on exotic holidays this year, but part of scotland s west coast has taken on a distinctly mediterranean look. the sea around the isle of arran has turned a stunning green blue. our climate change reporter, harriet bradshaw, has been investigating why. you d be forgiven for thinking this is a tourist ad for the mediterranean, but welcome to arran. this extraordinary colour has attracted lots of speculation. in the absence of any known sea samples being analysed, there is one theory experts seem to agree on. over the past 50 years, we have seen changes in the phytoplankton. i have come inland, near oban, to meet professor paul tett to find out more. he s been studying microscopic algae since the 1970s, known as phytoplankton. how rare is what we are seeing off the west coast, this turquoise colour? well, the only time i ve seen in my working life seen it in my working life