Sentences with phrase «sea sediments for»

Not exact matches

While there are management solutions to stabilizing the landscape, those solutions are not without challenges, Goodbred said, but the study notes that systematically breaching embankment sections to allow for delivery of sediment to the coastal sea might at least partially reduce problems.

Then the sediment cleared just enough for him to catch a glimpse of a stone church tower, crawling with hermit crabs, lying on the sea bed.

The study suggests that layers of sediments perhaps 10 to 20 meters thick can seal the sea floor and make seamounts the most important conduits for heat and fluid flow — especially on the sloping flank of a midocean ridge, says oceanographer John Sclater of the Scripps Institution of Oceanography in La Jolla, California.

In 1991, the IMO adopted guidelines which recommend that ships should avoid taking on ballast in shallow areas and during toxic blooms of marine algae; keep accurate records of where and when ballast is loaded; exchange ballast water at sea, where toxic organisms are rare; and discharge sediments into approved areas at the port of destination («End of the line for deadly stowaways», New Scientist, 24 October 1992).

The shale, named for the town of Eagle Ford, TX, is a geologic remnant of the ancient ocean that covered present day Texas millions of years ago, when the remains of sea life (especially ancient plankton) died and deposited onto the seafloor, were buried by several hundred feet of sediment, eventually turning into the rich source of hydrocarbons we have today.The shale was first tapped in 2008 and now has around 20 active fields good producing over 900 million cubic feet per day of natural gas.

Fumio Inagaki from the Japan Agency for Marine - Earth Science and Technology, who made the discovery, says the lake probably formed when carbon dioxide seeped out through the ocean floor from a deep - sea volcano and pooled under a blanket of solid, icelike CO2 hydrate and deep - sea sediment.

Records of sea surface temperature from oceanic sediment cores, for example, show that the magnitude of warming following several previous glaciations are well - correlated (www.ncdc.noaa.gov/paleo/recons.html).

In an area the size of the Wadden Sea, for instance, sediment turnover could drop by more than 130,000 liters each year.»

The scientists theorize that a warming Arctic environment has reduced sea ice cover, allowing for more wave action that stirs up sediments and mobilizes more radium.

Its large Edward Scissorhands - like claws with their elongated spines may have been used to capture prey, or they could have helped it to probe the sea floor looking for sea creatures hiding in sediment.

There, they collected mud from the sea floor, which builds up for millions of years like a giant layer cake as newer sediments pile on top of older ones.

Evidence for approximately contemporaneous global cooling in sediments that do contain YTT glass shards has been found in marine core oxygen isotope records from the South China Sea (3), as have terrestrial carbon isotope and pollen records from Northern India and Bengal (23).

Bacteria, however, have remained Earth's most successful form of life — found miles deep below as well as within and on surface rock, within and beneath the oceans and polar ice, floating in the air, and within as well as on Homo sapiens sapiens; and some Arctic thermophiles apparently even have life - cycle hibernation periods of up to a 100 million years while waiting for warmer conditions underneath increasing layers of sea sediments (Lewis Dartnell, New Scientist, September 20, 2010; and Hubert et al, 2010).

See Page 4 - 22, Figure 9: Geomagnetic field intensity level derived from composite volcanic records, not sea floor sediments, for the past 45 kyr.

As there is no explanation as to how climate changes could possibly affect the intensity of the earth's magnetic field, it was decided that it would be easier to believe that proxy sea floor sediment data should be adjusted («corrected») for sea water temperature.

Recent sediment remolding on a deep shelf, Ross Sea: implications for radiocarbon dating of Antarctic marine sediments.

However, foraminifera data are limited and difficult to obtain by deep - sea sediment coring, and the shells are not perfect proxies for ocean conditions.

This chemical weathering process is too slow to damp out shorter - term fluctuations, and there are some complexities — glaciation can enhance the mechanical erosion that provides surface area for chemical weathering (some of which may be realized after a time delay — ie when the subsequent warming occurs — dramatically snow in a Snowball Earth scenario, where the frigid conditions essentially shut down all chemical weathering, allowing CO2 to build up to the point where it thaws the equatorial region, at which point runaway albedo feedback drives the Earth into a carbonic acid sauna, which ends via rapid carbonate rock formation), while lower sea level may increase the oxidation of organic C in sediments but also provide more land surface for erosion... etc..

For this to happen, the organism typically must first become quickly buried in sediment on the floor of the sea or some other body of water.

Ice core data from Antarctic from ocean sediments show 8 episodes of very large ice flux — largest 14,600 years ago, meltwater pulse 1a — 1 - 3 meters sea level rise per century for several centuries.

Not only does it trap and hold sediment moving across the sea floor, but it provides cover and a habitat for myriads of marine life.

Black mangrove pneumatophores not only act as a «snorkel» for the roots to breath, they trap sediment and may remove chemicals from water running into the sea.

In their study of sediments from the Black Sea, Eckert et al. (2013, p. 431 in this issue of Geology), make this step by providing, for the first time, a basin - wide reconstruction of the evolution of the chemocline in this silled coastal basin over the Holocene.

the sea level raises for two reasons: 1] sediments washed from the land into the sea every year.

For Fred Singer, a climatologist at the University of Virginia and another co-author, the current warming «trend is simply part of a natural cycle of climate warming and cooling that has been seen in ice cores, deep sea sediments and stalagmites... and published in hundreds of papers in peer reviewed journals.»

