TropWATER, Centre for Tropical Water and Aquatic Ecosystem Research, College of Science and Engineering, James Cook University, Australia.
TropWATER, Centre for Tropical Water and Aquatic Ecosystem Research, College of Science and Engineering, James Cook University, Australia.
Mar Pollut Bull. 2021 Sep;170:112627. doi: 10.1016/j.marpolbul.2021.112627. Epub 2021 Jun 26.
The Reef 2050 Plan has identified a range of measures aimed at reducing end-of-catchment loads of sediment and nutrient and recognizes the role that freshwater wetlands may have in achieving this. However, quantitative information on the potential for tropical wetlands to filter agricultural runoff is scarce, so this paper describes a study that combines field data from a 10 ha wetland constructed on land previously used for sugar cane near Babinda, north Queensland with a water balance and denitrification model. During the 12-month monitoring period (from October 2017 to September 2018) we estimate that the nitrogen filtering capacity of the wetland was 52% (26% lost as gaseous denitrification from the water and soil, and 26% as sedimentation of particulate nitrogen, PN). The remaining nitrogen (48%) left in the drainage water and this emphasises the importance of the wetland hydrology in determining denitrification and filtering. The current estimates are highly variable, so we have also identified the key parameters that need to be measured in order to improve long-term wetland filtering capacity estimation. Babinda is in the Mulgrave-Russell catchment, where the Reef 2050 Water Quality Improvement Plan has set target reductions in DIN of 300 t and PN of 53 t by 2025. 10% of the DIN reduction target could be achieved from ~593 ha of wetland with the same mean denitrification properties as currently estimated for the Babinda wetland (i.e. 51 kg N ha year). This amounts to 2.3% of the total sugarcane area in this catchment that, as wetland, would also remove 56% of the 2025 PN reduction target.
《珊瑚礁 2050 计划》确定了一系列旨在减少集水区末端沉积物和养分负荷的措施，并认识到淡水湿地在实现这一目标方面可能发挥的作用。然而，关于热带湿地过滤农业径流的潜力的定量信息很少，因此本文描述了一项研究，该研究结合了位于昆士兰州北部巴布恩达附近曾经用于甘蔗种植的土地上建造的 10 公顷湿地的实地数据，以及一个水量平衡和反硝化模型。在 12 个月的监测期间（2017 年 10 月至 2018 年 9 月），我们估计湿地的氮过滤能力为 52%（26%通过水和土壤中的气态反硝化损失，26%作为颗粒态氮 PN 的沉淀损失）。剩余的氮（48%）留在排水中，这强调了湿地水文在决定反硝化和过滤方面的重要性。目前的估计值变化很大，因此，我们还确定了需要测量的关键参数，以便提高长期湿地过滤能力的估计值。巴布恩达位于马尔格雷夫-拉塞尔集水区，《珊瑚礁 2050 年水质改善计划》为该集水区设定了到 2025 年 DIN 减少 300 吨和 PN 减少 53 吨的目标。通过与巴布恩达湿地目前估计的相同平均反硝化特性（即 51 公斤氮/公顷/年）的大约 593 公顷湿地，可以实现 DIN 减少目标的 10%。这相当于该集水区总甘蔗面积的 2.3%，作为湿地，它还将去除 2025 年 PN 减少目标的 56%。
