LAGOS, Nigeria — Beneath an eight-lane expressway, Nigerian men stand waist-deep in the Lagos Lagoon, lowering buckets into murky water. Each load brings up sand, reshaping the coastline of Africa's largest city and driving away fish and livelihoods for some of its poorest people.
Not far from the bridge, wooden boats are loaded with sand. One of thousands of local dredgers, Akeem Sossu, 34, has been diving for sand for at least three years. He slips beneath the surface for about 15 seconds at a time, hauling up bucketloads bound for construction sites.
Akeem said he and his partner earn about 12,000 naira ($8) each per boatload, selling to a middleman who supplies larger buyers. Filling a boat takes about three hours. Formerly a tailor, he said dredging now supports his household.
''I come out early, sometimes 5 a.m. or 6 a.m., depending on the tide,'' he said.
Dredgers and local traders say the price of sand, crucial for making concrete, has risen steadily as development in Lagos has accelerated. A standard 30-ton truckload of what's known as sharp sand — coarse and gritty — now sells for about 290,000 naira, or roughly $202, reflecting strong demand.
The changes to the lagoon that buffers the megacity of about 17 million people are unmistakable. What was once an open stretch of water is increasingly broken up by sandy patches, narrowing channels and reshaping currents that support thousands of fishermen.
The transformation is most visible near Makoko, one of Lagos' oldest fishing communities. Dredging barges operate close to homes built on stilts, while reclaimed land and construction of upscale beachfront properties press in from the edges. Residents say the encroachment has destroyed fishing grounds and put many out of work.
Nearby, fishermen wait for the day's dredging to pause. They say that when it does, even briefly, some fish return.