C4POCollaboratory for Physical Oceanography

Significant observation

Harmful Algal Blooms

Dense orange-brown water swirling offshore of a green, wooded shoreline on the York River.

Each summer, dense algal blooms can develop in the lower Chesapeake Bay and its tributaries, discoloring the water and, at high enough concentrations, depleting oxygen and harming the fish, shellfish, and people who depend on the estuary. Blooms are notoriously patchy: they form, drift, and dissipate over hours to days, at spatial scales of tens to hundreds of meters — too fine for satellites to resolve through clouds and too fast for ship surveys to chase.

C4PO observes these events from the air. Beginning with an aerial survey and monitoring program for bloom events in the lower York River, the lab uses drone-based aerial remote sensing to map blooms at the neighborhood scale — in the shallow nearshore waters where blooms concentrate and where conventional platforms struggle to sample. These aerial observations complement in-water sampling and have supported collaborative studies of phytoplankton dynamics and water quality in the Bay.

20261 survey · 12 photos

July 31, 2026 · Lower York River, Gloucester Point

Drone survey, 17:59–18:14, from the Coleman Bridge past Gloucester Point Beach to the VIMS campus.

Reddish-brown water offshore of a pier on the York River.
Vehicles on the Coleman Bridge over the York River, with reddish-brown water beneath and beyond the span.
A band of reddish-brown water along the wooded York River shoreline.
Reddish-brown water around boats docked at a marina on the York River.
Reddish-brown water along the sand at a developed stretch of the Gloucester Point shoreline.
Reddish-brown water between rock breakwaters on either side of a pier.
People on the sand and in the water at Gloucester Point Beach, with reddish-brown water in the enclosed swimming area.
The Coleman Bridge and Gloucester Point from upriver, with reddish-brown water in the foreground.
Reddish-brown water with a sharp edge next to the fishing pier at Gloucester Point Beach.
Streaks of reddish-brown water in the York River.
The VIMS Gloucester Point campus and research pier, with reddish-brown water offshore.
A close view of the edge between reddish-brown and clear water.
201711 surveys · 83 photos

August 31, 2017 · Lower York River

Drone survey, 14:48–15:03.

Extensive brown water in the York River, with the Coleman Bridge in the distance.
Brown water in swirls along a green, wooded shoreline.
Brown water meeting the sand at a wooded point.
Dense orange-brown water filling the frame, with streaked structure.
The Coleman Bridge, houses, and piers, with brown water throughout.
The Coleman Bridge over brown and olive water with surface swirls.
The VIMS campus and pier with green water offshore.
Wide orange-brown water under haze.
A shoreline of houses and piers with dark brown water.
A grassy park shoreline with brown water and a small sailboat.
A wooded point with brown water and the bridge in the distance.

August 30, 2017 · Lower York River

Drone survey, 14:06–14:25.

A broad band of brown water meeting lighter water in the open river.
A dark brown plume in the York River, with the shoreline and bridge in the distance.
The Coleman Bridge and Gloucester Point, with streaked brown water beneath.
Bridge spans over brown and green streaked water.
Wide brown and olive water with a distant shoreline.
Open water with a brown band and a pier at the shoreline.
Wide hazy brown water reaching a distant shore.
Brown water with a shoreline town and the bridge in the distance.
The Coleman Bridge over dark brown water.
The Coleman Bridge with brown water beneath and a schooner beyond.

August 22, 2017 · Lower York River

Drone survey, 14:08–15:24.

Brown and olive water across the York River, with a distant shoreline.
A close view of the water surface, mottled purple-brown and green.
The Coleman Bridge and its approach at Gloucester Point, with brown water on one side and greener water on the other.
A dark red-brown streak with a sharp edge in lighter water.
A schooner under sail on the York River, with the Coleman Bridge behind.
A town and piers with a dark brown patch offshore.
A town and shoreline with olive and brown water.
The Coleman Bridge with brown streaks in the water.
The bridge roadway from above, with a boat wake crossing dark brown water.
A beach and piers with a brown plume near the shore.

August 21, 2017 · Lower York River

Drone survey, 12:03–12:07.

Brown water across the width of the York River, with the far shore in the distance.
A brown patch offshore of piers and houses, against greener water nearer the shore.
A dark brown patch offshore of a wooded shoreline.
The bridge, campus buildings and shoreline, with greenish water.
Campus buildings and a pier along the shoreline, the bridge in the distance.
A broad brown patch offshore of a wooded shoreline.
The bridge approach, beach and pier, with greener water nearer shore.
The bridge over the river with the wooded far shore beyond.

August 16, 2017 · Lower York River

Drone survey, 14:32–15:28.

The Gloucester Point shoreline with houses and a pier, and olive-green water offshore.
The Coleman Bridge roadway from above, with dark green water and a pale streak alongside.
A boat leaving a long wake on green water in the York River.
The Coleman Bridge from above with a boat passing beneath it.
A beach, pier and shoreline with green water and a distant point.
The VIMS campus from the air, with the drone visible over the water.

August 1, 2017 · Lower York River

Drone survey, 13:24–16:19.

A shoreline and town with a faint brown patch offshore.
Green water with brown wisps.
Dark streaks converging in the water off a wooded shoreline.
A campus building and rock breakwater with a dark brown patch offshore.
Brown streaks in the water crossed by a boat wake.
A pier with wide brown water and a distant shoreline.
A boat underway, its wake crossing a brown streak.
The Coleman Bridge over green and brown streaked water.
The bridge with brown patches in the water below.
The highway approach to the bridge, with a beach, pier, and brown plume.
The bridge and town from the air, with brown water.
A bridge pier with a brown plume extending from it.

July 30, 2017 · Lower York River

Drone survey, 12:37–13:11.

A marsh island and creek with brown water.
Piers and docks with brown patches in the water.
A marsh island with brown water in the surrounding channels.
A marsh island and sandbars with brown water.
A pier and dock with a brown patch near the shore.

July 27, 2017 · Lower York River

Drone survey, 15:10–16:13.

A faint brown plume in open water.
A dark brown patch beside a beach and rock breakwater, with people on the sand.
A T-shaped pier with dark brown water around it.
A long dark brown band along the shoreline, with the bridge in the distance.
The bridge over brown water.
Brown swirls beside a pier.
Curved rock breakwaters and a waterfront with brown water.
A waterfront with curved breakwaters, boats, and brown water.
The bridge from above, with brown water beneath.

July 26, 2017 · Lower York River

Drone survey, 16:26–17:12.

A dark brown band offshore of houses and a pier.
Looking straight down at a beach, rock breakwaters, and a boat ramp.
A long dark brown band offshore of the Gloucester Point shoreline.
The bridge approach and shoreline, with a dark brown patch beside a pier.
Green water with brown streaks near a dock.
Open blue-green water with a distant wooded shoreline.
A brown band offshore of a parking area and pier.
A beach and pier with a brown patch offshore and the bridge at left.

July 23, 2017 · Lower York River

Drone survey, 20:33.

Sunset over a wooded point on the York River, with orange sky reflected on the water.

July 22, 2017 · Lower York River

Drone survey, 09:17–09:19.

Brown swirls in the water along a wooded shoreline with a pier.
Brown streaks along a shoreline with piers and a marsh point.
Wide brown water with a pier in the foreground and a marsh point beyond.

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