Fri Sep. 27, 2013 11:52 AM PDT
rached-innov : Innovation, Science, Espace, Politique
Affichage des articles dont le libellé est Océan. Afficher tous les articles
Affichage des articles dont le libellé est Océan. Afficher tous les articles
samedi 28 septembre 2013
Why Carbon Pollution Is Destroying the Ocean?
Fri Sep. 27, 2013 11:52 AM PDT
mercredi 25 septembre 2013
Ocean vs. Space: Which Is the True Final Frontier?
Space may be called "the final frontier," but anyone who has seen a picture of a goblin shark or a vampire squid will agree that the ocean can be downright alien. Both realms are ripe for exploration, offer extensive potential benefits and come at a hefty price.
So which wins in a battle between the two for the title of the final frontier? Which area of exploration will result in the greater good for humanity? Dr. Paul Bunje, senior director of prize development and ocean health at the XPRIZE Foundation, and Alexandra Hall, senior director ofGoogle Lunar XPRIZE, met on the Social Good Summit stage to duke it out on Tuesday.
Space has been the clear leader for a long time. $17.8 billion dollars is going toward space exploration in 2013, compared to the $5 billion dollars that goes toward oceanic exploration. This discrepancy has led to skewed results: While 500 individuals have been sent into space, only three have visited the deepest part of the ocean, the Mariana Trench.
We have better maps of the surface of Mars than we do of our own ocean floor, and we understand more about the dark side of the moon than ocean life. Despite centuries of ocean exploration, we’ve only covered about 5% of the ocean.
Bunje insists that this needs to change.
“In that 5% we have some of the most amazing things on this planet. We’ve got a mountain range, the Mid-Atlantic Ridge, that has thousands of peaks taller than the Alps are, for instance," he said. "You’ve got, every time someone goes down, new species that are wondrous and unbelievably strange sometimes. And in reality, if you take all of the world’s oceans, that’s 99% of our living space on Earth, and we know almost nothing about it."
Bunje also said that there are three reasons why the oceans deserve more research love: food, jobs and oxygen.
The ocean produces 20% of the world’s protein supply, and 3 billion people rely on the ocean for their livelihood. The ocean also produces 70% of Earth’s oxygen. These statistics, to Bunje and other ocean activists, mean that dangers like ocean acidification and climate change need our attention.
Hall insists that the investment isn’t as skewed as it seems. The simple fact that getting into space comes with a very large dollar sign must be taken into account when comparing the budgets. She insists that the reasons to explore space include economic benefit, national security and something that cannot be simplified down to a monetary amount: the satisfaction of our own curiosity.
Benefits of space exploration aren’t just about walking on the moon anymore. Research to put astronauts into space has resulted in great advancements in technology and medicine, and has resulted in the creation of jobs and economic benefits.
Beyond that, Hall insists, is the more romantic reason to continue space exploration: Space is inspiring.
“ Finding out about the origin of our planet Earth and the rest of the solar system is something that that we have a deep need to know about,” she said.
Hall insists that space research benefits the planet as well. Seeing Earth from space created a concept of Planet Earth.NASA has more money in its budget to be used towards Earth sciences than should go towards planetary sciences, and it has resulted in significant breakthroughs, including information on the melting ice caps, climate change and ocean surface temperatures.
The good news, when it comes to space versus the ocean, is that it doesn’t have to be one or the other. Both Bunje and Hall are working on million-dollar contests to increase research in space and in the ocean. Additionally, billions of dollars in government funding go toward research projects every year, in the hopes that some of these innovations can become a reality. ...
BY TAYLOR CASTI
So which wins in a battle between the two for the title of the final frontier? Which area of exploration will result in the greater good for humanity? Dr. Paul Bunje, senior director of prize development and ocean health at the XPRIZE Foundation, and Alexandra Hall, senior director ofGoogle Lunar XPRIZE, met on the Social Good Summit stage to duke it out on Tuesday.
Space has been the clear leader for a long time. $17.8 billion dollars is going toward space exploration in 2013, compared to the $5 billion dollars that goes toward oceanic exploration. This discrepancy has led to skewed results: While 500 individuals have been sent into space, only three have visited the deepest part of the ocean, the Mariana Trench.
We have better maps of the surface of Mars than we do of our own ocean floor, and we understand more about the dark side of the moon than ocean life. Despite centuries of ocean exploration, we’ve only covered about 5% of the ocean.
Bunje insists that this needs to change.
“In that 5% we have some of the most amazing things on this planet. We’ve got a mountain range, the Mid-Atlantic Ridge, that has thousands of peaks taller than the Alps are, for instance," he said. "You’ve got, every time someone goes down, new species that are wondrous and unbelievably strange sometimes. And in reality, if you take all of the world’s oceans, that’s 99% of our living space on Earth, and we know almost nothing about it."
Bunje also said that there are three reasons why the oceans deserve more research love: food, jobs and oxygen.
The ocean produces 20% of the world’s protein supply, and 3 billion people rely on the ocean for their livelihood. The ocean also produces 70% of Earth’s oxygen. These statistics, to Bunje and other ocean activists, mean that dangers like ocean acidification and climate change need our attention.
Hall insists that the investment isn’t as skewed as it seems. The simple fact that getting into space comes with a very large dollar sign must be taken into account when comparing the budgets. She insists that the reasons to explore space include economic benefit, national security and something that cannot be simplified down to a monetary amount: the satisfaction of our own curiosity.
Benefits of space exploration aren’t just about walking on the moon anymore. Research to put astronauts into space has resulted in great advancements in technology and medicine, and has resulted in the creation of jobs and economic benefits.
Beyond that, Hall insists, is the more romantic reason to continue space exploration: Space is inspiring.
