250
for storm waves and the thin surficial fresh-water aquifers are becoming thinner and
more often damaged by overwash of seawater during storms. As fish communities
are impacted, local protein sources are diminishing.
Nevertheless, many coral species, especially those that live at lower light levels
on deeper reefs and offshore platforms, will likely survive. Some such species survived the mass extinction that eliminated the last of the dinosaurs ~66 million years
ago. Also, the “weedier” species should persist. On Florida reefs, for example,
despite successive die-offs of the major reef-building species, starting with the
branching corals in the 80s and followed by loss of many brain and boulder corals
in recent decades, some of the finger and encrusting species continue to thrive.
In 2005 I was on a live-aboard dive vessel in Papua New Guinea. We left out of
Rabaul and made observations in a hydrothermal discharge area in a remote region
in the outer islands. As we cruised past the island coastlines, one had to look carefully for signs of human habitation. Some of the hillsides had terraced gardens, but
virtually no cleared shorelines. After completing our research, the vessel continued
to Kimbe Bay, the home base of the vessel. Again, I noticed minimal signs of human
activity along the shoreline around this sizeable bay. There were two visible docks
and one wrecked vessel, but otherwise the shoreline was dominated by mangroves.
Inshore, behind the mangroves, were obvious signs of substantial human activities
including a resort, a marine lab, roads, villages, domestic livestock, and palm-oil
plantations. Papua New Guinea is in a very tectonically active area, where frequent
earthquakes can generate tsunamis; a fact of life for the local residents. I have wondered if some of the cultures that developed in these remote islands recognized the
threat of living too close to the shoreline, as well as the value of the mangroves in
mitigating threats from the sea. Or maybe the value of the food resources provided
by the mangroves was sufficient to encourage their preservation.
Over the next several days, I enjoyed some of the best shore-based diving left in
the world. If the nearshore reefs showed any evidence of bleaching events, it was
only on the shallowest reef flats; the hint of tannins from the nearby mangroves was
evident in the water. Yet with each dive further offshore, the water became clearer
and the evidence of coral mortality became more evident and extended deeper. The
condition of the inshore reefs provided testament to the value of intact shorelines
and extensive mangroves in protecting the reefs from human activities.
Thus, in the nearly 50 years that I have been diving, I have seen the decline first
of nearshore reefs, largely associated with local pollution sources and coastal development. As I was working to understand and communicate the effects of nutrients
on corals with algal symbionts, the reefs of Florida and around the Caribbean were
experiencing disease outbreaks and the first major episodes of coral bleaching,
especially on the offshore reefs. Each major bleaching event occurred during an El
Niño year and after an explosive, low-latitude volcanic eruption.
The majority of reef researchers consider the increase in anomalous oceanwarming events as the cause of the increase in mass coral-bleaching events. Based
upon my range of experiences and observations, including field, experimental and
literature research, and discussions with optical physicists and photosynthesis
experts, I strongly suspect that stratospheric ozone depletion has amplified the
P. Hallock
for storm waves and the thin surficial fresh-water aquifers are becoming thinner and
more often damaged by overwash of seawater during storms. As fish communities
are impacted, local protein sources are diminishing.
Nevertheless, many coral species, especially those that live at lower light levels
on deeper reefs and offshore platforms, will likely survive. Some such species survived the mass extinction that eliminated the last of the dinosaurs ~66 million years
ago. Also, the “weedier” species should persist. On Florida reefs, for example,
despite successive die-offs of the major reef-building species, starting with the
branching corals in the 80s and followed by loss of many brain and boulder corals
in recent decades, some of the finger and encrusting species continue to thrive.
In 2005 I was on a live-aboard dive vessel in Papua New Guinea. We left out of
Rabaul and made observations in a hydrothermal discharge area in a remote region
in the outer islands. As we cruised past the island coastlines, one had to look carefully for signs of human habitation. Some of the hillsides had terraced gardens, but
virtually no cleared shorelines. After completing our research, the vessel continued
to Kimbe Bay, the home base of the vessel. Again, I noticed minimal signs of human
activity along the shoreline around this sizeable bay. There were two visible docks
and one wrecked vessel, but otherwise the shoreline was dominated by mangroves.
Inshore, behind the mangroves, were obvious signs of substantial human activities
including a resort, a marine lab, roads, villages, domestic livestock, and palm-oil
plantations. Papua New Guinea is in a very tectonically active area, where frequent
earthquakes can generate tsunamis; a fact of life for the local residents. I have wondered if some of the cultures that developed in these remote islands recognized the
threat of living too close to the shoreline, as well as the value of the mangroves in
mitigating threats from the sea. Or maybe the value of the food resources provided
by the mangroves was sufficient to encourage their preservation.
Over the next several days, I enjoyed some of the best shore-based diving left in
the world. If the nearshore reefs showed any evidence of bleaching events, it was
only on the shallowest reef flats; the hint of tannins from the nearby mangroves was
evident in the water. Yet with each dive further offshore, the water became clearer
and the evidence of coral mortality became more evident and extended deeper. The
condition of the inshore reefs provided testament to the value of intact shorelines
and extensive mangroves in protecting the reefs from human activities.
Thus, in the nearly 50 years that I have been diving, I have seen the decline first
of nearshore reefs, largely associated with local pollution sources and coastal development. As I was working to understand and communicate the effects of nutrients
on corals with algal symbionts, the reefs of Florida and around the Caribbean were
experiencing disease outbreaks and the first major episodes of coral bleaching,
especially on the offshore reefs. Each major bleaching event occurred during an El
Niño year and after an explosive, low-latitude volcanic eruption.
The majority of reef researchers consider the increase in anomalous oceanwarming events as the cause of the increase in mass coral-bleaching events. Based
upon my range of experiences and observations, including field, experimental and
literature research, and discussions with optical physicists and photosynthesis
experts, I strongly suspect that stratospheric ozone depletion has amplified the
P. Hallock