Diatoms From Shallow Lakes in the Pantanal of Nhecolândia, Brazilian Wetland

Abstract

The diatom flora of the shallow lakes in the Pantanal of Nhecolândia is poorly known. Thus, our aim was to know the diatom biodiversity in three types of shallow lakes called "baías, salitradas and salinas", characterized by differences in pH, electrical conductivity, contact with the coalescent system and the presence of macrophytes. The samples were collected in dry and rainy seasons, from 2004 to 2007. For taxonomic identification, the material was cleaned with H 2 O 2 and analyzed using light microscopy. A total of 23 diatom species were identified and each lake presented a unique species richness and composition. The greatest species richness was found in the Baía da Sede Nhumirim (21 species), followed by the Salitrada Campo Dora (8 species) and finally the lowest species richness was observed in the Salina do Meio (3 species). Only Anomoeoneis sphaerophora Pfitzer var. sphaerophora and Craticula cf. buderi (Hustedt) Lange-Bertalot occurred in the three studied systems. Except for Eunotia binularis (Ehrenberg) Souza and Aulacoseira ambigua (Grunow) Simonsen, all the others are new records to the Brazilian Pantanal. Keywords: biodiversity; brackish water; freshwater; tropical wetland. RESUMODIATOMÁCEAS DE LAGOS RASOS DO PANTANAL DA NHECOLÂNDIA, ÁREA ÚMIDA BRASILEIRA. A flora de diatomáceas dos lagos rasos do Pantanal da Nhecolândia é pouco conhecida. Portanto, nosso objetivo foi conhecer a biodiversidade de diatomáceas que ocorrem em três diferentes tipos de lagoas denominadas de "baías, salitradas e salinas", caracterizadas por diferenças de pH, condutividade elétrica, contato com o sistema coalescente e presença de macrófitas. As amostras foram coletadas nos períodos de cheia e de seca, durante os anos 2004 a 2007. O material foi submetido à limpeza com água oxigenada (H 2 O 2 ) e analisado ao microscópio óptico para se proceder à identificação taxonômica. No total foram identificadas 23 espécies de diatomáceas e cada lagoa apresentou riqueza e composição de espécies distintas. A maior riqueza de espécies foi encontrada na Baía da Sede Nhumirim (21), seguida da Salitrada Campo Dora (8) e a Salina do Meio apresentou a menor riqueza de espécies (3). Somente Anomoeoneis sphaerophora Pfitzer var. sphaerophora e Craticula cf. buderi (Hustedt) Lange-Bertalot foram comuns aos três sistemas estudados. Com exceção de Eunotia binularis (Ehrenberg) Souza e Aulacoseira ambigua (Grunow) Simonsen, as demais espécies são citadas pela primeira vez para o Pantanal brasileiro. Palavras-chave: biodiversidade; água doce; água salobra; áreas úmidas tropicais. RESUMEN DIATOMÁCEAS DE LOS LAGOS RASOS DEL PANTANAL DENHECOLÂNDIA, ÁREA HÚMEDA BRASILERA. La flora de diatomeas de los lagos rasos del Pantal de Nhecolândia es poco conocida. Por lo tanto, nuestro objetivo fue conocer la biodiversidad de diatomáceas que ocurren en tres diferentes tipos de lagos rasos denominados de "baías, salitradas e salinas" caracterizadas por diferencias en el pH, la conductividad eléctrica, contacto con el sistema coalescente y la presencia ...

Structure and species composition of diatom community during the wet season in three floodplain lakes of Brazilian Pantanal

“…The highest number of Eunotiaceae were found in a marsh with a pH of 4.3 to 6.5, with EPAP a rare species found only at pH 4.8. Compared to the low diversity of Eunotia (2 species) found by Santos et al [ 45 ] for lakes in the Pantanal, with the majority of the lakes studied having alkaline waters, we can highlight that the highest occurrence of the genus in this study is actually due to more acidic environment.…”

“…Taxonomic studies contribute to the knowledge of biodiversity and provide the basis for the advancement of other approaches such as bioindication, environmental reconstruction, research on conservation and definition of priority areas such as the Pantanal, among many others. The more relevant works in the region are on the distribution of two species of diatoms and their association with the historical variation in water levels in the Paraná River [ 44 ]; the diatom flora in the Pantanal of Mato Grosso do Sul [ 45 ]; the history of the salinity in the southern Pantanal [ 46 ] and records of flood pulse dynamics [ 47 ]. Other studies, not related to diatoms, refer to the wetland carbon storage [ 48 ] and the influence that hydroclimatic variables exert on limnogeological processes [ 49 ].…”

Paleoecology explains Holocene chemical changes in lakes of the Nhecolândia (Pantanal-Brazil)

“…This extreme environment is unsuitable for aquatic macrophytes (Barbiéro et al, 2002). The presence of nonionizing forms of ammonia restricts biological diversity in the salinas (Mourão et al, 1988), except for alkaliphilic algae (e.g., certain diatom species), cyanobacteria, and archaea (de Santos & Sant'anna, 2010;de Santos et al, 2012).…”

“…Locally, the presence of the cordilheiras, which are vegetated sand ridges that stand 3-5 m above the lake surface, act as natural barriers to flood waters that drain the area during the austral summer. Both Soares et al (2003) and de Santos et al (2012) suggested that the isolation promoted by cordilheiras and the lack of surface water inflows are important controls on salina development. These processes are important to the completeness of late Holocene strata exhibited by some salinas, as flood water discharged across the surface of Lower Nhecolândia in vazantes can be erosive (McGlue et al, 2017).…”

Classificação dos Macrohabitat do Pantanal Brasileiro: Atualização para Políticas Públicas e Manejo de Áreas Protegidas

“…Figura 1 -A) Precipitação média mensal perto de Cuiabá (1933Cuiabá ( -1993 e nível d'água médio do rio Cuiabá em Cuiabá (1971)(1972)(1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988), norte do Pantanal (de acordo com Zeilhofer, 1996); e B) Precipitação média perto de Corumbá (1912Corumbá ( -1971 e nível d'água médio do rio Paraguai em Ladário (1979Ladário ( -1987 sul do Pantanal (de acordo com Hamilton et al, 1996). Fonte: Junk e Nunes da Cunha (2005). Os macrohabitat permanentemente aquáticos são representados pelos canais dos rios e lagos permanentes.…”