The ocean ecosystem is the most prominent of all the Earth's habitats, covering some 70% of the planet's surface and home to some 2.2 million species. The sea also happens to be a dominating element in my life, having grown up on a small, windswept island in the Irish Sea for half my life - surrounded 360-degrees by water. For me, the sea presents the most exciting assortment of wildlife on offer, with an unending treasure-trove of surprises to be had. The abundance of life at all levels - from the microscopic to the largest of mammals - is coupled with ever-changing weather conditions, lighting, tides, sea-states and moods. For a photographer, attempting to capture its inhabitants and this awesome interplay of elements presents an exhaustible lifetime of opportunities.