“ Finding out about the origin of our planet Earth and the rest of the solar system is something that that we have a deep need to know about,” she said.
Hall insists that space research benefits the planet as well. Seeing Earth from space created a concept of Planet Earth.NASA has more money in its budget to be used towards Earth sciences than should go towards planetary sciences, and it has resulted in significant breakthroughs, including information on the melting ice caps, climate change and ocean surface temperatures.
The good news, when it comes to space versus the ocean, is that it doesn’t have to be one or the other. Both Bunje and Hall are working on million-dollar contests to increase research in space and in the ocean. Additionally, billions of dollars in government funding go toward research projects every year, in the hopes that some of these innovations can become a reality. ...
BY TAYLOR CASTI
dimanche 8 septembre 2013
Le plus grand volcan terrestre gît dans le Pacifique
Nous connaissons moins bien les fonds marins que la surface de la Lune. En témoigne la découverte du plus grand volcan de la planète dans les profondeurs du Pacifique, jusque-là passé inaperçu. Aujourd’hui éteint, le massif Tamu affiche la même superficie que les îles britanniques !
Un volcan dont les pentes douces étonnent
Pour percer les secrets du massif Tamu, les chercheurs ont réalisé, depuis le navire JOIDES Resolution, plusieurs profils sismiques du site, ainsi que des forages pour récolter des échantillons de roche. Des mesures radiométriques ont confirmé leur âge : 144,6 ± 0,8 millions d’années. Après analyse, il a apparu que tous les prélèvements présentaient la même composition chimique, ce qui montre qu’ils sont issus d’une même source. Les données sismiques l’ont d’ailleurs confirmé : les roches résultent du refroidissement d’un magma qui s’est écoulé depuis le centre de l’édifice. Ces deux indices trahissent bien l’existence d’un seul et unique volcan.
Un détail jugé « anormal » a également surpris les chercheurs : la faible déclivité des pentes du volcan, puisqu’elle est majoritairement comprise entre 1° et 1,5°. Elle serait à mettre en relation avec l’important taux d’effusion et la faible viscosité de la lave qui a donné naissance au site, dont les racines descendent d’ailleurs à plus de 30 km de profondeur. Les autres volcans sous-marins ont des parois plus abruptes, c’est-à-dire dont la déclivité est supérieure à 5°.
Des datations en cours doivent encore le confirmer, mais le massif Tamu pourrait s’être formé en un million d’années, voire moins. Il se trouvait alors à l’intersection de trois plaques tectoniques(volcanisme de divergence), dont la plaque Pacifique sur laquelle il trône actuellement. Qui sait quelles surprises nous réservent encore les fonds océaniques ?
Le 08/09/2013 à 14:41 - Par Quentin Mauguit, Futura-Sciences
http://www.futura-sciences.com/magazines/terre/infos/actu/d/volcan-record-plus-grand-volcan-terrestre-git-pacifique-48795/#xtor=RSS-8
Le massif Tamu affiche une superficie d'environ 310.000 km2. Par comparaison, le Mauna Loa, un volcan hawaïen, présente une surface de 5.200 km2. © IODP
Les fonds marins ne sont pas uniformément plats au large du Japon, environ 1.500 km à l’est de ses côtes, dans le Pacifique. C’est précisément à cet endroit que se trouve Shatsky Rise, un plateau océanique d’origine volcanique de la taille de la Californie, lui-même recouvert de plusieurs massifs rocheux. En 2009, le site a fait l’objet d’une campagne scientifique organisée dans le cadre de l’International Ocean Drilling Program (IODP, expédition 324). Son but était alors de mieux comprendre la formation puis l’évolution du massif Tamu, dont le sommet culmine 2 km sous la surface de l’océan.
Ce choix n’est pas anodin puisqu’il s’agit du plus vieux et du plus grand édifice géologique du plateau. On pensait alors qu’il devait son existence au refroidissement de laves émises par plusieurs volcans. Un argument fort plaidait en ce sens, puisque le site affiche une surface de 310.000 km2 (environ 650 km de long, pour 450 km de large), soit l’équivalent de la superficie des îles britanniques. La surprise a donc été de taille lorsque les résultats sont tombés : le massif ne se compose que d’un seul volcan en bouclier !
Aux dernières nouvelles, le massif Tamu était éteint, et devrait le rester. Cependant, il est devenu le plus grand volcan connu sur Terre. Le fait étonne car la plupart des volcans sous-marins connus présentent des surfaces de quelques dizaines des kilomètres carrés. Pour se faire une idée, sa base, bien que plus petite, peut être comparée en ordre de grandeur à celle d'Olympus Mons (environ 500.000 km2), sur Mars, considéré comme le plus imposant du Système solaire avec ses 22,5 km d'altitude. L’information a été dévoilée dans la revue Nature Geoscience par William Sager, de l’université américaine Texas A&M, en collaboration avec d’autres spécialistes.
Les profils sismiques et les forages ont été réalisés depuis le JOIDES Resolution, un navire de recherche scientifique spécialisé dans les forages profonds. Il fait 144 m de long, et possède en son centre un derrick de 60 m de haut. © IODP/USIO
Les fonds marins ne sont pas uniformément plats au large du Japon, environ 1.500 km à l’est de ses côtes, dans le Pacifique. C’est précisément à cet endroit que se trouve Shatsky Rise, un plateau océanique d’origine volcanique de la taille de la Californie, lui-même recouvert de plusieurs massifs rocheux. En 2009, le site a fait l’objet d’une campagne scientifique organisée dans le cadre de l’International Ocean Drilling Program (IODP, expédition 324). Son but était alors de mieux comprendre la formation puis l’évolution du massif Tamu, dont le sommet culmine 2 km sous la surface de l’océan.
