Trace metal accumulation in mangrove sediments is of increasing global concern, as contaminants can easily remobilise to surrounding environments through a range of sediment geochemistry processes. Such processes are driven by various physical or biological disturbances, which tend to remobilise metals profligately. The present study aimed to investigate the effects of mangrove removal activities on trace metal concentrations in temperate mangrove sediments and adjacent mudflats. To understand patterns of trace metal mobilization due to the removal of mangroves, we measured levels of Fe, Cu, Zn, Pb, and Cd along with other sediment parameters (organic matter, pH, bulk density) during pre- and post-mangrove removal activities. Sediment cores from three different depths down to 30 cm were collected from the mangrove removal location and adjacent mudflats at Mangawhai Harbour Estuary, New Zealand, during pre/post-removal sampling events over a four-year period. Results indicate that levels of OM and trace metals were higher in mangrove sediments than adjacent mudflats, which is consistent with the inherent capacity of mangrove sediments to sequester trace metals. However, after the removal of mangroves, the levels OM and trace metals decreased in removal sites. During this period, we observed a decrease in OM and lower sediment pH levels, indicating an increase in sediment acidity which is associated with a lower sediment sequestering capacity. We also observed increases in trace metal concentrations in adjacent mudflats during the post-removal period, thus highlighting the far-reaching effects of mangrove removal activities. These findings provide important information to assist with future management strategies of temperate mangrove ecosystems.

红树林沉积物中的痕量金属积累越来越受到全球关注，因为污染物可以通过一系列沉积物地球化学过程轻松地转移到周围环境中。此类过程是由各种物理或生物干扰驱动的，这些干扰往往会使金属大量迁移。本研究旨在调查红树林去除活动对温带红树林沉积物和邻近滩涂中痕量金属浓度的影响。为了了解由于去除红树林而造成的痕量金属迁移的模式，我们在去除红树林之前和之后测量了Fe，Cu，Zn，Pb和Cd的水平以及其他沉积物参数（有机物，pH，堆积密度）活动。在四年的清除前/清除后采样活动中，从新西兰的Mangawhai港河口的红树林去除地点和邻近的滩涂收集了三个不同深度的沉积岩心，深度达30 cm。结果表明，红树林沉积物中的OM和痕量金属含量高于相邻的滩涂，这与红树林沉积物螯合微量金属的固有能力是一致的。但是，在去除红树林之后，去除位置的OM和痕量金属水平降低。在此期间，我们观察到OM降低和沉积物pH值降低，表明沉积物酸度增加，这与较低的沉积物螯合能力有关。我们还观察到在拆除后的期间，相邻泥滩中的痕量金属浓度有所增加，因此突出了红树林清除活动的深远影响。这些发现为重要的信息提供了有力的信息，有助于未来温带红树林生态系统的管理策略。