Who was the villain of Murder Under the Microscope 2010?

The villains were the rising average temperatures.

The victim was the "weedy sea dragon" and the crime site was Genoa.

Rising temperatures killed abalone, so sea urchins proliferated and ate all the kelp, which is vital for the sea dragon: With no kelp, the urchins eat young sea dragons and sea dragon eggs.

(see the related link to the MUTM site)