Ce choix n’est pas anodin puisqu’il s’agit du plus vieux et du plus grand édifice géologique du plateau. On pensait alors qu’il devait son existence au refroidissement de laves émises par plusieurs volcans. Un argument fort plaidait en ce sens, puisque le site affiche une surface de 310.000 km2 (environ 650 km de long, pour 450 km de large), soit l’équivalent de la superficie des îles britanniques. La surprise a donc été de taille lorsque les résultats sont tombés : le massif ne se compose que d’un seul volcan en bouclier !
Aux dernières nouvelles, le massif Tamu était éteint, et devrait le rester. Cependant, il est devenu le plus grand volcan connu sur Terre. Le fait étonne car la plupart des volcans sous-marins connus présentent des surfaces de quelques dizaines des kilomètres carrés. Pour se faire une idée, sa base, bien que plus petite, peut être comparée en ordre de grandeur à celle d'Olympus Mons (environ 500.000 km2), sur Mars, considéré comme le plus imposant du Système solaire avec ses 22,5 km d'altitude. L’information a été dévoilée dans la revue Nature Geoscience par William Sager, de l’université américaine Texas A&M, en collaboration avec d’autres spécialistes.
Les profils sismiques et les forages ont été réalisés depuis le JOIDES Resolution, un navire de recherche scientifique spécialisé dans les forages profonds. Il fait 144 m de long, et possède en son centre un derrick de 60 m de haut. © IODP/USIO
Un volcan dont les pentes douces étonnent
Pour percer les secrets du massif Tamu, les chercheurs ont réalisé, depuis le navire JOIDES Resolution, plusieurs profils sismiques du site, ainsi que des forages pour récolter des échantillons de roche. Des mesures radiométriques ont confirmé leur âge : 144,6 ± 0,8 millions d’années. Après analyse, il a apparu que tous les prélèvements présentaient la même composition chimique, ce qui montre qu’ils sont issus d’une même source. Les données sismiques l’ont d’ailleurs confirmé : les roches résultent du refroidissement d’un magma qui s’est écoulé depuis le centre de l’édifice. Ces deux indices trahissent bien l’existence d’un seul et unique volcan.
Un détail jugé « anormal » a également surpris les chercheurs : la faible déclivité des pentes du volcan, puisqu’elle est majoritairement comprise entre 1° et 1,5°. Elle serait à mettre en relation avec l’important taux d’effusion et la faible viscosité de la lave qui a donné naissance au site, dont les racines descendent d’ailleurs à plus de 30 km de profondeur. Les autres volcans sous-marins ont des parois plus abruptes, c’est-à-dire dont la déclivité est supérieure à 5°.
Des datations en cours doivent encore le confirmer, mais le massif Tamu pourrait s’être formé en un million d’années, voire moins. Il se trouvait alors à l’intersection de trois plaques tectoniques(volcanisme de divergence), dont la plaque Pacifique sur laquelle il trône actuellement. Qui sait quelles surprises nous réservent encore les fonds océaniques ?
Le 08/09/2013 à 14:41 - Par Quentin Mauguit, Futura-Sciences
http://www.futura-sciences.com/magazines/terre/infos/actu/d/volcan-record-plus-grand-volcan-terrestre-git-pacifique-48795/#xtor=RSS-8
Long term effort to develop capability to drill to the Earth's Mantle
The Integrated Ocean Drilling Program (IODP) is an international marine research program dedicated to advancing scientificunderstanding of Earth by sampling, instrumenting and monitoring subseafloor environments. Through multiple platforms-JOIDES Resolution, Chikyu and Mission-Specific-Platforms-some of the world's preeminent scientists explore the deep biosphere and subseafloor; environmental change; Earth processes and effects; and solid earth cycles and geodynamics; and other themes.
One of the missions will be to drill 6 km (3.7 miles) beneath the seafloor to reach the Earth's mantle -- a 3000 km-thick layer of slowly deforming rock between the crust and the core which makes up the majority of our planet -- and bring back the first ever fresh samples.
They must first find a way to grind their way through ultra-hard rocks with 10 km-long (6.2 miles) drill pipes.
They have already identified three possible locations -- all in the Pacific Ocean -- where the ocean floor was formed at relatively fast spreading mid-ocean ridges, says Teagle.
The hole they will drill will be just 30 cm in width all the way from the ocean floor to inside the mantle -- a monumental engineering feat.
IODP's initial 10-year, $1.5 billion program is supported by two lead agencies, the U.S. National Science Foundation (NSF) and Japan's Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
If Japanese support can be combined with other funding, Teagle says they could start drilling before the end of the decade, making it possible for humans to finally reach the Earth's mantle by the early 2020s.
To get to the mantle scientists will be relying on a purpose-built Japanese deep-sea drilling vessel called Chikyu, first launched in 2002 and capable of carrying 10 km of drilling pipes. It has already set a world-record for the deepest hole in scientific ocean drilling history, reaching 2.2 km into the seafloor.
What makes the task even more difficult is that, currently, the drill bits have a limited lifespan of between 50-60 hours before needing to be replaced, meaning drilling could take many years unless technology improves.
POSTED BY BRIAN WANG AT 9/08/2013
One of the missions will be to drill 6 km (3.7 miles) beneath the seafloor to reach the Earth's mantle -- a 3000 km-thick layer of slowly deforming rock between the crust and the core which makes up the majority of our planet -- and bring back the first ever fresh samples.
They must first find a way to grind their way through ultra-hard rocks with 10 km-long (6.2 miles) drill pipes.
They have already identified three possible locations -- all in the Pacific Ocean -- where the ocean floor was formed at relatively fast spreading mid-ocean ridges, says Teagle.
The hole they will drill will be just 30 cm in width all the way from the ocean floor to inside the mantle -- a monumental engineering feat.
