Last week, the BU Biogeoscience program coordinated a Saturday field trip to the Blue Hills Meteorological Observatory south of Boston. Blue Hills was founded in 1885 and is the oldest continuously operating weather observatory in the United States. We took a snowy hike up to the summit of Great Blue Hill to learn about the history of meteorological observations at the station and the data records available today. Blue Hills data shows clear increases in annual air temperature, decreases in pond ice season, and advances in the date of the first ripe blueberry on the hill over the last 100+ years. Amazing the value of careful long-term observations!
Blue Hills Meteorological Observatory (photo credit I-Fang Hsieh)
"Antique" temperature monitoring station at Blue Hills. Scientists maintain analog temperature records using mercury thermometers comparable to the instruments used in the late 19th century. The data is compared to modern meteorological equipment used in parallel at the site. (Photo credit: I-Fang Hsieh)
Finzi Lab graduate students Pat Sorensen, Allison Gill, I-Fang Hsieh hike down from the Great Blue Hill Summit (Photo Credit I-Fang Hsieh)
Field works slows down in the winter in our lab, so there is plenty of time to work through the piles of flux data we collected at the DOE SPRUCE Experiment last summer! We installed 20 auto chambers in SPRUCE treatment corrals in early May and collected continuous CO2 and methane flux measurements until late September. See the video below to watch the auto chambers open and close (chamber speed has been changed for the purpose of the video, usually chambers are closed for 20 minutes!).
In early October, Adrien and Marc successfully deployed the automated soil respiration system in the Hemlock Tower area of the Harvard Forest. Meant as a field test of the whole system, is has been providing us with good-quality soil respiration measurements for the last month over six locations in the hemlock stand. At first each chamber was measured once per hour, but analysis of the data showed we could measure each chamber every half-hour, doubling the number of measurements we can make. The system will remain in use until the weather gets too cold for it to function properly, at which time we will store the chambers and control box until we redeploy them after snowmelt in spring of 2016.
Next year we plan on installing six more soil respiration collars in a different area of the hemlock stand and move the control box from one area to the other approximately every week to increase the spatial resolution of our measurements. We hope a REU student will help us with the operation and maintenance of the system and with data analysis during.
The control box with the gas analyzer (green) to measure CO2 and the datalogger (black) to control everything and record measurements.
The whole system: six chambers and the control box protected under the white tarp.
Former graduate student Rose Abramoff set up a series of 3-feet deep transparent tubes at the Harvard Forest in 2012 to monitor the seasonality of root growth using a high-resolution minirhizotron camera to photograph and trace plant roots over time. We've been continuing her work this growing season to look at how root growth and root phenology in Hemlock stands respond to an invasive pest and to look at the effects of fertilization and soil warming on roots in a mixed oak stand. The camera takes images that are approximately 16 mm x 18 mm, allowing us to see plant roots, fungal mycelia, and occasionally even small soil insects as the camera is lowered through the soil profile. Below is a particularly exciting view from experimental plots in a mixed oak stand where plant roots and mycelia are visible!
On Monday October 12, 2015 members of the Finzi Lab Group and students from his course in Terrestrial Biogeochemistry went for a hike in the White Mountains of NH. Originally slated to hike the 8 mile Mt. Lafayette, Lincoln and Little Haystack loop trail....they fell to pieces [well, at least Adrien and Pat managed to bag Lafayette]! It was a great day for a hike with foliage at or just past peak color in the higher elevations. Good fun, good pizza on the way home and great camaraderie! And, after all...isn't that what its all about?
Patrick Sorenson [PhD student co-advised with Prof. Pamela Templer] and Adrien at the top of Mt Lafayette. Nice view and nice breeze!
Entering the Krummholz vegetation stage of the White Mountains. Here wind, snow, ice and soil/rock particles shear the tops off balsam fir and red spruce trees creating a dense but stunted forest.
Boreal forest understory at ~1000m asl. Balsam fir and red spruce dominate the canopy while various species of moss cover the forest floor. P>ET anyone?
Left to Right: Patrick Sorenson, Zachary Gilbert [BU CAS '16] and Nick Ray [PhD student / Fulweiler lab] nearing the Greenleaf AMC Hut.
It's just a nice picture!
On the way out we hiked past a large glacial erratic that had been split down the center presumably by repeated freeze-thaw over the last few thousand years. No sign of a tree growing atop the boulder so root growth not likely a large contributor to freeze-thaw in this case.
Graduate student Allison Gill spent much of the summer in rural Northern Minnesota measuring methane and CO2 fluxes from soil at the DOE Spruce and Peatland Responses Under Climatic and Environmental Change (SPRUCE) field site using autochambers. Her sites include experimental treatments with elevated CO2 and soil warming!
The Finzi Lab is excited to welcome a new graduate student into the lab this semester! I-Fang Hsieh, who has previously worked on changes in soil respiration in response to bamboo invasions, joined BU after completing a masters degree at National Taiwan University.
Graduate student Mustafa Saifuddin represented Harvard Forest at the Long-Term Ecological Research (LTER) All Scientists Meeting in Estes Park, CO along with other researchers from LTER sites across the globe! They had the opportunity to participate with hundreds of other scientists in working groups on topics like microbial ecology, scaling local measurements for use in ecosystem models, observing changes in vegetation community composition over long timescales, and diversity in the sciences. They also got to see these neat elk:
Lab manager Marc-Andre Giasson has been building automated soil respiration measurement systems, generally known as soil respiration autochambers. The system involves inserting PVC collars in the ground where measurements need to be made. A lid, which can be lowered or raised using a piston, is added. Air is pumped from the closed chamber through a series of tubing and valves and is routed through an infrared gas analyzer (IRGA), which measures the concentration of CO2 and water vapor in the air. The air is then routed back to the chamber. The rate of increase in CO2 in the chamber is converted to a soil respiration rate. Six chambers can be used with this specific control box; chambers are measured one at a time and each one is sampled every hour or so.
This system will be deployed at Harvard Forest for a few weeks this fall for field testing. It will also be deployed soon after snow melt in 2016 and will remain in operation until the autumn frosts. The system should also be deployed in subsequent years. The objective will be to measure soil respiration in hemlock stands infested by the hemlock woolly adelgid and to observe if soil respiration rates change as the infestation progresses and the trees die.