EPOW - Ecology Picture of the Week

Explanation:   Iceland stretches about 305 km (190 mi) north to south, and 485 km (300 mi) east to west.  If Iceland were shaped like a smooth ellipse (which it is, roughly), its coastline (the perimeter of the ellipse) would measure 1,273 km (791 mi; see Information below)  ... but Iceland actually has an immense coastline length of 4,988 km (3,099 mi).  How can that be, and what does this mean for people and wildlife?

For one thing, there is not just one coastline but many, including those of islands, islets, spits, peninsulas, bays, and fjords.  The "edge" of Iceland is greatly crenulated with nearly endless indentations and pieces.  And the closer you inspect it, the more accurately you measure it, the longer it gets ... because you include more and more, smaller-scale variations.  

This is essentially a problem in fractal geometry, which has been applied in coastline geography as well as in ecology in measuring landscape heterogeneity and diversity of habitat patches (including coastlines).  The coastlines of Iceland constitute a classic case of fractal measurement ... it is longer than one-dimensional straight lines laid over the coast, but not as extensive as a two-dimensional area.  So, the "length" -- including all the crenulations and indentations -- is a fraction between one and two dimensions; this is what is meant by a fractal dimension.  

From a practical perspective, the more corrugated and uneven is a coastline, the more interface there is between land and sea.  This may provide greater habitat for organisms that use such interface environments, including seals, nesting seabirds, and people who fish and whale for a living.  

So, in this way, Iceland's relatively small surface area rather belies its remarkably diverse and extensive coastlines and land-sea interface. 

Information: The perimeter of an ellipse can be estimated from its major axis 2a and minor axis 2b lengths, as 2(pi)sqrt[0.5(a²+b²)].  More precise estimates entail far more involved formulae.