Sánchez-Arias Luz Esther, Paolini Jorge, Rodríguez Jon Paul
Centro de Estudios Botánicos y Agroforestales, Instituto Venezolano de Investigaciones Científicas Regional Zulia, Maracaibo, Venezuela.
Rev Biol Trop. 2010 Jun;58(2):547-64.
Biochemical and microbiological properties of soils can provide information related to ecosystems environmental status. With the aim to determine the response of microbial biomass, and enzymatic and microbial activity in hypersaline (IS > or = 55 ups) and saline (IS<55 ups) mangrove soils exposed to interstitial salinities (IS) greater than 36 ups, these properties were measured in mono-specific forests of Rhizophora mangle at Laguna de la Restinga National Park (Margarita Island, Venezuela). During three seasons (dry, wet and transition), a total of 120 soil samples were collected from ten (5 hypersaline and 5 saline) randomly-selected sites of 1000 m2 each. Four soil samples (400-500 g) per plot were randomly collected with a corer at a depth of 10 cm using a 1 m2 quadrat; each sample consisted in the combination of 8 sub-samples (50-60 g ea.). Physical, chemical, enzymatic, biochemical and microbiological properties of soil samples were determined using standard laboratory protocols. The response of microbial biomass and microbial and enzymatic activity was analyzed taking into account spatial and climatic factors and interstitial salinity. Microbial biomass was linked to each locality conditions, and was not sensitive to seasonal or salinity differences. Microbial activity remained functionally active during the study period and presented variable responses. Dehydrogenase activity proved to be a good indicator for flooded and anoxic environments, and arginine ammonification resulted to be the more sensitive microbial activity to changes in salinity. Regarding enzyme activities, spatial variability was the most widespread response. We did not find a unique general pattern between enzymatic activities and spatio-temporal variation; and only the enzyme phosphatase was negatively affected by salinity. We conclude that microbial populations of mangrove soils and their activities have functional adaptations to flooded and highly-saline environments typical of a negative estuary, subjected to drastic changes due to weather and water dynamics. Future studies are needed to determine the relation between the "health" of mangrove forest and microbial populations, and their activities in mangroves soils.
土壤的生化和微生物特性能够提供与生态系统环境状况相关的信息。为了确定微生物生物量、酶活性和微生物活性在盐度大于36 ups的高盐（电导率≥55 ups）和盐渍（电导率<55 ups）红树林土壤中的响应情况，在拉古纳德拉雷斯廷加国家公园（委内瑞拉玛格丽塔岛）的红树单种林中对这些特性进行了测量。在三个季节（旱季、雨季和过渡季）期间，从十个（5个高盐和5个盐渍）随机选择的、每个面积为1000平方米的地点共采集了120个土壤样本。每个样地使用1平方米的样方，用取土钻在10厘米深度随机采集四个土壤样本（400 - 500克）；每个样本由8个亚样本（每个50 - 60克）组合而成。土壤样本的物理、化学、酶、生化和微生物特性使用标准实验室规程进行测定。考虑到空间和气候因素以及间隙盐度，分析了微生物生物量以及微生物和酶活性的响应情况。微生物生物量与每个局部条件相关联，并且对季节或盐度差异不敏感。在研究期间，微生物活性保持功能活跃并呈现出可变的响应。脱氢酶活性被证明是水淹和缺氧环境的良好指标，精氨酸氨化作用是对盐度变化最敏感的微生物活性。关于酶活性，空间变异性是最普遍的响应。我们没有发现酶活性与时空变化之间存在独特的一般模式；并且只有磷酸酶受到盐度的负面影响。我们得出结论，红树林土壤中的微生物种群及其活动对负河口典型的水淹和高盐环境具有功能适应性，由于天气和水动力的原因，这些环境会发生剧烈变化。未来需要开展研究以确定红树林森林的“健康”状况与微生物种群及其在红树林土壤中的活动之间的关系。
