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NATURE takes an intimate look at the snowy owl, a bird made popular by Harry Potter's faithful companion, Hedwig. "Snowies" stand out for their magical beauty, intelligence and charm. Viewers discover that these strikingly beautiful Arctic owls have a range of skills far more impressive than those required of magical messengers. It premieres Wednesday, October 24, 2012, on PBS.
A long-standing mystery in biology about the longer lifespans of bigger creatures may be explained by the application of a physical law called the Constructal Law.
What this law proposes is that anything that flows -- a river, bloodstream or highway network -- will evolve toward the same basic configuration out of a need to be more efficient. And, as it turns out, that same basic law applies to all bodies in motion, be they animals or tanker trucks, says Adrian Bejan, the J.A. Jones Professor of mechanical engineering at Duke and father of the Constructal Law.
In his latest theory paper, appearing Aug. 24 in the journal Nature Scientific Reports, Bejan argues that there is a universal tendency for larger things, animate and inanimate, to live longer and to travel further.
He starts his argument with an examination of the well-known observation in biology that larger animals tend to live longer. Bejan wanted to see if this general rule might apply to inanimate systems as well and proceeded to mathematically analyze the relationship in rivers, jets of air and vehicles.
He found, as a general rule, that bigger rivers are older and that larger jets of air, such as atmospheric jet streams, last longer. By his calculations, larger vehicles should also last longer, but hard evidence of that is lacking, he says, and there are outliers of course, like Subaru Justys with 300,000 miles.
By being larger and lasting longer, all of these systems also travel farther, he says.
If you look at a moving vehicle or animal simply as a mass in motion, that is, something flowing, "the spreading of the mass of vehicles and animals is completely analogous to the flow of water in river channels," Bejan says. "It is the same design."
Interestingly, if the body size and lifespan of known species of animals are plotted on a curve, it falls on a slope of about ¼. And then, following a different line of inquiry, if you plot the frequency of breathing to body size, that is a slope of -1/4.
When combined, these two insights about animal body size work out to a constant for the number of breaths per lifetime, Bejan says. This gives most creatures about the same number of breaths in their lifetime, but the larger, slower-breathing animals use their breaths up over a longer span of time. "So bigger means a longer lifespan," he said. "I was looking at this enigma about body size and longevity from a point of view that hadn't occurred to biologists," Bejan said.
The Constructal Law governs how big an engine a truck needs and how big a heart a whale needs. "There's no difference between a vehicle and an animal," Bejan said. "Being larger means two things, not one: you live longer and you travel farther."
There are, of course, notable exceptions to the rule: The 4-ounce Arctic Tern travels more than 44,000 miles a year.
"The size-effect on travel and life time is the same for the animate and the inanimate," Bejan argues. "Everything that moves enjoys the same design."
CITATION: "Why the bigger live longer and travel farther: animals, vehicles, rivers and the winds." Adrian Bejan, Nature Scientific Reports. Aug 24, 2012
Contact: Karl Leif Bates
karl.bates@duke.edu
919-681-8054
Duke University
Ενώ τα πύρινα μέτωπα στο νησί της Χίου μαίνονται για έκτη συνεχή ημέρα και η πυρκαγιά έχει ήδη καταστρέψει περισσότερα από 140 χιλιάδες στρέμματα δασικής και γεωργικής γης, η Διεύθυνση Δασών Χίου θεώρησε επαρκή την αναστολή του κυνηγιού για έξι μόνο μέρες! Συγκεκριμένα, προχώρησε στην αρχή αυτής της εβδομάδας στην έκδοση απόφασης αναστολής του κυνηγιού η οποία θα είναι σε ισχύ μέχρι την ερχόμενη Δευτέρα 27 Αυγούστου.
