by University of Sydney, September 28, 2017 in WUWT
Recent findings suggest that episodes of very rapid sea-level rise of about 20m in less than 500 years occurred in the last deglaciation, caused by periods of catastrophic ice-sheet collapse as the Earth warmed after the last ice age about 20,000 years ago.
Lead author, PhD candidate at the University of Sydney, Kelsey Sanborn, has shown this sea-level rise event was associated with “drowning” or death of coral reefs in Hawaii.
See also here
by McCormack et al., 2017, September 18, 2017 in FungalEcology
In light of the above findings, it would appear that, given the near-global distribution of this EM fungi and its importance in stimulating ecosystem productivity, the positive impact of elevated CO2 on C. geophilumproduction (~50% increase for a 200 ppm rise) represents a welcomed benefit for the future of Earth’s forests.
by University of California, September 12, 2017 in WUWT
A trend toward greater discrimination under higher CO2 levels is broadly consistent with tree ring studies over the past century, with field and chamber experiments, and with geological records of C3 plants at times of altered atmospheric CO2, but increasing discrimination has not previously been included in studies of long-term atmospheric 13C/12C measurements. We further show that the inferred discrimination increase of 0.014 ± 0.007‰ ppm−1 is largely explained by photorespiratory and mesophyll effects.
by Forschungsverbund Berlin e.V. (FVB), September 21, in ScienceDaily
With the help of satellite observations from 188 lakes worldwide, scientists have shown that the warming of large lakes amplifies their color. Lakes which are green due to their high phytoplankton content tend to become greener in warm years as phytoplankton content increases. Clear, blue lakes with little phytoplankton, on the other hand, tend to become even bluer in warm years caused by declines in phytoplankton. Thus, contrary to previous assumptions, the warming of lakes tends to amplify their richness or poverty of phytoplankton.
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by Alan Jones, interviews peter Ridd, July 28, 2017 in JoNova
Corals have a little thermometer built in them, when you take a core of them from many years ago we know what the temperature of the water was back when Captain Cook sailed up the coast, it was actually about the same temperature then. It was colder 100 years ago, but it has recovered from that. The temperatures on the reef are not even significantly warmer than average on a hundred year timescale.
Corals that bleach in one year will be less susceptible to bleaching in following years
by James Cook University and Université Catholique de Louvain, July 3, 2017, in ScienceDaily
Professor Wolanski said the study was subjective to the extent that there was a lack of oceanographic field data in the Great Barrier Reef itself for the 2016 el Nino event. By contrast, the amount of oceanographic field data in the Torres Strait and the northern Coral Sea was very good.
“What we presented is our best-informed attempt to reveal the mechanisms involved in causing the event, based on the available oceanographic data combined with the existing body of knowledge on the water circulation in and around the Torres Strait/Northern Great Barrier Reef region.”
by S.D. Connell et al., 2017 in Current Biology (in CO2 Science)
The increasing absorption of CO2 and associated decline in seawater pH values is thought to pose direct harm to marine life in the decades and centuries to come by affecting rates of survival, calcification, growth, development and/or reproduction. However, as ever more pertinent evidence accumulates, a much more optimistic viewpoint is emerging.
by Mote Marine Laboratory, June 5, 2017 in ScienceDaily
A controlled lab study led by Mote Marine Laboratory and published June 1 in the peer-reviewed journal PLOS ONE revealed that black band disease was less deadly to mountainous star coral (Orbicella faveolata) as water acidified, or decreased in pH.
by N.R. Evensen and P.J. Edmunds, 2017, J. Exp. Biology
Regardless of the actual mechanism responsible for the densely aggregated corals to maintain calcification rates in the face of ocean acidification, the study of Evensen and Edmunds, in their words, offers “a compelling case for differential densities of branching coral colonies (i.e. aggregation types) mediating the sensitivity of coral communities in at least some habitats” and it further supports “recent indications that neighboring organisms, such as conspecific coral colonies in the present example, can create small-scale refugia from the negative effects of ocean acidification” And that is more good news for those concerned about the future health of these important marine ecosystems.
by Rutgers University, June1, 2017 in SienceDaily
Stony corals may be more resilient to ocean acidification than once thought, according to a Rutgers University study that shows they rely on proteins to help create their rock-hard skeletons.
“The bottom line is that corals will make rock even under adverse conditions,” said Paul G. Falkowski, a distinguished professor who leads the Environmental Biophysics and Molecular Ecology Laboratory at Rutgers University-New Brunswick. “They will probably make rock even as the ocean becomes slightly acidic from the burning of fossil fuels.”
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by P. Ventura et al., 2016,
Writing as background for their work, Ventura et al. (2016) say that “non-calcifying photosynthetic anthozoans have emerged as a group that may thrive under high carbon dioxide partial pressure (pCO2) conditions via increased productivity,” yet they add that “the physiological mechanisms underlying this potential success are unclear.”
by Eghbert Elvan Ampou et al., 2017
The clear link between mortality and sea level fall also calls for a refinement of the hierarchy of El Niño impacts and their consequences on coral reefs.