News
Dealing with Dead Zones: Hypoxia in the Ocean
When water runs off of farmland and urban centers and flows into our streams and rivers, it is often chock-full of fertilizers and other nutrients. These massive loads of nutrients eventually end up in our coastal ocean, fueling a chain of events that can lead to hypoxic "dead zones" — areas along the sea floor where oxygen is so low it can no longer sustain marine life. In this episode, we're joined by NOAA scientist Alan Lewitus to explore why dead zones form, how the problem of hypoxia is growing worse, and what we're doing about it.
Source: National Oceanic and Atmospheric Administration (NOAA)
Author: Troy Kitch
Read the full article here.
Dimethylsulfide (DMS) production in polar oceans may be resilient to ocean acidification
Abstract.
"Emissions of dimethylsulfide (DMS) from the polar oceans play a key role in atmospheric processes and climate. Therefore, it is important we increase our understanding of how DMS production in these regions may respond to environmental change. The polar oceans are particularly vulnerable to ocean acidification (OA). However, our understanding of the polar DMS response is limited to two studies conducted in Arctic waters, where in both cases DMS concentrations decreased with increasing acidity. [...]"
Source: Biogeosciences (under Review)
Authors: Frances E. Hopkins et al.
DOI: 10.5194/bg-2018-55
Read the full article here.
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
Ocean science research is key for a sustainable future
"Human activity has already affected all parts of the ocean, with pollution increasing and fish-stocks plummeting. The UN’s recent announcement of a Decade of Ocean Science provides a glimmer of hope, but scientists will need to work closely with decision-makers and society at large to get the ocean back on track. [...]"
Source: Martin Visbeck
Author: Nature Communications
DOI: 10.1038/s41467-018-03158-3
Read the full article here.
High total organic carbon in surface waters of the northern Arabian Gulf: Implications for the oxygen minimum zone of the Arabian Sea
Abstract.
"Measurements of total organic carbon (TOC) for two years in Kuwaiti waters showed high TOC levels (101.0–318.4, mean 161.2 μM) with maximal concentrations occurring within the polluted Kuwait Bay and decreasing offshore, indicating substantial anthropogenic component. Analysis of winter-time data revealed a large increase in density over the past four decades due to decrease in Shatt Al-Arab runoff, implying that the dissolved/suspended organic matter in surface waters of the northern Gulf could be quickly injected into the Gulf Deep Water (GDW). [...]"
Source: Marine Pollution Bulletin
Authors: Turki Al-Said et al.
DOI: 10.1016/j.marpolbul.2018.02.013
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
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.
Earth’s Oceans Suffocate as Climate Change and Nutrient Loading Create “Dead Zones”
"A new research study from a Global Ocean Oxygen Network (GO2NE) team of scientists reveals that the number of low- and zero oxygen sites in the world’s oceans have increased dramatically in the past 50 years. The Intergovernmental Oceanographic Commission of the United Nations created the GO2NE working group to provide a multidisciplinary, global view of deoxygenation, with the end goal of advising policymakers on preserving marine resources by countering low oxygen. [...]"
Source: environmental monitor
Author: Karla Lant
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
The effect of bio-irrigation by the polychaete Lanice conchilega on active denitrifiers: Distribution, diversity and composition of nosZ gene
Abstract.
"The presence of large densities of the piston-pumping polychaete Lanice conchilega can have important consequences for the functioning of marine sediments. It is considered both an allogenic and an autogenic ecosystem engineer, affecting spatial and temporal biogeochemical gradients (oxygen concentrations, oxygen penetration depth and nutrient concentrations) and physical properties (grain size) of marine sediments, which could affect functional properties of sediment-inhabiting microbial communities. [...]"
Source: PLOS
Authors: Maryam Yazdani Foshtomi et al.
DOI: 10.1371/journal.pone.0192391
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