IODP's initial 10-year, $1.5 billion program is supported by two lead agencies, the U.S. National Science Foundation (NSF) and Japan's Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
If Japanese support can be combined with other funding, Teagle says they could start drilling before the end of the decade, making it possible for humans to finally reach the Earth's mantle by the early 2020s.
To get to the mantle scientists will be relying on a purpose-built Japanese deep-sea drilling vessel called Chikyu, first launched in 2002 and capable of carrying 10 km of drilling pipes. It has already set a world-record for the deepest hole in scientific ocean drilling history, reaching 2.2 km into the seafloor.
What makes the task even more difficult is that, currently, the drill bits have a limited lifespan of between 50-60 hours before needing to be replaced, meaning drilling could take many years unless technology improves.
POSTED BY BRIAN WANG AT 9/08/2013
lundi 26 août 2013
Science points to a new global warming source: the sea
 |
| Lightning strikes on the Pacific Ocean on Panama Bay on June 24, 2013. Oceans that grow more acidic through Man's fossil fuel burning emissions, can amplify global warming by releasing less of a gas that helps shield Earth from radiation, a study said Sunday. |
Oceans that grow more acidic through Man's fossil fuel burning emissions, can amplify global warming by releasing less of a gas that helps shield Earth from radiation, a study in Nature Climate Change said Sunday.
And the authors warned the potentially vast effect they uncovered is not currently factored into climate change projections.
Scientists say that Man's carbon dioxide (CO2) emissions contribute to planetary warming by letting the Sun's heat through the atmosphere but trapping heat energy reflected back from Earth, so creating a greenhouse effect.
They also lower the pH balance of the world's oceans, making them more acidic, and hamper production of dimethyl sulphide (DMS), a sulphur compound, by plankton, said the study.
DMS released into the atmosphere helps reflect incoming radiation from the Sun, reducing surface temperatures on Earth.
Using climate simulations, the team said an 18 percent decline in DMS emissions by 2100 could contribute as much as 0.48 degrees Celsius (0.9 deg Fahrenheit) to the global temperature.
"To our knowledge, we are the first to highlight the potential climate impact due to changes in the global sulphur cycle triggered by ocean acidification," the authors wrote.
"Our result emphasises that this potential climate impact mechanism of ocean acidification should be considered in projections of future climate change."
They warned that ocean acidification may also have other, yet unseen, impacts on marine biology that may provoke further declines in DMS emissions.
Explore further: Dire outlook despite global warming 'pause': study
More information: dx.doi.org/10.1038/nclimate1981
Journal reference: Nature Climate Change
© 2013 AFP
16 hours ago
Read more at: http://phys.org/news/2013-08-science-global-source-sea.html#jCp
And the authors warned the potentially vast effect they uncovered is not currently factored into climate change projections.
Scientists say that Man's carbon dioxide (CO2) emissions contribute to planetary warming by letting the Sun's heat through the atmosphere but trapping heat energy reflected back from Earth, so creating a greenhouse effect.
They also lower the pH balance of the world's oceans, making them more acidic, and hamper production of dimethyl sulphide (DMS), a sulphur compound, by plankton, said the study.
DMS released into the atmosphere helps reflect incoming radiation from the Sun, reducing surface temperatures on Earth.
Using climate simulations, the team said an 18 percent decline in DMS emissions by 2100 could contribute as much as 0.48 degrees Celsius (0.9 deg Fahrenheit) to the global temperature.
"To our knowledge, we are the first to highlight the potential climate impact due to changes in the global sulphur cycle triggered by ocean acidification," the authors wrote.
"Our result emphasises that this potential climate impact mechanism of ocean acidification should be considered in projections of future climate change."
They warned that ocean acidification may also have other, yet unseen, impacts on marine biology that may provoke further declines in DMS emissions.
Explore further: Dire outlook despite global warming 'pause': studyMore information: dx.doi.org/10.1038/nclimate1981
Journal reference: Nature Climate Change
© 2013 AFP
16 hours ago
Read more at: http://phys.org/news/2013-08-science-global-source-sea.html#jCp
mardi 16 juillet 2013
The color of the ocean: The SABIA-Mar mission
A large aquamarine-colored plankton bloom is shown stretching across the length of Ireland in the North Atlantic Ocean in this image, captured on 6 June 2006 by Envisat's Medium Resolution Imaging Spectrometer (MERIS), a dedicated ocean color …more
By monitoring the color changes in the ocean, such as those caused by photosynthetic pigments in phytoplankton, scientists learn more about the overall health and functioning of our planet. Such studies also could help future missions better observe and understand alien oceans.
Remote sensing of ocean color is a currently well-established science that provides information about water composition and the depth of light penetration based on the ocean color, as seen from space. Ocean color satellites are part of an Earth observing system and, due to its importance in understanding the state of the ocean and its evolution, the international scientific community has agreed to joint efforts to keep a constant constellation of ocean color satellites orbiting our planet.
The first of those ocean color sensors was the CZCS (Coastal Zone Color Scanner) Experiment, launched by NASA in 1978 onboard the Nimbus-7 satellite as part of a proof-of-concept of the capability to measure suspended and dissolved particles in ocean waters from space. Photosynthetic pigments were the main focus of this pioneering mission. Quantifying and monitoring those pigments is essential to understand the systemic functioning of our planet, since photosynthesis is the process responsible for turning carbon dioxide (CO2) into our breathable oxygen (O2) and for the planet's primary production that sustains the trophic web (the food web). In this way, plants and microalgae provide food and air for most of Earth's life forms, especially the macroscopic forms such as animals, obviously including humans.
