Mysterious ‘shadow zone’ traps 2000-year-old water
"A MYSTERIOUS abyss in the ocean known as the “shadow zone” traps ancient water dating back to 400AD. We now know why it’s there.
IT’S called the “shadow zone” and it lies around two kilometres below the surface in an ocean abyss where trapped water dates back to the fourth century.
This ancient water, which is between 1000 and 2000 years old, dates back to when the ancient Germanic tribe the Goths instigated the end of the Western Roman Empire and the rise of Medieval Europe. [...]"
50-years of data from a 'living oxygen minimum' lab could help predict the oceans' future
The mass of data, collected in two new Nature family papers, could help scientists better predict the impact of human activities and ocean deoxygenation on marine environments. Currently, oxygen minimum zones (OMZs) constitute up to 7 percent of global ocean volume. Continued expansion of OMZs in the northeastern subarctic Pacific has the potential to transport oxygen-depleted waters into coastal regions, adversely affecting nutrient cycles and fisheries productivity. [...]"
Source: University of British Columbia (media contact: Chris Balma)
Ocean acidification could doom key Arctic fish species: study
Ocean acidification combined with warming of the world oceans and loss of oxygen is having a severe impact on key Arctic marine species such as polar cod in the Barents Sea, according to a new study conducted by German scientists.
"The eight-year interdisciplinary study, which began in 2009 and involved more than 250 scientist in the German research network on ocean acidification BIOACID (Biological Impacts of Ocean Acidification), investigated how different marine species respond to ocean acidification – a change in the ocean chemistry that occurs when carbon dioxide (CO2) from the atmosphere dissolves in seawater.
In addition to ocean acidification, the study, Exploring Ocean Change: Biological Impacts of Ocean Acidification, also examined the cascading effect of other stressors such as ocean warming, deoxygenation, overfishing and eutrophication – the increased concentration of nutrients in estuaries and coastal waters that causes harmful algal blooms, ocean dead zones and fish kills. [...]"
Source: The Independent Barents Observer
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. [...]"
A Giant Blob of Floodwater From Harvey Is Still Moving Through the Gulf
"The rain began on August 25, and it would fall, remarkably, for four more days. We know now that Hurricane Harvey dumped as much as 60 inches of rain over parts of Texas. Twenty trillion gallons in all. The equivalent of the entire Chesapeake Bay. Enough to push the Earth’s crust down two centimeters. [...]
What oceanographers do know about the interface of freshwater and ocean comes from studying rivers that naturally empty into the sea. The key is density. Because freshwater lacks dissolved salt, it is less dense and floats atop seawater. It becomes a barrier between the air and the ocean water, which can have nasty consequences. “The freshwater sitting on the salty water cuts off the oxygen from the atmosphere getting into the ocean, and then you get the dead zone,” says Steve DiMarco [...]"
Source: The Atlantic
Acidifying oceans a bad trip for marine ecosystems
"A more acidic ocean under climate change threatens to reconfigure entire ecosystems by advantaging some fish species to the detriment of others, a new study has found. The research is one of only a few that go beyond the lab to study how species interactions are changing in nature under more extreme conditions.
Researchers from the University of Adelaide and the University of Hong Kong showed that a higher concentration of carbon dioxide in the oceans, which reacts to turn seawater more acidic, favors common fish species, allowing them to double their populations. But that might also mean the downfall of rarer, subordinate competitors, leading to biodiversity loss and a total restructuring of fish communities, with numerous ecological impacts. [...]"
Chesapeake Bay dead zone this summer worst since 2014
In June, federal scientists predicted a bigger-than-average oxygen-deprived dead zone in the Chesapeake Bay this summer, and it turns out they were right.
Researchers with the Virginia Institute of Marine Science who study bay hypoxia announced Monday that the total amount of dead zones this summer was the worst since 2014, and a 10 percent increase over last year.
Source: Daily Press
Low Oxygen Dead Zones in the Pacific Ocean are Growing
"Every year, we see wildfires wreak havoc on large regions of the West United States, and each year scientists attempt to forecast exactly how bad the upcoming fire season is going to be by assessing things like weather, moisture levels, and a bevy of different factors. [...]"
Source: Mind Guild
What Scientists Are Learning About the Impact of an Acidifying Ocean
"The effects of ocean acidification on marine life have only become widely recognized in the past decade. Now researchers are rapidly expanding the scope of investigations into what falling pH means for ocean ecosystems."
Source: NewsDeeply: Oceans Deeply
Ocean Acidiﬁcation More Rapid in Coastal Oceans
"New research under the joint NCCOS Competitive Research Program and NOAA Ocean Acidification Program finds the combined effects of anthropogenic and biological carbon dioxide (CO2) inputs may lead to more rapid acidiﬁcation in Chesapeake Bay and other coastal water compared to the open ocean. The results indicate that eutrophication can exacerbate ocean acidification (OA) where animal and plant respiration contributes a far greater acidification in the coastal oceans relative to the open ocean. [...]"
Source: The National Centers for Ciastal Ocean Science