A comparative analysis of lead and iron in Lunularia cruciata
Liverworts are one of the earliest known land plants. They are nonvascular, lack a cuticle, and do not have true roots. Due to having different physiological mechanisms and a notably high heavy metal tolerance compared to later evolved plants, they have been proposed as bioindicators. For our study, we examined iron and lead content in the liverwort Lunularia cruciata and its soil substrate at two sites using atomic absorption spectroscopy. The first site was in a residential zone and likely to have been painted with lead-based paint during the 1970s. The second site was behind a well-maintained parking lot with unpainted infrastructure. On average, we found significantly higher levels of both iron and lead in both the soil and thallus of L. cruciata thallus at the residential site. Although the infrastructure tested negative for lead, it may have contained lead-based products in the past which could have made its way into L. cruciata and the soil. Further molecular studies of the liverwort thallus could provide insight into the physiological mechanisms of heavy metal tolerance in L. cruciata.
Results of atomic absorption spectroscopy analyses. (a) Mean iron content in L. cruciata (two sample t test; t= 3.74, 4 d.f., p-value < 0.05) and (b) mean lead content (two sample t test; t= 3.11, 4 d.f., p < 0.05). On average, higher levels of both iron and soil were found at site 1. Bars are ± SE.
Lichen and moss biodiversity in the Lanphere Dunes of Humboldt County, Arcata, Ca
Coastal dune mats are made up of communities of vascular plants and cryptogams. While many studies have focused on vascular plants, little is known about the lichens and mosses that make up the cryptogamic community. I surveyed ridge and swale dune populations in the Lanphere Dunes of Humboldt County, Arcata, California and identified the lichen and moss species present. I also surveyed a nearby pine stand for epiphytic lichen and moss diversity. I found common Pacific Northwest species in both locations, with potential for a larger amount of biodiversity existing in other areas of the Lanphere Dunes. Some of the species found were Cladonia pyxidata, Usnea cornuta, Ceratodon purpureus, and Kindbergia oregnana. By providing the species list, further studies can be done to examine the roles cryptogamic species play in the Lanphere Dunes and whether they have any influence on vascular plant abundance and success.