Watermelon snow
Watermelon snow , also called snow algae , pink snow , red snow , or blood snow , is a phenomenon caused by "Chlamydomonas nivalis" , a species of green algae containing a secondary red carotenoid pigment ( astaxanthin ) in addition to chlorophyll . 
<triplet> Watermelon snow <subj> Chlamydomonas nivalis <obj> has cause <triplet> Chlamydomonas nivalis <subj> Watermelon snow <obj> has effect <triplet> carotenoid <subj> pigment <obj> subclass of