And that alternates with a sediment that looks like this.

This sediment is 100 percent made up of the shells of microscopic plants.

Lots of evidence from sediment cores and the pollen types, oxygen isotopes and so on.

And the black rock is the sediment on the sea bottom in the absence of plankton.

And these plants need sunlight, so we know when we find that sediment there's no ice overhead.

The animals or organisms have now been extracted from the sediment for all of the samples collected.

This resulted in a reduction of the estimated area of oil contaminated sediment to approximately 65 square kilometres.

Generated run off is less erosive and less polluting as crop residues reduce sediment transport into river waters.

Well, an excavation was begun immediately, and more and more little bits of skull started to be extracted from the sediment.

It doesn't matter what kind of sediment you're using to grind up, whether it's bacteria or any other plants or animals.

Iraq's general contention is that the model predictions of subtidal sediment contamination used by Kuwait to estimate biomass losses are not reliable.

It's a basin, and rivers flow down from the highlands into the basin, carrying sediment, preserving the bones of animals that lived there.

The models used are a Model for the Assessment and Remediation of Sediment ( MARS ) and an Oil Spill Contingency and Response Model ( OSCAR ).

In those claims, Saudi Arabia estimated the total area of oil contaminated sediment in all the affected sites to be approximately 73 square kilometres.

And we take samples of the sediment, and it tells us the CO2 level of the ocean, and therefore the CO2 level of the atmosphere.

And all the sediment is then put through these screens, and where we go again through it very carefully, looking for small bone fragments, and it's then washed.

They take the sediment itself, they extract the oil from it, and from that they can produce compounds which turn out to be very specific to particular microbial groups.

And if you look north here, there's a big river that flows into the lake that's been carrying sediment and preserving the remains of the animals that lived there.

It's because lipids are so tough, they can get preserved in sediment and last the hundreds of millions of years necessary, and be extracted and tell us who was there.

That signal was so strong, it could only have been produced by 10 trillion tons of water buried in the sediment, collected over millions and billions of years by the impact of asteroids and comet material.

Bitumen permeates the dirt at the surface or, where thin layers of compost and sediment intervene, somewhat below basement levels. Grasping a handful of dirt from a riverbank does leave one s hand more oily than tarred, and the greasy dirt is somewhat sandy.

Rice paddies need to be constantly flooded, and, because they are often located on steep slopes, this leads to significant runoff of fertilizers and sediment. Shifting to corn not only reduces water consumption it also cuts the amount of pollution that reaches city residents downstream.

The chalk itself's composed by plankton which has fallen down from the sea surface onto the sea floor, so that 90 percent of the sediment here is skeleton of living stuff, and then you have that millimeter thick red layer, and then you have black rock.

Recent monitoring and assessment data, including the results of approximately 3,000 transects carried out by Saudi Arabia and sediment samples which it analysed, show that high levels of oil contamination still remain in some coastal sediments that were exposed to oil spills resulting from Iraq's invasion and occupation of Kuwait.

At the same time, the material brought back from land to sea include nutrients and trace elements that cause a boom among plankton, which in turn feed other marine biota. Locally, but sometimes still at a grand scale, the shock waves cause major sediment slides on steep underwater slopes such as those of the continental shelves.

Meanwhile, the technology used at drilling and production platforms has developed tremendously, but the challenges regarding depth, weather, and sediment structure have grown even more, as easy to exploit oil fields have been exhausted. Blowouts have become the most troublesome type of oil spills, and in deep water they tend to continue for a considerable time because of the difficulties faced in containing them.