It's not easy to count white polar bears on white sea ice. But in Spring 2016, Russian and American scientists used infrared cameras and high resolution aerial photographs to locate warm-blooded mammals on the sea ice of the Chukchi Sea. It's the first comprehensive mammal survey ever in this region.
Polar Bear Visible To Infrared Cameral
Very interesting and valuable research, but this article propagates a false notion that polar bears are invisible in the infrared. Their thermoregulation is extremely efficient (as are all arctic animals) but they can definitely be detected with infrared cameras.
This month, scientists from the USA and Russia are working together to estimate the size of a never-before surveyed subpopulation of polar bears, using infrared thermal camera technology attached to an airplane. Sound like something out of a James Bond movie? Actually, thermal imaging has been used in wildlife studies for quite some time to detect mammals such as squirrels, deer and kangaroos, as well as birds like woodpeckers and ducks. But this survey will be the first to use the technology on polar bears at such a large scale.
The survey, carried out by NOAA Fisheries and Russian scientists from the Russian State Research and Design Institute for the Fishing Fleet, is taking place in the Chukchi Sea, which lies between the US State of Alaska and Eastern Russia and spans almost 600,000 km2 in area (almost the size of Australia). The Chukchi Sea is home to one of 19 subpopulations of polar bears in the Arctic, as well as several species of seal, two of which will also be the focus of this survey.
Once proven successful, this new method will be added to the toolbox of techniques used by scientists to monitor population trends over time. Why do we need this information? The biggest threat to polar bears globally is climate change. We need to understand how bears are responding to a warming Arctic so their populations can be properly managed. Understanding whether populations are declining, stable or increasing in size helps with this. Less summer sea ice as a result of climate change has already been shown to affect body weight, number of cubs born, and even survival of young polar bears in some areas of the Arctic.
Many of us think of the Arctic as a remote, pristine place that is shielded from the negative effects of the southern world. For most of us, polar bears are not our neighbours, but the activities taking place in our own backyards are undoubtedly causing their Arctic home to feel the heat. The Chukchi Sea polar bears are no exception. The Chukchi Sea is influenced by the warmer waters of the Pacific and Atlantic Oceans, and researchers have predicted that some of the greatest losses of polar bear habitat will occur here by the 21st century. This survey is therefore an important piece of the conservation puzzle for Russia and the USA, who in 2007 formed a bilateral Agreement to conserve and manage this shared polar bear subpopulation.
Polar bear hair has a hollow core which effectively prevents the infrared emission, or heat signature, of the polar bear from escaping the fur. This helps the bear retain its heat and stay warm. ... When imaged with an infrared camera, only the exposed parts of the rabbit were detectable
Polar bears are nearly undetectable by infrared cameras. Thermal cameras detect the heat lost by a subject as infrared, but polar bears are experts at conserving heat. The bears keep warm due to a thick layer of blubber under the skin. Add to this a dense fur coat and they can endure the chilliest Arctic day.
Pregnant polar bears dig dens in the snow where they give birth and nurse their young. Occupied dens look like ordinary snow banks. It is possible but not desirable to stand on top of one, stomping around and even jumping up and down without realizing that a bear and her cubs might be curled in a hollow just below the surface.
All of which underscores a key challenge for polar bear researchers: wild polar bears are tough to keep track of. When they are not hiding in dens that look like ordinary snow banks, they roam the vast wilderness of sea ice and tundra, usually far from human infrastructure.
Traditional wildlife collars armed with GPS transmitters helped, but only to a point. Male polar bears, with their bulging necks, simply slide traditional neck collars over their heads and leave them lying in the snow. Young polar bears grow so quickly that collars become uncomfortably tight and potentially dangerous in a matter of months. Various devices intended to release collars remotely often fail, leading some researchers to arm collars with several redundant remote-release systems, but even these do not always work.
Why is there so much interest in locating dens? In the United States, federal agencies prohibit disturbances within one mile of polar bear dens. The pro-hibition goes a long way toward stopping activities such as road construction and drilling for oil from troubling a mother bear and her cubs. But there is also a need to find dens as part of the ongoing quest to better understand polar bears and how they live. When York and Kirschhoffer climb into dens, it is not for sport, but rather to characterize the dens, to better understand how young polar bears spend their first few months of life. And Smith, working with Kirschhoffer and others, has been interested in how bears behave immediately after they emerge from dens, which requires knowledge of den locations.
