CYANOPHYCEAE / CYANOBACTERIA IN RED MANGROVE FOREST AT MOSQUITOS AND COQUEIROS ESTUARIES , SÃO LUÍS , STATE OF MARANHÃO , BRAZIL

This paper provides the results of a taxonomic survey of the Cyanophyceae/Cyanobacteria in a frenge red mangrove forest in the estuaries of Estreito dos Mosquitos and Coqueiros, São Luís, State of Maranhão, Brazil. A total of 15 taxa were identified in 8 families, as follows: Synechoccaceae (2), Chroococcaceae (1), Hyellaceae (1), Xenococcaceae (1), Oscillatoriaceae (1), Scytonemataceae (2), Phormidiaceae (5) and Pseudanabaenaceae (2). The species listed in this paper are all new descriptions for Maranhão, and one of them is a new ocurrence for Brazil.


INTRODUCTION
According to Dor (1984), the main focus of papers on mangrove associated algae has been on "Bostrychietum", the species communities belonging to the genera Bostrychia, Catenella and Caloglossa.It is interesting to notice that studies of blue-green mangrove algae are usually secondary objectives on mangrove algae research worldwide (Branco, 1991).
Taxonomic studies on the Cyanophyceae are very scarce and limited to Dor (1984), who studied the vertical zonation and morphological adaptations of the epiphytic blue-green algae found at Sinai Estuary's mangroves and Lambert et al. (1989), who reported 27 taxa of blue-green algae and their relative abundance (in different substracts), for South African mangroves.
There is a total lack of knowledge on the phycological flora in frenge red mangrove forest.Regarding the taxonomy of the Cyanophyceae, no studies on estuarine mangrove environments, such as those of Maranhão, have been published.
This paper provides the results obtained from a qualitative study of the Cyanophyceae growing on Rhizophora dominated mangroves at Mosquitos and Coqueiros estuaries, in the Maranhão State, Brazil.

MATERIAL AND METHODS
The Mosquitos strait separates São Luís Island from the continent.This strait is 5 km long and 104 m wide, extending from Southeast to Northwest, and linking the Arraial Bay with São Marcos Bay.The coordinates are latitude 2 o 38'12''S and longitude 44 o 23'35''W (Fig. 1).
Two sampling areas were chosen, and in each one, a vertical transect (seaward landward) was established.Along the transects, stations were marked at 100 m intervals, and samples collected every 10 m.Algae were collected by scrapping the trunks and roots of Rhizophora mangle L, where they usually grow.
In each area, five points were taken, and 12 samples were made from each one, totaling 60 samples from the Mosquitos strait, and also 60 samples from the Coqueiros strait.
Samples were stored in polietilene bottles and preserved in 4% formaldehyde solution.They were finally deposited in the Biology Herbarium (HDB) of the Federal University of Maranhão.
The distribution of the species in Brazil, is presented by states.
Comments: Acording Komárek & Anagnostidis (1999), Aphanothece castagnei does not occur in aquatic biotops; this statement has made the accurate identification of the species more difficult.However, the material studied showed the same habitat conditions as described by Branco et al. (1996), in Rio de Janeiro and São Paulo States: plant massed formed on the mud accumulated on plantlets.
Comments: Material perifytic, living on mangrove macroalgae.Komárek & Anagnostidis (1999) stated that material from marine water or mangrove are questionable and need confirmation.
Because of this, the specimen studied could not be acurately identified.
Comments: The material was not identified at the specific level because it was insufficient, so it was impossible to measure it.Xenococcaceae Xenococcus Thur. in Born.et Thur.1880.X. pyriformis Setch. et Gardn. in Gardn. 1918.University of California Publications in Botany, 6:436, 1918. (Figs. 7 and 9) Colonies small, shining, blue-green, singular or occasionally coalescent, 9.0-11.0mm long, 5.4 mm diameter; sheath conspicuous, dense, hyaline; cells slight angular when young, and pyriforms subsphericals when adult; same bacocyte angle and size for all cells, gonads formed by successive divisions.
Comments: The material wasn't deposited in herbarium because it was insufficient.
Comments: This species was not identified with accuracy because of the diameter of trichomes.Our material presents trichomes with diameter higher than the studied by Desikachary (1959) but, it occur in the same habitat, estuary water.
The material was not deposited in the herbarium because it was insufficient.
Material examined: Coqueiros Estuary.Distribution in Brazil: reported for the first time for Brazil.
Comments: The material was not deposited in the herbarium because it was insufficient.
Among the species identified, Leptolyngbya crosbyanum Tilden is reported for the first time for Brazil, and the other fourteen (14) species are cited for the first time for Maranhão.The species occurring in most of the samples were Scytonema insulare Sant'Anna, Scytonema arcangelii Bornet et Flahault, Microcoleus chthonoplastes Thuret ex Gomon, Leibleinia pellucida (Umezaki) Branco, SantAnna, Azevedo & Sormus e Pleurocapsa sp.