Neptune's Cup

Associated Smithsonian Expert: Klaus Ruetzler, Ph.D.

Dr. Klaus Ruetzler examines sponges maintained in a running-seawater system at the wet lab in Carrie Bow Cay, Belize.

Photo credit: Molly K. Ryan

Dr. Klaus Ruetzler is a research zoologist and curator of sponges in the Department of Invertebrate Zoology at the Smithsonian National Museum of Natural History. His current research focuses on the diversity and ecology of sponges from submarine caves on the Mesoamerican Barrier Reef of Belize (Central American Caribbean). He is also working on a book describing 40 years of Smithsonian research on this coral reef ecosystem for which he founded the Smithsonian Carrie Bow Marine Field Station in 1972. He grew up in Austria and first became interested in sponges when he explored submarine caves, using self-made scuba gear, in Croatia, Adriatic Sea, where sponges make up most of the colorful fauna. He turned his early observations into a dissertation and earned a doctorate at the University of Vienna. He was hired by the Smithsonian Institution when a position for a sponge specialist became available.

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This image was obtained from the Smithsonian Institution. The image or its contents may be protected by international copyright laws.

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Hadromerid sponge (Raspailia hispida)
Courtesy of Bernard Picton, Encyclopedia of Marine Life of Britain and Ireland, CC-BY-NC-SA

About Hadromerid Sponges (Order Hadromerida): Reproduction

Hadromerid sponges are egg layers (oviparous). However, unlike chickens for example, fertilization is external, happening outside of the female. The female releases her egg cells and the male releases his sperm cells into the sea. Fertilization occurs as the eggs and sperm have chance encounters. This means that a large proportion of hadromerid eggs might never be fertilized. Male sponges tend to spew out huge amounts of sperm, presumably to increase the chance of meet-ups with eggs. Like all sponges, hadromerids are also able to reproduce asexually. Pieces of the adult sponge can bud off and grow into new sponges.

Mermaid's glove sponge in habitat (Haliclona oculata)
Courtesy of Bernard Picton, Encyclopedia of Marine Life of Britain and Ireland, CC-BY-NC-SA


About Sponges (Phylum Porifera): Habitat

Sponges live in every ocean on Earth, and in some freshwater as well. They have colonized incredibly diverse habitats, from the deep, cold ocean bottom to warm, tropical seas and rough, rocky shorelines battered by waves. Some sponges are tiny dots, and others large enough for a person to get inside. They also come in a shocking variety of shapes, some quite symmetrical like cups or balls, but many asymmetrical like globs, bushes, or bread crusts. Some excavate limestone, such as mollusk shells, and live inside. Sponges may live alone or fuse with other sponges into large, underwater reefs. It turns out that this variety helps explain their ability to be successful on Earth in so many habitats. Sponges are transformers; they can change their shape by moving their cells around. Their cells can even convert to other cell types to adapt their bodies to whatever habitat or conditions they find themselves.