Whale Brains, Squid Eggs, Bryozoan – Oh My!
“Anyone else find some crazy orange jelly blobs washing up on the beach today?” I texted to a group thread of badass ocean-inspired women – a thread I can rely on to help identify the unfamiliar marine critters and organisms I find in tide pools or washed up during my runs along the beach.
“Pacific Sea Pork – or some other type of colonial tunicate would by my guess” one of the girls responds. Someone jokes “a piece of a whale’s brain”, another one guesses “Squid eggs!” It’s hard to identify without a picture, but we finally land on something I had not heard of – a type of Bryozoan.
It turns out, bryozoans are simple aquatic filter-feeding invertebrates that are found in marine and freshwater environments around the world. These microscopic organisms form sedentary colonies that attach to objects like rocks, plants, docks, or other structures. The colonies can take many different forms, sizes, and textures depending on the species – ranging from gelatinous blobs to fans, bushes, and sheets. Some warm-water species can form colonies that are over 3 ft in circumference! How would you like to find that attached to the bottom of your hull?
The colonies are made up of individual organisms called zooids which are typically less than one millimeter in length and are enclosed in a wall of tissue called the zooecium, which in many species can secrete calcium carbonate to form skeletal structures. Within each colony, there are different types of zooids that coexist to ensure the survival and reproductivity of the group. These vary in structure and specialized functionality, whichincludes feeding, brooding eggs, defending against predators, and cleaning.
The autozooid is the most common type found in all species of Bryozoa– this type of zooid supplies food and nutrients to the rest of the colony using a crown of cilia tentacles that move planktonic particles suspended in the water towards its mouth and into its U-shaped gut. Although each zooid is an individual animal, each one is interconnected with the rest of the colony through pores – sharing nutrients and transmitting chemical signals to function in tight coordination with the other zooids. Now that’s what I call communal living!
Bryozoa feeding structures. Photo Credit Christian Schawarz
