In this crowded space in a tide pool at Enderts Beach in California’s Jedediah Smith Redwoods State Park, goose barnacles fill the gaps left by California mussels while acorn barnacles attach directly to the mussels themselves. The snails and black limpets are a little more mobile but all have evolved some sort of hard enclosure to protect against drying out at times like these when the tide has receded, and also against the birds who prey upon them. They may not be able to evolve fast enough to survive their biggest enemy as we not only warm the oceans but acidify them too. But for the moment I will bear them witness, this beautiful little world that exists only in the narrowest strip up and down our coasts, halfway on land and halfway in water.