Defending America’s submerged borders

Almost two hundred years ago, a flotilla of six Navy ships, crewed by about 350 military and civilians, including botanists and mineralogists, left port to explore the vast Pacific Ocean, north and south.  The U.S. Exploring Expedition, a deliberate step by an emerging nation with an eye on becoming a world power, collected navigational data useful to U.S. seafarers and documented natural characteristics of the great Pacific to help U.S. naval operations and encourage seaborne commerce.   The expedition improved coastal and ocean surveys in waters central to U.S. interests over the next century, brought numerous biological and geological specimens to the U.S. for study, and helped form the U.S. ocean science community.  First requested by Congress in 1828, the Expedition earned endorsement from John Quincy Adams and sailed during the presidencies of Andrew Jackson and Martin Van Buren.

During his first administration, President Trump supported a policy of mapping, exploring, and characterizing the ocean.  In his Presidential Memorandum of 19 November 2019 President Trump stated that: “It is the policy of the United States to act boldly to safeguard our future prosperity, health, and national security through ocean mapping, exploration, and characterization.”  The memo eventually led to the establishment of the National Ocean Mapping, Exploring and Characterizing (NOMEC) Strategy of June 2020.  NOMEC draws attention to the fact that vast areas of the world’s oceans remain largely unexplored, under-mapped, and sparsely characterized.  President Trump’s NOMEC directive focuses on America’s Exclusive Economic Zone (EEZ), the region extending seaward 200 nautical miles from a nation’s coast and 12-mile territorial sea.  In its EEZ a sovereign state has exclusive rights regarding exploration and use of marine resources.

The priority given to characterizing the EEZ stems from appreciation of the need to freshly demarcate U.S. borders and to protect growing ocean infrastructure upon which American society increasingly depends.  While the EEZ emerged as an administrative boundary enabling countries to manage resources, today the reasons for defending the EEZ go well beyond protecting resource sovereignty.  Americans depend on ocean infrastructure for energy, communications, food, goods of all kinds, and data for weather forecasting.  More than thirty percent of us live in coastal counties, and this coastal population has grown in tandem with the ports and harbors that sustain local communities and bring goods from the rest of the world to America’s shores and take our exports abroad.

Fully half of America is submerged — our submerged land holdings (11.3 million km² or almost 3 billion acres) match in surface area our land holdings.  The U.S. also has claims of “Extended Continental Shelf” beyond 200 nautical miles of about 1 million square kilometers (the area of Texas plus New Mexico).  As of January 2024, the National Oceanic and Atmospheric Administration (NOAA) reported “…only 52 percent of U.S. waters have been minimally mapped and only a fraction of that has been explored or characterized.”  The portion of U.S. waters with adequate characterization of the water column between the wavy surface and craggy bottom is far less.

Submerged America holds riches.  It is home to reefs abounding in life and wrecks that chronicle and entomb our history.  It contains minerals, oil, and natural gas found on and beneath the sea floor.  America pioneered development of offshore oil and gas resources, from use of ocean piers as drilling platforms in California at the start of the 20^th century to the first free-standing exploration wells in the shallow waters of the Gulf of America after World War II to the present proliferation of production platforms moored in waters as deep as 8000 feet.  The Gulf Data Atlas shows some 3500 oil and gas structures now speckle the Gulf, about 3200 in use. Today’s offshore structures represent high-value investments vulnerable to damage that would have catastrophic consequences economically and environmentally.

The EEZ and Territorial Sea house critical energy infrastructure in addition to platforms for extraction.  Underwater networks of pipes transport oil and gas from offshore drilling to shore-based distribution systems.  Power cables carry electrons from offshore wind farms to the electrical grid.  While not yet numerous in the U.S. EEZ, power cables abound on the seafloor of coastal China and our European allies. Fiber optic cables traverse the abyssal plains carrying the vast majority of global internet traffic between continents.  Some pipes and cables “sit proud” with features extending above the surrounding seabed, while others are flush with the bottom or buried.  They also scallop along coasts and cut across seas, straits, and bays, where they all become shallow to crawl on land to connect to hubs ashore.  They bunch at a few landing sites.

