It Looks Like a Fjord and It Is Nothing Like a Fjord

The form is a shallow, irregular, low-lying coastline of many small rocky islands, reefs and skerries, separated by shallow winding channels and broad inlets with gentle shores. There are no cliffs of any height and no deep water. Seen from above it resembles a shattered plate, with rock and water interleaved across a wide zone rather than a single defined shoreline. Navigating it means threading between hazards that are barely submerged, which is why such coasts carry dense networks of marked channels.

The two are produced by the same process on different ground:

• •A fjord is deep, narrow, steep-sided and long
• •It forms where a glacier deepened an existing mountain valley
• •This form is shallow, broad and low throughout
• •It forms where ice crossed low ground with no valleys to follow
• •So the ice scoured and plucked unevenly across a wide area
• •Rising sea level then flooded the resulting uneven surface

The distribution follows the low lying parts of formerly glaciated regions. The Baltic coasts of Sweden and Finland are the type examples, with archipelagos containing tens of thousands of islands. Similar coasts occur in parts of Nova Scotia, in Maine and around some Scottish islands. These regions are also still rising after the removal of the ice, so new skerries emerge from the sea within living memory and channels that carried boats a century ago have become too shallow, which local charts have to be revised to reflect.

Continuing uplift after the ice melted is unusually visible on these coasts and it has measurable consequences. The land in the northern Baltic is rising by up to nine millimetres a year, which is among the fastest rates anywhere, so the sea retreats by a metre or more of horizontal distance each year on a gentle shore. Harbours built a few centuries ago sit inland. Property boundaries extending to the water have generated a body of law about who owns newly emerged ground. And communities keep dredging channels that were once deep enough without help.

The form has consequences beyond scenery. The sheltered water behind thousands of islands produces calm navigable routes running for hundreds of kilometres, which shaped trade and settlement along those coasts and still supports an enormous recreational boating culture. The shallow brackish water among the islands is exceptionally productive and supports fish nurseries and vast bird populations. And the thin soil on the islands supports a distinctive vegetation, which along with continuing uplift makes these coasts a natural laboratory for studying how communities colonise new ground.

Ice crossing low ground with no valleys to follow scours unevenly across a wide area, and rising sea level floods the result, producing a shallow archipelago of skerries and winding channels rather than the deep narrow trench a fjord makes. The Baltic coasts of Sweden and Finland are the type examples, and they are still rising, so new skerries appear within living memory.