Until 2003, if you wanted a map of Cape Cod Bay (or any other spot along Massachusetts, or for that matter, the entire U.S. coast), this is what you got:
As any boater or fisherman can attest, such nautical charts – while invaluable – barely scratch the surface (sorry for the pun) of what there is to know about the seafloor. Is it rocky? Covered in seagrass? Or a shifting landscape of mud and sand? If you dropped a trawl, would it come up full of scallops, cod, or flounder? Or would the net be shredded by oyster-covered rocks?
In 2003, scientists at the U.S. Geological Survey’s Woods Hole Coastal and Marine Science Center teamed up with colleagues at EPA and Massachusetts’ Office of Coastal Zone Management and Division of Marine Fisheries to begin answering such questions and incorporating them into a new generation of seafloor maps. Here’s one example:
To the untrained eye, it may not look like much of an improvement. But, as scientists involved in the work explained at a public event at the Ocean Explorium in New Bedford, maps like this one represent the first detailed geological maps of the Massachusetts seafloor. I came away from that event with a wealth of maps and photos – topographical, geological, biological.
But before we get to the maps themselves, there’s a question that deserves to be answered: Who cares? Why do maps of the seafloor matter to anyone except the scientists who make them?
Here are five ways seafloor maps impact each and every one of us.
1. Where’s the fish?
Achieving both economic and ecological sustainability in fishing is a matter of taking just as many fish as can possibly be taken without putting undue stress on the population. Finding that magic number is incredibly difficult. First, there’s the challenge of even figuring out how many fish there are. Then there’s the fact that not all fish are equal in the eyes of either nature or the consumer. Fish for fish, egg-bearing females are far more valuable to a population than males (assuming there are enough males around to fertilize the eggs). And taking fish that have already had a chance to reproduce is less damaging to the population than taking an equal number of immature fish.
Luckily for all involved, animals at different stages in life often seek out different types of habitat to suit their particular needs at that time. One way that regulators can protect important and vulnerable portions of populations is by prohibiting fishing in areas used intensively for mating and in nursery grounds that are important to the survival and growth of juveniles. In this era of intense pressure on both fish and fishermen, getting the boundaries of such areas right is crucial and high-quality seafloor maps can help.
For example, scientists with the Division of Marine Fisheries have used a combination of topographic maps and underwater photographic or video surveys to determine that spawning cod cluster in areas with steep, rocky slopes. As it turns out, some closed areas include such rocky slopes but also adjacent flat or sandy areas that are unlikely to be major breeding grounds. So the maps can help fishery regulators refine closed areas to give fishermen access to as much area as possible without putting additional pressure on the targeted fish populations.
2. Powering the dream
New England’s coastal waters hold enormous renewable energy potential. A report from GE released earlier this year concluded that offshore wind energy development could provide almost a quarter of the region’s energy needs. Efforts to harness that resource are gearing up: witness Cape Wind, Deepwater Wind, and proposals for development of areas south of Martha’s Vineyard and in waters co-regulated by Massachusetts and Rhode Island.
And while the east coast’s tidal energy potential is significantly less than the west coast’s, there’s enough to spark interest on the part of both municipal and commercial developers. Tidal energy projects intended for Cape Cod Canal and Muskeget Channel are in the planning and permitting phases.
Think about what goes into such underwater construction – wind turbine foundations, tidal turbine anchors, energy transmission lines, to name a few – and it’s clear that good seafloor maps are essential. There are the basics: How deep is the water? Is the bottom flat or sloped? Rocky or sandy? What lives there that needs to be taken into account? Seismic mapping reveals what’s below the surface of the seafloor – crucial information for anyone planning to dig. And maps of sediment movement, tidal flows, and currents can help developers plan for erosion around anchors or foundations.
One of the great things about the new maps for Massachusetts’ seafloor is that they’re publicly available. That means developers, local communities, and regulators have a common information base that can be used pro-actively to determine the best locations for offshore energy development. That’s the whole idea behind Massachusetts’ Ocean Management Plan. This mapping project was an independent effort that actually predated the Ocean Management Plan’s development, but the maps have been central to planning efforts. And regulators and mappers are now working together closely to determine what areas and types of data need the most attention going forward.
