An unusually dense bloom of the cyanobacterium Gloeotrichia echinulata in Loch Watten, a Scottish highland loch, during July 2023

Abstract

Loch Watten is a large (surface area 373 ha), very shallow (mean depth 2.6 m, maximum depth 3.7 m), high alkalinity, low altitude loch in Caithness, north mainland Scotland, with a predominantly improved and rough grassland catchment area of 5,578 ha (Fig. 1). There are two inflows to the north of the loch with an outflow to the Wick River in the south of the loch, draining for about 12 km to the North Sea at Wick.