Although the CZCS mission was successful, when this sensor stopped working in 1986, there was a ten year wait until a new ocean color mission was sent into space to continue those studies. These new ocean color sensors – named MOS, OCTS and POLDER – were launched in 1996.
Maintaining ocean color space-borne platforms in orbit is an important goal, since scientists want to observe the ocean over long periods of time. Recently, Brazil and Argentina joined this international constellation to provide valuable data and help to prevent another ocean color data gap. The mission is called SABIA-Mar, an acronym which means Argentinean-Brazilian Satellite of Environmental Information of the Sea (the name works both in Spanish and Portuguese, the official languages of the respective countries). The name "Sabiá" means "true thrush", a group of birds form the genus Turdus that are common in the region of Argentina and Brazil.
The SABIA-Mar mission is an initiative of Agência Espacial Brasileira – AEB (Brazilian Space Agency), Instituto Nacional de Pesquisas Espaciais - INPE (National Institute for Space Research), both from Brazil and CONAE Comisión Nacional de Actividades Espaciales (National Commission of Space Activities) from Argentina. Its technical characteristics are still a matter of discussion, so these institutions put together a workshop in Buenos Aires (March 14-15th of 2013) and Brasília (May 13-14th of 2013) the capitals of Argentina and Brazil, respectively. The workshop community was composed of government and private institutions from both countries, and now the greater international community of potential users of the satellites is also being asked to contribute and provide their critiques and demands.
A colorful summer marine phytoplankton bloom fills much of the Baltic Sea in this Envisat image. While individually microscopic, phytoplankton chlorophyll collectively tints the surrounding ocean waters, providing a means of detecting these …more
"The satellite must supply the highest number of demands as possible." says Petrônio de Souza, Director of Space Policy and Strategic Investments from AEB.
"It is necessary to know what the future SABIA-Mar users need," reaffirmed the Brazilian Manager of the mission, Marco Antônio Chamon, during the workshop in Brasília. As is usual for most of the other ocean color missions, the data will be available for free to interested users worldwide.
The main decision from these meetings was the agreement on splitting the SABIA-Mar mission into two satellites: one focused on imaging the global oceans, expected to launch in 2018, and another for regional studies, planned for 2019.
Imaging specific regions requires a higher spatial resolution and represents a technological jump for both countries involved. But the regional data also represents a scientific challenge for the whole ocean color research community. The open ocean is well known for its deep blue color, caused by water molecules interacting with sunlight. But coastal zones and interior water bodies such as lakes and rivers have much more complex color patterns, because they are highly influenced by suspended sediments, dissolved organic matter and phytoplankton (microalgae). It is currently hard to precisely partition the contribution of each one of these substances, so these water bodies will be the focus of the regional camera to be placed onboard the regional SABIA-Mar satellite.
The actual objective of this space mission is to better understand the Earth's carbon cycle, as well as to help fisheries and aquiculture, detect and monitor pollution and harmful algal blooms, follow species at risk, evaluate water quality and water visibility, and study climate and environmental changes. The mission will also aid coastal management efforts and national sovereignty and defense measures.
But while we can observe the ocean in the present, we also need to envision the ocean in the future. Ocean color remote sensing naturally is a space-borne vocation, and the discoveries of Earth possibly could be extrapolated to other planets and moons inside and outside the Solar System. Perhaps remote sensing of Earth will inspire future missions to observe the frozen ocean of Jupiter's moon Europa and the hydrocarbon lakes of Saturn's moon Titan in the coming decades.
The knowledge gained from the ocean color science may also help astrobiologists to hunt for extraterrestrial life. Ocean color is presently the only way to monitor phytoplankton from local to global scales, and its variation in density and composition through several time scales. Scientists are currently identifying the range of sunlight absorption by each photosynthetic pigment known to exist on Earth's plants and algae. Future optical sensors onboard deep space satellites or probes may look for those pigments in the nearer exoplanets. While still a matter of speculation, if such sensors turn out to be possible, the big distances involved will demand a much higher precision and accuracy than what the present ocean color science state-of-the-art technology has.
Photosynthetic pigments are the result of an evolutionary adaption of Earth's life to the available light, and depend on the Sun's distance, age and magnitude. Astrobiologists are now considering other possible photosynthetic pigments adapted to different types of stars and distances from them. For example, the forest and algae colors of other worlds may be very different than our green patterns. We can assume there could be extraterrestrial habitats verging into red and yellow colors, for instance.
By better comprehending terrestrial life and considering the biochemical possibilities, we should be able to explore whether some of our closest neighbors may harbor extraterrestrial life "as we know it", or at least, what we can assume alien life may possibly be like.
by Bruno Martini, Mauricio Almeida Noernberg
Publié le 16 juillet 2013
Read more at: http://phys.org/news/2013-07-ocean-sabia-mar-mission.html#jCp
"The satellite must supply the highest number of demands as possible." says Petrônio de Souza, Director of Space Policy and Strategic Investments from AEB.
"It is necessary to know what the future SABIA-Mar users need," reaffirmed the Brazilian Manager of the mission, Marco Antônio Chamon, during the workshop in Brasília. As is usual for most of the other ocean color missions, the data will be available for free to interested users worldwide.
The main decision from these meetings was the agreement on splitting the SABIA-Mar mission into two satellites: one focused on imaging the global oceans, expected to launch in 2018, and another for regional studies, planned for 2019.
Imaging specific regions requires a higher spatial resolution and represents a technological jump for both countries involved. But the regional data also represents a scientific challenge for the whole ocean color research community. The open ocean is well known for its deep blue color, caused by water molecules interacting with sunlight. But coastal zones and interior water bodies such as lakes and rivers have much more complex color patterns, because they are highly influenced by suspended sediments, dissolved organic matter and phytoplankton (microalgae). It is currently hard to precisely partition the contribution of each one of these substances, so these water bodies will be the focus of the regional camera to be placed onboard the regional SABIA-Mar satellite.