I should have said that the paleoclimatologists who study sea floor sediments are pretty confident that the high lattitude arctic ocean has not been ice free for many hundreds of thousands of years.

It is also possible for cold climates to increase chemical weathering in some ways, by lowering sea level to expose more land to erosion (though I'd guess this can also increase oxydation of C in sediments) and by supplying more sediments via glacial erosion for chemical weathering (of course, those sediments must make it to warmer conditions to make the process effective — downhill and downstream, or perhaps via pulsed ice ages -LRB-?)-RRB-.

What is true is that there is very very strong evidence from paleoclimate data (deep sea sediment cores) for changes in the distribution of chemical tracers that must reflect changes in the deep circulation in the Atlantic.

Using a computer model of wave - induced current stresses, the team estimated how powerful currents would need to be for forces they exert at the sea floor to exceed a «critical force» that triggers sediment suspensions and could lead to underwater mudslides.

«It is thought that the carbon dioxide in the sea exists in equilibrium with that of exposed rock and bottom sediment containing limestone CaCO3 (or sea shells for that matter).

«The primary sources of calcium carbonate for deep sea sediments are pelagic calcitic coccolithophores and foraminifera that grow dominantly in the phototic zone (typically upper 100 m) and to a lesser extent aragonitic pteropods.

Meanwhile the people predicting a return to the ice cover that existed since the Holocene maximum according to sea floor sediment cores have no physical process to account for their assertions of returning ice.

Tremblay, L.B., G.A. Schmidt, S. Pfirman, R. Newton, and P. DeRepentigny, 2015: Is ice - rafted sediment in a North Pole marine record evidence for perennial sea - ice cover?

This has never happened before because the sea ice never retreated very much in the summer and the water temperature could not rise above zero because of the ice cover... The permafrost is acting as a cap for a very large amount of methane (CH4), which is sitting in the sediments underneath in the form of methane hydrates.

Quantitative measurement of the sea ice diatom biomarker IP25 and sterols in Arctic sea ice and underlying sediments: further considerations for palaeo sea ice reconstruction.

Furthermore, this interpretation is in line with high abundances of the ostracode species Acetabulastoma arcticum found in these sediments of Core PS2200 - 5 (Fig. 2a) and Core 96/12 -1 PC from Lomonosov Ridge (see Fig. 1 for location), proposed to be a proxy for a perennial sea ice cover with > 75 % sea ice concentrations (Supplementary Fig. 8) 46.

That means, the presence of IP25 in the sediments is a direct proof for the presence of past Arctic sea ice.

Strong katabatic winds related to the ice sheets (shown tentatively as stippled black arrows), were probably responsible for ice - free polynya - type conditions off the major ice sheets, causing phytoplankton and sea - ice algae productivity recorded in cores PS2138 - 3 and PS2757 - 8 (for the region off the Greenland - Laurentide Ice Sheet no proof from sediment cores are available.

By combination of this sea ice proxy IP25 with (biomarker) proxies for open - water phytoplankton productivity such as brassicasterol, dinosterol or a specific tri-unsaturated HBI (HBI - III) 37,38,39,40,41, a more precise (semi-quantitative) reconstruction of present and past Arctic Ocean sea ice conditions from marine sediments are now available (Supplementary Fig. 1; see Metho 6ds for some more details).

They live only in a few borderline places, however; for global temperatures scientists use not only other species of trees but a wide variety of «proxies» from ice cores, coral reefs, cave deposits, the sea floor, pollen in lake sediments, boreholes in rock and so forth.

Then, by analysing the sediments for chemical fossils made by certain microscopic plants that live in sea ice and the surrounding oceans, Knies and his co-workers were able to fingerprint the environmental conditions as they changed through time.

Likewise, continuously increasing SST [sea surface temperature], reaching maximum values of ~ 9 °C at ~ 180 cm (~ 10 ka [10,000 years ago]-RRB-, strongly coincides with the absence of IP25 [proxy for sea ice] in the sediment.

An ancient catastrophe that killed half of the marine species in the oceans - and swept the land clear for the dinosaurs to dominate - may have been tied to icy - methane crystals buried in sea - sediments.

Bottom waters at depths of 50 or 100 m might warm relatively quickly with a collapse in sea ice cover, but it would take centuries for that heat to diffuse through the 100 - 150 m of sediment column to the hydrate stability zone.

«Ship - based observations show that methane concentrations in the air above the East Siberian Sea Shelf are nearly twice as high as the global average... Layers of sediment below the permafrost slowly emit methane gas, and this gas has been trapped for millennia beneath the permafrost.

As there is no explanation as to how climate changes could possibly affect the intensity of the earth's magnetic field, it was decided that it would be easier to believe that proxy sea floor sediment data should be adjusted («corrected») for sea water temperature.

In the 1970s, the first comprehensive analysis of oxygen isotopes in sediments from cores taken from the sea floor established for the first time that the timing of the Ice Ages was linked to subtle changes in the Earth's orbit around the Sun as suggested long ago by Serbian mathematician Milutin Milankovitch.

We reconstructed sea surface temperature, El Niño — Southern Oscillation (ENSO) activity, and the tropical Pacific zonal gradient for the past millennium from Galápagos ocean sediments.

Scientists at Newcastle University, in North East England, working with colleagues in Africa, say the sea cucumber is important because it is responsible for cleaning up the sea bed by consuming and mixing marine sediments.