Sea levels

 Many people might think that the sea has stayed the same level since the beginning of Earth, but in reality sea level has not always been the same. From researching today, we know that when we look at edges of continents submerged today were once dry in the past. And on the other hand, looking at many sedimentary rocks proves to us that the sea level has once covered land far passed the present shorelines. The submergence of part of a continent beneath seawater could result from either subsidence of the land, rise in sea level, or a combination of both. Therefore, it is difficult to determine exactly how sea levels has changed independently of the uplift and subsidence of continents.

 

From using the distribution of marine sedimentary deposits on continents, scientists can date back the sea level to about 140 million years ago. About 50 to 100 million years ago global sea level was about 200 meters higher than it is now. So you ask yourself…why does sea level rise and fall? If you think of the world ocean as a container, there are two big picture possibilities that come to mind: Either the container changed the amount of water it had or it changed the size of the container that holds the water. Either one of these possibilities could explain the increasing or decreasing of sea levels.

 

One easy explanation, which relates to today’s crisis is the fluctuation of the growth and melting of glaciers. 21,000 years ago (last ice age), the sea level was at least 100 meters lower than it is today because of all the water stored as ice on land. If the remaining glaciers melt, mostly covering Greenland and Antarctica, then the global sea level will rise an additional 80 meters.

 

Another explanation for the fluctuating sea levels is that the size of the actual ocean basin changes through time. If ocean-basin depths decrease, then the water spreads out onto previous dry land, therefore raising sea level without changing the volume of water in the oceans. This hypothesis of changing the size of the ocean basins is necessary because there are times in history when shoreline sedimentary deposits show changes in sea level without geologic evidence for the presence of glaciers. A third possibility to the rising of sea levels is plate tectonics. To link plate tectonics with sea level you need to make use of the fact that the elevation of seafloor relates to its age.

 

 

 

 

 

Contamination

As chemicals and toxins have been increasingly more popular with time, the subject of soil contamination has become more and more important. Today, humans have to be prepared and organized in a case if a major toxic or chemical spill were to occur. Thus, research in bioremediation is becoming more and more common. Using natural bacteria and/or other organisms to “eat away” at the toxic material, is a natural and very useful method. Just like the Exxon oil spill scientists used bacteria that ate away at the carbon in the oil, to reduce the overall affect to the environment. Research in this subject could save many species and and prevent keystone habitats from anthropogenic destruction. We all learned in class that soil can absorb, filter, and buffer all kinds of liquids. Whether it be rain or chemicals from a non-point pollution source, soil has the ability to retain and/or filter chemicals from getting into waterways or even groundwater sources.

Contamination of soil by crude oil occurs around the world because of equipment failure, natural disasters, deliberate acts, and human error. However, conventional approaches to clean-up come with additional environmental costs. Detergents, for instance, become pollutants themselves and can persist in the environment long after any remediation exercise is complete. A more environmentally friendly approach is to bioremediation, which uses natural or engineered microbes that can metabolize the organic components of crude oil. Stimulating such microbial degradation in contaminated soil often involves the use of expensive fertilizers containing nitrogen and phosphorus, and again may come with an additional environmental price tag despite the bio label. Many studies have been researched and preformed, when looking around on the internet I found an article on Science Daily actually says that Chicken Manure, yes CHICKEN MANURE, has the ability to biodegrade crude oil in contaminated soil. Research in China, “the team added chicken manure to soil contaminated with 10 percent volume to weight of crude to soil. They found that the almost 75% of the oil was broken down in soil with the fowl additive after about two weeks. Whereas additive-free soil was naturally remediated to just over 50%.”

There are also other uses of bioremediaton, like, the use of genetic engineering to create organisms specifically designed for bioremediation has great potential. The bacterium Deinococcus radiodurans (the most radioresistant organism known) has been modified to consume and digest toluene and ionic mercury from highly radioactive nuclear waste. There are some plants that naturally buffer the chemicals and the roots actually clean the contaminate. Mycoremediation is the use of fungi to return a contaminated environment to a less contaminated one. Overall there are many different uses and methods of bioremediation that are all very useful and environmentally friendly. Research in this subject is important for the benefit of comfortable living for multiple species, including ourselves.

Climate on Our Soil

When we think of Global Warming we think of the sea level rising and the glacier ice caps melting away, but what people dont’t really know is how the soil can responde differently as well. As winters get milder, changes occur underfoot and go largely unnoticed until critical thresholds are reached. Railroad tracks are deformed from the changes that are warming the land. Rocky peaks crack apart and spill into ravines. Whole mountainsides lose footing, creating flows of ice and mud that move as fast as a BMW on the Autobahn.

About 24 percent of land area in the Northern Hemisphere is underlain by perennially frozen ground. Scientists call this permafrost. Another 57 percent extends down into much of the United States and Europe that freezes seasonally. This is a scary statistic and can cause dramastic changes to soil that has been frozen year round can end up being detrimental to humans and the environment around them. On a LiveScience I found out that: Permafrost exists at depth, and the surface layer above it freezes seasonally. When the seasonal freezing is of shorter duration, owing to climate warming, the seasonal thaw runs deeper and extends into the former permafrost. The active layer — freezing and thawing each year — grows deeper. Because water in the soil expands when frozen and loses volume upon melting, it causes uneven movements in the ground surface. Under sustained climatic warming, the consequences of disappearing permafrost could be very severe for structures.

Within a 4 degree (C) rise of global temperature about 20 percent rainfall will decrease, obviously causing less run-off water but will be destructive to the soil’s moisture content. Though it will cause less run-off in the southern-hemisphere, Global warming will cause more smowmelt which is importatn source of runoff. Up to one-half of the mass of moutains glaciers and small ice caps may melt away over the next hundred years which could substantially change the health and content for each soil.

Antoni Lewkowicz of the University of Ottawa has studied several northern landslides and rockslides that he says can be at least partially attributed to thinning and weakening of ice or permafrost caused by climate warming. In one case, an earthquake broke off a weakening glacier in the Yukon. About 500,000 tons of ice raced down a mountain.

“By the time it reached the bottom it would have been going about 140 mph,” Lewkowicz said. These landslides can destroy buildings in seconds and if the Earth continues to get hotter than these ice slides will only become more common.

Many researchers are studying carbon sequestration, the process of plant life absorbing the carbon that humans or other animals have been putting into our atmosphere. While the CO2 amounts are about 380 ppm in the atmosphere today, and rising, researchers are trying to find a method or species of plant that would be able to absorb/consume the massive amounts of carbon reducing the greenhouse gas tremendously. They are looking for a way so that the plants will sustain the carbon and not just put massive amounts back into the environment.

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