Distribution of Microbial Communities Associated with the Dominant High Marsh Plants and Sediments of the United States East Coast

Abstract

Microbial communities in the sediment and associated with the dominant type of standing dead plant were collected from the high marsh zones of 10 sites along the eastern coast of the United States from Maine to Florida. Microbial community composition was examined using T-RFLP, and bacterial and fungal abundance was determined microscopically. Within the sediment, community composition was strongly correlated with latitude, indicating that biogeographical factors are important determinants of sediment community composition, whereas abundance was positively and strongly correlated with sediment organic matter content. A strong biogeographical effect was observed for both bacterial and fungal abundance on standing dead plants, but there was no clear relationship between community composition and latitude. Microbial community composition was more similar among plants of the same type (i.e., related plant species) suggesting that plant type (i.e., substrate quality) is primarily responsible for the determining community composition on standing dead plants.

Patterns of fungal diversity and composition along a salinity gradient

“…Most of what is known about how biodiversity varies along environmental gradients stems from research on plants and animals, although recent studies suggest that microorganisms may exhibit similar gradient patterns. Within the bacteria, for instance, diversity and composition appear to vary along gradients of primary productivity (Horner-Devine et al, 2003), latitude (Blum et al, 2004;Yergeau et al, 2007), disturbance (Johnsen et al, 2001;Muller et al, 2001), climate (Yergeau et al, 2007) and salinity (Blum et al, 2004;Crump et al, 2004;Bernhard et al, 2005Bernhard et al, , 2007. However, even less is known about the variation of fungal diversity and composition along similar gradients.…”

Ecosystem structure in disturbed and restored subtropical seagrass meadows

“…Fill sites were characterized by a near absence of organic matter in the top 10 cm, which is not surprising given that the fill material was created from mined limestone. Organic matter content is an important determinant of microbial community structure in terrestrial systems (Sessitsch et al 2001;Girvan et al 2003;Blum et al 2004), and our results support this relationship for seagrass ecosystems. Microbes mediate the remineralization of organic matter in marine sediments.…”

“…For example, soil structure (Sessitsch et al 2001;Girvan et al 2003;Chau et al 2011), nutrient content (Ramirez et al 2010), pH (Fierer & Jackson 2006;Tripathi et al 2012), biogeographical factors (Blum et al 2004;Hartman et al 2008), sediment organic matter content (Blum et al 2004), and the presence and composition of vegetation (Nacke et al 2011) have all been shown to be important in structuring microbial communities in terrestrial ecosystems. In aquatic systems, changes in microbial abundance and diversity are correlated with redox potential and pH differentials associated with soil depth (Sørensen et al 2007;Hartman et al 2008).…”

Efeitos ambientais da disposição oceânica de esgotos por meio de emissários submarinos: uma revisão

“…A colonização, composição e atividade dos microrganismos presentes nos sedimentos são influenciadas, entre outros fatores, pela granulometria e pela quantidade e qualidade da matéria orgânica presente 87 . Grãos maiores e mais angulosos favorecem a colonização por microrganismos; aumentos na quantidade e na qualidade de matéria orgânica estão correlacionados a aumentos da densidade e da biomassa bacterianas 88 .…”

“…Grãos maiores e mais angulosos favorecem a colonização por microrganismos; aumentos na quantidade e na qualidade de matéria orgânica estão correlacionados a aumentos da densidade e da biomassa bacterianas 88 . Alterações na composição específica de bactérias também foram relacionadas com mudanças na qualidade nutricional dos sedimentos 87 . Desse modo, as modificações causadas nos sedimentos pelo despejo de efluentes domésticos por emissários submarinos, como diminuição da textura, aumento da quantidade de matéria orgânica e alteração da qualidade do sedimento, também devem ser levadas em conta, uma vez que afetam a estrutura e o papel da microbiota desses ambientes, fazendo com que processos importantes, como a transferência de matéria aos organismos bentônicos e a decomposição de matéria orgânica, não sejam tão eficientes comparativamente a regiões não impactadas 67 , o que afeta todo o ecossistema.…”