On the phenotypic level, Höss et al. (2001) and Meinelt et al.
(2004) showed that HSs have a potential to act as xenohormones.
Höss et al. (2001) reported that a variety of humic isolates increased
the life-time offspring number in C. elegans, whereas in
an ornamental fish (swordtail, Xiphophorus helleri Heckel), increasing
exposure concentrations led to increased shares of females if
fertilized eggs were exposed