What color is YOUR water? Monitoring the Coastal Ocean Through Color Anna R. McGaraghan*, Kendra Negrey, and Raphael M. Kudela University of California Santa Cruz *[email protected] What is Ocean Color? What do the colors mean? Ocean color as measured from satellite is a When the water looks especially green, it means there are a prominent tool in modern oceanography. lot of microscopic algae (phytoplankton) growing near the Satellite sensors record reflected light from the surface. surface of the water. Different colors represent how light interacts with different parTcles in the water. When the water looks murky and brown it means there is sediment, or mud, suspended in the water. Our eyes can do the same thing! People have been observing and recording the color of the water from the shore for centuries. Changing colors reflect the changing parTcles in the water. Phytoplankton blooms oNen turn the water green, but a dense bloom of certain species can be orange, brown or red. Colors below all from Monterey Bay! How is ocean color measured here? Why does it maer? In Monterey Bay, the water color is recorded each week in Monterey and Santa Monitoring the changing color of water can help researchers recognize paerns in Cruz while researchers are collecTng phytoplankton samples. the state of the ocean. Paerns can hold the keys to understanding phenomena like red Tdes and harmful algal blooms, weather events, and climate change. This color chart is used, and the color is recorded along with several other water quality measurements. Red Tdes, oNen harmless, are Harmful Algal Blooms are not. They are easy to see. (Can you spot the oNen colorless – but subtle changes in whale?) color can reveal changes in the phytoplankton community. Lingulodinium bloom (HAB) Pseudo-nitzschia bloom (HAB) Santa Cruz 15 April 2015 #UCSCcolorgallery Akashiwo bloom (harmless) Weekly colors at the Santa Cruz Wharf in 2014 ShiN from diatoms to dinoflagellates Diatoms + turbidity + rain Highest domoic acid Cochlodinium Join us! Santa Cruz High Tech: Two smartphone apps are available that gather water color Low Tech: informaon from all over the world. Water color exhibits can be found at the Santa Cruz Wharf and HydroColor Citclops Download either the Exploratorium in San Francisco. Take a photo and app and submit contribute to our Instagram gallery! water color photos from anywhere! Exploratorium Photos posted to the gallery allow us to compare Monterey Bay and San Francisco Bay, and observe Scan code at right for color chart and more info, or visit how the colors change through Tme. hUp://oceandatacenter.ucsc.edu/PhytoBlog/color.html .