7
The terminology used in this book to characterize oceanographic topography
should also be defined. Shallow coastal areas, for example, are important for sequestering and storing blue carbon, but how are these areas defined? In the field of
oceanography, the coastal area corresponding to the continental shelf with depths
shallower than 200 m is normally defined as the coastal area, and the area of the
ocean extending from the continental slope to the deep sea is defined as the offshore
area (Fig. 1.2). However, photosynthesis is impossible without light, and because
light sufficient for photosynthesis does not penetrate to ocean depths greater than
about 200 m, marine plants are not found on the seabed at depths greater than
200 m. The euphotic zone is the part of the water column where there is adequate
light for photosynthesis. The depth of the euphotic zone depends on the transparency of the water and varies from place to place; the euphotic zone may be as shallow as several tens of meters and up to 80 m deep in coastal areas that are hardly
affected by human activities. In this book, the coastal zone from the coastline to the
depth of the euphotic zone is referred to as the shallow coastal area, and the sea
above the continental shelf from the depth of the euphotic zone to 200 m is defined
as the coastal offshore area. Areas deeper than 200 m are defined as the open ocean.
Maximum high tide
Minimum low tide
200m
Open ocean
Intertidal zone
Subtidal zone
Coastal offshore area
Shallow coastal area
Euphotic zone
Deep sea
Coast
Beach area
Continental shelf
Outside bay
Inner bay
Estuary
Rivers
Coastal offshore area
Fig. 1.2 Oceanographic topography and structure as defined in this book. This classification differs somewhat from the classification generally used in oceanography and divides the coastal area
into a shallow and offshore region. The estuary, the inland bay, and the area outside of the bay are
included in the shallow coastal area
1 Blue Carbon: Characteristics of the Ocean’s Sequestration and Storage Ability…
The terminology used in this book to characterize oceanographic topography
should also be defined. Shallow coastal areas, for example, are important for sequestering and storing blue carbon, but how are these areas defined? In the field of
oceanography, the coastal area corresponding to the continental shelf with depths
shallower than 200 m is normally defined as the coastal area, and the area of the
ocean extending from the continental slope to the deep sea is defined as the offshore
area (Fig. 1.2). However, photosynthesis is impossible without light, and because
light sufficient for photosynthesis does not penetrate to ocean depths greater than
about 200 m, marine plants are not found on the seabed at depths greater than
200 m. The euphotic zone is the part of the water column where there is adequate
light for photosynthesis. The depth of the euphotic zone depends on the transparency of the water and varies from place to place; the euphotic zone may be as shallow as several tens of meters and up to 80 m deep in coastal areas that are hardly
affected by human activities. In this book, the coastal zone from the coastline to the
depth of the euphotic zone is referred to as the shallow coastal area, and the sea
above the continental shelf from the depth of the euphotic zone to 200 m is defined
as the coastal offshore area. Areas deeper than 200 m are defined as the open ocean.
Maximum high tide
Minimum low tide
200m
Open ocean
Intertidal zone
Subtidal zone
Coastal offshore area
Shallow coastal area
Euphotic zone
Deep sea
Coast
Beach area
Continental shelf
Outside bay
Inner bay
Estuary
Rivers
Coastal offshore area
Fig. 1.2 Oceanographic topography and structure as defined in this book. This classification differs somewhat from the classification generally used in oceanography and divides the coastal area
into a shallow and offshore region. The estuary, the inland bay, and the area outside of the bay are
included in the shallow coastal area
1 Blue Carbon: Characteristics of the Ocean’s Sequestration and Storage Ability…