Σύμφωνα με τις περιβαλλοντικές οργανώσεις Αρκτούρος, Αρχέλων, Ελληνική Εταιρεία Περιβάλλοντος και Πολιτισμού, Ελληνική Εταιρεία Προστασίας της Φύσης, Ελληνική Ορνιθολογική Εταιρεία, Καλλιστώ, Δίκτυο Μεσόγειος SOS, MΟm-Εταιρία Μελέτης και Προστασίας της Μεσογειακής Φώκιας και WWF Ελλάς η απόφαση αυτή είναι υποκριτική και περιβαλλοντικά απαράδεκτη. Η αναστολή του κυνηγιού για ικανό χρονικό διάστημα είναι ένα από τα απολύτως απαραίτητα και επείγοντα μέτρα για τη σταδιακή αποκατάσταση της άγριας πανίδας μετά από πυρκαγιά.
Στη Χίο, όπως και σε κάθε φυσική περιοχή που πλήττεται από πυρκαγιά, η άγρια πανίδα υφίσταται σοβαρές επιπτώσεις και είναι ιδιαίτερα ευάλωτη: πολλά ζώα που δεν προλαβαίνουν ή δεν μπορούν να διαφύγουν αποτεφρώνονται, ενώ όσα επιβιώνουν χάνουν τους χώρους όπου τρέφονται, ξεχειμωνιάζουν και φωλιάζουν. Σε συνθήκες αποκατάστασης οικοσυστημάτων που έχουν πληγεί από πυρκαγιές, η θήρα συνιστά σοβαρό παράγοντα κινδύνου για τους πληθυσμούς της ορνιθοπανίδας, αλλά και για άλλες ομάδες πανίδας, τόσο εξαιτίας της άμεσης θανάτωσης των ατόμων όσο και εξαιτίας της όχλησης που προξενεί σε είδη που δεν αποτελούν στόχους. Επίσης, τόσο οι καμένες περιοχές, όσο και οι άκαυτες νησίδες βλάστησης και θέσεις με φυσική βλάστηση περιμετρικά των καμένων εκτάσεων, πρέπει να προστατευθούν, καθώς πρόκειται να αποτελέσουν την πηγή για τον επανεποικισμό των πυρόπληκτων περιοχών με είδη πανίδας αλλά και χλωρίδας.
Υπό αυτές τις σοβαρές συνθήκες είναι κρίσιμη η αναστολή της φετινής κυνηγετικής περιόδου σε ολόκληρο το νησί της Χίου και κυρίως στις άκαυτες εκτάσεις, έτσι ώστε να διασφαλισθούν ασφαλή καταφύγια για την άγρια ζωή. Ιδιαίτερη έμφαση πρέπει να δοθεί στην αυστηρή φύλαξη των άκαυτων νησίδων βλάστησης όπου από τις αρχές του Σεπτέμβρη θα σταθμεύσουν χιλιάδες μικρόπουλα κατά το μεταναστευτικό τους ταξίδι προς το Νότο και τα οποία αναμένεται να κινδυνεύσουν από την εκτεταμένη παράνομη συλλογή τους με ξόβεργες, μια πρακτική που συντελείται στη Χίο κάθε χρόνο.
Επικροτούμε την πρωτοβουλία του Κυνηγετικού Συλλόγου Χίου να παροτρύνει τα μέλη του να απέχουν από τη θήρα. Έχοντας την πεποίθηση ότι ιδιαίτερα αυτός συμμερίζεται την αγωνία μας για την επιβίωση της άγριας πανίδας τον καλούμε να συνηγορήσει στην παραπάνω πρόταση.
Καλούμε την κεντρική δασική υπηρεσία, την πολιτική ηγεσία του Υπουργείου Περιβάλλοντος, Ενέργειας και Κλιματικής Αλλαγής, αλλά και την αρμόδια Αποκεντρωμένη Διοίκηση, να δώσουν εντολή για την επέκταση της απόφασης της Διεύθυνσης Δασών Χίου για τη φετινή κυνηγετική περίοδο. Υπενθυμίζουμε ότι μετά τις καταστροφικές πυρκαγιές του 2007, με την έλλειψη πολιτικής βούλησης από το τότε ΥΠΕΧΩΔΕ και τις περιφερειακές αρχές, αφέθηκε η απόφαση απαγόρευσης κυνηγιού αποκλειστικά στα κατά τόπους Δασαρχεία και δεν πάρθηκαν επαρκή μέτρα για όλες τις πυρόπληκτες περιοχές.
