Abstract
Net primary productivity estimates were made for the major macrophyte dominated habitats of the Nauset Marsh system, Cape Cod, Massachusetts. Above-ground primary productivity of short form
Spartina alterniflora, the dominant habitat of the system, was 664 g m
−2 y
−1. Productivity of the other dominant angiosperm (
Zostera marina) was estimated to range from 444–987 g m
−2 y
−1. The marsh creekbank habitat was dominated by an intertidal zone of fucoid algae (
Ascophyllum nodosum ecad.
scorpioides, 1179 g m
−2 y
−1;
Fucus vesiculosus, 426 g m
−2 y
−1), mixed intertidal filamentous algae (91 g m
−2 y
−1), and a subtidal zone of assorted macroalgae (68 g m
−2 y
−1). Intertidal mudflats were dominated by
Cladophora gracilis, with net production ranging from 59–637 g m
−2 y
−1. These angiosperm and macrophyte and macrophyte dominated habitats produce over 3 × 10
6 kg y
−1 of biomass (1·2 × 10
6 kg carbon y
−1). Twenty-eight per cent (28%) of this carbon production is derived from the
Zostera and macroalgae habitats. Although
S. alterniflora is considered the major macrophyte primary producer in Nauset Marsh and other north temperate salt marshes, it is concluded that other habitats also contribute significantly to total system carbon production.