The actual objective of this space mission is to better understand the Earth's carbon cycle, as well as to help fisheries and aquiculture, detect and monitor pollution and harmful algal blooms, follow species at risk, evaluate water quality and water visibility, and study climate and environmental changes. The mission will also aid coastal management efforts and national sovereignty and defense measures.
But while we can observe the ocean in the present, we also need to envision the ocean in the future. Ocean color remote sensing naturally is a space-borne vocation, and the discoveries of Earth possibly could be extrapolated to other planets and moons inside and outside the Solar System. Perhaps remote sensing of Earth will inspire future missions to observe the frozen ocean of Jupiter's moon Europa and the hydrocarbon lakes of Saturn's moon Titan in the coming decades.
The knowledge gained from the ocean color science may also help astrobiologists to hunt for extraterrestrial life. Ocean color is presently the only way to monitor phytoplankton from local to global scales, and its variation in density and composition through several time scales. Scientists are currently identifying the range of sunlight absorption by each photosynthetic pigment known to exist on Earth's plants and algae. Future optical sensors onboard deep space satellites or probes may look for those pigments in the nearer exoplanets. While still a matter of speculation, if such sensors turn out to be possible, the big distances involved will demand a much higher precision and accuracy than what the present ocean color science state-of-the-art technology has.
Photosynthetic pigments are the result of an evolutionary adaption of Earth's life to the available light, and depend on the Sun's distance, age and magnitude. Astrobiologists are now considering other possible photosynthetic pigments adapted to different types of stars and distances from them. For example, the forest and algae colors of other worlds may be very different than our green patterns. We can assume there could be extraterrestrial habitats verging into red and yellow colors, for instance.
By better comprehending terrestrial life and considering the biochemical possibilities, we should be able to explore whether some of our closest neighbors may harbor extraterrestrial life "as we know it", or at least, what we can assume alien life may possibly be like.
by Bruno Martini, Mauricio Almeida Noernberg
Publié le 16 juillet 2013
Read more at: http://phys.org/news/2013-07-ocean-sabia-mar-mission.html#jCp
lundi 15 juillet 2013
Le vacarme des icebergs dans l'océan
On sait que le bruit des humains et de leurs moteurs perturbe les animaux marins mais on mesure mal l'effet des sons d'origine naturelle. Une nouvelle étude a découvert une puissante source de pollution sonore, assez inattendue : la dérive des icebergs, parfois aussi bruyante que des navires pétroliers. Cette découverte pourrait aider à mieux comprendre le lien entre le bruit et les modes de vie de la faune marine.
Les icebergs génèrent une énergie sonore importante lorsqu’ils se forment à partir du vêlage d’un glacier. Mais il apparaît qu’ils libèrent aussi une intense énergie, tout au long de leur dérive...
Le bruit d'origine humaine dans les océans va jusqu'à provoquer des échouages d’animaux marins. D’une manière générale, il est suspecté de les désorienter et de perturber leur mode de vie. Les baleines à bec sont probablement les mammifères marins les plus sensibles aux perturbations sonores. S’il est difficile de rencontrer ces animaux en mer, ce sont bien souvent les premiers à s’échouer sur les plages à la suite d’essais militaires. On estime qu’en moyenne, le bruit des océans a augmenté de 12 dB ces dernières décennies.
La pollution sonore est de plus en plus étudiée, au détriment du bruit naturel. Pourtant, certains événements naturels peuvent être beaucoup plus bruyants qu’on le pense. La formation des icebergs par vêlage des glaciers et la fracturation des blocs de glace émettent un bruit terrible dans l’océan. De façon plus surprenante, une nouvelle étude montre que la simple dérive des icebergs, depuis leur lieu de formation jusqu’aux eaux chaudes, libère une énergie sonore énorme. Durant son existence, l’iceberg fournit une énergie équivalente au bruit généré par les moteurs de 214 supertankers (pétroliers de haute capacité) pendant 20 minutes !
De sa naissance à sa mort, l’iceberg A53a a été pisté à l’aide d’un réseau d’hydrophones. Une équipe de l’Oregon State University a pu enregistrer et analyser les bruits que générait le bloc de glace de 55 km par 25 km. L’iceberg s’est formé en mer de Weddell, dans l’océan Austral, en avril 2007, puis a pris le chemin du large en empruntant le détroit de Bransfield (entre la péninsule Antarctique et les Shetland du Sud). Il a dérivé vers le nord en mer de la Scotia, et a commencé à fondre dans les eaux plus chaudes en juillet 2007. Leurs résultats sont publiés dans la revue Oceanography.
La dislocation de la glace est bruyante
Au début de son trajet, l’iceberg rencontra un plancher océanique qui se situait à seulement 124 m de fond. Le frottement du sol a forcé le bloc de glace à se retourner de 192°, processus qui engendra des tremblements harmoniques semi-continus sur les six jours suivants. Dans le détroit de Bransfield, A53a rencontra à nouveau un plancher océanique peu profond, à 265 m, et se mit à tourner comme une toupie.
L’énergie sonore émise sur l’ensemble de son cycle de vie était de 6,7 x 107 joules. Mais cette énergie ne provenait pas du bruit généré par le raclement de l’iceberg au fond de l’océan. « L’énergie provient de sa désintégration rapide à mesure que l'iceberg fond et se disloque, détaille Robert Dziak, principal auteur de l’étude. Nous appelons ces sons les tremblements de glace, parce que le processus et les sons qui en résultent sont un peu comme ceux produits par les tremblements de terre. »
Des glaçons dans l’eau chaude
Jusqu’à présent, on pensait qu’un iceberg à la dérive produisait du bruit de façon significative uniquement lorsqu’il grattait le fond océanique, ou participait à une collision. Or, cette étude met en avant que l’iceberg, sur l’ensemble de son cycle de vie, génère une énergie sonore loin d’être négligeable. « Pensez à ce qui se passe lorsque vous versez une eau chaude dans un verre rempli de glaçons. Les bris de la glace et les craquements peuvent être vraiment bruyants. Maintenant, extrapolez cela à un iceberg géant et vous comprendrez l'ampleur de l'énergie sonore », explique encore Robert Dziak.
