Baseline Report of the Census of Marine Life 2003


The Unknown Ocean: Baseline Report of the Census of Marine Life

I. Separating the Known, Unknown, and Unknowable

II. The Dimensions


III. Three Large Tasks

What did live in the oceans?
What lives in the oceans now?
What will live in the oceans of the future?

IV. The Baseline of Known, Unknown, and
Unknowable Life in Six Ocean Realms

The Human Edges


The Hidden Boundaries

Continental Margins
Abyssal Plains

The Central Waters

The Light Zone
The Dark Zone

The Active Geology – Seamounts, Vents and Seeps
The Ice Oceans – Arctic and Antarctic
The Microscopic

V. Technology for Discoveries

Commercial and Military





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Welcome to the Baseline Report of the Census of Marine Life (CoML,, a cooperative international research program. CoML audaciously aims to assess and explain the diversity, distribution, and abundance of life in the oceans. This Baseline Report offers a framework for considering marine life and reports essential elements of today’s knowledge and its limits. The report is intended for readers concerned with marine life, including environmental journalists, teachers, and resource and research managers as well as researchers.

Overall, the strategy of CoML is to clarify and make much more accessible what we know, to identify what we do not know and why we do not know it, to learn much more of what is knowable, and also to identify what we may never know or at least not learn for a very long time, well beyond the life of the research program. While audacious, CoML humbly recognizes the formidable limits to knowledge. Good reasons including size and the inaccessibility of the deep explain why no one has before tried the task of CoML.

A census requires dividing the whole of the oceans into parts. The oceans do not divide into easily defined, separate compartments. Waters and animals move. In this Baseline Report, we offer a division of six realms that encompass all life from the surface of the nearshore to the bottom of the deep ocean. We hope the framework of realms and of zones within some of the realms helps readers appreciate the diversity, distribution, and abundance of marine life.

Along with the framework, the baseline offers facts, for example, about numbers of known and unknown species and about the quantity of marine life and how it is broadly distributed. However, the baseline is not a great wet database reporting estimates of the number or tonnage of animals in every species. The program looks forward to developing and sharing more of this kind of information, as well as explanations of why matters are as they are. A companion document, the CoML Research Plan 2003, explains how the new knowledge could be won.

The senior scientist of the CoML, Ronald O’Dor, led the preparation of this Baseline Report. Many CoML scientists assisted him, especially members of the International Scientific Steering Committee and leaders of CoML projects. Their names are listed in the Acknowledgments. Thanks to all and to the government agencies, marine laboratories, universities, natural history museums, and other organizations that are making the census possible.

We have aimed at a level of detail such that many readers might read this entire document with profit, but with less detail and citation than in scientific papers. A bibliography lists sources for the information in the report.

Initiated in the year 2000, CoML intends to publish its formal census in 2010. The 2010 census will surely be “born digital” and much of it will probably appear to users as an on-line dynamic atlas. CoML looks forward to issuing interim reports as research progresses. We hope this Baseline Report usefully orients the many people concerned with marine life, including researchers in the program itself and those who support it. And, we hope the baseline prepares the way for a near future in which vastly superior and more complete information about marine life is readily available to all who would constructively use it.

J. Frederick Grassle,
Chair, International Scientific Steering Committee
Census of Marine Life

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With several species of fish being discovered weekly and countless marine organisms still unknown, assaying reports of trouble in the oceans requires a global Census of Marine Life (CoML). Already, more than 300 scientists from 53 countries are at work in CoML. After three years of organizing and demonstrating the opportunities and feasibility of the global effort with initial explorations, CoML here draws a baseline for exploration to 2010.

Challenges to explorers include the vastness of the oceans stretching far wider than land and their darkness as much as 11 km underwater. The size of marine organisms ranges a hundred million million million fold, from drifting bacteria through shrimplike krill and familiar fish, up to whales that swim as fast as 50 km/hr.

The census divides itself into three tasks. History, like the 400-year record of fish catches assembled for Denmark, tells what lived in the ocean. Exploration, like the submarine discovery of sponge gardens nearly 4 km deep in a gap in the Mid-Atlantic Ridge, tells what lives in the ocean now. Only combining historical trends with what lives now can answer the core question of what will live in the ocean tomorrow.

Technology and difficulty divide the oceans into realms for exploration. In the nearshore zone and on continental shelves and slopes, fish, shellfish, and lobster abound. In the light zone of the ocean’s central water, drifting microbes photosynthesize food that miniature shrimp and swimming fish eat. In the dark of central water, jellyfish swarm, and in the sediment snowed from above onto the abyssal plain, microbes and worms prosper. Around active seafloor vents, heat-resistant microbes survive. In polar oceans, algae photosynthesize on the underside of ice. The small, drifting organisms that photosynthesize all the primary food make up almost all the 145,000 million tons of marine biomass. Small animals like krill account for most of the animal mass, while prominent large animals, like fish and whales, constitute only a small crucial percentage. In all oceanic realms, finding and naming species of animals show unflagging progress as well as unknowns yet to resolve. Estimating populations and biomass tto distinguish between decline, fluctuation, and shift has only begun.

New technology opens today’s unknowable to exploration and enables translation of the unknown to known. Techniques for accessing archives and visualizing the past in dusty records rank as new technology. Sounds from animals serve as signatures, while sounds from sonar reveal shapes in the darkness of the ocean. Sea lions carrying telemetry devices and tankers towing plankton recorders ally themselves with marine scientists. Video cameras photograph unknown giants deep in the sea, and luminescence reveals both the shape of marine organisms and their spectral signatures. The speed and economy of reading genomes — spinoffs from human genome sequencing — make the identification of species by the series of compounds on a gene similar to scanning a barcode in a market.

This report provides a baseline encompassing all the oceanic realms and a prefilter for explorations likely to yield the great surprises about marine life, past and future. Discovery is ahead.