CHAPTER 3
 EFFECTS OF HABITAT DIFFERENTIATION ON MICROBIAL ENZYME
 ACTIVITIES IN THE EVERGLADES

 Introduction


 Organic matter accumulation within wetlands is a consequence of the balance

between net primary production (NPP) and microbial heterotrophic metabolism.

Microbial decomposers play a crucial role in carbon (C) cycling and are responsible for

driving the C energy flow up the detrital food chain. The mineralization of organic

nutrients by the microbial community exerts an appreciable influence on energy flow by

regulating nutrient availability for further decomposition and primary production (Elliot

et al., 1984). Mineralization of plant matter is governed by the chemical and physical

properties of available substrates such as lignin, nitrogen (N), and phosphorus (P)

(DeBusk and Reddy, 1998; Berg, 2000; Fioretto et al., 2000; Kourtev et al., 2002a) as

well as other environmental and physiochemical influences. Therefore, changes in these

parameters associated with different litter types and nutrient conditions have the potential

to alter peat accumulation rates and potentially topography over time.

 The microbial degradation of particulate organic matter (POM), such as plant litter,

has been shown to be most influenced by the enzymes involved in lignocellulose

degradation, P cycling and N cycling (Sinsabaugh et al., 1991; Sinsabaugh and

Moorhead, 1994), which are often considered the rate limiting steps in degradation

(Chr6st and Rai, 1993). Due to the sometimes complex macrophytic structure, a large

quantity of diverse enzymes may be necessary to complete degradation (Eriksson and