A lighthouse and pine tree in shadow at sunset. The words Did You Know are in blue at the base of the image

Did You Know – Concretions – What are They?

Have you noticed those circles around the tidepool entrance? They’re not dinosaur footprints or asteroid impact craters. They’re concretions, a fascinating geological feature. Let’s dive into what makes them so special. A concretion is a solid, tightly packed mass of minerals that forms inside sedimentary rock, often with a round shape. Concretions happen when minerals from groundwater settle and stick the sediment together, usually around … Continue reading Did You Know – Concretions – What are They?

A bright green sea anemone with shell fragments clinging to its tentacles rests on wet sand among seaweed and small rocks in a tide pool.

What’s in the Tidepools? – April 2026

(Yellow Gilled Sea Goddess – NPS Photo/Rick A.) Here is a sampling of what our volunteers observed during the final month of this tidepool season — thank you to everyone who contributed. Remember to send in your photos; we truly appreciate sharing them with everyone. Don’t forget to visit the Tidepool Videos page and our YouTube page. Enjoy the virtual visit through the tidepools and Cabrillo. Added … Continue reading What’s in the Tidepools? – April 2026

A vibrant purple and blue sea slug with bright orange spines crawls among brown and pink seaweed in a shallow tide pool.

What’s in the Tidepools? – March 2026

(Red Sea Urchin – NPS Photo/D. Orr) Here is a sampling of what our volunteers observed during the month — thank you to everyone who contributed. Remember to send in your photos; we truly appreciate sharing them with everyone. Don’t forget to visit the Tidepool Videos page and our YouTube page. Enjoy the virtual visit through the tidepools and Cabrillo. Continue reading What’s in the Tidepools? – March 2026