, actually does exist and is not so far away as all that. It is the portion of the north coast of São Paulo, in the municipalities of São Sebastião, Caraguatatuba and Ubatuba, some three hours away from the city of São Paulo by car.
Concealed in the sand of the beaches, incrusted in the rocks of the wild seaboard, or simply hidden in the depths of the sea, some are beautiful and unique, others may even cause fear, like the Diopatra cuprea worm. They have probably been there, one step from being discovered by man, for time immemorial. All that was missing was someone with good luck and disposition to turn over the sands and coastlines at the right moment and place. This someone is the researchers from FAPESP’s thematic project that aims to map the biodiversity of the benthonic marine fauna present off the São Paulo coast, coordinated by Antonia Cecília Zacagnini Amaral, from the Biology Institute (IB) of the Campinas State University (Unicamp).
After carrying out extensive collections between January 2001 and December 2002 at stretches of the coastline of these three cities, almost always at spots which had not yet been a target for exploratory work in the past, the researchers on the project halted the fieldwork and went off to analyze what they had caught. Up until now, they have managed to clock up 535 different species, amongst which some with such an intriguing aspect as the reddish colonies of Symplegma rubra tunicates, beings that look like little bubbles stuck to rocks or cliffs, and the sea serpent Amphiodia riisei, an echinoderm that belongs to the same taxonomic group as starfish.
In the midst of this half a thousand distinct species cataloged, 52 were identified as being new to science. They are beings that have never been described before in any place in the world by the literature specialized in benthos. Hence the proportion of one new species of bethonic fauna for every ten identified on the north coast of São Paulo, the impressive figure mentioned at the beginning of this article.
“And take note that these figures refer to only 30% of the samples collected,” explains Cecília. “The other 70% are still being studied.” In terms of size, 40 of the 52 species belong to the so-called meiofauna. They are animals that are held back in a mesh of 0.05 millimeters. The other 12 new species are representatives of macrofauna, large sized animals.
Among the 52 new species, there are some interesting discoveries, above all for those who work with taxonomy. For example, they caught five varieties of D. cuprea, an annelid worm from the same group as the earthworm, that can reach a length of 15 centimeters and a width of 8 millimeters, and which was identified for the first time over 200 years ago. Each one of these varieties, in spite of being very similar, is actually a different species, which will be described in minute detail by a specialist in this kind of marine animal.
For those who do not have trained eyes and find D. cuprea in the sands of the beaches, the five varieties are regarded as the same. “The most impressive thing is that these five species were found in just one stretch of the São Paulo coastline,” says Cecília. “Imagine how many there may be on the whole Brazilian coastline.” Fortunately, a few specimens of these diversified crawling beings, like Eunice sebastiani, used as bait for fish, escaped the fishermen, but not the collections of the researchers.
The novelties of the project are not limited to the identification of species that are new to science. The fieldworks on the beaches, seaboards and on the bottom of the sea (up to a maximum depth of 45 meters) in São Sebastião, Caraguatatuba and Ubatuba recorded for the first time on the Brazilian coast five families and 28 species of marine benthos whose existence had never been corroborated on Brazilian soil. They were species that were known to exist abroad, but not here. Following a line that was less academic and more applied, in which the knowledge generated may have some impact on the local communities, the team headed by the biologist from Campinas State University (Unicamp) began to analyze more and more at length the most abundant varieties of mollusks, crustaceans and marine worms in the region. The basic idea behind this effort for more practical ends is to understand how and where these abundant populations of marine benthos live and what exactly is their interaction with the environment.
Possibility of cultivation
Amongst the species gathered more frequently, some may have an economic interest, perhaps even capable of commercial exploitation, such as the unprecedented banks of Mytella charruana, a kind of mussel (called sururu in the northeast) that were located by the scientists at spots on the north coast. The Tivela mactroides mollusk, with its gray shell from which an edible shellfish is extracted, is another example of a resource with economic potential. “A student on the project is going to study specifically the biology of this species, to see whether it is possible to cultivate it industrially,” says Cecília. Other equally abundant species are labeled by the researchers as bioindicators.
Their occurrence in a place signals some aspect of the ruling environmental conditions there. This is the case of Capitella capitata, present in large quantities in the bay at Caraguatatuba, according to the samples picked up for the project. Of a reddish color, this worm, which can reach a few centimeters in length, is a typical presence in sand located close to areas where household sewage is spilled out.
On rocky coastlines, an exotic species called Isognomon bicolor, probably introduced to the Brazilian coastline by means of the ballast water of ships, seems to be competing for, and occupying, the space of native species, such as one of the species of mussel commercially exploited, the Perna perna. According to the project’s coordinator, this is something that may bring about the extinction of mussels locally, which will have socioeconomic consequences. The only venture aimed at the study of marine fauna to be part of Biota/FAPESP, a program that is carrying out a detailed mapping of all the diversity of plants and animals that there are in the state of São Paulo, the project on benthos also enjoys the participation of researchers from another two universities from São Paulo, the University of São Paulo (USP) and Unesp (São Paulo State University), besides collaborators from other states and even from abroad.
“If there weren’t any specialists in a given species here, we wouldn’t hesitate to look for someone abroad to help us,” Cecilia explains. To assist the work of other colleagues who may come to study the marine fauna that inhabit the seabeds, the team of researchers is drawing up a manual to identify benthos found off the São Paulo coastline. Cards that describe 110 of the more than 500 species cataloged are now ready.
Benthic Marine Diversity in the State of São Paulo (nº 98/07090-3); Modality Thematic project; Coordinator Antonia Cecília Zacagnini Amaral – Unicamp; Investment R$ 2,500,000.00