Η πολιτική απαξίωση που γνώρισε το περιβάλλον και η διαχείρισή του, ανεξαρτήτως κυβερνήσεων, τις τελευταίες δεκαετίες, αποτελεί αδιαμφισβήτητα τη βαθύτερη αιτία της οικολογικής και οικονομικής καταστροφής που βιώνει σήμερα η κοινωνία της Χίου. Η επόμενη μέρα και οι αποφάσεις που θα ληφθούν θα είναι αδιάψευστος μάρτυρας για το αν επιτέλους η καταστροφή μας διδάσκει, ή αν οδεύουμε, εν μέσω κρίσης, ολοταχώς προς την επόμενη.
Επικοινωνία:
NOAA researchers are getting a comprehensive view of the ocean floor using a new instrument, and have confirmed that there are high numbers of young sea scallops off of Delaware Bay.
Unofficially dubbed the "Seahorse" because of its curved and spiny profile, the instrument is the latest and most sophisticated version of a survey system developed at the Woods Hole Oceanographic Institution (WHOI) and used on sea scallop resource surveys conducted by NOAA's Northeast Fisheries Science Center (NEFSC). This is the first year that the sea scallop survey has used both a dredge and the Seahorse's multisensory, integrated, benthic ecosystem sampling capability concurrently.
"The Seahorse results from nearly a decade of commitment to research and development by the fishing industry, our academic partners, NMFS, and other specialists working toward a mutual goal using a variety of funding sources," said Bill Karp, science and research director at the NEFSC. "Joint efforts like this take advantage of each party's strengths. We get good results, and I intend to continue engaging fishermen, academia, and other experts to help us make progress on a range of scientific and technical issues important to better managing our fisheries."
The Seahorse is equipped with stereo cameras and strobes (to take color images), a CTD (to measure conductivity, temperature and depth), fluorometer (to measure chlorophyll), spectrometer (to measure water color and trace chemicals in the water), dissolved oxygen sensors, and a high resolution side scan imaging system, among other instruments.
"We are excited about this new system because it gives us a way to make a significant leap forward in understanding scallop biology, ecosystem effects, and how well resource management is working," said Deborah Hart, a mathematical biologist at the NEFSC's Woods Hole Laboratory who also leads the agency's sea scallop stock assessment effort.
Towed behind a ship at around six knots (about 7 miles per hour) and flying about two meters (roughly six feet) above the sea floor, the Seahorse provides a view of the ocean floor more detailed than any obtained to date by the NEFSC's resource surveys. Initially the Seahorse is only being used for surveying sea scallop abundance and distribution, but investigations of other species, benthic habitat, and ecosystems studies are among other potential uses of the technology.
"The applications of this integrated technology are nearly limitless," said Scott Gallager, a WHOI scientist and co-developer of the Seahorse. "By integrating optical imaging with very high spatial resolution with side scan acoustics imaging, we can greatly expand our knowledge of seafloor characteristics and biological community structure."
This year's NEFSC sea scallop survey of the Mid-Atlantic area and Georges Bank was conducted aboard the 146-foot Research Vessel Hugh R. Sharp, operated by the University of Delaware, and used for the annual NEFSC surveys since 2008. The survey left June 1 on the first of three legs and started off of the Delmarva Peninsula. It then worked its way north off of New Jersey and Long Island and finished up on Georges Bank, east of Cape Cod. The third and final leg returned to NEFSC's Woods Hole Laboratory July 7.
