Wastewater from Southern California's 23 million residents adds nitrogen to the ocean, and that nitrogen can make toxic algal blooms worse. Pseudo-nitzschia diatoms produce domoic acid, a neurotoxin that harms sea lions, seabirds and people who eat contaminated shellfish. Diatoms need both nitrogen and silicon to multiply, and silicon brought up from the deep has declined for decades. When nitrogen is plentiful but silicon is short, the diatoms stop dividing but keep making toxin. A computer model found that nitrogen from land raised domoic acid levels within 15 kilometres of shore by about 25 percent on average, and more than 50 percent in some spots near outfalls.

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.