Icicles go with the flow.

These sharp shards are the visual, tangible interplay between the competing — or collaborating — forces of temperature and water. Freezing temperatures meet up with warmed, dripping water to produce beautiful and curious ice points, which are just the tip of the iceberg in ‘cicle science.

As mesmerizing as it is to watch icicles form and fade from our eaves, there are other fascinating phenomena in the frozen family of these curious columns. 

Ice spikes are among these spectacles. Like stalagmites, the ground-dwelling mirror images of the stalactites that hang from a cave’s ceiling, ice spikes turn icicles on their heads. They show themselves as an inverted icicle that projects upward from the surface of frozen water, seemingly defying gravity as they grow. Ice spikes can occur on bird baths, pet water bowls left outside, or other sitting water. They can also occasionally appear on ponds. Scientists have even mechanically achieved these small pinnacles on ice cubes using distilled water.

These spikes are unusual but can occur when conditions are just right. Also called ice candles, ice towers, ice vases and ice pyramids, it takes the combination of temperature, air flow above the water, concentration of water impurities and shape of water body to make these frozen forms.

When water freezes quickly, it can expand by up to nine per cent. Consider how a full-to-the-brim ice tray in your freezer produces ice that overruns its container top. On occasion, the water below the mostly-frozen ice can push through the last bit of liquid on the still-unfrozen surface — or can find a flaw in the surface to produce these upward shooting icicles. This is the result of physics, not biology, and is described by what is known in physics as the Bally-Dorsey Model. 

Another icicle of interest is the brinicle.  he brinicle, or brine icicle, is an underwater stalactite-like spear found in very cold places such as Antarctica. These form in salty ocean water, below the sea ice — which is less salty. Forming as a hollow ice spear, a brinicle grows downward because salts and minerals are expelled from the water as it freezes, from the top downward, toward the sea floor. 

Think of a brinicle as an inverted chimney, or tube of ice. Brinicles contains a super-saline interior, yet a fresher water crusty exterior that freezes because the salt and other minerals are pulled out of it. 

Sometimes called a finger of death, a brinicle, ominously, can extend all the way to the bottom of the ocean and freeze anything – including sea creatures, not all of them move quickly enough) — in its path. The brinicle ice flow may even spread and cover the sea floor. A recent discovery, brinicles have only been oberved by humans since the 1960s and their formation was filmed just 13 years ago.

Getting back to icicles: When is an icicle not an icicle? When it is a rusticle. This type of icicle is similar to the others only in its shape.  Rusticles usually occur in the ocean due to and on human-made structures such as mooring chains and shipwrecks.

Rusticles are rust icicles made by mineral-loving bacteria and fungi in the ocean that oxidize iron and steel. The portmanteau of words was coined by American oceanographer Robert Ballard, who first observed them on the Titanic during an expedition in 1986. Made of iron, microbes, and sometimes other minerals, including calcium, chloride, magnesium, sodium, silica and sulfate, they could be called a mineralicle. So, Dr. B. and I are both wordsmiths.

The cycles of these ‘cicles make for exciting explorations of science and nature, but what they all have in common is that they get to the point.  Not always quickly, but surely.

Suzan Bellincampi is Islands director for Felix Neck Wildlife Sanctuary in Edgartown and the Nantucket Wildlife Sanctuaries. She is also the author of Martha’s Vineyard: A Field Guide to Island Nature and The Nature of Martha’s Vineyard.