Chapter 4 (Continued) 



PHYSICAL/BIOGEOCHEMICAL/BIOLOGICAL INTERACTIONS 4-42 



Energy Cycles 4-42 



Biogeochemical Cycles 4-48 



Nutrient cycle 4-48 



Organic matter cycle 4-50 



Interactions Affecting the Productivity 



and Distribution of Biota 4-53 



Phytoplankton 4-53 



Macroalgae 4-55 



Zooplankton 4-55 



Benthic invertebrates 4-56 



Squid 4-57 



Finfish, birds, and marine mammals 4-57 



Decomposers 4-57 



BIOLOGICAL PRODUCTIVITY 4-58 



Primary Productivity 4-58 



Secondary Productivity 4-58 



CLASS LEVELS AND AN INTRODUCTION 



TO THE SUBTIDAL AND INTERTIDAL SUBSYSTEMS 4-59 



Introduction 4-59 



The Subtidal Subsystem 4-59 



Class: open water (water column) 4-61 



Class: unconsolidated bottom 4-72 



Class: rock bottom 4-74 



The Intertidal Subsystem 4-75 



Class: rocky shore 4-78 



Class: sand beach 4-86 



BEACH DUNE PLANT COMMUNITIES 4-96 



RESEARCH NEEDS 4-97 



REFERENCES 4-100 



CHAPTER 5: THE ESTUARINE SYSTEM 5-1 



DATA SOURCES AND COMPILATION OF DATA 5-11 



DISTRIBUTION OF THE ESTUARINE SYSTEM 5-12 



ABIOTIC FACTORS 5-14 



Geology 5-14 



Hydrography 5-18 



Freshwater flow 5-18 



Tidal exchange 5-18 



Topography 5-20 



Winds 5-20 



General Hydrographic 



Characteristics of Maine Estuaries 5-21 



Casco Bay/Portland Harbor/Fore River 5-22 



Presumpscot and Royal estuaries 5-22 



Kennebec estuary 5-24 



Sheepscot estuary 5-24 



Hockomock, Montsweag, and Nubble Bays 5-27 



Damariscotta River estuary 5-30 



Penobscot River estuary 5-30 



Union River estuary 5-33 



