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surface that encroaches upon the land as glaciers melt back into the ocean, that
encroaches when all the droplets swell up from the depths, that encroaches when the
land itself recedes and retreats. Together, those droplets deliver sands and muds to
the land, erode high cliffs, and rearrange the face of the continents. Sea level is
always changing, from instant to rippling instant, from minute to swelling minute,
from hour to tidal hour, from storm to surging storm, from glacier to melting glacier,
from continent to levered continent.
It is the work of geologists to pin the accumulated waves upon the sand.
Who are these adventurers who follow the droplets, who track the shorelines by
the sands and silts and swashes they carry and carve, speck by speck, into edges and
ledges of lands, across space, and deep into ancient time? Who are these naturalists
who face down bears and crocodiles and machete-bearing defenders? They are the
boundary-hunters, who wield their corers in the quietest coves and most catastrophic
coasts, seeking the stories of grains and remains of former life. Their explorations
have helped distinguish where water today is rising and where land is falling, and
why, and for how long, and what the water conditions are like.
This book has told some of the stories of some of those droplets on some of those
journeys in some of those ages, stories published first in the cliffs and cores studied
by the geologists.
From Riggs’ descriptions of ancient sea levels found in unexpected places, and
Mallinson’s examination of an ice age’s worth of sea level variation, and the Kemp
and Horton salt marsh studies to track the coast at various time scales, to Walsh’s
work with high tech equipment for examining where the sea edge is now to
Lagomosino’s use of similar equipment to track mangroves in the most exotic
reaches of the ocean basins, the present location of sea level is difficult to pin precisely on an air-sea interface that never rests, and the effects of individual events like
storms (Manda) on the groundwater in North Carolina, the mangroves in Florida
(Wingard), and the residues of tsunami and earthquakes (Hawkes) can change the
sea level topography in just a few minutes or days. Currents from tides or storms can
scour around substantial items (Culver). During the course of human history and
pre-history, in the Basque Country (Leorri) and in North Carolina (Mallinson,
Culver), scarps and barrier islands of different heights indicate the continental outlines our ancestors lived on, and as human civilization has matured, human handiwork has tweaked and wreaked the process rates and in most places in the world, the
oceans are swelling and the glaciers are melting, gradually drowning the margins of
the continents. We can find similar events in the ancient past through sediment
cores, explained to us by Farrell in the United States, in Malaysia by Parham, and in
rocks in Senegal by Culver. Corals, delicate and demanding, and stressed as they are
in today’s world, have been shown through Hallock’s work that they are tracers of
not only sea level, but also of turbidity, temperature, ultra-violet light penetration,
and climate oscillations such as el Nino.
The adventurers in this book are the trackers of the cumulative effects, the sea
level heights, of all of those water particles adding up on land and sea. They answer
the question of what is the waterline: it is the marshes, the mangroves, the salt flats,
the forams and corals, and we can see its fluctuations through time against a wobbly
J. Moses-Hall
surface that encroaches upon the land as glaciers melt back into the ocean, that
encroaches when all the droplets swell up from the depths, that encroaches when the
land itself recedes and retreats. Together, those droplets deliver sands and muds to
the land, erode high cliffs, and rearrange the face of the continents. Sea level is
always changing, from instant to rippling instant, from minute to swelling minute,
from hour to tidal hour, from storm to surging storm, from glacier to melting glacier,
from continent to levered continent.
It is the work of geologists to pin the accumulated waves upon the sand.
Who are these adventurers who follow the droplets, who track the shorelines by
the sands and silts and swashes they carry and carve, speck by speck, into edges and
ledges of lands, across space, and deep into ancient time? Who are these naturalists
who face down bears and crocodiles and machete-bearing defenders? They are the
boundary-hunters, who wield their corers in the quietest coves and most catastrophic
coasts, seeking the stories of grains and remains of former life. Their explorations
have helped distinguish where water today is rising and where land is falling, and
why, and for how long, and what the water conditions are like.
This book has told some of the stories of some of those droplets on some of those
journeys in some of those ages, stories published first in the cliffs and cores studied
by the geologists.
From Riggs’ descriptions of ancient sea levels found in unexpected places, and
Mallinson’s examination of an ice age’s worth of sea level variation, and the Kemp
and Horton salt marsh studies to track the coast at various time scales, to Walsh’s
work with high tech equipment for examining where the sea edge is now to
Lagomosino’s use of similar equipment to track mangroves in the most exotic
reaches of the ocean basins, the present location of sea level is difficult to pin precisely on an air-sea interface that never rests, and the effects of individual events like
storms (Manda) on the groundwater in North Carolina, the mangroves in Florida
(Wingard), and the residues of tsunami and earthquakes (Hawkes) can change the
sea level topography in just a few minutes or days. Currents from tides or storms can
scour around substantial items (Culver). During the course of human history and
pre-history, in the Basque Country (Leorri) and in North Carolina (Mallinson,
Culver), scarps and barrier islands of different heights indicate the continental outlines our ancestors lived on, and as human civilization has matured, human handiwork has tweaked and wreaked the process rates and in most places in the world, the
oceans are swelling and the glaciers are melting, gradually drowning the margins of
the continents. We can find similar events in the ancient past through sediment
cores, explained to us by Farrell in the United States, in Malaysia by Parham, and in
rocks in Senegal by Culver. Corals, delicate and demanding, and stressed as they are
in today’s world, have been shown through Hallock’s work that they are tracers of
not only sea level, but also of turbidity, temperature, ultra-violet light penetration,
and climate oscillations such as el Nino.
The adventurers in this book are the trackers of the cumulative effects, the sea
level heights, of all of those water particles adding up on land and sea. They answer
the question of what is the waterline: it is the marshes, the mangroves, the salt flats,
the forams and corals, and we can see its fluctuations through time against a wobbly
J. Moses-Hall