The microbial mass produced within standing-decaying marshgrass
by ascomycetes such as
Phaeosphaeria spartinicola and
Mycosphaerella sp. 2 has several avenues through which it
flows into the marsh food web. A prominent avenue is via the
shredding/grazing of saltmarsh periwinkles (Littoraria
irrorata). These snails become active upon the decaying blades
whenever the blades are wet (tides, rain, and probably especially,
dew), and avidly tear out and eat the decaying leaf material. They
selectively remove fungal-rich portions. This selectivity appears
to be strong enough that the rate of fungal production in areas of
high snail density is reduced. (This is in contrast to the
apparent effects of two other shredders:
coffeebean snails and a
talitrid amphipod [Graça et al., Mar.
Biol. 136:281-289].) Output from the long-lived periwinkles is likely to be
mostly as devoured young ones (both tiny settled snails, and especially
veligers in the plankton) and fecal pellets. See Newell, 1996, J Exp Mar
Biol Ecol 200:187-206, and Newell & Porter, 2000, pp. 159-185,
in Weinstein & Kreeger, Concepts and Controversies in Tidal Marsh
Ecology, Kluwer.