Results were positive not only for the Seahorse's performance but also for what the survey found -- lots of juvenile "seed" scallops in portions of the Mid-Atlantic. Especially high numbers of seed were seen in the "Elephant Trunk" area off of Delaware Bay. The largest numbers of juvenile scallops ever recorded in the NEFSC scallop survey were observed in this area during the 2002 and 2003 surveys; the value of these scallops when they were harvested between 2007 and 2011 was around $500 million at the dock. According to Hart, the 2012 observations appear similar to those from 2002, which bodes well for the future.
The observations from the NEFSC were complemented by similar findings from surveys conducted by the Virginia Institute of Marine Sciences (VIMS) and the scallop industry in the Hudson Canyon and Delmarva areas. These surveys were done on commercial fishing vessels, using the same type of 8-ft dredge used by NEFSC surveys. The NEFSC survey team and the VIMS scientists are encouraged by what they have seen, especially since scallop recruitment in the Mid-Atlantic has been poor for the last three years.
Many of the juveniles observed in these surveys could grow to commercial size in about three years if given the chance to grow before they are harvested. Rotational area closures are successfully used in the Northeast to maintain a profitable and sustainable scallop fishery.
The area-based management of the Atlantic sea scallop fishery depends heavily on survey data. In addition to the NEFSC sea scallop survey, other important sources of data include area-specific cooperative surveys with the fishing industry and academic institutions. Among those are surveys conducted using the University of Massachusetts Dartmouth School of Marine Science and Technology (SMAST) video survey system, which captures video footage at specific locations.
The move toward an integrated survey began in 2007 when the NEFSC started calibrating dredge tows made by different vessels using the HabCam system. Hundreds of these "joint tows" were conducted between 2007 and 2011, providing a baseline for integrating scallop abundance data collected by HabCam into the survey.
The 2011 NEFSC sea scallop survey was conducted in three legs from May through June. The first leg was a dredge survey covering the Mid-Atlantic (Virginia to Long Island) region, the second leg was a dredge survey covering Georges Bank. The third leg was a HabCam survey only and was conducted over parts of Georges Bank covered by the earlier dredge surveys. It was the first large-scale HabCam survey, intended as a prototype for future surveys, and used an earlier version of the HabCam system. More than 2.5 million photographs were taken by the instrument during the 8-day cruise. These promising results encouraged the NEFSC to transition to a survey that combines the strengths of more than one sampling system.
"Dredges collect sea scallops that we can measure, weigh, and collect biological samples from, in order to determine age and growth rates, and to examine other biological characteristics," said Hart. "A towed camera and oceanographic sensor system doesn't collect animals, but documents everything it sees and measures the environment continuously as the vehicle moves along. The combination of physical samples and continuous imaging are giving us a more complete understanding of both scallop populations and how they interact with their environment."
The Seahorse takes up to 10 overlapping, high resolution digital still images per second, creating a continuous underwater image "ribbon" or mosaic of the seafloor. Navigation and other systems data are displayed on a series of monitors for the pilot, who controls the towed system with a joystick. Hundreds of thousands of real-time optical and acoustic images as well as oceanographic and environmental data are collected each day by the vehicle, helping researchers to document the ways in which commercially valuable stocks like sea scallops and their habitats change over time.
The HabCam concept has been developed over about a decade by the HabCam group, with assistance from NEFSC scientists. The HabCam group includes WHOI scientists, engineers, and commercial fishermen. The various HabCam models have been funded by different sources over time, through the sea scallop fishery management plan's Research Set-Aside Program, the Northeast Consortium, NOAA Fisheries Service, the WHOI Ocean Life Institute, MIT Sea Grant, and NOAA's Integrated Ocean Observing Systems Program.
The Seahorse version of HabCam, version 4, was supported by research and development funds provided by NOAA Fisheries Service's Office of Science and Technology specifically to develop this technology.
