Mellander Per-Erik, Ezzati Golnaz, Murphy Conor, Jordan Phil, Pulley Simon, Collins Adrian L
Agricultural Catchments Programme, Department of Environment, Soils and Landuse, Teagasc, Johnstown Castle, Ireland.
Irish Climate Analysis and Research Units, Department of Geography, Maynooth University, Co. Kildare, Ireland.
Discov Geosci. 2024;2(1):60. doi: 10.1007/s44288-024-00067-5. Epub 2024 Sep 12.
Climate change is likely to exacerbate land to water phosphorus (P) transfers, causing a degradation of water quality in freshwater bodies in Northwestern Europe. Planning for mitigation measures requires an understanding of P loss processes under such conditions. This study assesses how climate induced changes to hydrology will likely influence the P transfer continuum in six contrasting river catchments using Irish national observatories as exemplars. Changes or stability of total P (TP) and total reactive P (TRP) transfer processes were estimated using far-future scenarios (RCP4.5 and RCP8.5) of modelled river discharge under climate change and observed links between hydrological regimes (baseflow and flashiness indices) and transfer processes (mobilisation and delivery indices). While there were no differences in P mobilisation between RCP4.5 and RCP8.5, both mobilisation and delivery were higher for TP. Comparing data from 2080 (2070-2099) with 2020 (2010-2039), suggests that P mobilisation is expected to be relatively stable for the different catchments. While P delivery is highest in hydrologically flashy catchments, the largest increases were in groundwater-fed catchments in RCP8.5 (+ 22% for TRP and + 24% for TP). The inter-annual variability of P delivery in the groundwater-fed catchments is also expected to increase. Since the magnitude of a P source may not fully define its mobility, and hydrological connections of mobilisation areas are expected to increase, we recommend identifying critical mobilisation areas to target future mitigation strategies. These are hydrologically connected areas where controls such as soil/bedrock chemistry, biological activity and hydrological processes are favourable for P mobilisation.
气候变化可能会加剧陆地向水体的磷（P）转移，导致欧洲西北部淡水水体水质恶化。制定缓解措施需要了解在这种情况下的磷流失过程。本研究以爱尔兰国家观测站为范例，评估了气候引起的水文变化可能如何影响六个不同河流集水区的磷转移连续体。利用气候变化下模拟河流流量的远期情景（RCP4.5和RCP8.5）以及观测到的水文状况（基流和暴涨指数）与转移过程（ mobilisation和输送指数）之间的联系，估算了总磷（TP）和总反应性磷（TRP）转移过程的变化或稳定性。虽然RCP4.5和RCP8.5之间在磷的 mobilisation方面没有差异，但TP的 mobilisation和输送都更高。将2080年（2070 - 2099年）的数据与2020年（2010 - 2039年）的数据进行比较表明，不同集水区的磷 mobilisation预计相对稳定。虽然在水文暴涨的集水区磷的输送最高，但最大的增加发生在RCP8.5情景下的地下水补给集水区（TRP增加22%，TP增加24%）。预计地下水补给集水区磷输送的年际变异性也会增加。由于磷源的大小可能无法完全定义其迁移性，并且预计 mobilisation区域的水文联系会增加，我们建议确定关键的 mobilisation区域，以制定未来的缓解策略。这些是水文相连的区域，在这些区域，诸如土壤/基岩化学、生物活性和水文过程等控制因素有利于磷的 mobilisation。
