Berniewood Hogan
IT'S BERNIE SANDERS WITH A STEEL CHAIR!
This is why we need a Green New Deal from the Progressive Left and we need to drop centrism and capitalism straight into the middle of the ocean.
News Feature: Deadly deficiency at the heart of an environmental mystery
News Feature: Deadly deficiency at the heart of an environmental mystery
During spring and summer, busy colonies of a duck called the common eider (Somateria mollissima) and other wild birds are usually seen breeding on the rocky coasts around the Baltic Sea. Thousands of eager new parents vie for the best spots to build nests and catch food for their demanding young broods.
But Lennart Balk, an environmental biochemist at Stockholm University, witnessed a dramatically different scene when he visited Swedish coastal colonies during a 5-year period starting in 2004. Many birds couldn’t fly. Others were completely paralyzed. Birds also weren’t eating and had difficulty breathing. Thousands of birds were suffering and dying from this paralytic disease, says Balk. “We went into the bird colonies, and we were shocked. You could see something was really wrong. It was a scary situation for this time of year,” he says.
Based on his past work documenting a similar crisis in several Baltic Sea fish species, Balk suspected that the birds’ disease was caused by a thiamine (vitamin B1) deficiency. Thiamine is required for critical metabolic processes, such as energy production and proper functioning of the nervous system. This essential micronutrient is produced mainly by plants, including phytoplankton, bacteria, and fungi; people and animals must acquire it through their food.
Scenes such as the one in Sweden, seen again and again in recent years in a variety of species in Europe and North America, have Balk and other researchers worried that something in the environment is causing widespread thiamine shortages, which could explain these specific episodes—as well as possibly larger-scale wildlife population collapses. “This could be a very serious source of mortality,” says Stephen Riley, a fish ecologist at the United States Geological Survey (USGS) Great Lakes Science Center in Ann Arbor, MI.
Researchers generally agree that the crises in seabirds, fish, and other marine species have thiamine deficiencies in common. But much remains unknown. Is a thiamine shortage the root cause of the problem in every case? What might be driving such a widespread environmental vitamin deficiency? As instances of sick and dying wildlife continue to arise, though, a sense of urgency is building among researchers trying to figure out what’s going on. “I don’t think we agree in our assessment of it other than that it is a real issue,” says Clifford Kraft, a freshwater ecologist at Cornell University in Ithaca, NY.
Recurring Patterns
As a young researcher in the late 1980s, Balk started out examining the impacts of industrial pollution and endocrine disruptors on fish health. But he was so taken aback upon seeing the effects of thiamine deficiency on fish, he abandoned his earlier work to focus on this problem instead. In the late 1990s, Balk saw that several fish species in the Baltic Sea, including Atlantic salmon (Salmo salar), had trouble reproducing. Many of the larvae couldn’t swim straight and were lethargic before dying. When he supplemented the larvae with thiamine, almost all survived. In contrast, almost all of the larvae not treated with thiamine supplements died. Balk concluded that the fish were suffering from a thiamine deficiency (1).
Just a few years earlier, researchers had begun seeing similar devastation among fish in the Laurentian Great Lakes. Since 1995, researchers including John Fitzsimons, then a fish biologist for the Canadian government and now retired, had documented a thiamine deficiency that devastated populations of lake trout (Salvelinus namaycush) and several species of salmon in the Great Lakes (2). The fish were not reproducing and had difficulty maintaining their balance while swimming. “It’s like the fish were drunk. They lost their balance and would fall on their side,” says Fitzsimons. At first, researchers thought pollutants were to blame, but the suspicion was not borne out in tests. In a moment of inspiration, Fitzsimons realized the fish must be lacking a nutrient.
“One day the fish would be fine, and the next they would be lying on their side. It got me wondering if they had some sort of deficiency,” he recalls. Fitzsimons supplemented eggs from sick fish with thiamine and other B vitamins. He found that just less than 10% of fish eggs injected with thiamine died. The other B vitamins had no therapeutic effect. In contrast, he saw greater than 75% mortality in the control specimens that received no added vitamins. Fitzsimons and his colleagues concluded a thiamine scarcity was behind the paralysis and population declines of fish in the Great Lakes (2, 3).
After witnessing similar symptoms resurface in wild birds in 2004, Balk concentrated on exploring how far the disease reached. In 2009, his team documented symptoms in European herring gulls (Larus argentatus) and the common starling (Sturnus vulgaris) in addition to S. mollissima from sites across northern Europe. The researchers saw that the thiamine concentration in L. argentatus egg yolk was as much as 41% lower in birds from the Baltic Sea area compared with birds taken from around Iceland. The researchers also saw a drop in several biomarkers of thiamine activity, including thiamine-dependent enzymes, indicating that the vitamin was scarce in some birds around the Baltic Sea.
Balk’s team treated sick birds with thiamine injections and found that all but 1 of 10 paralyzed adult L. argentatus recovered over a 2-week period. None of the untreated birds showed signs of improvement. In addition, 10 young birds fed a thiamine solution on the first and second days after hatching were vigorous and active, whereas 10 young birds fed a saline solution were lethargic and apathetic and began to die approximately 4 days after hatching. Similar tests on S. vulgaris and S. mollissima also suggested that individuals were suffering as a result of thiamine deficiency. Balk reported that the deficiency was hampering the birds from breeding, which could be contributing to declines in local seabird populations (4).
Telltale Signs
It was certainly not the first time such symptoms had been seen in birds. In the 1880s, Christiaan Eijkman, a doctor working in the Dutch East Indies, observed paralysis in chickens, noting that they were experiencing weakness in their legs reminiscent of a disease known as beriberi, which was afflicting people across Asia at the time.
Eijkman linked the paralysis to the chickens’ diet of predominately cooked white rice, which he believed must be toxic; but his colleague, Gerrit Grijns, later came to suspect the rice had been stripped of some vital protective substance by modern milling processes. In some parts of Asia where people’s diets also relied largely on white rice, beriberi affected nearly 30% of the population. Eijkman shared a Nobel Prize in 1929 for his observations that aided the discovery of thiamine—the first vitamin to be identified (5). Today, instances of thiamine deficiency among people are rare because the vitamin is added to a wide range of processed foods, such as breakfast cereal. But deficiency does still occur among refugees with poor diets and among those who have alcoholism because their bodies have difficulty absorbing the vitamin.
Still another group at risk are people who eat a lot of fermented fish, notes Riley, because the fish are rich in the enzyme thiaminase, which breaks down thiamine. In fact, a diet of thiaminase-rich fish, it turned out, was the culprit in the case of thiamine-deficient Great Lakes trout and salmon.
In 2005, a team including Don Tillitt, an environmental toxicologist at the USGS, reported that salmon and lake trout were eating mainly alewives (Alosa pseudoharengus), an invasive species of fish that is rich in thiaminase. Tillitt and his colleagues fed 17 female lake trout, from a hatchery in Michigan, a diet consisting of only alewives. The team found that the fish laid eggs with a total thiamine concentration of approximately 2.5 nmol/g. In contrast, 13 fish were fed only bloaters (Coregonus hoyi)—prey fish lacking thiaminase—laid eggs with approximately 12 nmol/g. The researchers saw that nearly 20% of the young fish died when their mothers were fed only alewives. But all the young survived when their mothers were fed bloaters (6, 7).
“Thiamine deficiency almost completely stopped all reproduction in some fish species in the Great Lakes, causing huge population declines,” says Tillitt.