Large pipes also bring salt water to desalination plants on land, including about fifty around the world with a capacity of 100,000 cubic meters per day, enough water to serve a city of about a half million people.  And engineers find new uses for the oceans.  China Daily reports a Beijing infrastructure company has teamed with the AI enterprise DeepSeek to build an underwater computing center to benefit from the cool and constant temperature of the water near the seabed.  Viewed from above with the water removed, the seafloor looks increasingly like the model railroad set of crazed hobbyists.

The shore in turn hosts ports that link America to the global economy.  Ships queue up miles from harbor entrance control points and proceed through shallow segments of coastal zones to load and unload their cargoes.  As ships transit “innocently” through another nation’s EEZ they can do damage, as happened to telecommunications cables in the Red Sea (February 2024), Baltic (November 2024, January 2025, February 2025), and Taiwan Strait (January and February 2025).  Ports could become more crowded as the flux of ships on the water exceeds the capacity of ports accommodating them.  Ship Universe reported in its 6 March 2025 newsletter that “container traffic has grown exponentially, doubling every 15 years, while many ports have not expanded at the same rate” and “longer wait times lead to ships idling offshore for days or weeks…”   A ship of course can be prey or predator.

As the coastlines and EEZ of the U.S. (and the rest of the world) continue to industrialize.  the offshore environment grows target-rich and vulnerable.  Defending assets that now aggregate in the EEZ depends on ability to sense and respond to a new generation of threats.

The U.S. Navy adeptly and routinely searches out large, sophisticated submarines from adversary navies.  Quiet, small nuisances like a dragged anchor, a tiny mine near a U.S. port, or a battery-powered undersea drone that can disable a rig win little attention.  While the “Watkins Report” on U.S. Ocean Policy (2004) noted that “National security requires greater awareness, knowledge, and observation of ocean and coastal area,” in the intervening years the pace of ocean industrialization has accelerated while American coastal surveillance has lingered behind.

NOMEC offers the oceanographic foundation needed to support surveillance decisions and then maintain the effectiveness of that surveillance as oceanic conditions change in the temporally and spatially dynamic U.S. EEZ.  But the USA cannot survey and deploy everywhere at once.  Mindful of offshore industrial clusters, we can set priorities to characterize the natural ocean and its bottom to determine kinds of surveillance assets to deploy, how, and where.  The Gulf of America stands out as an ideal testbed: logistically manageable, affordable, all-season, free of undersea military complications, and full of resident ocean industry and able academic ocean surveyors.

Rather than detecting a large sub in the deep ocean, future surveillance systems would need to identify a small underwater drone dropped silently from a transiting freighter intent on damaging ships in a nearby port.  The threat of sabotage to underwater pipeline and cable networks requires the capacity to detect the anchor dragging on the seabed before a pipe is damaged or a cable cut. We need a network that can monitor underwater threats from criminals, terrorists, extremists or near peer adversaries.  As USAF General VanHerck alerted the nation in June 2023, “… autonomous drones carrying sensors, kinetic weapons and non-kinetic “effectors” could be one future tool, not just in the Arctic, but also off the eastern seaboard, the western seaboard, or around the globe wherever we need to be to help defend beyond U.S. boundaries”.

Improved characterization accurately describes the natural ocean background and thus helps identification of what differs, the potential threat itself.  New monitoring technologies improve our ability to collect information about the natural state of diverse volumes of water and their floors, from aquatic DNA filters performing liquid biopsies that tell the abundance and kinds of marine life to compact units for sonar scanning of what lies below.   With each month, instruments without a crew can do more to characterize the water volume, explore, and map.  Already an autonomous platform can linger almost infinitely on solar and wind energy while on the surface, then it can dive for safety, characterize natural ocean features, or inspect installation structures below the surface.

Which government agencies are charged with overseeing ocean monitoring and coordinating data collection from the EEZ for security requirements?  NOAA collects research data as well as continual operational measurements in discrete regions that accumulate in national data centers for weather and climate, fishing, plastic debris, and reefs and wrecks that earn marine protection.  While NOAA routinely shares this information with the Navy, it has not been asked, tasked or noticeably funded to collect or prepare specific information upon which defensive surveillance could rely.

