One can only imagine how many thousands of times scientists have wrung their hands for lack of a decent specimen. Diligently collected, catalogued, preserved and protected, specimens provide a baseline for future comparisons, a tangible trail of changing conditions. Without these research reference points that transcend time, science would be sorely diminished.
Dr. Mark B. Edlund is working to ensure that, at least with regard to the diatoms of a remote lake in north-central Mongolia, an extensive collection will exist for future researchers.
Diatoms are a large group of microscopic algae that grow as single cells or small colonies, and they are an important part of the "primary producer" community in most aquatic habitats. They often live within narrow environmental conditions, which means that they can be important indicators of change, e.g. pollution, water temperature, nutrient levels and salinity.
"Diatoms are incredibly valuable as a tool for water quality monitoring," Dr. Edlund explains. "And they are one of the primary tools used in paleo-ecology, a discipline that uses fossil organisms to decipher environmental history."
Dr. Edlund doesn't hesitate to compare diatoms to the long-extinct dodo bird.
"There's been a wonderful case recently regarding the value of specimens," Dr. Edlund explains. "Scientists in England have made important new discoveries about the dodo bird's place in evolution. They wouldn't have been able to do that if someone hadn't had the forethought to preserve a specimen."
In that case, DNA was extracted from a centuries-old preserved dodo bird residing at the Oxford Museum of Natural History.
"Maybe little diatoms in a jar don't seem as colorful as the dodo, but it's the same thing." Dr. Edlund says. "The very existence of a collection represents potential research."
The recipient of a 3-year postdoctoral NSF International Research Fellow Award for his work on diatoms in Mongolia's Lake Hovsgol National Park, Dr. Edlund and his collaboration of American and Mongolian scientists have made over 600 collections of diatoms to date from Lake Hovsgol. They have established permanent herbarium collections in both countries, at the National University of Mongolia, and at the California Academy of Sciences, the University of Michigan, and the Science Museum of Minnesota in the U.S.
Building on his experience from a previous NSF-sponsored expedition to Mongolia in 1996, a number of factors led Dr. Edlund to choose the Lake Hovsgol region for further study. Lake Hovsgol is one of the most pristine large lakes on earth, and therefore globally significant as a natural laboratory for the study of ecology and evolution. And unlike most lakes on earth, which are only 10,000-13,000 years old, Lake Hovsgol is estimated to be over 1.6 million years old. The lake region contains two ancient ecoregions: the entire Hovsgol drainage basin and watershed to the east, and a large part of the Darhad basin to the west. The basins themselves are "tectonic grabens", depressed areas of the earth's crust featuring a number of faults, and are part of the larger Baikal Rift Zone that contains Russia's famous Lake Baikal.
"Lake Hovsgol is one of these flukes of nature," Dr. Edlund says. "When you have a lake of this type that has existed for that length of time, you begin to see different outcomes of evolutionary processes. You often end up with communities of organisms that are unique, endemic, not found anywhere else. That is the basis of our work there."
Despite its scientific value, the most recent biotic survey of Lake Hovsgol had been done nearly a century ago, with few other works addressing the diversity and ecology of the primary aquatic producers. The lack of extensive sampling led Dr. Edlund and his collaborators, Dr. Eugene Stoermer of the University of Michigan and Dr. Ts. Jamsran of Mongolian State University, to conclude that the biodiversity of diatoms in Lake Hovsgol was severely underestimated.
Accessing a number of microscope slides from the 1903 collection initially made by a Russian zoologist, Dr. Edlund's team discovered that a number of species originally described were still alive and well in Lake Hovsgol. And a number of diatoms were endemic to that lake. He confirmed the results by taking a sediment core of material approximately 150 years old, and comparing it to recent samples. Again he found the same species complex existed in both the core samples and in the lake today.
A key component of Dr. Edlund's research visit was his training of Mongolian scientists and students to study and use diatoms in their research. He also taught a number of courses on diatoms, general algae, and general aquatic ecology at the National University of Mongolia. His extensive work with Ms. N. (Sonya) Soninkhishig, now a doctoral candidate at the university, led to her status as the only specialist with a primary focus on diatoms in the entire country of Mongolia.
Lake Hovsgol has been named Mongolia's first International Long-Term Ecological Research (ILTER) site, but this status does not guarantee protection from impending threats, including the potential mining of one of the world's largest untapped phosphorite deposits on the western shore of the lake; possible spills from cargo and fuel oil shipments crossing the lake; ecotourism overdevelopment; livestock overgrazing; and water use issues.
For the time being, Lake Hovsgol remains oddly devoid of the zipping boats and jet skis so prevalent on large lakes in the rest of the world. The few homes scattered around the lake are the traditional "gers" of semi-nomadic Mongolians still living the old ways. But should Lake Hovsgol someday succumb to major change, Dr. Edlund and his team of scientists have documented its current biotic diversity for the benefit of future researchers.
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