--------------------------------------------------------------- The following message was sent to you via AVO Web Email System: --------------------------------------------------------------- Name: Krista Bartz Email Address: Krista_Bartz@nps.gov Subject: Metric for volcanoes as a driver of Hg in lake fish? Message: Greetings, As part of a broader study of mercury in resident lake fish, I'm trying to figure out a simple metric to quantify the potential for lake trout in 13 lakes in Katmai and Lake Clark National Parks and Preserves to have acquired mercury released from nearby volcanoes. Thus far, I've been putting aside details like (1) the complexities of mercury biogeochemical cycling and (2) wind at the time of volcanic eruption, and computing the metric via ArcMap. For example, I've used the "Point Distance" tool in ArcMap to sum the distance between the centroid of each lake and all volcanoes within a radius of X km (e.g., 200 km). Those centroids with the lowest sums would signify lakes with the greatest potential for a "Hg from volcanoes" effect over time -- hypothetically, at least. This begs several questions. First, what radius makes most sense, given how far volcanic ash/gaseous vapors travel? 10 km? 100 km? 1000 km? Can you give me a ballpark estimate, or is it not that simple? Second, when computing this metric, would it make most sense to include only volcanoes listed as "historically active" on your website, rather than volcanoes listed as "active in the Holocene" or further back in time? If so, would you call Crater Peak, Cerberus, and Falling Mt "historically active"? They're not listed separately on your website, but they're included as separate volcanoes in my GIS data layer. Third, can you think of other metrics in the literature that signify potential volcano effects on biota that are more elegant or process-based than what I'm proposing? If so, I'm all ears, because I'm not familiar with the volcano lit. Sincerely, Krista ---------------------------------------------------------------- REMOTE IP ADDRESS: 165.83.60.222 USER AGENT/BROWSER: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36 REFERRING PAGE: https://www.avo.alaska.edu/contact.php