3. There’s gold in them thar waters
The phrase “offshore mining” probably conjures images of oil rigs, and that’s certainly one example. In addition, scientists have discovered that certain areas of the seafloor are rich in metals and rare earth elements. In January, Papua New Guinea granted the world’s first deep-sea mining permit to a Canadian company that plans to mine copper and gold.
We’re unlikely to see either oil drilling or metal mining spring up in New England waters. For one, we simply don’t have the hydrothermal vents that produce the metal ores. And, while the idea of opening New England’s coastal waters to oil drilling has come up in Congress multiple times in the past decade (most recently this May), it has repeatedly been rejected.
But in New England, sand alone is riches enough for some. Two thirds of northeast beaches are eroding, some at an alarming rate of 60 feet per year. With sea level expected to rise at least three feet in the coming century (three times what it’s done in the past century), that situation will only get worse. Since 1978, Massachusetts state law has restricted the construction of new sea walls. And I don’t see many coastal property owners volunteering to get out of the way and let nature take its course. So we’re left with beach nourishment – rebuilding beaches and dunes with sand.
Where does all the sand come from? Some comes from dredging projects (take the sediment from where it’s causing problems, and put it back where we want it). But offshore sand mining is another possibility that local planners are pursuing. Massachusetts’ Ocean Management Plan allows for non-commercial sand mining, and that’s one of the primary offshore activities being incorporated into a special plan (formally, a District of Critical Planning Concern) for the waters around Cape Cod.
Finding the best places for mining – places where there’s lots of sand and not much else, where endangered species and fishing activities would be least disrupted – depends on seafloor (and ocean) maps.
4. Can you hear me now?
Ferries and bridges are the conduits that allow people and goods to flow to and from islands. Ships and planes fill the bill when it’s intercontinental travel or trade on the line. But the global community would fall back to pieces without telecommunications. And for more than a century – yes, since the days of telegraphs – global communications has relied on cables laid across or buried beneath the ocean floor.
Detailed seafloor maps can help reduce the ecological impact of our collective communications addiction by revealing the least destructive paths for those cables. Case in point: Comcast is planning to lay a fiber optic cable between Falmouth (Cape Cod) and Tisbury (Martha’s Vineyard) to provide high-speed internet. The Office of Coastal Zone Management has worked with Comcast to determine a path for the cable that avoids “hard, complex” seafloor – rocky areas with nooks and crannies that many marine species consider prime real estate.
5. Because it’s there.
When asked why he wanted to climb Mount Everest, George Mallory famously replied “Because it’s there.” The simple joy of discovery – conquest over the unknown, if you like – has driven many of humanity’s most inspiring endeavors. Plain old curiosity is the only realistic reason for decades and billions of dollars spent on space exploration. And, in my personal opinion, that’s just fine. The ability to ask and answer questions about our world is one of the things that makes us human.
But, for any number of reasons, exploration of our own planet hasn’t kept pace. You may have heard that we know more about the surface of Mars than we do about the bottom of the ocean. Perhaps surprisingly, that doesn’t just refer to the deep, dark, distant recesses of the ocean. The mapping of Massachusetts’ seafloor that began in 2003 and continues today is some the first of its kind. In the U.S., the only other areas with anything comparable are portions of California’s coast. And, as the scientists involved are quick to point out, even these new maps are only first drafts and leave much to be explored. They estimate that some 60% of Massachusetts’ seafloor still hasn’t been fully mapped with modern techniques.
State waters comprise fully one fifth of Massachusetts’ total area and, globally, oceans cover three quarters of the planet’s surface. In an age when anyone with an internet connection can view high-resolution satellite imagery of virtually any spot on Earth’s land masses with a click of the mouse, the mystery of the ocean’s floor seems too tantalizing to ignore.