Yet a more accurate picture of the seascape from surface to bottom contributes crucially to improving Maritime Domain Awareness (MDA), a perennial goal of the U.S. Navy wherever it operates.  Implementing NOMEC represents an opportune step to enabling appropriate surveillance and informing defensive decisions.  Already the Navy routinely collects data on ocean conditions for forward deployed forces around the world, to search out large, sophisticated submarines from adversary navies, and prepare for mine and counter-mine operations, to name a few tasks.  But,the Navy does not collect data from the U.S. EEZ.

The United States Department of Homeland Security (DHS) includes the world’s best Coast Guard (USCG) that does many things very well. The USCG can regulate, arrest law breakers, rescue, operate in ice, assure safe navigation, and even interdict large, crewed, homemade submersibles carrying drugs.  The USCG, however, lacks comprehensive ocean sensing, analysis, data base management and prediction capability.   The mission of the USCG does not include comprehensive ocean characterization to support critical undersea surveillance, nor is it adequately equipped for undersea ocean characterization or surveillance.

The Navy, the Defense Department’s U.S. Northern Command, NOAA, and DHS have all contributed to general planning for national maritime security challenges as seen from decades of Homeland Security Presidential Directives, Presidential Decision Directives, Maritime Security Plans, and Maritime Domain Awareness plans of many titles.  None of these, however, comprehends growing Anthropocene ocean vulnerabilities. Their focus is on identifying the threat mechanism.  There is scant (or no) mention of foundational ocean data needed to support surveillance decisions and operations.  The President’s NOMEC initiative can fill that gap.

While NOMEC may be a government responsibility, it does not imply a government-only solution.  The Navy and USCG should have major roles to plan, direct, and oversea any national effort to characterize our waters for protective reasons because they will likely use that data for security decisions. But the growing presence of U.S. ocean industries offers a wealth of experience and assets that can expedite the mapping and continually characterize priority EEZ installation areas, perhaps under contracts with NOAA or Navy or both.  Part of the solution can come from ocean research institutions that deploy ships, drones, and permanent monitors in the ocean.

While coordinating ocean data collection would unquestionably benefit national security, a larger question emerges: What parts of the government defend against threats to the American homeland in the EEZ?   Some may look to the Northern Command, the primary defender against an invasion of the U.S.  It owns North American Aerospace Defense Command (NORAD) and can task the Navy, when necessary, but its best skills are in detecting and deflecting threats from space, the air, or the sea surface, not beneath the waves up close to shore.

The Navy must continue to understand, characterize, and predict the whole ocean, especially those ocean areas forward, near potential competitors.  The U.S. continues as a global maritime nation that must ensure open sea lanes and at least deter hostility, and its place in the middle of the global ocean system has enabled commerce and unique security.  However, priority grows to monitor better the U.S. EEZ, to lift awareness of the critical role it plays in national security, and to look outward from our true sovereign edges.  Not least, thoroughly understanding our own vulnerabilities will lift our understanding of the vulnerability of others.

NOMEC was not originally directed at defense of offshore areas upon which America increasingly depends, but the reality of snipped cables and blasted pipelines makes NOMEC even more important.  President Trump could:

• Continue and invigorate NOMEC with a focus on characterizing the U.S. EEZ particularly a) around critical offshore infrastructure; and b).to advance resource discovery.
• Insert NOMEC principles, now missing, into national Maritime Domain Awareness planning and top-level maritime security decision directives.
• Harness U.S. commercial and academic talent by creating incentives for the U.S. private sector to participate.
• Designate the Gulf of America as the first ocean test bed to be characterized fully using modern sensors and data techniques.

Finally, the President could consider these as steps toward a larger vision … he said “act boldly” … an extension of the proposed aerial Golden Dome for America, a sophisticated Blue Collar that safeguards offshore and undersea installations with high dependency ranking.  To meet its goals, the new shield must not stop at the sea surface but extend to the seafloor at America’s submerged borders.

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Jesse H. Ausubel directs the Program for the Human Environment at The Rockefeller University. His essays include a Michelson Lecture at the United States Naval Academy on advances in ocean sensing