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290S. MEDEANIC & I. C. S. CORREATable I. Indicative values of palynomorphs encountered in the Holocene lagoon sediments in the coastal plain of RioGrande do Sul for paleoclimatic reconstructions.Palynomorphs Distribution Palaeoclimatic implicationsPollen and spores of terrestrialand aquatic vascular plantsMICROALGAEDinoflagellate cystsPrasinophycean phycomataChlorophytaBotryococcusSpirogyra, Pediastrum,Zygnema, MougeotiaPseudoschizaeaFUNGIGlomusTetraploaHyphaeSCOLECODONTSPALYNOFORAMINIFERSAll ecosystems of the coastalplainsThe oceans and the seasThe oceans and the seasFreshwater-brackish waterenvironmentsFreshwater fluvial, lacustrineenvironmentsGrow at the edge of streamsand in pondsPrincipal plant in the coastalplain that fix and supportdunesSporadically in salt andbrackish-water marshesNumerous hyphae in organicrich sedimentsSalt marshes and beachesOceans and seasIncrease in frequency, abundance and taxonomicvariety from the lagoon samples indicate onaugmentation of fresh-water input into lagoons (morehumid climate)Increasing of marine water influence(transgressions) occurred as a results of temperatureriseIncreasing of marine water influence(transgressions) occurred as a results of temperatureriseBrackish-water lagoon environments, increasingin the past was connected with drier climateSignificant freshwater input into lagoons mayserve as indicator of humidity increaseSignificant freshwater input into lagoons mayserve as indicator for humidity increaseIncrease in frequency in lagoon sediments maybe indicative for the shallow lagoons and an proximityof the coast indicative for drier climateSalt and brackish-water marshes and mangrovesIndicative of humid and warm climate,freshwater input during pluvial periods and transportby riversIndicators of shallow water basins, the beaches,showing the coast proximity to the lagoons occurredwhen climate changes became drierSea level rise (transgressions) caused bytemperature increasepalynomorphs, resistant to destruction and importantfor palaeoenvironmental reconstructions have beenrecently reported (Jarsen & Elsik 1986, van Geel &Aptroot 2006).Use of fungal palynomorphs for the elevatedsalinity environments of the coastal plains, spreadinthe Quaternary, has not been sufficientlyelaborated yet. The abundance and taxonomicvariability of mycorrhizic Glomus and itsimportance for dune stabilization was shown byCordazzo & Stümer (2007), who studied Glomus inthe roots of Panicum racemosum, a species that fixesand supports dunes. Limaye et al. (2007) registeredan increase in Glomus in the sediments, formedduring the Late Glacial Period of the Pleistocene inIndia, related to active erosion processes under a dryand continental climate. Fungal palynomorphs ofTetraploa are common in the salt and brackish-watermarshes of coastal plains (Medeanic et al. 2001,Limaye et al. 2007).Figure 1. Map of the coastal plain of the Rio Grande doSul State, Brazil, with the location of the core-drillingsites.Pan-American Journal of Aquatic Sciences (2010), 5(2): 287-297