Portskewett The village lost its railway station (on the Newport to Gloucester line) when it was closed under the Beeching Axe in 1964. Black Rock, on the Severn estuary immediately south east of the village, has been an important crossing point of the River Severn for many centuries. Numerous coins found in the mud show that it was in constant use throughout the Roman period, on the route between Aquae Sulis (Bath) and Venta Silurum (Caerwent). By the 18th century, a regular ferry service crossed the Severn estuary from Black Rock to New Passage on the Bristol side, carrying passengers, cattle
Aphanizomenon flos-aquae it had a profound effect on natural killer cells (NKCs). "A. flos-aquae" triggers the movement of 40% of the circulating NKCs from the blood to tissues. Some compressed tablets of powdered "A. flos-aquae" cyanobacteria (named as "blue green algae") have been sold as food supplements, notably those filtered from Upper Klamath Lake in Oregon. Aphanizomenon flos-aquae Aphanizomenon flos-aquae is a brackish and freshwater species of cyanobacteria found around the world, including the Baltic Sea and the Great Lakes. "Aphanizomenon flos-aquae" can form dense surface aggregations in freshwater (known as "cyanobacterial blooms"). These blooms occur in areas of high nutrient loading,