Canyons attract large game fish like marlin, and each summer the fish attract charter boats and fishing tournaments, like the White Marlin Open shown in this photo. This map shows the nearshore coastal zone off the Mid-Atlantic. The outer edge of the continental shelf lies in an area approximately 50 fathoms (300 feet) deep. The federal government controls an "exclusive economic zone" (EEZ) that extends farther out, to around 200 nautical miles from the coastline. Credits: Photograph, White Marlin Open; map, NOAA

WE STROLL ACROSS THE BEACH at Ocean City, Maryland, dip our toes in the surf, and look out to sea. As tides and seasons pass one after another, the ocean seems endless and timeless.

But 18,000 years ago, if we had been alive and standing at the ocean's edge, we would have stood in a different location, miles east of Ocean City, at the bottom of what is today the Atlantic Ocean. Over long periods of time, the coastline has moved and changed. In that long-ago era, the coastline lay farther east because the sea's level was 400 feet lower than today. A period of global cooling had locked up the earth's water in glaciers.

With the sea level lower, the area that is now a continental shelf was then dry land. Archeological evidence indicates that paleo-Indians once inhabited this coastal plain. There was no Chesapeake Bay then, only a river valley through which flowed what is now the Susquehanna River, stretching across this plain eastward to the ancient coastline. Starting around 15,000 years ago, the earth warmed, the glaciers melted, the sea rose, and the coastal plain flooded. Over several thousand years, the valley filled, creating the Chesapeake Bay. Rising waters moved the ocean-facing coastline westward, where it eventually reached its current location.

Even though people can no longer walk across this plain, Marylanders and residents of our neighboring states today retain important connections to this ocean region next door. Chesapeake Quarterly generally focuses on the Bay and its watershed, but in this issue, we take a broader view of the Chesapeake region and look at some of the diverse, surprising natural resources offshore — and at emerging concerns about how best to conserve them.

One of these resources is Norfolk Canyon, a giant submerged valley that lies about 60 miles east of the mouth of the Chesapeake Bay. This underwater chasm developed from the ancient channel of the Susquehanna River. This river channel also carved the Bay, so you can think of the canyon as an offshore echo of our great estuary. In recent years, scientists have used new technologies to explore both Norfolk Canyon and Baltimore Canyon, its neighbor to the north off Ocean City, Maryland. Research expeditions brought back a trove of data and images about the biologically rich communities there. Living in these canyons, for example, are brightly colored, temperate-water, deep-sea corals like the one pictured on the cover of this magazine (see The Grand Canyons off Our Coast). But the scientists also saw plenty of plastic bags and other garbage, a reminder that these remote deep-water habitats are linked to the people living on and near the coast.

Plastic garbage is one of many present-day and future human impacts in the ocean portion of Maryland's coastal heritage that warrant our attention. The coastal zone supports a variety of important economic activities, some of which could harm the environment and some of which conflict with each other.

• Oil and gas development. The federal government is moving to allow companies to conduct exploratory drilling for oil and gas on the outer continental shelf from Virginia to Georgia starting in 2017. This prospect has raised concerns that oil spills from these operations to the south could affect Maryland's coastal waters.

• Wind energy. In December 2014 federal regulators issued leases for the development of offshore wind turbines in waters 10 nautical miles east of Ocean City, Maryland. With turbine towers sitting atop pilings sunk into the ocean floor, will the noise from survey work and construction drive away or harm game fish? Will it affect the migrations and behavior of marine mammals such as dolphins and endangered right whales? Federal agencies are evaluating these risks, and University of Maryland researchers are gathering information that could help answer these questions (see Whale Watching, Beneath the Waves). In addition, Defense Department officials have voiced worries that offshore wind and oil energy facilities will interfere with naval exercises and training off the Mid-Atlantic coast.

• Commercial and recreational fishing. Fishing is an important business in the Mid-Atlantic, so potential conflicts in the coastal zone could affect harvests, earnings, and jobs. In 2012, commercial landings in the Mid-Atlantic totaled $488 million. In Maryland alone, the recreational fishing industry reported that $637 million in sales helped support 5,683 jobs.

• Climate change. Trends in ocean conditions are already altering the habitats of commercially valuable fish. The Northeast Fisheries Science Center, part of the National Oceanic and Atmospheric Administration, has reported that warming temperatures led half of 36 Mid-Atlantic fish stocks to shift their range northward over past decades in search of cooler water. Fisheries could also be affected as ocean water grows more acidic, an effect of increasing carbon dioxide in the atmosphere. This acidity could weaken the hard skeletons that make up deep-sea corals, which provide important habitat for fish species and other creatures.

• Shipping traffic and navigation. The Panama Canal is currently being widened and deepened to allow access by new cargo ships that are larger and carry more freight than existing vessels do. That change is expected to increase traffic to and from East Coast ports, like Baltimore, that are retrofitting their docks and other facilities to serve these large vessels.

In recent years, government, academic, and non-profit organizations have been considering how best to manage these environmental effects and conflicts in use. Many of the management decisions will be made by federal agencies, like the Bureau of Ocean Energy Management, which have the lead role and jurisdiction in managing much of the Mid-Atlantic's coastal zone.

Now a group called the Mid-Atlantic Regional Planning Body is leading a new effort to improve planning and coordination among the many federal and state agencies and other organizations that share an interest in this coastal zone. In 2010, the Obama administration established a National Ocean Policy that called for this planning at the regional level. The planning body, formed in 2013 to create a new regional framework for this work, is scheduled to release a draft Ocean Action Plan for public comment in summer 2016 and to finalize it later in the year. The hope is that this and other efforts will help to balance uses and conservation of natural resources in our ocean zone next door.

— Jeffrey Brainard