Paper: High-latitude biomes and rock weathering mediate climate-carbon cycle feedbacks on eccentricity timescales.
Authors: David De Vleeschower, Anna Joy Drury, Maximilian Vahlenkamp, Fiona Rochholz, Diederik Liebrand & Heiko Pälike
Featured image: Benthic foraminifera collected from the North Sea in 2011. Image courtesy of Hans Hillewaert, licensed under CC BY-SA 4.0
Faced with a rapidly warming world, we all have the same questions on our collective minds: how will climate change restructure Earth and what can we do to adapt to those changes? One thing we do know is that the climate is intimately connected to the carbon cycle. When large amounts of carbon get moved between reservoirs (on land and in the ocean and atmosphere), changes in climate ensue. Currently, carbon stored on land is being moved to the atmosphere through anthropogenic CO2 emissions, causing global warming and its various cascading effects. What’s more, looking back in Earth’s history, researchers have established that moving carbon from the atmosphere to the ocean, or back onto land, has had a cooling effect. Just this past year, researchers from the University of Southampton investigated several factors affecting past carbon-climate connections, offering new understandings that could help address climate action moving forward.
Continue reading “It’s complicated; deciphering mixed signals of the carbon-climate relationship in Earth’s past”
Featured Image: Plumes of muddy, sediment-laden water at the Chesapeake Bay Bridge near Annapolis, MD. Photo courtesy of Jane Thomas/ IAN, UMCES.
Paper: Seabed Resuspension in the Chesapeake Bay: Implications for Biogeochemical Cycling and Hypoxia
Authors: Julia Moriarty, Marjorie Friedrichs, Courtney Harris
A memorable feature of the Chesapeake Bay, the largest estuary in the USA, is that the water is very murky and looks like chocolate milk. Former Senator Bernie Fowler has conducted public “wade-ins” over the past 50 years in one of the Bay’s tributaries, seeing how deep the water is before he can no longer see his white tennis shoes, and let’s just say it is never very deep. This is because of the high concentrations of sediment, or small particles of sand and organic material, in the water. Besides making it harder for seagrasses to grow and serving as food for the economically-important oyster, sediment impacts the biological processes that determine how much oxygen and nutrients are available in the water for algae and fish.
Continue reading “Muddy waters lead to decreased oxygen in Chesapeake Bay”
Paper: Freshening of the western Arctic negates anthropogenic carbon uptake potential
Authors: R.J. Woosley and F.J. Millero
Journal: Limnology and Oceanography
As human generated emissions of carbon dioxide continue to increase, scientists seek to understand the potential for ‘sinks’, or places that the excess CO2 can move in the global carbon cycle, to take up and store some of the increased emissions. Understanding how these carbon sinks may react to increasing global emissions helps to better predict both the rate of atmospheric increase in the future and the potential response of global ecosystems, including major sinks in forests and oceans.
Continue reading “The role of carbon in a changing Arctic”
Featured Image: Eastern Scheldt Estuary near Zeeland, Netherlands. Photo courtesy Wikimedia Commons/ Luka Peternel, CC BY-SA 4.0 license.
Paper: Carbon and Hydrogen Isotope Signatures of Dissolved Methane in the Scheldt Estuary
Authors: Caroline Jacques, Thanos Gkritzalis, Jean-Louis Tison, Thomas Hartley, Carina van der Veen, Thomas Röckmann, Jack J. Middelburg, André Cattrijsse, Matthias Egger, Frank Dehairs & Célia J. Sapart
Estuaries are dynamic coastal environments where freshwater and saltwater collide and mix. Across the world, estuaries regularly have higher methane concentrations in the water than would be expected from equilibrium with the atmosphere. If the water was in equilibrium, or at a happy balance, with the atmosphere, then there would be no net transfer of methane to the atmosphere. Because there is more methane than expected in the water, estuaries are a source of this potent greenhouse gas, methane (CH4), to the atmosphere. The problem is that the processes leading to the excess methane in the estuary’s surface water are not well known in many European estuaries.
Continue reading “Isotopes Begin to Unlock the Mystery of Methane Source in the Scheldt Estuary”
Paper: A 23 m.y. record of low atmospheric CO2
Featured image: Modern vascular land plants (Raphanus sativus), growing in a carbon dioxide experiment (Figure 1A from Jahren et al., 2008)
Authors: Ying Cui, Brian A. Schubert, A. Hope Jahren
Carbon dioxide is a greenhouse gas, trapping warmth within the Earth’s atmosphere. Sixty years of measurements on Hawaii’s Mauna Loa summit have shown rising amounts of carbon dioxide in our atmosphere. In addition, the carbon dioxide levels in our modern atmosphere are significantly higher than those we have seen on Earth over the last 800,000 years, according to measurements on bubbles of ancient air trapped in Antarctic ice. When combined with measurements of global temperatures, these direct measurements are irrefutable evidence for rapid modern climate change. However, understanding our current position relative to Earth’s climate farther back in time is trickier, since scientists have to estimate atmospheric composition indirectly (through a “proxy”). A new study tackles this problem with a new method of estimating past carbon dioxide, showing that modern carbon dioxide levels have been unprecedented since at least 7 million years ago.
Continue reading “New 23 million year record of atmospheric carbon dioxide highlights current human influence on the atmosphere”
Featured Image: Permafrost thaw slumps draining into a river on the Peel Plateau in western Canada. Photo courtesy Scott Zolkos, lead author of the paper.
Paper: Experimental Evidence That Permafrost Thaw History and Mineral Composition Shape Abiotic Carbon Cycling in Thermokarst-Affected Stream Networks
Authors: Zolkos, Scott & Suzanne E. Tank.
The rivers and streams of the Arctic transfer atmospheric heat into the surrounding permafrost (perennially frozen) soil. At the same time, surface soils up to 1 meter deep undergo annual freeze-thaw cycles. When warmer air arrives in the summer months, the combination of warming air and river water can thaw large chunks of ice-rich permafrost soil along the stream’s edge. Thawed permafrost breaks away from the surrounding hillsides and causes catastrophic slope failures, transporting huge amounts of sediment into the nearby waterways. As the stream water becomes murky it takes on the appearance of chocolate milk, and simultaneously, the geochemistry of the water changes.
Continue reading “Hillsides collapsing into Arctic streams can trigger CO2 release to the atmosphere”