title: Seasonal seawater temperature as the major determinant for populations of culturable bacteria in the sediments of an intact mangrove in an arid region.
abstract: Mangroves are highly productive marine ecosystems where bacteria (culturable and non-culturable) actively participate in biomineralization of organic matter and biotransformation of minerals. This study explores spatial and seasonal fluctuations of culturable heterotrophic bacteria and Vibrio spp. in the sediments of an intact mangrove ecosystem and determines the dominant environmental factors that govern these fluctuations. Sediment samples were collected monthly from three stations in the mangroves of Laguna de Balandra, Baja California Sur, Mexico, through an annual cycle. Physicochemical parameters included seawater temperature, salinity, and concentration of dissolved oxygen. Viable counts of culturable heterotrophic bacteria and Vibrio spp. were made. In one sample (March 2003), nutrient concentrations (ammonium, nitrites, nitrates, and phosphates), organic matter, pH and sediment texture were also determined. General cluster analyses, analysis of variance of specific variables, and several principal component analyses demonstrated that seawater temperature is the principal determinant of seasonal distribution of culturable heterotrophic bacteria and Vibrio spp. in mangrove sediments. Soil texture, concentration of nutrients, and organic matter concentration contribute to heterogenicity to a lesser extent. A large spatial variation in bacterial populations was observed over short distances ( approximately 1 m) in sampling areas within the same site. These analyses show that the culturable bacterial distribution in sediments of mangroves has high spatial and temporal heterogeneity.
authors.affiliation: Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Mexico City, Mexico.
authors.forename: Barbara
authors.initials: B
authors.lastname: Gonzalez-Acosta
authors.forename: Yoav
authors.initials: Y
authors.lastname: Bashan
authors.forename: Norma Y
authors.initials: NY
authors.lastname: Hernandez-Saavedra
authors.forename: Felipe
authors.initials: F
authors.lastname: Ascencio
authors.forename: Gustavo
authors.initials: G
authors.lastname: Cruz-Agüero
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000254:growth & development*; D044822:Biodiversity; D015169:Colony Count, Microbial; D017753:Ecosystem; D019015:Geologic Sediments / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D008800:Mexico; D009566:Nitrates / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D009930:Organic Chemicals / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D010710:Phosphates / Q000032:analysis; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D012492:Salts / Q000032:analysis; D012621:Seasons; D012623:Seawater / Q000382:microbiology*; D013696:Temperature; D014733:Vibrio / Q000235:genetics / Q000254:growth & development; D014871:Water Microbiology
chemical_list: D009566:Nitrates; D009573:Nitrites; D009930:Organic Chemicals; D010710:Phosphates; D000644:Quaternary Ammonium Compounds; D012492:Salts; D010100:Oxygen