Luquillo CZO: The role of hot spots and hot moments in tropical landscape evolution and functioning of the critical zone

点击翻译按钮获取中文摘要

The structure and function of the critical zone (CZ) plays a central role in sustaining Earth's life support system. During the first phase of the Luquillo Critical Zone Observatory (LCZO1), investigators identified differences in rock type, deep weathering, geomorphology, and topography as the dominant drivers of key CZ processes such as nutrient supply, greenhouse gas emissions, and water quantity and quality. Building on this foundation, LCZO2 will evaluate the role of "hot spots and hot moments" in the CZ: locations or time periods that disproportionately impact the environment as a whole. "Hot spots and hot moments" are particularly relevant to humid tropical environments such as the LCZO, which are characterized by high physical, geochemical, and biological diversity in space and time. Critical zone processes can occur at very small to very large spatial scales. For example, bedrock weathering occurs at a millimeter spatial scale, while wholesale changes in vegetation and carbon cycling occur over several kilometers such as along elevation gradients. Critical zone processes can also vary over time; oxidation-reduction reactions occur in soils on the scale of minutes, and catastrophic events such as hurricanes and landslides occur at decadal time scales. Investigators will identify, quantify, and model the role of "hot spots and hot moments" in a range of CZ processes and use that knowledge to predict the rates of CZ processes across the Luquillo Mountains and in other montane areas with high temperature and rainfall. Specific focal areas include: 1) the importance of knickpoints and landscape position as hot spots for weathering, soil development, and biogeochemical cycling; 2) the role of "hot spots and hot moments" in redox fluctuations and mineral weathering for C and nutrient retention and loss; 3) the role of "hot spots" for sediment production and "hot moments" in stream flow for the transport of sediment, C, and nutrients from mountains to the sea; and 4) the development of climate and hydrologic models to scale up "hot spots and hot moments" in time and space. The data collected and synthesized will transform the understanding of the controls on key CZ processes such as weathering, soil development, C and nutrient storage and loss, soil and sediment transport, and ultimately landscape evolution and the effects of climate change. The project will provide an unprecedented level of detail on "hot spots and hot moments" in a tropical system. The results of this research will allow us to accurately and precisely 'earthcast' the effects of environmental change on important environmental processes such as flooding, erosion, and landslides. Because all critical zones have "hot spots and hot moments" of significant environmental processes, the development of the "hot spots and hot moments" concept in the CZ context will promote cross-site integration, the development of conceptual models of the CZ, and provide a venue for the Earth science community to develop and test novel approaches to CZ science.The LCZO2 will continue to collaborate with University of Puerto Rico (UPR) students and scientists to enhance the participation of underrepresented groups in the Earth and environmental sciences. LCZO2 will also contribute to an existing 'Schoolyard' environmental education program at high schools in Puerto Rico. This program has a successful record of incorporating new data and research techniques into the curriculum and provides professional development for the teachers in addition to research opportunities for students. The diverse group of co-PIs, senior personnel, and collaborators will provide strong role models for research students and postdocs. Our robust collaborations with local and federal agencies and educational institutions provide access to policy makers and other stakeholders that will help us to translate science into policy-relevant findings. Informal forums will be used to share our research findings and to emphasize the significance of CZ research to environmental decision makers dealing with questions such as soil erosion that can fill reservoirs, water quality that degrades water supply and coral reefs, and carbon storage that counteracts the effects of global increases in carbon dioxide. An inclusive and comprehensive engagement plan will encourage participation by scientists not yet affiliated with the LCZO2. The plans for cross-CZO modeling, open sharing of data and samples, and cyberseminars that are open to the public will strengthen the CZO network as a whole and enhance the availability of CZ science to the public and decision-makers.