摘要
红树林是一种特殊的生物海岸类型,具有多种生态系统服务功能。以广东湛江高桥红树林湿地为研究区,在英罗湾的湾内和湾口的两片红树林集中分布区,沿水动力梯度,垂直于海岸布设两条样线进行柱状取样,并采用矩值法计算平均粒径、分选系数、偏度和峰度等粒度参数,分析了沉积物在水平和垂直方向上的粒度特征,旨在了解研究区红树林湿地生境演变过程。结果表明:1)沉积物以粉粒和砂粒组分为主,随着红树林发育成熟度和沉积过程,红树林内带和表层样点均呈细化趋势。2)粒度分布曲线可以看出,红树林外带更多受水动力条件的影响,样点沉积过程相似,内带的沉积因水动力条件和生物过程的影响而复杂,但白骨壤纯林的沉积环境相对稳定。3)粒度参数受水动力条件和生物地貌过程影响,空间异质性显著。水平方向上,湾内样线自内带向外表现为平均粒径变小(质地粗化)趋势,湾外样线平均粒径变化趋势性不明显,但有红海榄群落分布的中间带样点的粒度更细;沉积物分选性属于较差到差,频率曲线呈负偏到很正偏,峰度呈平坦到尖锐的分布。垂直方向上,自表层向下平均粒径减小、分选性变差、偏态值增加、峰态增加,反映出林下环境的沉积过程。4)相关性分析表明,粒度参数与不同粒级体积含量相关,平均粒径和峰度参数与黏粒、粉粒含量正相关而与砂粒含量负相关,分选系数和偏度与细颗粒物含量显著负相关。粒度参数之间的相关性表现为平均粒径与峰度正相关,而与分选系数和偏度负相关,分选系数与峰度负相关,偏度与峰度负相关。研究区沉积物的形成过程有多种作用共同参与,红树林的存在改变了海岸的水动力条件而影响沉积过程,研究结果对于了解百年尺度上红树林湿地的生物地貌形成过程具有一定意义。
Mangrove coast is a special type of biological coast and it provides a variety of ecosystem services. To understand the evolution of the habitat of mangrove wetland, sediment cores along a hydrodynamic gradient in the inner and outer gulf of Yingluo Bay, the grain size characteristics （average grain size, sorting coefficient, skewness and kurtosis） of the sediments in the horizontal and vertical directions were analyzed using the moment method. The results showed that the sediments were mainly composed of silt and sand components, the surface samples of mangrove zone showed a trend of refinement with thematuration and deposition process of mangrove forests. The grain size distribution curve showed that the outer mangrove was more affected by hydrodynamic conditions than inner mangrove. The deposition processes of inner zone and outer zone were similar. The inner deposition was complicated by the influence of hydrodynamic conditions and biological processes. However, the sedimentary environment of the pure stand of Avicennia marina was relatively stable. Grain size parameters were affected by the hydrodynamic conditions and biogeography processes, and spatial heterogeneity was significant. In horizontal direction, the average particle size of the inner sample line of the bay turned to be small （texture coarsening） from inside to outside. The average particle size of the outer samples showed no obvious trends but become finer in intermediate zone distributed with Rhizophora stylosa trees. The sediment segregation was poor to worse, the frequency curve was negative biased to positive bias, and the peak presented from fiat to sharp distribution. In vertical direction, the average particle size decreased from the surface to deeper layer, the separation became worse, the skewness increased, and the peak state increased too, reflecting the deposition process of the forest understory environment. The correlation analysis showed that the grain size parameters of the sediments were related to different volume levels, the average grain size and kurtosis parameters were positively correlated with the content of clay and grains, and negatively correlated with the sand content, the separation coefficient and skewness were negatively correlated with the fine particulate matter content. The average grain size was positively correlated with the kurtosis, but negatively correlated with the sorting coefficient and the skewness. The separation coefficient was negatively correlated with the kurtosis, and the skewness was negatively correlated with the kurtosis. A variety of roles were involved in the formation of sediment, and mangrove forests changed the hydrodynamic conditions of the coast, which affected the deposition process in turn. The results are significant to understand the biomechanical processes of mangrove wetlands on a century scale.
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2017年第11期9-17,共9页
Journal of Beijing Forestry University
基金
中央级公益性科研院所基本科研业务费项目(CAFYBB2014QB018)
国家自然科学基金项目(41306079
31100413)
关键词
红树林
湿地
沉积物
粒度
mangrove
wetland
sediment
grain size
