Seminar and Events Schedule

Global emissions of methane and carbon dioxide – the view from space

With the launch of several new satellites, scientists are increasingly able to monitor carbon dioxide and methane from space, creating a vast new record of greenhouse gas measurements in regions that were previously difficult to monitor. The first half of this talk focuses on methane emissions from China, the world’s largest emitter of anthropogenic greenhouse gases. We specifically use observations from the GOSAT satellite to evaluate the success of China’s methane emissions policies. The second half of this talk will focus on carbon dioxide sources and sinks estimated using NASA’s OCO-2 satellite. We quantify on how sources and sinks from the biosphere have been changing from year-to-year; understanding this variability is key to creating better future predictions of the global carbon cycle.With the launch of several new satellites, scientists are increasingly able to monitor carbon dioxide and methane from space, creating a vast new record of greenhouse gas measurements in regions that were previously difficult to monitor. The first half of this talk focuses on methane emissions from China, the world’s largest emitter of anthropogenic greenhouse gases. We specifically use observations from the GOSAT satellite to evaluate the success of China’s methane emissions policies. The second half of this talk will focus on carbon dioxide sources and sinks estimated using NASA’s OCO-2 satellite. We quantify on how sources and sinks from the biosphere have been changing from year-to-year; understanding this variability is key to creating better future predictions of the global carbon cycle.

Cold season biogeochemistry and carbon emissions in northern ecosystems 

Summer is a great time to measure fluxes of CO2 and methane in northern tundra and boreal ecosystems: It’s warm, it’s bright, plants are growing, students have summers free for internships, only the bugs can be bad. Consequently, most of our understanding of carbon biogeochemistry is based on growing season emissions. However, carbon emissions during the fall, winter, and spring can be an important and overlooked component of annual carbon emissions. This seminar will examine the role of non-growing season emissions in the annual C cycle and explore how cold-season biogeochemistry may differ from the growing season.

What Limits Productivity in Northern Hardwoods?  Surprising Findings from the First Long-Term N x P Addition Experiment in a Temperate Forest

The productivity of temperate forests on glaciated soils has been assumed to be nitrogen limited, although theory suggests that ecosystem productivity should be co-limited by multiple nutrients, including phosphorus. Experimental tests of N vs. P limitation in temperate forests are needed to better understand the capacity of ecosystems to balance the acquisition of limiting resources. In 2011, in the White Mountains of New Hampshire, USA, we began a full-factorial N x P fertilization experiment in 13 stands of young, mid-aged, and mature northern hardwoods in three sites that span a range of native soil fertility. Contrary to past assumptions, but credible after decades of anthropogenic N deposition, after 4 years we found a greater response of aboveground growth to P addition than to N addition. Consistent with aboveground P limitation, retranslocation of foliar P was proportionately higher than retranslocation of N, and P addition decreased foliar N, suggesting an alleviation of growth limitation by P. Surprisingly, this aboveground response was not associated with reduced allocation to root production under P addition; instead root growth increased in response to N addition, at the plot scale. Soil respiration, similarly, which should reflect effort allocated belowground for nutrient acquisition, was higher pretreatment where N availability was low and was also most reduced by N addition where N availability was low. There was no effect detected of P addition on soil respiration. In summary, both diameter growth and foliar responses suggested P limitation, while both root growth and soil respiration suggested N limitation. The combination of N limitation belowground and P limitation aboveground may contribute to the maintenance of co-limitation of forest production in these northern hardwood ecosystems.

A systematic perspective for understanding complex forest-water nexus: consistency, variations, sensitivity and resilience

Forests as natural reservoirs and filters can store, release, and purify water through their interactions with hydrological processes. Forest-water nexus is complex, and highly variable across both space and time, especially under global environmental changes. There are always debates on forest-water relationships. For example, whether forestation decrease streamflow or not? Thus, we need a systematic perspective to understand complex forest-water nexus. In this talk, we will firstly provide background information regarding global forest dynamics and historical debates on forest-water relationships. Then we will introduce a systematic framework to understand complex forest-water nexus. We will focus on addressing two questions. What are relationships between forest and water at a watershed scale? Can these relationships be predicted by a generalized simple model? To answer these questions, we will then discuss relationships between forest change and annual mean flow as an example. The talk will provide facts about consistency and variations in watershed-scale forest-water relationships based on a global metadata analysis and demonstrate how to use ecohydrological sensitivity and watershed resilience to understand consistent and variable forest-water nexus through case studies in China and Canada. At last, the talk will provide suggestions for future studies to understand complex forest-water nexus.

Due to time zone conflicts between Arizona and Chengdu China we will have two options to attend seminar on Monday:

1) 8:30-9:30 am MST on a live zoom call with Dr. Zhang

2) A streamed rebroadcast of the earlier seminar during our regular 11:30-12:30 MST meeting time.

Impact at Scale: A practical guide to letting your EcoInformatic superpowers loose in the world a.k.a. Ecological experiments I have abandoned and other regrets

Scientists are no strangers to entrepreneurship, it’s just that we see our customers as the Program Officers at NSF, and our sales and marketing is channeled through the arcane system of publications and conference abstracts.  For better or worse, all this structure puts big barriers to refining solutions and driving adoption rapidly, because we all know that time is not on our side for the many crises that we’re working on.  I’ll talk about where my academic background has helped me, but more often has led me astray in my effort to build scalable systems (aka businesses) that solve environmental challenges.  If you’re on the fence about starting a company, I recommend taking the leap.