We discuss and comment on the role agriculture will play in the containment of the CO2 problem and address protocols for terraforming the planet Earth.
A model farm template is imagined as the central methodology. A broad range of timely science news and other topics of interest are commented on.
Friday, May 24, 2013
Revising Darwin’s Sinking-Island Theory
It amazes me that folks are still pitching the idea that we will see radical sea level shifts over the next two hundred years. That is complete nonsense. It accepts the worse case scenario of our climate modeling regime gone mad. It will still happen in geological time as we swing through our orbit about Sirius. This is of course not understood at all but is a surprisingly real conjecture.
Better though this item cleans up some unfinished business for myself
related to the serious release of water since the last Ice Age.
I would like to see coral reefs established artificially in the
natural Goldilocks zone worldwide. This is easily done by simply
placing matrices of cheap mesh on the sea bed and maintaining a low
charge for a few months. This establishes a working bed for the
coral and shellfish to attach to and start the process of reef
Using that method, it is no trick to grow barrier reefs everywhere
coral at least is able to prosper.
A satellite image of
Maupiti, one of the Society Islands, which is on its way to becoming
an atoll. Submerged reef appears in pale blue
The three different
formations of South Pacific coral-reef islands have long fascinated
geologists. Tahiti’s coral forms a “fringing” reef, a shelf
growing close to the island’s shore. The “barrier” reefs
of Bora Bora are separated from the main island by a calm lagoon.
Finally, an “atoll,” such as Manuae, appears as a ring of
coral enclosing a lagoon with no island at its center.
The question of how
reefs develop into these shapes over evolutionary time produced an
enduring conflict between two hypotheses, one from English naturalist
Charles Darwin and the other from geologist Reginald Daly. But in a
paper recently published in the journal Geology, researchers at MIT
and Woods Hole Oceanographic Institution (WHOI) use modern
measurements and computer modeling to resolve this old conundrum.
proposed that fringing reefs, barrier reefs and atolls reflect
different stages in a dramatic process that occurs as an island sinks
into the ocean floor — the ultimate fate of all of the world’s
volcanic ocean islands. As young volcanic rock cools and is carried
away from a volcanic “hot spot” by the movement of tectonic
plates, an island sinks as much as a few millimeters per year.
As the island
sinks, resident coral reefs on the island flanks grow upward toward
the sea surface. The living coral organisms up top, and their
symbiotic algae, get enough sunlight to keep pace with the sinking of
the island. As the coral grows upward and the island sinks down, a
fringing reef progresses to a barrier reef, and eventually to a
Darwin’s reef theory can’t explain the trajectories of all
volcanic ocean-island systems, as MIT/WHOI graduate student
Michael Toomey and collaborators Taylor Perron, the Cecil and Ida
Green Assistant Professor of Geology at MIT, and Andrew Ashton, a
coastal geomorphologist at WHOI, discovered.
Islands, they realized, show a different kind of progression: For
example, the researchers found fringing reef where they expected to
find no reef development and drowned barrier reefs where they
expected living barrier reefs. “Those islands are just not sinking
into atolls like the Society Islands,” Toomey says, “so we wanted
to develop a model to explain these differences.”
They turned to
the theory of Darwin’s challenger, Reginald Daly, who argued that
sea-level cycles, not island subsidence, were the key to
understanding coral formations. Sea level drops during ice ages, when
water becomes locked in ice sheets on land, and then rises between
glaciations as the ice melts. Daly suggested that exposure to
increased wave energy during sea-level drops would erode an island
away; then, as sea level rises, the coral would regrow on submerged
researchers decided to consider the ideas of both Darwin and Daly,
creating a computer model focusing on the relationships among coral
growth, sunlight availability, water depth and erosion. In
combination with island subsidence rates, the model calculates how a
coral reef develops as sea level varies over hundreds of thousands of
and subsidence are delicately balanced: If the combination of
sea-level change and island sinking deepens the water faster than the
coral can grow, the reef will drown; if the coral grows faster than
the water deepens, the coral growth will catch up with the sea
surface, then slow down as the reef is exposed to eroding waves
at sea level.
The team can
model Darwin’s scenario by including island subsidence but no
glacial sea-level cycles. As expected, the configuration that emerges
does not resemble current reef formations. So, they added in a
sea-level history based on geological evidence and paleoclimate data,
which allows the model to account for a sea level oscillating between
the present level and 120 meters below that level every 100,000
the model, running a course of four glacial cycles (400,000 years)
into the past, yielded a coral-reef distribution that matched up well
with the real-world observations. The barrier reefs, drowned barrier
reefs, and other forms were all in the correct places on the map.
“What this shows,” Perron says, “is that while island
subsidence is important, as Darwin suggested, sea-level oscillations
are also important for determining the distribution of reef types
around the world.”
sink ‘just right’
geological time machine is sophisticated enough to explain why the
Society Islands follow the Darwin progression but others do not.
According to the simulations without sea-level oscillations, most of
the environment would be likely to make the Darwin progression. But
when the sea-level oscillations are included, Ashton says, “It
turns out there is only a little ‘Goldilocks’ zone, a narrow
range of subsidence and reef-accretion rates, in which you can get
the parameters the model needed to create that tiny zone of Darwin
progression match up with Tahiti’s actual growth and subsidence
rates. That is, Tahiti has subsided just slowly enough for the deep
lagoon to develop over the last few glacial cycles without drowning
Hawaii is sinking so quickly (more than 2 millimeters per year)
that it will never see Darwin’s configuration. All it can do is
form a little reef terrace every time the sea level falls to its
lowest point. When sea level rises as ice sheets melt at the end of
each glacial period, the reef drowns and stays drowned.
big revelation is that coral reefs are very sensitive to sea-level
changes. This is useful information, notes Peter Burgess, a
professor and chair of earth sciences at Royal Holloway, University
of London, because using this model to explore different scenarios
of real-world reef formation can help produce a record of how sea
level oscillated over long time scales. “It’s helpful to know how
fast the sea level has changed in the past,” he says, “because
there is a high probability it will change rapidly in the next couple
hundred years, and we’d like to understand how that change might
was supported by the Andrew W. Mellon Foundation and the Ralph E.
Hall Endowed Funds for Innovative Research through the Woods Hole