Revealing enigmatic mucus structures in the deep sea using DeepPIV

Many animals build complex structures to aid in their survival, but very few are built exclusively from materials that animals create ^1,2. In the midwaters of the ocean, mucoid structures are readily secreted by numerous animals, and serve many vital functions^3,4. However, little is known about these mucoid structures owing to the challenges of observing them in the deep sea. Among these mucoid forms, the 'houses' of larvaceans are marvels of nature⁵, and in the ocean twilight zone giant larvaceans secrete and build mucus filtering structures that can reach diameters of more than 1 m⁶. Here we describe in situ laser-imaging technology⁷ that reconstructs three-dimensional models of mucus forms. The models provide high-resolution views of giant larvacean houses and elucidate the role that house structure has in food capture and predator avoidance. Now that tools exist to study mucus structures found throughout the ocean, we can shed light on some of nature's most complex forms.