Category Archives: Science

UMass students report on Arctic Paleoclimate

Congratulations to three students of the Castañeda Biogeochemistry lab group who recently published their research findings on Arctic paleoclimatology!

For his graduate work, Dr. Boyang Zhao examined lake sediment cores from Southern Greenland to examine the area’s paleoclimate history during the Norse inhabitation period, and, most importantly, during the sudden exodus of Norse people out of Greenland in the 15th Century. The full paper can be found here, in the journal Science Advances. In the manuscript, we utilize the hydrogen isotope ratios of organic biomarkers, along with other chemical indicators in the lake sediments, to conclude that the climate shifted toward drier conditions, likely stressing the agricultural practices and thereby contributing to the abandonment of Norse settlements. To read more, here are some popular science outlets that reported on Boyang’s work: IFLS, UMass, Science, CNN.

A view of sheep pastures and agricultural fields, near Igaliku, Greenland.
Drs. Isla Castañeda, Tobias Schneider, Boyang Zhao, and Ray Bradley (UMass Amherst) admire and process a lake sediment core from a small lake in Greenland.

Secondly, congratulations to Kurt Lindberg (UMass, ’20) on a recent publication in the journal Climate of the Past (link). Kurt worked with me and Isla on his senior thesis at UMass, in which he characterized Arctic climate change during the Mid-Pleistocene Transition. Kurt’s research utilized organic biomarkers preserved in the Lake El’gygytgyn drillcore from Northeast Russia to reconstruct temperature, and vegetation/aridity. The time period he studied was from 0.8 to 1.2 million years ago, which marked a critical transition interval in Earth’s climate history when global temperatures were cooling and ice ages were becoming more severe. Kurt is continuing to examine Arctic climate change as a graduate student at the University at Buffalo.

Kurt Lindberg (UMass ’20) processing lake sediment for organic biomarkers. Kurt used this research to characterize Arctic climate change during the Mid-Pleistocene Transition.

Most recently, Carly Lombardo, a current UMass undergraduate student working on the Lake El’gygytgyn project, shared the results of our research at the Northeast Section meeting of the Geologic Society of America. This was Carly’s first time presenting at a scientific conference, and her research prompted quite a bit of discussion at the meeting. Great job, Carly! Her research explores the history of wildfires at Lake El’gygytgyn, again using organic biomarkers preserved in the lake’s sediments. Wildfires are typically quite rare in the Arctic tundra, but appear to be increasing in frequency as a results of climate warming. Here, Carly was testing how temperature, aridity, and vegetation interact to control fire activitiy. In this case, Lombardo analyzed Polycyclic Aromatic Hydrocarbons, which are common byproducts of wildfires. Lombardo will also be sharing her research at the upcoming Massachusetts Undergraduate Research Conference, and a video link of her presentation can be found here.

UMass Amhest researchers Carly Lombardo and Will Daniels at the 2022 NE GSA meeting in Lancaster, PA.

UMass Geologists in Greenland

I’d be hard pressed to find a better way to decompress from my NASA-HERA mission than a field expedition to the Arctic. I went from 6 weeks in a 600 square foot pod to 2 weeks in the vast expanses of Greenland’s fjords and tundra. And it was wonderful. I’ll share some photos and experiences here.

A panoramic view of Sillisit and Tunulliarfik Fjord

From June 29 to July 11, 2018, I traveled with a research group from University of Massachusetts to South Greenland in a scientific campaign to calibrate paleoclimate proxies. The overarching goal of the project, which is led by UMass professors Isla Castañeda and Ray Bradley, is to test the hypothesis that climate change may have forced the exodus of Norse settlers from Greenland around the year 1450 AD. Sediment cores have already been collected, and our efforts this field season were to collect soil, sediment, and plant samples in order to improve our understanding of leaf wax and GDGT systematics in these Arctic systems. Continue reading

HERA XVII – NASA Mission Prep

Well, this is my last full week at the University of Massachusetts before I take a 2 month leave-of-absence to participate in the Human Exploration Research Analog (HERA) mission at the Johnson Space Center in Houston, TX.  I will be living with 3 others in the HERA habitat for 45 days, during which time we will have very limited contact with the outside world, eat delicious freeze-dried foods, shower in a ‘hygiene module’, and simulate flying a spaceship. Weird? Exciting! Continue reading

Lindavia intermedia

This blogpost is about a complicated little diatom. We just published a short nomenclatural article in the online journal Notulae Algarum that rectifies naming problems that have plagued the centric diatom currently known as Lindavia intermedia. The diatom was originally described from samples taken in Alaska (hence my interest), but has undergone a myriad of genus changes and status changes (ie. changing from a variety to a species). In writing the article, I learned a great deal about the rules of taxonomy and how we name organisms, especially algae. A fun project, and special thanks to Mark Edlund and Phil Novis for helping get this out. For more on this diatom, refer to the article here, or to the Western Diatoms webpage.

Internal view of a Lindavia intermedia valve under SEM

Valve view of Lindavia intermedia under a light microscope

ASLO 2015 – Granada, Spain

In March of 2015 I had the pleasure of attending a scientific conference for the Association for the Science of Limnology and Oceanography (ASLO). This year the meeting was held in Granada, Spain. So much great science! I gave a talk on past temperature changes in Alaska and what impact that had on lake ecosystems. Lake E5 is such a wonderful model lake!

I didn’t take many pictures within the conference, but want to share these pictures from beautiful Grenada and the surrounding area. Enjoy.