À lui seul, le glacier Sermeq Kujalleq produit 35 milliards de tonnes d’icebergs par an, soit 10 % des icebergs du Groenland. Avec ces chiffres, on peut donc concevoir que le bruit généré par la totalité des icebergs dans le monde est énorme. Aujourd’hui, personne n’est en mesure de dire si ce vacarme a un effet sur les populations marines. Mais compte tenu de ces résultats, il serait intéressant de se pencher sur la question. Y répondre permettrait peut-être d’en savoir plus sur le lien entre le bruit et les modes de vie des animaux marins.
Les icebergs génèrent une énergie sonore importante lorsqu’ils se forment à partir du vêlage d’un glacier. Mais il apparaît qu’ils libèrent aussi une intense énergie, tout au long de leur dérive...
Le bruit d'origine humaine dans les océans va jusqu'à provoquer des échouages d’animaux marins. D’une manière générale, il est suspecté de les désorienter et de perturber leur mode de vie. Les baleines à bec sont probablement les mammifères marins les plus sensibles aux perturbations sonores. S’il est difficile de rencontrer ces animaux en mer, ce sont bien souvent les premiers à s’échouer sur les plages à la suite d’essais militaires. On estime qu’en moyenne, le bruit des océans a augmenté de 12 dB ces dernières décennies.
La pollution sonore est de plus en plus étudiée, au détriment du bruit naturel. Pourtant, certains événements naturels peuvent être beaucoup plus bruyants qu’on le pense. La formation des icebergs par vêlage des glaciers et la fracturation des blocs de glace émettent un bruit terrible dans l’océan. De façon plus surprenante, une nouvelle étude montre que la simple dérive des icebergs, depuis leur lieu de formation jusqu’aux eaux chaudes, libère une énergie sonore énorme. Durant son existence, l’iceberg fournit une énergie équivalente au bruit généré par les moteurs de 214 supertankers (pétroliers de haute capacité) pendant 20 minutes !
 |
| Contrairement à ce que l'on pensait, c'est lorsque l'iceberg fond qu'il fait le plus de bruit. © Robert Dziak, Oregon State University |
De sa naissance à sa mort, l’iceberg A53a a été pisté à l’aide d’un réseau d’hydrophones. Une équipe de l’Oregon State University a pu enregistrer et analyser les bruits que générait le bloc de glace de 55 km par 25 km. L’iceberg s’est formé en mer de Weddell, dans l’océan Austral, en avril 2007, puis a pris le chemin du large en empruntant le détroit de Bransfield (entre la péninsule Antarctique et les Shetland du Sud). Il a dérivé vers le nord en mer de la Scotia, et a commencé à fondre dans les eaux plus chaudes en juillet 2007. Leurs résultats sont publiés dans la revue Oceanography.
La dislocation de la glace est bruyante
Au début de son trajet, l’iceberg rencontra un plancher océanique qui se situait à seulement 124 m de fond. Le frottement du sol a forcé le bloc de glace à se retourner de 192°, processus qui engendra des tremblements harmoniques semi-continus sur les six jours suivants. Dans le détroit de Bransfield, A53a rencontra à nouveau un plancher océanique peu profond, à 265 m, et se mit à tourner comme une toupie.
L’énergie sonore émise sur l’ensemble de son cycle de vie était de 6,7 x 107 joules. Mais cette énergie ne provenait pas du bruit généré par le raclement de l’iceberg au fond de l’océan. « L’énergie provient de sa désintégration rapide à mesure que l'iceberg fond et se disloque, détaille Robert Dziak, principal auteur de l’étude. Nous appelons ces sons les tremblements de glace, parce que le processus et les sons qui en résultent sont un peu comme ceux produits par les tremblements de terre. »
Des glaçons dans l’eau chaude
Jusqu’à présent, on pensait qu’un iceberg à la dérive produisait du bruit de façon significative uniquement lorsqu’il grattait le fond océanique, ou participait à une collision. Or, cette étude met en avant que l’iceberg, sur l’ensemble de son cycle de vie, génère une énergie sonore loin d’être négligeable. « Pensez à ce qui se passe lorsque vous versez une eau chaude dans un verre rempli de glaçons. Les bris de la glace et les craquements peuvent être vraiment bruyants. Maintenant, extrapolez cela à un iceberg géant et vous comprendrez l'ampleur de l'énergie sonore », explique encore Robert Dziak.
À lui seul, le glacier Sermeq Kujalleq produit 35 milliards de tonnes d’icebergs par an, soit 10 % des icebergs du Groenland. Avec ces chiffres, on peut donc concevoir que le bruit généré par la totalité des icebergs dans le monde est énorme. Aujourd’hui, personne n’est en mesure de dire si ce vacarme a un effet sur les populations marines. Mais compte tenu de ces résultats, il serait intéressant de se pencher sur la question. Y répondre permettrait peut-être d’en savoir plus sur le lien entre le bruit et les modes de vie des animaux marins.
