Local Research at Morningside Park

History

Morningside Park is a scenic green space in Upper Manhattan, bordering the eastern edge of Columbia University and stretching along the rocky cliffs between Harlem and Morningside Heights. Designed in the late 1800s by Frederick Law Olmsted and Calvert Vaux, the park features dramatic stone outcrops, winding trails, and quiet wooded areas that offer a peaceful retreat from the city.

One of its highlights is the man-made pond and waterfall near the park’s southern end. Created in the 1980s on the site of a long-abandoned construction project, the pond is maintained by NYC Parks and serves as both a tranquil gathering spot and a small wildlife habitat. Its continued upkeep by NYC Parks, in partnership with Friends of Morningside, reflects the community’s ongoing commitment to preserving the park’s natural beauty and history.

Like many small urban ponds, the pond in Morningside Park faces a persistent challenge -  outbreaks of algal blooms. Seen in early summer as bright green mats, algal blooms often appear during warm months, when sunlight, stagnant water, and excess nutrients from city water, ground water runoff or from bird droppings, create ideal conditions for algae to thrive. While some algae are natural and even beneficial, excessive growth can block sunlight, reduce oxygen levels, and make the water less hospitable to fish and turtles that inhabit this beautiful pond.

In recent years, however Morningside Pond has been plagued by Microcystis, a type of cyanobacterium that thrives in still, nutrient-rich water. Unlike most algae, Microcystis can fix atmospheric nitrogen, allowing it to survive even when nitrogen levels in the water are low. In a pond enriched with inorganic phosphate from runoff, fertilizers, and natural debris, this gives it a powerful competitive edge. It spreads quickly across the surface, forming thick mats that block sunlight, lower oxygen levels, and crowd out other aquatic plants and organisms.

These blooms not only cloud the water but can also release toxins that harm fish, turtles, and birds, making the pond less hospitable to wildlife. NYC Parks monitors these conditions closely and works with community partners to manage nutrients, increase water circulation, and maintain a healthy aquatic ecosystem.