The Ocean is losing its breath: declining oxygen in the world's ocean and coastal waters; summary for policy makers
"Oxygen is critical to the health of the ocean. It structures aquatic ecosystems, impacts the biogeochemical cycling of carbon, nitrogen and other key elements, and is a fundamental requirement for marine life from the intertidal zone to the greatest depths of the ocean." [...]
Source: UNESCO (UNESDOC)
Authors: Denise Breitburg et al.
How ocean warmth triggers glacial melting far away
"The melting of glaciers on one side of the globe can trigger disintegration of glaciers on the other side of the globe, as has been presented in a recent paper by a team of AWI scientists, who investigated marine microalgae preserved in glacial deposits and subsequently used their findings to perform climate simulations. The study highlights a process with alerting consequences for modern ice sheets: continuous warming of the ocean can result in a massive loss of polar ice mass, and consequently to rapid sea level rise."
Source: Science Daily
North Pacific freshwater events linked to changes in glacial ocean circulation
"There is compelling evidence that episodic deposition of large volumes of freshwater into the oceans strongly influenced global ocean circulation and climate variability during glacial periods. In the North Atlantic region, episodes of massive freshwater discharge to the North Atlantic Ocean were related to distinct cold periods known as Heinrich Stadials. [...]"
Authors: E. Maier et al.
2018 AGU Fall Meeting
The Fall Meeting 2018 is a unique opportunity to highlight the latest discoveries, insights, and advances for our global community of Earth and space scientists, and at the same time to raise appreciation of the value and impact of our science among world leaders in Washington, D.C.
The 2018 meeting also marks the beginning of AGU’s Centennial in 2019, a time to reflect on the meaning of a century of discovery and to look ahead to the essential contributions that our science will make to understanding our world, informing policy decisions, sparking innovation, and protecting the health and welfare of people everywhere.
- Session Proposal and Tutorial Talk Acceptance Notifications: mid-June 2018
- Early abstract submission deadline: 25 July 2018, 11:59 PM EDT
- Abstract and Town Hall Submission Deadline: 1 August 2018, 11:59 PM EDT
- Scientific Program Released and Abstract and Sessions’ Scheduled Days/Times Notifications Sent: 1 October 2018
Get more information about the meeting on the official homepage.
Start Date: 12/9/18
2018 AGU Fall Meeting
Conveners: Jim Ammerman/Long Island Sound Study, and Jim O'Donnell/University of Connecticut
Single cell genomic and transcriptomic evidence for the use of alternative nitrogen substrates by anammox bacteria
"Anaerobic ammonium oxidation (anammox) contributes substantially to ocean nitrogen loss, particularly in anoxic marine zones (AMZs). Ammonium is scarce in AMZs, raising the hypothesis that organic nitrogen compounds may be ammonium sources for anammox. Biochemical measurements suggest that the organic compounds urea and cyanate can support anammox in AMZs. [...]"
Source: The ISME Journal
Authors: Sangita Ganesh et al.
Early Palaeozoic ocean anoxia and global warming driven by the evolution of shallow burrowing
"The evolution of burrowing animals forms a defining event in the history of the Earth. It has been hypothesised that the expansion of seafloor burrowing during the Palaeozoic altered the biogeochemistry of the oceans and atmosphere. However, whilst potential impacts of bioturbation on the individual phosphorus, oxygen and sulphur cycles have been considered, combined effects have not been investigated, leading to major uncertainty over the timing and magnitude of the Earth system response to the evolution of bioturbation. [...]"
Source: Nature Communications
Authors: Sebastiaan van de Velde et al.
Coupling of ocean redox and animal evolution during the Ediacaran-Cambrian transition
"The late Ediacaran to early Cambrian interval witnessed extraordinary radiations of metazoan life. The role of the physical environment in this biological revolution, such as changes to oxygen levels and nutrient availability, has been the focus of longstanding debate. Seemingly contradictory data from geochemical redox proxies help to fuel this controversy. As an essential nutrient, nitrogen can help to resolve this impasse by establishing linkages between nutrient supply, ocean redox, and biological changes. [...]"
Source: Nature Communications
Authors: Dan Wang et al.
Oxygen minimum zones in the early Cambrian ocean
"The relationship between the evolution of early animal communities and oceanic oxygen levels remains unclear. In particular, uncertainty persists in reconstructions of redox conditions during the pivotal early Cambrian (541-510 million years ago, Ma), where conflicting datasets from deeper marine settings suggest either ocean anoxia or fully oxygenated conditions. By coupling geochemical palaeoredox proxies with a record of organic-walled fossils from exceptionally well-defined successions of the early Cambrian Baltic Basin, we provide evidence for the early establishment of modern-type oxygen minimum zones (OMZs). [...]"
Source: Geochemical Perspectives Letters
Authors: R. Guilbaud et al.
Ecology and evolution of seafloor and subseafloor microbial communities
"Vast regions of the dark ocean have ultra-slow rates of organic matter sedimentation, and their sediments are oxygenated to great depths yet have low levels of organic matter and cells. Primary production in the oxic seabed is supported by ammonia-oxidizing archaea, whereas in anoxic sediments, novel, uncultivated groups have the potential to produce H2 and CH4, which fuel anaerobic carbon fixation. [...]"
Source: Nature Reviews Microbiology
Authors: William D. Orsi