The intertidal mudflats of Barr Al Hikman, a nature reserve at the south-east coast of the Sultanate Oman, are crucial nursery grounds for numerous crab species. In return, these crabs are a vital element of the ecology, as well as the regional economy, a new publication in the scientific journal Hydrobiologia shows. ‘These important functions of the crabs should be considered when looking at the increasing human pressure on this nature reserve’, first author and NIOZ-researcher Roeland Bom says.
Blue swimming crab
The mudflats of Barr Al Hikman are home to almost thirty crab species. For his research, Bom, together with colleagues in The Netherlands and at the Sultan Qaboos University in Oman, looked at the ecology of the two most abundant species. Bom: ‘Barr Al Hikman is also home to the blue swimming crab Portunus segnis. That is the species caught by local fishermen. This crab uses the mudflats
Millions of years ago, ancient humans living on the African savanna likely gazed up in wonderment at the bright moon and star-filled sky. This cosmic backdrop wasn’t too different from the one we see today; but how they interacted with it almost assuredly was. It wasn’t until humans came to view the stars as tools that we became masters at understanding their movements.
By some 7,000 years ago, a group of nomadic people living on the African savanna became the first-known humans to record the motions of the stars at a site called Nabta Playa. This cattle-worshiping cult of hunters and gatherers built the world’s oldest stone circle to track the arrival of the summer solstice, as well as the seasonal monsoons they depended on for water and food.
“This was the dawn of observational astronomy,” J. McKim Malville, a professor emeritus at the University of Colorado and archaeoastronomy expert,
Thunderbolts are traditionally the weapon of the gods, but in 1967 the CIA were wondering whether they, too, could call down bolts of lightning from the heavens at will.
The idea is contained in a proposal from a scientist, sent to the CIA’s Deputy for Research ‘Special Activities’ and passed on to the chief of the Air Systems division. The scientist’s name has been redacted in the declassified document from the CIA’s archive, but the proposal mentions a previous discussion with the CIA, indicating they were being taken seriously.
The guided lightning concept is based on the observation that lightning follows a path of ionized air known as a step leader. Once the leader stroke reaches the ground and makes a circuit, the lightning proper is formed and a current flow, typically around 300 million Volts at 30,000 Amps.
The scientist suggests that artificial leaders could “cause discharges to occur