"It is a great example of collaboration and cooperation between NEFSC, the HabCam group, and the crew of the research vessel Hugh Sharp," Hart said of the recently-completed 2012 at-sea survey, which produced more than 7 million stereo images in 30 days at sea.
Calculating abundance and biomass from HabCam data requires more sophisticated model-based estimation methods than those used for data collected in the dredge-only survey. Hart and NEFSC colleague Burton Shank are now working on that aspect of the project. Dredge surveys provide several hundred stations or data points of information, while the Seahorse HabCam system provides millions of continuous samples.
"It is perfect for ecosystem-based management since it puts data into context," Hart said. "The Seahorse takes an unbroken series of stereo camera images that can help answer, or raise, questions about how things relate to each other. Although we are focused on sea scallops, these data can be mined for many other projects, including estimates of fish abundance, estimating the impacts of fishing and other human activities on the sea floor, and understanding the dynamics of and interrelationships between organisms that live at the bottom of the sea.
Contact: Shelley Dawicki
Shelley.Dawicki@noaa.gov
508-495-2378
NOAA Fisheries Northeast Fisheries Science Center
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This is a moose mother and her newborn calf. Credit: Dr. Joel Berger |
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Based on ten years of fieldwork in the Tetons of Wyoming, WCS Conservation Biologist, University of Montana Professor and study author Dr. Joel Berger looked at whether body size of juvenile moose and maternal presence were related to survival of the young animals. In animals from elk to lizards and fish, size matters, and larger individuals enjoy a survival advantage. However, results of Berger's study showed that for juvenile moose, body mass had no significant effect on overwinter survival. Maternal presence did.
The study, "Estimation of Body-Size Traits by Photogrammetry in Large Mammals to Inform Conservation" appears in the early view section of the on-line edition of the journal Conservation Biology.
The study found that orphaned moose in their first winter were subjected to 8 to 47 times more aggression from adult moose than were young moose whose mothers were present. Overall, the survival of orphan calves was about 8 times lower than those with mothers.
Along with facing more aggression from kicking by adult females and being displaced from the best feeding areas, Berger theorized that orphans incur greater metabolic costs and expend more energy in deep snow. Why orphans were attacked more was not clear, but Berger raised the possibility that mothers were trying to maintain more resources for their own offspring.
"These findings highlight the importance of maternal presence rather than body size and suggest policy changes may be warranted in how harvest quotas are set," said Berger. "In some circumstances, the shooting of mothers with young has been permitted under the assumption that calf survival is minimally affected. Clearly, that is not the case."
In another development from the study, Berger pioneered a new method to estimate the size of juveniles without resorting to immobilization by darting or netting by helicopters – both methods that are stressful to wildlife. Instead, Berger used photogrammetry—a process of using photographs to determine the properties of objects. Digitally measuring head sizes on photographs enabled estimation of juvenile body mass in a quick and non-invasive fashion.
Berger said, "Other methods of acquiring data on large animals are exhaustive, expensive and more invasive. Photogrammetric assessment has shown to be accurate, widely deployable and much easier on the animals and scientists, and the findings in this study illustrate the method can be used to inform conservation planning."
Contact: Scott Smith
ssmith@wcs.org
718-220-3698
Wildlife Conservation Society
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A male rock sparrow: His song reveals a lot about his qualities as a potential mate, so females will be listening carefully to his performance. A team of researchers from the Max Planck Institute for Ornithology in Seewiesen and the University of Copenhagen have discovered that the tempo, the pitch, and the amplitude of song reflect male reproductive success. Credit: Henrik Brumm/MPI for Ornithology |
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The song of male songbirds is multifaceted and has two main functions: to repel rivals and to attract mates. Females often pay attention to certain features within a song, such as the presence of special syllables, to assess the quality of the singing male. A team of researchers from the Max Planck Institute for Ornithology in Seewiesen and the University of Copenhagen has now found that the tempo, the pitch, and the amplitude of song reflect male reproductive success in rock sparrows. Surprisingly, the more successful and older males sang their songs with a higher pitch and a slower tempo than yearling males. However, older males lost paternity more often in their own nest but could more than compensate this by a larger number of extra-pair young, resulting in the highest reproductive success. Cuckolded males regardless of whether they were young or old, sang louder – perhaps as a response to the absence of their unfaithful mate.
