Background:

The Parque Nacional Lagunas de Zempoala (PNLZ) is located in a transitional zone between the Nearctic and Neotropical regions, and harbors a great phycofloristic diversity. The lakes studied were Zempoala, Compila, To natihua and Prieta, and the stream that flows into Zempoala lake. With the exception of Zempoala lake, the others are studied for the first time.

Goals:

To study of phycofloristic composition of aquatic environments of the PNLZ.

Methods:

The samples (23) were collected in March-April 2011, using a towed net of 20 μm. Ten L of water were filtered and algae mixed with aquatic plants were collected. The samples were fixed with 4% formalin. Water temperature pH, and con ductivity were measured. Samples were observed under light microscopy (LM) and scanning electron microscopy (SEM).

Results:

The pH of the studied lakes was 7.1-8.8, the surface water temperature was recorded between 14.2-17°C and the conductivity varied between 112-124 μS cm-1. Fifty-five species were identified, with a dominance of Chlorophyceae (13), Cyanophyceae (12), Trebouxiophyceae (9), Euglenophyceae (7) and Zygnematophyceae (6). Some common blue-greens were Woronichinia and Planktolyngbya. Others such as Cryptomonas (Cryptophyta), Ceratium and Peridinium (Dinoflagellata) were abundant. Chlorophyta encompassed the entire study area (Scenedesmus, Eudorina, Botryococcus and Lagerheimia). They emphasize Staurastrum and Cosmarium (Charophyta). Three benthic genera Prasiola, Chara and Nitella were recorded in PNLZ. Other green algae grew as metaphytes and epiphytes. 39.3% of the species are cosmopo litan; others have tropical and neartic affinities. Ten new registries were determined for Mexico.

Conclusions:

Compared to other Mexican lakes, those studied here can be considered of high richness and diversity, particularly with respect to phytoplankton. The lack of knowledge and the disturbance of the continental aquatic environments, threaten the survival of the phytoplankton community, so it is important to integrate studies that include various areas of biology, as well as public policies for their management and conservation.