08/16/07

GREENING A BARREN GAP

L: Diane Husic, professor of biology, and Carl Salter, associate professor of chemistry, stand amid the warm-season grasses that are helping re-green the Lehigh Gap. R: Dead trees from a more toxic time.

About thirty minutes northwest of Bethlehem lies the biggest Superfund clean-up site east of the Mississippi. A stretch of the Blue Mountains bordering the Lehigh River at the Lehigh Gap near Palmerton, Pennsylvania, the former site of ore smelting operations by the New Jersey Zinc Company was so tainted by toxic metals that its lifeless ground was often compared to the surface of the moon. Now owned and managed by the Lehigh Gap Nature Center (LGNC), that once-barren landscape is being restored to the green countryside it once was. And the process is not only an environmental triumph, it's an opportunity for Moravian College students to perform meaningful scientific research and gain valuable field experience.

A chance to observe both the greening of the Gap and the findings of Moravian researchers occurred earlier this summer, when professor of biology Diane Husic, who sits on the LGNC board of directors, led a group of students and faculty on an informal tour along some of the site's hiking trails. With the flora of summer in full bloom, the ongoing restoration was readily apparent. Areas unaffected by the contamination were suitably lush and verdant, while those undergoing rejuvenation displayed various degrees of growth. Across the Lehigh River, bleak tracts of as-yet unrestored land acted as stark reminders of how much change has occurred and how much more needs to be done. A key to the comeback at the Gap, professor Husic told the group, is the planting of warm-season grasses, which help counter the topsoil erosion that occurred when mineral toxicity eliminated most plant life. "Their deep roots hold on to the soil and keep it from being eroded," she explained. "And as old roots die off, they add organic matter that helps build rich topsoil." The grasses are slow to take up the toxic metals from the soil, which helps keep the toxins from entering the food chain.

Following the nature walk, the group convened at the center's Osprey House pavilion, where students participating in Moravian's SOAR (Student Opportunities for Academic Research) program presented research they'd conducted at the Gap. Yi Li '08 and  Gregory Niehoff '08 described their efforts to examine the effects of heavy metal toxicity on four Lehigh Gap plant species. Working with Dr. Husic, they found that the plants showing visible signs of stress were not necessarily the ones with the highest contamination levels. Brian Bircheck '08, working with professor of biology Frank Kuserk, surveyed and identified aquatic macroinvertebrates from pond and stream water in the Gap area. Though more samples will be needed to fully evaluate the quality of the Gap's waterways, the number and variety of insects, snails and other invertebrates found there is a good omen. Armando Villifane '07, who also worked with professor Kuserk, examined soil microorganisms. By consulting with a researcher who conduced a similar survey in 1973 (a few years after the smelting operations ceased), Armando was able to take samples from the same sites for comparison. The increase in microbe numbers that he documented is another encouraging sign of the Gap's comeback. After the presentations, LGNC executive director Dan Kunkle thanked the Moravian students and faculty members for their contributions to the Gap project, and stated how impressed he was with the quality of their work.

Yi Li '08 presents her research at the LGNC pavillian.


Lehigh Valley Nature Center
January 2007 Gap project meeting at Moravian