26 October - Biological Challenges

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Paternalism of "science-based" medicine

Lately I find myself getting more and more incensed with colleagues who seem to preach science-based medicine as the be-all and end-all in the truth about everything. I have blogged about this many times, and some of the references I make below are expanded upon in some of my recent posts. 

It is my belief that all interventions should be approached with equanimity, if not equipoise. 

Astroturfing diseases

Is it possible that some of the 40% of Americans who have at least one chronic disease are suffering from an astroturfed disease? And is it possible that there are more astroturfed diseases cropping up every day? How can this be? That would be some futuristic dystopia, nothing to do with our reality.

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Greenhouse Gase Increases Linked to Changes in Ocean Currents

Pesticides: Easier Detection Of Pollution And Impact In RiversImage via Wikipedia

 How Do Water Filtration Systems Work Anyways?

Recent examinations suggest that bottled water is the same as tap water with respect to pollution and drinking bottled water only means that you are paying more money to drink the same chemicals. There are many top-performing home Water Filtration Systems offered currently. A quality home water purification system is the most important and effective machine we will use.

Killer Algae: Key Player In Mass Extinctions

Supervolcanoes and cosmic impacts get all the terrible glory for causing mass extinctions, but a new theory suggests lowly algae may be the killer behind the world's great species annihilations.

Today, just about anywhere there is water, there can be toxic algae. The microscopic plants usually exist in small concentrations, but a sudden warming in the water or an injection of dust or sediment from land can trigger a bloom that kills thousands of fish, poisons shellfish, or even humans. James Castle and John Rodgers of Clemson University think the same thing happened during the five largest mass extinctions in Earth's history.

Dead zone (ecology)

Dead zones are often caused by the decay of algae during algal blooms

Remains of organisms found within sediment layers near the mouth of the Mississippi River indicate four hypoxic events before the advent of artificial fertilizer. In these sediment layers,anoxia-tolerant species are the most prevalent remains found. The periods indicated by the sediment record correspond to historic records of high river flow recorded by instruments at Vicksburg, Mississippi.

It might be expected that fish would flee this potential suffocation, but they are often quickly rendered unconscious and doomed. Slow moving bottom-dwelling creatures like clams, lobsters and oysters are unable to escape. All colonial animals are extinguished. The normal re-mineralization and recycling that occurs among benthic life-forms is stifled.

According to Fred Below, a professor of crop physiology at the University of Illinois at Urbana-Champaign, corn requires more nitrogen based fertilizer because it produces a higher grain per unit area than other crops and, unlike other crops, corn is completely dependent on available nitrogen in soil. The results, reported 18 March 2008 in Proceedings of the National Academy of Sciences, showed that scaling up corn production to meet the 15-billion-gallon goal would increase nitrogen loading in the Dead Zone by 10–18%. This would boost nitrogen levels to twice the level recommended by the Mississippi Basin/Gulf of Mexico Water Nutrient Task Force (Mississippi River Watershed Conservation Programs), a coalition of federal, state, and tribal agencies that has monitored the Dead Zone since 1997. The task force says a 30% reduction of nitrogen runoff is needed if the Dead Zone is to shrink.

Dead zones are reversible. The Black Sea dead zone, previously the largest dead zone in the world, largely disappeared between 1991 and 2001 after fertilizers became too costly to use following the collapse of the Soviet Union and the demise of centrally planned economies in Eastern and Central Europe. Fishing has again become a major economic activity in the region.^[11]

Creeping Dead Zones

The cause of anoxic bottom waters is fairly simple: the organic matter produced by phytoplankton at the surface of the ocean (in the euphotic zone) sinks to the bottom (the benthic zone), where it is subject to breakdown by the action of bacteria, a process known as bacterial respiration. The problem is, while phytoplankton use carbon dioxide and produce oxygen during photosynthesis, bacteria use oxygen and give off carbon dioxide during respiration. The oxygen used by bacteria is the oxygen dissolved in the water, and that’s the same oxygen that all of the other oxygen-respiring animals on the bottom (crabs, clams, shrimp, and a host of mud-loving creatures) and swimming in the water (zooplankton, fish) require for life to continue.

