Often the remediation strategies are complex and controversial. In the case of Hudson River, there is a heated debate about whether PCB-contaminated sediments should be removed—dredged with high-tech methods that theoretically minimize environmental harm—or left undisturbed. That debate pivots on the episodic storm phenomenon: Are the contaminated sediments there to stay, or could they get stirred up when the next hurricane washes through the Hudson Valley?
Aside from cleanup initiatives, parts of the Hudson need to be dredged for navigational purposes. Dredging is not that costly or difficult, but finding a place to put contaminated sediments is a problem. The Port of New York has been filling up abandoned Pennsylvania coal mines with its contaminated mud, but that is not a long-term solution.
While the problems of American estuaries are complicated and expensive, they pale in comparison to Asian estuaries. The entire nation of Bangladesh lies within the estuary and lower floodplain of the Ganges-Brahmaputra River. Global sea-level rise is causing a loss of land, increased flooding, and increased salt intrusion in these estuaries.
The demand for water upstream for irrigation and domestic use significantly reduces freshwater flow through these systems. The Indus River and Huang Ho estuaries have suffered from drastic reductions of freshwater flow over the past several decades, and the impact of these human alterations is just now being recognized.
New policies about land use, water diversion, and even global carbon dioxide production which affects global warming and sea level rise will be needed to protect these vulnerable estuarine environments and their human inhabitants. One of the challenges of estuarine research is that most of the significant problems are interdisciplinary, involving physics, biology, chemistry, geology, and often public policy and economics.
Estuaries are also incredibly diverse, coming in all shapes and sizes. As scientists, one of our roles is to predict changes in the environment, given different natural and human-induced influences. To foresee the health of estuaries in the future, we have some fundamental questions to answer about the present and the past.
How far will salt intrude if river flow is cut in half? Do changes in river flow increase or decrease the rate at which sediments shoal the estuary? What effect do such changes have on the fish that spawn in fresh water? What we learn will be critical for a human population that increasingly values coastal waters.
We will develop better policies only if we can ground them in better science. He uses techniques that span isotope geochemistry, next generation DNA sequencing, and satellite tagging to study the ecology of a wide variety of ocean species.
He recently discovered that blue sharks use warm water ocean tunnels, or eddies, to dive to the ocean twilight zone, where they forage in nutrient-rich waters hundreds of meters down. Born in New Zealand, Simon received his B.
With much of his work in the South Pacific and Caribbean, Simon has been on many cruises, logging 1, hours of scuba diving and hours in tropical environs. He has been a scientist at Woods Hole Oceanographic Institution since Gregory Skomal is an accomplished marine biologist, underwater explorer, photographer, and author. He has been a fisheries scientist with the Massachusetts Division of Marine Fisheries since and currently heads up the Massachusetts Shark Research Program.
For more than 30 years, Greg has been actively involved in the study of life history, ecology, and physiology of sharks. His shark research has spanned the globe from the frigid waters of the Arctic Circle to coral reefs in the tropical Central Pacific. Much of his current research centers on the use of acoustic telemetry and satellite-based tagging technology to study the ecology and behavior of sharks.
He has written dozens of scientific research papers and has appeared in a number of film and television documentaries, including programs for National Geographic, Discovery Channel, BBC, and numerous television networks. His most recent book, The Shark Handbook, is a must buy for all shark enthusiasts. Robert D. He served in the U. Navy for more than 30 years and continues to work with the Office of Naval Research. A pioneer in the development of deep-sea submersibles and remotely operated vehicle systems, he has taken part in more than deep-sea expeditions.
In , he discovered the RMS Titanic , and has succeeded in tracking down numerous other significant shipwrecks, including the German battleship Bismarck , the lost fleet of Guadalcanal, the U. He is known for his research on the ecology and evolution of fauna in deep-ocean hydrothermal, seamount, canyon and deep trench systems. He has conducted more than 60 scientific expeditions in the Arctic, Atlantic, Pacific, and Indian Oceans. Sunita L. Her research explores how the larvae of seafloor invertebrates such as anemones and sea stars disperse to isolated, island-like habitats, how larvae settle and colonize new sites, and how their communities change over time.
The exact amount of salinity will vary depending on environmental factors and can not be precisely defined. The salinity is usually measured in a range rather than an exact amount. Brackish water sources are most commonly found at transitional points of water where fresh water meets seawater.
These bodies of water are known and referred to as estuaries. In many places around the world, brackish water appears naturally, and it forms an important habitat for some unique animal species.
It can cause environmental damage, however, since it is harmful for organisms that have not adapted to it. This becomes an issue when such water is deliberately cultivated, as is done in some regions to farm desirable food fish.
It is also unpleasant to drink, and it may cause health problems. The term "brackish" was first used to describe portions of the potable water table that had been contaminated by salt water in the s. The mixing of salt and fresh created mildly salty water that was not as salty as seawater, but still distasteful.
Many people also noted that the water was harmful, due to unique microorganisms that cause human illness that thrive in it. In nature, estuaries are a common site of brackish water.
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