18
1. Introduction
Threats to marine systems are often selective in the segment of a given
population that they impact. Chapter 5 presents further means to disaggregate a population-here by age cohort and size class in order to investigate
the differential impacts that fishing can have on the demographics of a population. The "array" tools used in this chapter also can come very handy for
spatially explicit modeling, as Chapter 6 demonstrates for the case of fishing a highly mobile species.
Marine protected areas (MPAs}-variously referred to as no-take reserves, harvest refugia or marine parks-are an increasingly popular tool
for marine conservation that will appear in several chapters in the book.
Chapter 6 illustrates the various degrees of success that a no-take reserve,
which completely excludes fishing, may have for marine conservation, depending on movement rates of the species, adjustments in fishing effort,
and relative size of the reserve, among other things. One of the models of
Chapter 6 has been designed with a user interface to facilitate exploration
of the effects that alternative initial conditions and assumptions may have
on the system 's dynamics. Adding a user interface to the dynamic model
may be particularly appropriate if it is the goal to make the model available
to a larger audience who may be content with simply using the model,
rather than contributing to its development.
If you are already well versed in dynamic modeling and familiar with the
STELLA software used in this book, you may wish to browse through the
chapters of Part I and quickly move on to the specific applications of Part
II. Part II consists of Chapters 7 to 18.
Phytoplankton are the foundation of the marine food web on which all
the species featured in this book depend. Chapter 7 presents a model of the
atmosphere-ocean interaction, concentrating on the carbon (C0 2
) cycle and
its links to iron (Fe) concentrations in the ocean's surface layers. The model
demonstrates how to translate stochiometric equations into STELLA, and
how to trace chemical elements-much like the cohorts of a populationthrough different stages.
Chapter 8 demonstrates the dynamics and multiple feedback mechanisms
between phytoplankton, light and nutrients in the coastal ocean. The
model integrates the concepts of nutrient uptake kinetics, light utilization
and photosynthesis with respect to changing environmental conditions.
Chapter 9 presents a model of an eelgrass community, addressing in a
coastal ecosystem context issues of nutrient loading on productivity. This
chapter also highlights the need for changes in land use activities to address
the health of near-shore ecosystems.
The model of Chapter 10 deals with the different life stages of marine invertebrates. Special attention is given to anthropogenic disturbances of benthic invertebrate communities and potentials for recovery after disturbances
took place.
Chapter 11 explores the linkages between marine and avian systems
(horseshoe crabs and seabirds) and considers the impact of human activities (catch by fishermen) on both systems.
1. Introduction
Threats to marine systems are often selective in the segment of a given
population that they impact. Chapter 5 presents further means to disaggregate a population-here by age cohort and size class in order to investigate
the differential impacts that fishing can have on the demographics of a population. The "array" tools used in this chapter also can come very handy for
spatially explicit modeling, as Chapter 6 demonstrates for the case of fishing a highly mobile species.
Marine protected areas (MPAs}-variously referred to as no-take reserves, harvest refugia or marine parks-are an increasingly popular tool
for marine conservation that will appear in several chapters in the book.
Chapter 6 illustrates the various degrees of success that a no-take reserve,
which completely excludes fishing, may have for marine conservation, depending on movement rates of the species, adjustments in fishing effort,
and relative size of the reserve, among other things. One of the models of
Chapter 6 has been designed with a user interface to facilitate exploration
of the effects that alternative initial conditions and assumptions may have
on the system 's dynamics. Adding a user interface to the dynamic model
may be particularly appropriate if it is the goal to make the model available
to a larger audience who may be content with simply using the model,
rather than contributing to its development.
If you are already well versed in dynamic modeling and familiar with the
STELLA software used in this book, you may wish to browse through the
chapters of Part I and quickly move on to the specific applications of Part
II. Part II consists of Chapters 7 to 18.
Phytoplankton are the foundation of the marine food web on which all
the species featured in this book depend. Chapter 7 presents a model of the
atmosphere-ocean interaction, concentrating on the carbon (C0 2
) cycle and
its links to iron (Fe) concentrations in the ocean's surface layers. The model
demonstrates how to translate stochiometric equations into STELLA, and
how to trace chemical elements-much like the cohorts of a populationthrough different stages.
Chapter 8 demonstrates the dynamics and multiple feedback mechanisms
between phytoplankton, light and nutrients in the coastal ocean. The
model integrates the concepts of nutrient uptake kinetics, light utilization
and photosynthesis with respect to changing environmental conditions.
Chapter 9 presents a model of an eelgrass community, addressing in a
coastal ecosystem context issues of nutrient loading on productivity. This
chapter also highlights the need for changes in land use activities to address
the health of near-shore ecosystems.
The model of Chapter 10 deals with the different life stages of marine invertebrates. Special attention is given to anthropogenic disturbances of benthic invertebrate communities and potentials for recovery after disturbances
took place.
Chapter 11 explores the linkages between marine and avian systems
(horseshoe crabs and seabirds) and considers the impact of human activities (catch by fishermen) on both systems.