The "creeping dead zones" are areas in the ocean where it appears that phytoplankton productivity has been enhanced, or natural water flow has been restricted, leading to increasing bottom water anoxia. If phytoplankton productivity is enhanced, more organic matter is produced, more organic matter sinks to the bottom and is respired by bacteria, and thus more oxygen is consumed. If water flow is restricted, the natural refreshing flow of oxic waters (water with normal dissolved oxygen concentrations) is reduced, so that the remaining oxygen is depleted faster.

Many of the areas where increasing bottom water anoxia has recently been observed are near the mouths of major river systems.

The apparent cause of the creeping dead zones is agriculture, specifically fertilizer. While fertilizer is necessary to foster bumper agricultural crops, it also runs off the fields into the streams and rivers of a watershed. When the fertilizer reaches the ocean, it just becomes more nutrients for the phytoplankton, so they do what they do best: they grow and multiply. Which leads to more organic matter reaching the bottom, more bacterial respiration, and more anoxic bottom water.

Super goby helps salvage ocean dead zone

The Benguela ecosystem lies off the coast of Namibia. It exists in waters only 120 metres deep that used to be a rich sardine fishery, but in the 1960s the sardine population crashed because of overfishing and environmental factors, and the region was invaded by algal blooms and swarms of jellyfish.When the algae die they sink to the bottom and decay, releasing large quantities of the poisonous gas hydrogen sulphide. Nevertheless, local fish called bearded gobies have flourished.

Expanding Threat of Hypoxia in U.S. Coastal Waters

The interagency report notes that incidents of hypoxia -- a condition in which oxygen levels drop so low that fish and other animals are stressed or killed -- have increased nearly 30-fold since 1960. Incidents of hypoxia were documented in nearly 50 percent of the 647 waterways assessed for the new report, including the Gulf of Mexico, home to one of the largest such zones in the world.

The impact of the BP Deepwater Horizon oil spill on oxygen levels in the Gulf of Mexico was not considered in this report because the spill had not yet occurred at the time the report was completed.

Related Stories

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Study Shows Continued Spread Of 'Dead Zones'; Lack Of Oxygen Now A Key Stressor On Marine Ecosystems(Aug. 15, 2008) — A new study shows that the number of "dead zones" -- areas of seafloor with too little oxygen for most marine life -- has increased by a third between 1995 and 2007. Dead zones are now "the key ...  > read more

How Healthy Are America's Coasts? (Dec. 29, 2008) — The overall condition of the nation's coastal waters has improved slightly, based on a recently released environmental assessment. The overall condition of America's coasts is rated as "fair," based ...  > read more

Aquatic 'Dead Zones' Contributing to Climate Change (Mar. 12, 2010) — The increased frequency and intensity of oxygen-deprived "dead zones" along the world's coasts can negatively impact environmental conditions in far more than local waters. Scientists explain that ...  > read more

Coastal Dead Zones May Benefit Some Species, Scientist Finds(Oct. 16, 2008) — A Brown ecologist has found that coastal "dead zones" may not be so dead after all. In a paper published this month in the journal Ecology, Andrew Altieri has found that the commercially valuable ...  > read more

Ocean 'Dead Zones' Trigger Sex Changes In Fish, Posing Extinction Threat (Apr. 3, 2006) — Oxygen depletion in the world's oceans, primarily caused by agricultural run-off and pollution, could spark the development of far more male fish than female, thereby threatening some species with ...  > read more

These Shells Don't Clam Up: Innovative Technique To Record Human Impact On Coastal Waters(Dec. 13, 2008) — Using stable isotope techniques, scientists have demonstrated it is possible to identify and trace wastewater inputs to estuaries and coastal food webs by studying the organic matrix in the shell of ...  > read more

Manganese Damages Immune Response In Marine Animals, Research Finds (Aug. 15, 2009) — Hypoxia, or lack of oxygen, in bottom waters is a well known environmental problem. New research in Sweden adds to the list of ill effects: hypoxia leads to increased levels of manganese, which ...  > read more

Record-Setting Dead Zones Predicted For Gulf Of Mexico, Chesapeake Bay (July 17, 2008) — Record-setting "dead zones" in the Gulf of Mexico and Chesapeake Bay appear likely this summer, according to new forecasts. Scientists make the annual forecasts using models driven by nutrient load ...  > read more