An earlier version of the MACS camera system has already provided highly detailed, 3D images of ice and snow under the extreme environmental conditions around Mount Everest in the Himalayas. "We have now used this experience to develop an advanced camera instrument for remote sensing of polar regions, which, in addition to a channel for visible light, also has channels for near-infrared and thermal-infrared radiation," says Jörg Brauchle from the DLR Institute for Optical Sensor Systems in Berlin who is flying on board Polar 6. "In this way, we are closing the gap between very costly, detailed exploration on the ground and large-scale, but lower-resolution, remote sensing data acquired from space."
As lateral thermal damage is more pronounced in patients with an inflamed appendix [17, 18], and drawing on the literature [12], we hypothesized that lateral thermal spread would be greater with higher power settings and that the heating of nearby tissue, including the cecum and the mesoappendix, could lead to complications. The aim of this study was to investigate the lateral thermal spread during monopolar-aided appendectomy at different ESU power settings using real-time infrared thermography and to evaluate the severity of thermal injury to the affected tissue.
The spread of heat generated by ME through tubular anatomic structures can cause thermal injury of the intestinal wall in the regions distant to the surgical site, its necrosis and even perforation. Despite certain limitations of this study, the observed effects of monopolar coagulation can bear clinical relevance and require further investigation.
A thermographic camera (or infrared camera) detects infrared light (or heat) invisible to the human eye. That characteristic makes these cameras incredibly useful for all sorts of applications, including security, surveillance and military uses, in which bad guys are tracked in dark, smoky, foggy or dusty environs ... or even when they're hidden behind a boat cover.
Wavelength (also called frequency) is what makes each of these types of light different from one another. At one end of the spectrum, for example, we have gamma rays, which have very short wavelengths. On the flip side of the spectrum, we have radio waves, which have much longer wavelengths. In between those two extremes, there's a narrow band of visible light, and near that band is where infrared wavelengths exist, in frequencies from 430 THz (tetrahertz) to 300 GHz (gigahertz).
Sometimes, objects are so hot that they put off visible light -- think about the red, blazing-hot coils on an electric stove or the coals in a campfire. At a lower temperature those objects won't glow red, but if you can definitely put your hand near them you can feel the heat, or infrared rays, as they flow outward towards your skin.
In a situation like this, humans rely on electronic tools for assistance. In essence, thermal imaging devices are a like a sidekick for our eyesight, extending our visual range so that we can see infrared in addition to visible light. Empowered with this expanded visual information, we become the superheroes of the electromagnetic spectrum.
In 1800, a British astronomer named Sir William Herschel discovered infrared. He did so by using a prism to split a ray of sunlight into its different wavelengths and then holding a thermometer near each color of light. He realized that the thermometer detected heat even where there was no visible light -- in other words, in the wavelengths where infrared exists.
Using thermal cameras, fire fighters can locate people trapped inside structures, home in on hot spots and pinpoint structural problems before someone gets hurt. Scientists can find Arctic polar bear dens deep within snow banks. Ancient ruins often exhibit different heat signatures than the soil and rocks surrounding them, meaning archaeologists can use imagers to find their next excavation site.
Germany just can't get enough of little polar bears, but its zookeepers seem unsure about how best to deal with them. Earlier this week the country's tabloid press agonized over the deaths of two tiny Eisbär cubs in a Nuremberg zoo, who were presumably eaten by their inexperienced mother, Vilma, after zookeepers decided not to intervene. Then on Wednesday, a fresh round of photographs and videos revealed that a third cub at the same zoo had been "rescued" by zookeepers after another mother, Vera, showed signs of rejecting her offspring. "Sweet, sweeter, sweetest!" cooed the daily, Die Welt over photos of the still nameless rescued cub, who was born five weeks ago. The decision to intervene came after the death of the two other cubs triggered a broader debate in Germany about the ethics of allowing nature to take its course in the decidedly unnatural environment of a public zoo. 2ff7e9595c
Comments