Le 15/07/2013 à 15:49 - Par Delphine Bossy, Futura-Sciences
http://www.futura-sciences.com/magazines/environnement/infos/actu/d/ocean-video-vacarme-icebergs-ocean-47753/#xtor=RSS-8
http://www.futura-sciences.com/magazines/environnement/infos/actu/d/ocean-video-vacarme-icebergs-ocean-47753/#xtor=RSS-8
vendredi 12 juillet 2013
Deep oceans warming at an alarming rate
 |
British Antarctic Survey
A new re-analysis of data from the ocean depths suggests dramatic warming of
the deep sea is under way because of anthropogenic climate change, scientists say.
|
Despite mixed signals from warming ocean surface waters, a new re-analysis of data from the depths suggests dramatic warming of the deep sea is under way because of anthropogenic climate change. The scientists report that the deep seas are taking in more heat than expected, which is taking some of the warming off the Earth’s surface, but it will not do so forever.
"Some of the heat (from human-caused global warming) is going into melting sea ice and heating the surface, but the bulk is going into the oceans,” said climate researcher Kevin Trenberth of the National Center for Atmospheric Research, a coauthor on a new research paper reporting on the deep ocean warming in the journal Geophysical Research Letters.
How Global Warming Will Change Your Life
The study involved the bringing together of a diverse suite of data, ranging from satellite measurements of the surface waters to ship observations at all depths, instruments mounted on elephant seals, ARGO profilers (a large collection of small, drifting-robotic probes deployed worldwide), and data-gathering instruments moored in place. The data include temperature, salinity, depth, and altimetry of the ocean surface, going back decades.
Piecing together different kinds of data from different times and sometimes from sparse data sets was the key challenge, Trenberth explains, but that is the specialty of his coauthors at the European Center for Medium Range Weather Forecasts in the U.K
“They have one of the most sophisticated data assimilation systems,” Trenberth said. That has allowed for a new view of not only how the deep sea is heating up, but how winds and El Niño events play into it all.
Winds blowing on the oceans can drive water into the deep ocean as well as cause upwelling of deep waters, which can release massive amounts of heat. The 1998 El Niño year, for instance, was the hottest on record because the oceans were releasing a lot of heat from the ocean into the atmosphere, Trenberth explained to DNews.
Think the Planet Isn't Warming? Check the Ocean: Analysis
The new re-analysis of ocean data is not the last word on what's happening in the deep seas, but the best estimate of what is happening.
“It's more than speculation and suggestion,” agrees climate scientist Gavin Schmidt of NASA's Goddard Institute for Space Studies, “and it's probably right to a reasonable degree. The fact of the matter is we'll never be able to get data from below 400 meters in the middle of the Pacific Ocean” because there is not enough money invested in ocean sensors to cover such places. “So we have to use physics to fill in the gaps.”
The bottom line, says Trenberth, is that the heat of global warming is going to different places. “So global warming is continuing even though it’s not always manifested as a strong surface temperature increase. It’s just manifesting itself in different ways.”
Larry O'Hanlon
"Some of the heat (from human-caused global warming) is going into melting sea ice and heating the surface, but the bulk is going into the oceans,” said climate researcher Kevin Trenberth of the National Center for Atmospheric Research, a coauthor on a new research paper reporting on the deep ocean warming in the journal Geophysical Research Letters.
How Global Warming Will Change Your Life
The study involved the bringing together of a diverse suite of data, ranging from satellite measurements of the surface waters to ship observations at all depths, instruments mounted on elephant seals, ARGO profilers (a large collection of small, drifting-robotic probes deployed worldwide), and data-gathering instruments moored in place. The data include temperature, salinity, depth, and altimetry of the ocean surface, going back decades.
Piecing together different kinds of data from different times and sometimes from sparse data sets was the key challenge, Trenberth explains, but that is the specialty of his coauthors at the European Center for Medium Range Weather Forecasts in the U.K
“They have one of the most sophisticated data assimilation systems,” Trenberth said. That has allowed for a new view of not only how the deep sea is heating up, but how winds and El Niño events play into it all.
Winds blowing on the oceans can drive water into the deep ocean as well as cause upwelling of deep waters, which can release massive amounts of heat. The 1998 El Niño year, for instance, was the hottest on record because the oceans were releasing a lot of heat from the ocean into the atmosphere, Trenberth explained to DNews.
Think the Planet Isn't Warming? Check the Ocean: Analysis
The new re-analysis of ocean data is not the last word on what's happening in the deep seas, but the best estimate of what is happening.
“It's more than speculation and suggestion,” agrees climate scientist Gavin Schmidt of NASA's Goddard Institute for Space Studies, “and it's probably right to a reasonable degree. The fact of the matter is we'll never be able to get data from below 400 meters in the middle of the Pacific Ocean” because there is not enough money invested in ocean sensors to cover such places. “So we have to use physics to fill in the gaps.”
The bottom line, says Trenberth, is that the heat of global warming is going to different places. “So global warming is continuing even though it’s not always manifested as a strong surface temperature increase. It’s just manifesting itself in different ways.”
Larry O'Hanlon
Discovery News
7 hours ago
lundi 1 juillet 2013
How Big Is The Ocean?
While the Earth's oceans are known as five separate entities, there is really only one ocean. So, how big is it? As of 2013, it takes up 71% of the Earth, houses 99% of the biosphere, and contains some of Earth's grandest geological features.
YouTube link
(thanks Cora)
Posted by Gerard on 6/30/2013
http://presurfer.blogspot.com/2013/06/how-big-is-ocean.html
YouTube link
(thanks Cora)
Posted by Gerard on 6/30/2013
lundi 6 mai 2013
Gorgeous Concept Designs for Underwater Cities
While some pieces of conceptual architecture guide out imagine toward distant planets, others plunge us into the depths of the ocean. These underwater cities concepts, dreamed up by illustrators, architects, and designers, imagine the sorts of structures we might inhabit beneath the watery surfaces.
dimanche 22 avril 2012
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