stream

A human parasite with a streamlined mitochondrion

Mitochondria, as they are defined in textbooks, are essential for eukaryotic cells--including our own--because they make large amounts of energy as they use oxygen. However, some eukaryotic cells, including important parasites of humans--such as Entamoeba histolytica, the causal agent of amoebic dysentery--live in environments that are too oxygen poor to support this process. Nevertheless, Entamo...

Freeze-dried mats of microbes awaken in Antarctic streambed

An experiment in a dry Antarctic stream channel has shown that a carpet of freeze-dried microbes that lay dormant for two decades sprang to life one day after water was diverted into it, said a University of Colorado at Boulder researcher. The results showed the resilience of life in the harsh polar environment, where temperatures are below freezing for most of the year and glacial...

Geoscientists follow arsenic from chicken feed to streambeds

What happened to the chicken when she crossed the road is less important that what happens to what she eats when it is used as fertilizer. Organic arsenic is fed to poultry to prevent bacterial infections and improve weight gain. A little bit of arsenic is taken up by the tissue and the majority of it is excreted in urine. Poultry litter -- the wood chips, feathers, droppings, and urine fr...

Pesticides in the nation's streams and ground water

Today, the U.S. Geological Survey released a report describing the occurrence of pesticides in streams and ground water during 1992-2001. The report concludes that pesticides are typically present throughout the year in most streams in urban and agricultural areas of the Nation, but are less common in ground water. The report also concludes that pesticides are seldom at concentrations likely to...

Beaver dams create healthy downstream ecosystems

Beavers, long known for their beneficial effects on the environment near their dams, are also critical to maintaining healthy ecosystems downstream. Researchers have found that ponds created by beaver dams raised downstream groundwater levels in the Colorado River valley, keeping soil water levels high and providing moisture to plants in the otherwise dry valley bottom. The results will be publis...

Swimming 'to the left' gets bacteria upstream, and may promote infection

Yale engineers who study both flow hydrodynamics and how bacteria propel themselves report that one reason for the high incidence of infections associated with catheters in hospital patients may be that some pathogenic bacteria swim "to the left," in a study published in Physical Review Letters. "Escherichia coli (E. coli) and some other pathogenic bacteria with flagella interact with th...

Farmed salmon could become an invasive species in forest streams

Ever since the Norwegians expanded commercial farming of salmon in the 1960s, the industry has continued to rapidly grow worldwide. It has expanded to such a degree that prices for farmed salmon have plummeted and, there is concern that farmed fish may become the next invasive species. "Farmed fish escaping from marine net pens might become an invasive species in British Columbia, Washing...

Climate change impacts stream life

Climate change is warming Welsh streams and rivers, affecting the number and variety of some of their smallest animals, a major Cardiff University study has found. Rivers and streams are key ecosystems for many aquatic species and form important links with surrounding habitats, yet little emphasis has been given so far to the ecological effects of climate change on these running-waters....