A collaborative research effort between Northwestern University and the University of Wyoming is shedding light on the potential impact of methane production in Arctic lakes on climate change, as well as how climate change affects this methane production.
In a recent study published in the journal Science Advances, researchers examined waxy coatings of leaves, preserved as organic molecules in sediment from the early-to-middle Holocene period. This era, occurring 11,700 to 4,200 years ago, was marked by significant warming driven by gradual changes in Earth’s orbit. The team analyzed these wax biomarkers, once part of common aquatic brown mosses, preserved in sediment layers beneath four lakes in Greenland.
Their findings indicated that during the middle Holocene warming, lakes across a broad range of Greenland’s climates started producing methane, a potent greenhouse gas. Understanding the relationship between warming and methane production is crucial because of the climate-warming potential of methane compared to carbon dioxide.
While the study provides valuable insights, researchers currently lack a comprehensive understanding of the quantity of methane produced in Arctic lakes and how ongoing warming will impact methane production. The study suggests that continued warming could lead to increased methane emissions from lakes, highlighting the importance of studying these dynamics.
Jamie McFarlin, the study’s lead author, emphasized the significance of these findings, noting that “we can look to these signs from the past to help predict our future. We suspect this process is going to become more and more important in the future of these lakes.”
Magdalena Osburn, the study’s senior author, added, “Living on a warming planet, we can look to these signs from the past to help predict our future.”
Arctic and boreal landscapes are experiencing the most rapid warming globally, making it vital to understand the interplay between rising temperatures and methane production in these lakes.
To investigate these dynamics, the research team collected new data from two lakes in Greenland (Wax Lips Lake and Trifna Sø) and analyzed published data from two additional lakes (Lake N3 and Pluto Lake). They compared the hydrogen isotopic composition of aquatic plant waxes in sediment to biomarkers from terrestrial plants and other sources. This analysis revealed methane signatures in the early-middle Holocene period, reflecting increased methane production.
These findings suggest that some methane was absorbed by aquatic mosses living in the lakes, potentially through a symbiotic relationship with methane-consuming bacteria. While the study does not provide a definitive assessment of the net effect on atmospheric methane levels, it underscores the vulnerability of Arctic lakes to climate-driven changes in methane cycling.
Yarrow Axford, a co-author of the study, emphasized the importance of this research by stating, “The Arctic has huge areas covered in lakes. Not every lake has mosses that will record methane dynamics, but our study also highlights that those vast swaths of Arctic lakes are vulnerable to climate-driven changes in methane cycling, whether mosses are on site to witness those changes or not. This is yet another way that rapid warming in the Arctic could affect global climate.”