Female birds often have a hard job to do in order to assess the quality of a prospective mate. Many males literally dress up their feathers to impress females. For songbirds, it is apparently easier as they are able to modify their songs in a sensational manner. However, the question remains as to which song trait a female should pay particular attention - should she perhaps monitor the number of all song syllables a male is able produce? For species with large song repertoires this would take quite long. Therefore females are better off to listen to special features within male song, such as the so-called "sexy syllables" in the songs of canaries. This means, the more a certain song trait a male is able to sing, the higher its quality, and the female can look forward to healthy and strong offspring. This also might hold true for the trait song amplitude, as in some species loud song is more attractive than silent song.
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Hopefully, these two have no problems with infidelity: A rock sparrow couple enjoying their nestbox home. Researchers have now found out that males whose female companion plays away from home sing louder: Probably in a desperate attempt to tighten the pair bond to the unfaithful partner with particularly impressive sound volume. Credit: Henrik Brumm/MPI for Ornithology |
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An international team of researchers headed by Henrik Brumm from the Max Planck Institute for Ornithology in Seewiesen apparently has now found the opposite scenario in a population of rock sparrows in the French Alps. The researchers recorded the songs of male rock sparrows in two subsequent breeding seasons with a special emphasis on the amplitude. The conditions in the field make measurements of amplitude relatively difficult, making it a rather neglected topic in behavioural research. The birds were nesting exclusively in wooden nestboxes that were attached to utility poles and which they also used as singing posts. In this way the researchers were able to attach the microphones to the pole in a defined distance to the singing bird, which is essential for a reliable determination of the sound pressure level. Additionally, the researchers conducted a paternity analysis by means of the microsatellite method.
Rock sparrows sing a very simple song that consists of only one element that is repeated several times to form a song bout. This is in clear contrast to other birds such as the nightingale, which has a huge repertoire of different song types. Surprisingly, the researchers found that those birds that were singing at a lower rate and a higher pitch sired a larger number of extra-pair young in other nests. Successful males, which were mostly older, could be distinguished from their younger, yearling rivals by their slower song tempo. Older males had a higher status and probably they did not need to advertise it by their song. In contrast, one-year old males were not able to compensate for the lower attractiveness by a higher song rate and a lower pitch. Moreover, those males that sang louder were more likely to lose paternity in their own nest; but again there were age-dependent differences: Older males had a higher loss of paternity in their own nest and sang at higher amplitudes compared to their younger rivals. "The high amplitude song of males that lost paternity is not a quality characteristic but rather the desperate attempt to tighten the pair bond to the unfaithful partner", says Erwin Nemeth, first author of the study. The older males were able to compensate their paternity loss in their own nest by gaining more extra-pair young, whereas there is nothing else for the younger yearling males but to wait for better times in the next year.
Original work:Erwin Nemeth, Bart Kempenaers, Giuliano Matessi, Henrik Brumm Rock sparrow song reflects male age and reproductive success PLoS One, published online on August 23, 2012
Contact: Dr. Erwin Nemeth
enemeth@orn.mpg.de
43-664-456-8191
Max-Planck-Gesellschaft
Athens, Greece. Credit: GNTO
Cities – with their concrete canyons, isolated greenery, and congested traffic – create seemingly chaotic and often powerful wind patterns known as urban flows. Carried on these winds are a variety of environmental hazards, including exhaust particles, diesel fumes, chemical residues, ozone, and the simple dust and dander produced by dense populations.
