Stevens, J.L.; Evans, G.E., and Aguirre, K.M., 2012. Human beach use affects abundance and identity of fungi present in sand.

To determine whether abundance and diversity of fungal species differed among very low use, residential, and commercial beaches and whether human use had a measurable effect on sand fungi, samples were collected for two consecutive years from South Carolina beaches along a continuum of human use. For both years, more fungi (colony-forming units [CFUs] per gram dry weight sand) were isolated from high-use beach sand samples than low-use beach sand samples (analysis of variance, p < 0.05), but there was no evidence of accumulation of fungi over a tourist season or from year to year. In fact, fungal abundance was greatest for all three sites in May and July and significantly decreased in September. A positive correlation was found between census of beach-goers and fungal CFUs. Potential pathogens (fungi which grew at 37°C) were selected, and DNA-based sequence identifications were made. These included two potential human pathogens—one of which was found on commercial beaches only. Sand grain size and color ranged from smallest/whitest in samples from very low use beaches to largest/darkest in those from higher use beaches, suggesting that relative oxygen, mineral, or nutrient content or extent of absorptive surface might also affect fungal niche occupancy. These data suggest that a mixture of parameters influence abundance and diversity of beach fungi, but that level of human use is one significant factor. The absence of year-to-year accumulation of fungi is a novel observation. This study adds to the growing number of reports of beach sand as a reservoir of fungal and other nonbacterial organisms that can affect human health.