May 2013, Vol. 5, No.25

Waterline

Spiders reveal mercury pollution in waterbodies  

Spiders living along lake shores can predict mercury pollution, a study conducted at Texas Christian University (Fort Worth) revealed. 

Researchers examined the transport of mercury through insects that spend part of their life in water and part on land, and the effects fish predation of these insects has on transport. Fish were found to reduce transport of mercury by larger insects, but terrestrial spiders consume smaller insects, according to the abstract of a recent report on the study. 

Researchers studied 10 ponds, both with and without fish, that had different levels of mercury contamination. They found that the long-jawed orb weaver, a common shoreline spider, consumed small aquatic insects, such as midges, that emerged from the ponds, according to a Dick Jones Communications (Wooster, Ohio) news release. The spiders had average mercury levels correlating to these small emergent insects, as well as to the ponds where the insects lived. The spiders then are consumed by birds, contributing to the spread of mercury contamination, the news release says. 

Mercury contamination in lakes often is monitored by sampling fish, but some waterbodies contain no fish, and the fish-sampling process is time-intensive and expensive, the news release says. Using terrestrial spiders to monitor waterbodies can help scientists and environmental managers monitor an aquatic ecosystem regardless of its fish population and has the potential to be a more efficient monitoring method, the news release says. 

A report on the study, “Effects of Fish on Emergent Insect-Mediated Flux of Methyl Mercury Across a Gradient of Contamination,” was published in the Feb. 5 issue of Environmental Science & Technology. 

  

Water, water everywhere, even on the moon  

New evidence shows water was present on the moon while it was forming. Traces of water have been found within the crystalline structure of mineral samples taken from the lunar highland upper crust. These samples were during the Apollo missions, according to a University of Michigan (Ann Arbor) news release.  

During the past 5 years, research supporting the historical presence of water on the moon has been accumulating. Previous research identified hydroxyl ions, which contain one atom of hydrogen and one atom of oxygen, on the moon. For the current study, researchers detected about 6 ppm of water, in the form of hydroxyl groups, in grains of the samples of highland rock, the news release says.  

The moon’s highland rocks were thought to have formed early in its history. This provides evidence that the interior of the moon contained significant amounts of water during its early molten state, before the crust solidified, the news release says.  

Findings from the study, performed by researchers at the University of Notre Dame (South Bend, Ind.), NASA, and the University of Michigan, was published in the Feb. 17 issue of Nature Geoscience.  


 

Using solids from mines to remove phosphorus from wastewater   

Residuals from acid mine drainage can be used to remove phosphorus from agricultural and municipal wastewater, according to research published in the journal Water, Air & Soil Pollution.  

Acid mine drainage, which consists of acid and dissolved metals, is produced when sulfide minerals associated with coal and metal deposits are exposed to air and moisture. Drainage is neutralized during remediation with such bases as limestone or lime, and iron-rich solids form, according to a U.S. Geological Survey (USGS) news release. 

For the study, a USGS researcher and IAP World Services (Cape Canaveral, Fla.) researcher identified a new process that uses these solids to filter phosphorus from wastewater. The researchers also found that the phosphorus can be stripped from the residuals. The solids can be reused for additional treatment cycles, and the phosphorus can be recycled into fertilizer, the news release says. The technology reduces the need for solids disposal, decreases drainage treatment costs, and prevents harm to aquatic ecosystems. 

 

Map details environmental stresses of the U.S. Great Lakes  

  

A new mapping project tells the story of the U.S. Great Lakes’ environmental health. The high-resolution spatial analyses maps identify locations and ranges of environmental stresses affecting ecological services provided by the five lakes. 

A team led by University of Michigan (Ann Arbor) researchers worked together on the Great Lakes Environmental Assessment and Mapping project, according to a university news release.  

The team gathered data and mapped 34 individual stressors for the region, which spans nearly 1448 km (900 mi). Stressors, mapped on the scale of 0.8 km (0.5 mi), include coastal development, pollutants, fishing pressure, climate change, invasive species, and toxic chemicals. To rank the importance of different stressors, the team surveyed 161 researchers and natural resource managers from the area, the news release says.  

The Great Lakes provides recreational and commercial ecosystem services, such as fishing, boating, and beach use. By comparing maps of these services to maps of stresses, researchers determined that often locations that provided the most services were disproportionately stressed, the news release says. This provides a scientific foundation to manage the ecosystem by providing planners and government officials with information needed to prioritize areas to invest in environmental restoration and natural resource protection, the news release says.  

The project, which began in 2009 with funding from the Fred A. and Barbara M. Erb Family Foundation (Bloomfield Hills, Mich.), will continue acquiring data to update and map additional stressors, the news release says. 

An article detailing this effort was published Dec. 17 in the Proceedings of the National Academy of Sciences. Read more at www.greatlakesmapping.org