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USC Dornsife Scientific Diving: A Note on the Rock Islands of Palau

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


By Iñaki Pedroarena-Leal

As a natural wonder and an iconic screensaver, the Rock Islands of Palau are just as much of a biological marvel as they are an attraction for nature enthusiasts worldwide. The seemingly endless limestone islands—well over three hundred—collectively form an intricate marine environment. Each island seems a match of the next in its complete saturation of jungle vegetation growing on steep limestone walls. The biodiversity living on and around each rock island is, simply put, spectacularly impressive.

Days into my Palauan research scuba diving expedition, I have trekked through several of the islands with the guidance and knowledge of King Sam, head ranger for the Department of Conservation and Law and Enforcement for the State of Koror, as well as local fishermen whose quotidian knowledge of the area is unparalleled.


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They have shared with me their local names for many of the islands that reflect the dramatic change in the topography, as each rock island appears to be uniquely more jagged and peaked than the previous one.

The shapes of the islands are mostly attributed to tectonic activity that abruptly uplifted sea coral during the Miocene period. In addition to this initial ancient protrusion from the ocean’s waters, erosion from eons of precipitation, acidified upon contact with the vegetation on the island, has caused further rock sculpturing.

Perhaps the most singular remarkable part of this rock island environment occurs between the interphase of the fringing reef and the base of the rock that projects from the ocean’s surface, what is known as the sea level notch. This section of the rock island environment is home to shallow coral reefs and sea grasses.

The quantity of biodiversity existing in this particular zone rivals that of coral reefs outside the rock islands. Here, giant clams, sharks, dugongs, sea cucumbers, turtles, sea snakes, endless species of tropical fish, and many other types of marine organisms culminate in an environment that is highly intertwined and interdependent.

Yet, in what seems a natural version of a Greek tragedy, the rock islands are destined to eventually disappear as erosion slowly returns these long stranded coral islands back to the ocean’s sub-surface. Now, as I have experienced the Rock Islands firsthand, it is perplexing to imagine these Palauan waters without their iconic elaborate labyrinth of islands, appearing as it once did in history, as an uninterrupted shallow ancient sea. Fortunately, this unavoidable natural process will take many thousands of years to fully take effect on the rock islands.

What is more presently worrisome, posing a greater eminent danger to the rock islands and their unique marine biosphere, is the maltreatment of the islands and their marine environment by human activity, inducing changes that have and continue to alter the coral reefs to their detriment. After witnessing these truly majestic Rock Islands of Palau firsthand, it has become a very personal experience to witness the human process by which such a singular environment has begun to disappear in a fraction of the time it took for them to be created.

Since my first desk calendar and, eventually, computer screensaver, I have always admired the Rock Islands of Palau in their photographic form, making them a top priority on my “bucket” list” to witness in real time. As I check-off this particular goal, I leave the Rock Islands of Palau humbly appreciative and hugely motivated to proactively assist in any manner possible, to conserve and protect them. They are truly a unique natural phenomenon of limestone-sculpted island outcroppings saturated with steep hanging jungle that abruptly and spectacularly mesh with fringing coral reefs of incredible biodiversity.

About the Author: Iñaki Pedroarena-Leal is a current Junior in the University of Southern California’s Dornsife College of Letters, Arts, and Sciences. He is pursuing a double B.A. in Economics and Environmental Studies. His family’s agricultural history in Baja California, México, and his deeply rooted passion for the ocean, are both instrumental in his goal of practicing the aquaculture industry in an environmentally sustainable manner.

Editor’s note: Scientific Research Diving at USC Dornsife is offered as part of an experiential summer program offered to undergraduate students of the USC Dana and David Dornsife College of Letters, Arts and Sciences. This course takes place on location at the USC Wrigley Marine Science Center on Catalina Island and throughout Micronesia. Students investigate important environmental issues such as ecologically sustainable development, fisheries management, protected-area planning and assessment, and human health issues. During the course of the program, the student team will dive and collect data to support conservation and management strategies to protect the fragile coral reefs of Guam and Palau in Micronesia.

Instructors for the course include Jim Haw, Director of the Environmental Studies Program in USC Dornsife, Assistant Professor of Environmental Studies David Ginsburg,, SCUBA instructor and volunteer in the USC Scientific Diving Program Tom Carr and USC Dive Safety Officer Gerry Smith of the USC Wrigley Institute for Environmental Studies

Previously in this series:

Catching Up with Scientific Diving at USC Dornsife: Surfgrass Monitoring at Catalina

Catching up with Scientific Diving at USC Dornsife: The Robot Submarine

Catching up with Scientific Diving at USC Dornsife: Diving into the Aquarium of the Pacific

USC Dornsife Scientific Diving: Moving Forward to Guam and Palau 2012

USC Dornsife Scientific Diving: Finding My Career Through This Course

USC Dornsife Scientific Diving: The Devaluation of Ecosystem Services

USC Dornsife Scientific Diving: Why USC Dornsife was the Right Decision For Me

USC Dornsife Scientific Diving: Why Experiential Learning is Vital to Academic Life

USC Dornsife Scientific Diving: My Walden South of Los Angeles

USC Dornsife Scientific Diving: Crown-of-Thorns Outbreaks and Anthropogenic Pollution

USC Dornsife Scientific Diving: The International Policy Rationale for the Military Buildup on Guam and Some Environmental Drivers

USC Dornsife Scientific Diving: Marine Ecology from Antarctica to Micronesia

USC Dornsife Scientific Diving: Palau Water Supply

USC Dornsife Scientific Diving: The Contributions of J. S. Haldane to Dive Safety

USC Dornsife Scientific Diving: Human Impacts on Mangrove Forests

USC Dornsife Scientific Diving: Global Sea Cucumber Fisheries

USC Dornsife Scientific Diving: Palauan Mermaids

USC Dornsife Scientific Diving: The California Spiny Lobster

USC Dornsife Scientific Diving: The Invasion of the Coconut Rhinoceros Beetle

USC Dornsife Scientific Diving: The Coconut Crab in Guam

USC Dornsife Scientific Diving: The Ordot Dump and Layon Landfill

USC Dornsife Scientific Diving: Marine Ecosystem Based Management

USC Dornsife Scientific Diving: The Navy Dive Tables

USC Dornsife Scientific Diving: Entangled in the Excitement of Every New Day

USC Dornsife Scientific Diving: Economic Effects of the Revised Military Buildup in Guam

USC Dornsife Scientific Diving: The Guam and Calayan Rails

USC Dornsife Scientific Diving: Chamorro Women and the Spanish

USC Dornsife Scientific Diving: Diving into Apra Harbor’s Western Shoals and CB Junkyard

USC Dornsife Scientific Diving: Remaking What We’ve Lost – A Look At Artificial Reefs

USC Dornsife Scientific Diving: Ecosystem Monitoring in the Ngederrak Marine Conservation Area

USC Dornsife Scientific Diving: Micronesia Regional Shark Sanctuary

USC Dornsife Scientific Diving: Palau, Above the Waterline

USC Dornsife Scientific Diving: Jellyfish Lake

USC Dornsife Scientific Diving: Preserving Palau’s Resources through Protected Area Networks

Dr. Jim Haw is Ray R. Irani Professor of Chemistry and director of the Environmental Studies Program in the USC Dana and Dornsife College of Letters, Arts and Sciences. He is also a scientific, technical and recreational diver.

More by Jim Haw