Faculty 2 Biology/Chemistry, Universität Bremen, Bremen, Germany.
Institute for Marine Research and Observation, Ministry of Marine Affairs and Fisheries, Negara, Bali, Indonesia.
Oecologia. 2021 Apr;195(4):843-858. doi: 10.1007/s00442-021-04865-3. Epub 2021 Feb 9.
Leaf litter and its breakdown products represent an important input of organic matter and nutrients to mangrove sediments and adjacent coastal ecosystems. It is commonly assumed that old-grown stands with mature trees contribute more to the permanent sediment organic matter pool than younger stands. However, neither are interspecific differences in leaf decay rates taken into account in this assumption nor is our understanding of the underlying mechanisms or drivers of differences in leaf chemistry sufficient. This study examines the influence of different plant species and ontogenetic stage on the microbial decay of mangrove leaf litter. A litterbag experiment was conducted in the Matang Mangrove Forest Reserve, Malaysia, to monitor leaf litter mass loss, and changes in leaf litter chemistry and microbial enzyme activity. Four mangrove species of different morphologies were selected, namely the trees Rhizophora apiculata and Bruguiera parviflora, the fern Acrostichum aureum and the shrub Acanthus ilicifolius. Decay rates of mangrove leaf litter decreased from A. ilicifolius to R. apiculata to B. parviflora to A. aureum. Leaf litter mass, total phenolic content, protein precipitation capacity and phenol oxidase activity were found to decline rapidly during the early stage of decay. Leaf litter from immature plants differed from that of mature plants in total phenolic content, phenolic signature, protein precipitating capacity and protease activity. For R. apiculata, but not of the other species, leaf litter from immature plants decayed faster than the litter of mature plants. The findings of this study advance our understanding of the organic matter dynamics in mangrove stands of different compositions and ages and will, thus, prove useful in mangrove forest management.
叶凋落物及其分解产物是红树林沉积物和相邻沿海生态系统中有机物质和养分的重要来源。通常认为，成熟树木的老龄林分比幼龄林分更有助于永久性沉积物有机物质库的形成。然而，在这种假设中没有考虑到不同物种间叶片分解速率的差异，也没有充分了解叶片化学性质差异的潜在机制或驱动因素。本研究考察了不同植物物种和个体发育阶段对红树林叶片凋落物微生物分解的影响。在马来西亚马当红树林保护区进行了一个凋落物袋实验，以监测叶片凋落物质量损失、叶片凋落物化学性质和微生物酶活性的变化。选择了四种不同形态的红树林物种，即 Rhizophora apiculata 和 Bruguiera parviflora 两种乔木、Acrostichum aureum 一种蕨类和 Acanthus ilicifolius 一种灌木。红树林叶片凋落物的分解速率从 A. ilicifolius 降低到 R. apiculata，再降低到 B. parviflora，最后降低到 A. aureum。在分解的早期阶段，叶片凋落物的质量、总酚含量、蛋白沉淀能力和多酚氧化酶活性迅速下降。未成熟植物的叶片凋落物在总酚含量、酚类特征、蛋白沉淀能力和蛋白酶活性方面与成熟植物的叶片凋落物不同。对于 R. apiculata，但不是其他物种，未成熟植物的叶片凋落物比成熟植物的叶片凋落物分解得更快。本研究的结果提高了我们对不同组成和年龄的红树林林分中有机物质动态的理解，从而将有助于红树林森林管理。
