By way of NASA and Landsat technology, Detecting Detrimental Change in Coral Reefs
Situated in shallow clear water, most coral reefs are visible to satellites that use passive remote sensing to observe Earth’s surface. But coral reefs are complex ecosystems with coincident coral species, sand, and water all reflecting light. Dustan found that currently orbiting satellites do not offer the spatial or spectral resolution needed to distinguish between them and specifically classify coral reef composition. So instead of attempting to classify the inherently complex coral ecosystem to monitor their health, Dustan has instead started to look for change—how overall reflectance for a geographic location varies over time.
Dustan uses a time series of Landsat data to calculate something called temporal texture¬—basically a map showing where change has occurred based on statistical analysis of reflectance information. While Dustan cannot diagnosis the type of change with temporal texture he can establish where serious changes have occurred. Coral communities have seasonal rhythms and periodicities, but larger, significant changes show up as statistical outliers in temporal texture maps and often correlate with reef decline.
The Landsat data confirm quantitative field study of coral health at Carysfort reef. Between the first field study in 1974 and over the next twenty-five years coral had declined 92 percent. That decline is due to several factors environmental stress factors , including pollution, culminating with diseases that kill the weakened coral.
Dustan tested this work in the U.S. because he had a robust study site and because prior to 1999 coverage of reefs outside of the U.S. was spotty. With the Landsat 7 launch in 1999 a new global data acquisition strategy was established and for the first time the planet’s coral reefs were systematically and regularly imaged, greatly increasing our knowledge of reefs.

Carysfort Reef is located in the eastern portion of the Florida Keys National Marine Sanctuary, offshore of Key Largo. Credit: NOAA
Larger image. Carysfort is just to the west of where the map reads Atlantic Ocean.

Reef environments provide habitat for hundreds of fish species including the butterflyfish shown here in the Florida Keys National Marine Sanctuary. Credit: Chris Huss.
Spiders Hunt Prey With Unique Vision Traits
Jumping spiders, which hunt by pouncing on their prey, gauge distances to their unsuspecting meals in a way that appears to be unique in the animal kingdom, a new study finds.
The superability boils down to seeing green, the researchers found.
There are several different visual systems that organisms use to accurately and reliably judge distance and depth. Humans, for example, have binocular stereovision. Because our eyes are spaced apart, they receive visual information from different angles, which our brains use to automatically triangulate distances. Other animals, such as insects, adjust the focal length of the lenses in their eyes, or move their heads side to side to create an effect called motion parallax — nearer objects will move across their field of vision more quickly than objects farther away.
However, jumping spiders (Hasarius adansoni) lack any kind of focal adjustment system, have eyes that are too close together for binocular stereovision and don’t appear to use motion parallax while hunting. So how are these creatures able to perceive depth?
Researchers in Japan have now discovered that the arachnids accurately sense distances by comparing a blurry version of an image with a clear one, a method called image defocus.
Jumping spiders have four eyes densely packed in a row: two large principal eyes and two small lateral eyes. The spider uses its lateral eyes to sense the motion of an object, such as a fly, which it then zeros in on using its principal eyes, Akihisa Terakita, a biologist at Osaka City University in Japan and lead author of the new study, explained….
Note the four little beads on the spider's head are its eyes
In one college lab we were divided up into small groups where our assignment consisted of building a terrarium of local plant and animal life. I caught a couple small spiders that were jumping around on the sandy shore of a local lake. In addition to packing the terrarium we were supposed to identify and write up as much as we could about every living thing in the little ecological worlds that now existed in our tanks. So to get a better look at the spiders we placed them in a covered culture dish so we could get a close look under a stereo microscope. Getting a good look at the eyes of our spiders was a fascinating discovery. Seeing pictures and video is great, but not quite up to the experience of seeing the spider’s unique anatomical features up close.
Grape seed extract kills head and neck cancer cells, leaves healthy cells unharmed
Nearly 12,000 people will die of head and neck cancer in the United States this year and worldwide cases will exceed half a million.
A study published this week in the journal Carcinogenesis shows that in both cell lines and mouse models, grape seed extract (GSE) kills head and neck squamous cell carcinoma cells, while leaving healthy cells unharmed.
“It’s a rather dramatic effect,” says Rajesh Agarwal, PhD, investigator at the University of Colorado Cancer Center and professor at the Skaggs School of Pharmaceutical Sciences.
It depends in large part, says Agarwal, on a healthy cell’s ability to wait out damage.
“Cancer cells are fast-growing cells,” Agarwal says. “Not only that, but they are necessarily fast growing. When conditions exist in which they can’t grow, they die.”
Grape seed extract creates these conditions that are unfavorable to growth. Specifically, the paper shows that grape seed extract both damages cancer cells’ DNA (via increased reactive oxygen species) and stops the pathways that allow repair (as seen by decreased levels of the DNA repair molecules Brca1 and Rad51 and DNA repair foci).
Fascinating news, but the usual caveat; let’s consult with our doctors before we go off on some self administered cancer treatment. Thus far they have only tested this treatment on cell lines and mice.

Peninsula cooter Pseudemys peninsularis is a species of freshwater turtle. native to the Florida peninsula. very attractive fresh water turtles. If they fell safe in a relatively undisturbed area they enjoy a nice bask in the sun. In an otherwise great data base, I could not find them in the Online Turtle Taxonomic Literature Database and PDF Library.
This week’s science question: Name the five basic functions of the human kidney in two to ten words each. Unless I forget I’ll post the answers Monday.