In a paper published in the American Institute of Physics (AIP) journal Physics of Fluids, researchers present the unexpected finding that pollutant particles, rather than scattering randomly, prefer to accumulate in specific regions of the urban environment and even form coherent structures. "The unexpected finding is coherent patterns in fluid flows were thought to have no real analog in nature," said Wenbo Tang of Arizona State University in Tempe. "In previous studies, the existence of these patterns in fluid flows was only verified with idealized 'theoretical' flows. It was not known if such structures were robust enough to manifest in the environment."
The researchers were able to verify this by using a new mathematical formula, the first of its kind, to simulate the long-term random motion of pollutant particles as would be found in the real world. These more realistic simulations revealed that coherent patterns emerged from the random motions of particles carried along by the urban flow. The results can be used to generate maps of well and poorly mixed regions and highlight urban areas that are most susceptible to high concentrations of pollutants, indicating locations that should be avoided or remedied.
According to the researchers, the modeling capabilities developed in this project directly benefit decision makers addressing issues related to urban pollution, human comfort, and the effects of climate change on urban areas. The research also aims to understand the interconnection of urban flows with the regional and global atmosphere.
Contact: Charles Blue
cblue@aip.org
301-209-3091
American Institute of Physics
Ocean Circulation
A new record of past temperature change in the tropical Atlantic
Ocean's subsurface provides clues as to why the Earth's climate is so
sensitive to ocean circulation patterns, according to climate scientists
at Texas A&M University.
Geological oceanographer Matthew Schmidt and two of his graduate students teamed up with Ping Chang, a physical oceanographer and climate modeler, to help uncover an important climate connection between the tropics and the high latitude North Atlantic. Their new findings are in the current issue of PNAS (Proceedings of the National Academy of Sciences).
The researchers used geochemical clues in fossils called foraminifera, tiny sea creatures with a hard shell, collected from a sediment core located off the northern coast of Venezuela, to generate a 22,000-year record of past ocean temperature and salinity changes in the upper 1,500 feet of water in the western tropical Atlantic. They also conducted global climate model simulations under the past climate condition to interpret this new observational record in the context of changes in the strength of the global ocean conveyor-belt circulation.
"What we found was that subsurface temperatures in the western tropical Atlantic rapidly warmed during cold periods in Earth's past," Schmidt explains.
"Together with our new modeling experiments, we think this is evidence that when the global conveyor slowed down during cold periods in the past, warm subsurface waters that are normally trapped in the subtropical North Atlantic flowed southward and rapidly warmed the deep tropics. When the tropics warmed, it altered climate patterns around the globe."
He notes that as an example, if ocean temperatures were to warm along the west coast of Africa, the monsoon rainfall in that region would be dramatically reduced, affecting millions of people living in sub-Saharan Africa. The researchers also point out that the southward flow of ocean heat during cold periods in the North Atlantic also causes the band of rainfall in the tropics known as the Intertropical Convergence Zone to migrate southward, resulting in much drier conditions in northern South American countries and a wetter South Atlantic.
"Evidence is mounting that the Earth's climate system has sensitive triggers that can cause abrupt and dramatic shifts in global climate," Schmidt said.
"What we found in our subsurface reconstruction was that the onset of warmer temperatures, thought to reflect the opening of this 'gateway' mechanism, occurred in less than a few centuries. It also tells us that it might be a good idea to monitor subsurface temperatures in the western tropical Atlantic to assess how the strength of the ocean conveyor might be changing over the next few decades as Earth's climate continues to warm."
"One way to prepare for future climate change is to increase our understanding of how it has operated in the recent past."
This research was funded by the National Science Foundation.
As one of the world's leading research institutions, Texas A&M is in the vanguard in making significant contributions to the storehouse of knowledge, including that of science and technology. Research conducted at Texas A&M represents an annual investment of more than $700 million. That research creates new knowledge that provides basic, fundamental and applied contributions resulting in many cases in economic benefits to the state, nation and world.
Contact: Keith Randall
keith-randall@tamu.edu
979-845-4644
Texas A&M University
