News

Oceanic crustal carbon cycle drives 26-million-year atmospheric carbon dioxide periodicities

Abstract.

"Atmospheric carbon dioxide (CO2) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, and orogenic events and have previously been linked to an extraterrestrial mechanism. [...]

Source: Science Advances
Authors: R. Dietmar Müller and Adriana Dutkiewicz
DOI: 10.1126/sciadv.aaq0500

Read the full article here.


Meridional overturning circulation conveys fast acidification to the deep Atlantic Ocean

Abstract.

"Since the Industrial Revolution, the North Atlantic Ocean has been accumulating anthropogenic carbon dioxide (CO2) and experiencing ocean acidification1, that is, an increase in the concentration of hydrogen ions (a reduction in pH) and a reduction in the concentration of carbonate ions. The latter causes the ‘aragonite saturation horizon’—below which waters are undersaturated with respect to a particular calcium carbonate, aragonite—to move to shallower depths (to shoal), exposing corals to corrosive waters. [...]"

Source: Nature
Authors: Fiz F. Perez et al.
DOI: 10.1038/nature25493

Read the full article here.


Carbonate chemistry of an in-situ free-ocean CO2 enrichment experiment (antFOCE) in comparison to short term variation in Antarctic coastal waters

Abstract.

"Free-ocean CO2 enrichment (FOCE) experiments have been deployed in marine ecosystems to manipulate carbonate system conditions to those predicted in future oceans. We investigated whether the pH/carbonate chemistry of extremely cold polar waters can be manipulated in an ecologically relevant way, to represent conditions under future atmospheric CO2 levels, in an in-situ FOCE experiment in Antarctica. [...]"

Source: Scientific Reports
Authors: J. S. Stark et al.
DOI: 10.1038/s41598-018-21029-1

Read the full article here.


Effects of ocean acidification and hydrodynamic conditions on carbon metabolism and dissolved organic carbon (DOC) fluxes in seagrass populations

Abstract.

"Global change has been acknowledged as one of the main threats to the biosphere and its provision of ecosystem services, especially in marine ecosystems. Seagrasses play a critical ecological role in coastal ecosystems, but their responses to ocean acidification (OA) and climate change are not well understood. There have been previous studies focused on the effects of OA, but the outcome of interactions with co-factors predicted to alter during climate change still needs to be addressed. [...]"

Source: PLoS ONE
Authors: Luis G. Egea et al.
DOI: 10.1371/journal.pone.0192402

Read the full article here.


On the effect of low oxygen concentrations on bacterial degradation of sinking particles

Abstract.

"In marine oxygen (O2) minimum zones (OMZs), the transfer of particulate organic carbon (POC) to depth via the biological carbon pump might be enhanced as a result of slower remineralisation under lower dissolved O2 concentrations (DO). In parallel, nitrogen (N) loss to the atmosphere through microbial processes, such as denitrification and anammox, is directly linked to particulate nitrogen (PN) export.  [...]"

Source: Scientific Reports
Authors: Frédéric A. C. Le Moigne
DOI: 10.1038/s41598-017-16903-3

Read the full article here.


Repeated storage of respired carbon in the equatorial Pacific Ocean over the last three glacial cycles

Abstract.

"As the largest reservoir of carbon exchanging with the atmosphere on glacial–interglacial timescales, the deep ocean has been implicated as the likely location of carbon sequestration during Pleistocene glaciations. Despite strong theoretical underpinning for this expectation, radiocarbon data on watermass ventilation ages conflict, and proxy interpretations disagree about the depth, origin and even existence of the respired carbon pool. [...]"

Authors: A.W. Jacobel
Source: Nature Communications
DOI: 10.1038/s41467-017-01938-x

Read the full article here.


Oxygenation as a driver of the Great Ordovician Biodiversification Event

Abstract.

"The largest radiation of Phanerozoic marine animal life quadrupled genus-level diversity towards the end of the Ordovician Period about 450 million years ago. A leading hypothesis for this Great Ordovician Biodiversification Event is that cooling of the Ordovician climate lowered sea surface temperatures into the thermal tolerance window of many animal groups, such as corals. [...]"

Source: Nature Geoscience
Authors: Cole T. Edwards
DOI: 10.1038/s41561-017-0006-3

Read the full article here.


A dynamic microbial community with high functional redundancy inhabits the cold, oxic subseafloor aquifer

Abstract.

"The rock-hosted subseafloor crustal aquifer harbors a reservoir of microbial life that may influence global marine biogeochemical cycles. Here we utilized metagenomic libraries of crustal fluid samples from North Pond, located on the flanks of the Mid-Atlantic Ridge, a site with cold, oxic subseafloor fluid circulation within the upper basement to query microbial diversity. [...]"

Source: The ISME Journal
Authors: Benjamin J. Tully et al.
DOI: 10.1038/ismej.2017.187

Read the full article here.


A strong case for limiting climate change

"As a gigantic carbon sink, the ocean has taken up about a third of the carbon dioxide (CO2) released into the atmosphere by human activities. But when absorbed by seawater, the greenhouse gas triggers chemical reactions, causing the ocean to acidify. Ocean acidification affects ecosystems and important services the ocean provides to humankind. This includes the regulation of the Earth's climate, food provision, recreation as well as biodiversity as a condition for intact and functioning ecosystems. [...]"

Source: EurekAlert

Read the full article here.


Methane fluxes from coastal sediments are enhanced by macrofauna

Abstract.

"Methane and nitrous oxide are potent greenhouse gases (GHGs) that contribute to climate change. Coastal sediments are important GHG producers, but the contribution of macrofauna (benthic invertebrates larger than 1 mm) inhabiting them is currently unknown. Through a combination of trace gas, isotope, and molecular analyses, we studied the direct and indirect contribution of two macrofaunal groups, polychaetes and bivalves, to methane and nitrous oxide fluxes from coastal sediments. [...]"

Source: Scientific Reports
Authors: Stefano Bonaglia et al.
DOI: 10.1038/s41598-017-13263-w

Read the full article here.


Showing 1 - 10 of 20 results.
Items per Page 10
of 2