In a groundbreaking discovery, scientists have documented the first appearance of the rare siphonophore Rhizophysa eysenhardtii in False Bay, extending the known range of this elusive organism by an impressive 450 km.
This exciting finding, published in the journal African Invertebrates, not only adds a new chapter to our understanding of marine life in the region but also underscores the intricate biodiversity thriving within the Great African Seaforest.
This siphonophore, belonging to the phylum Cnidaria—home to jellyfish, corals, and sea anemones—represents a fascinating array of marine organisms. Siphonophores like Rhizophysa eysenhardtii are unique colonies of specialised individuals known as “zooids,” which work cohesively to function as a single organism. Discovered by marine biologist Dr. Jannes Landschoff from the Sea Change Project and his team during freediving expeditions between June and September 2022, the sighting was met with elation.
"When I saw this siphonophore for the first time, I got so excited and couldn’t believe my eyes,” said Dr. Landschoff. “I immediately knew it was a special discovery, and I wanted to learn more about this exquisite life form."
Dr. Gill Mapstone, the first author of the study from the Natural History Museum in London, remarked on the significance of this observation. “These animals are rarely documented despite their ecological importance,” she said. The researchers employed underwater photography and videography to capture the siphonophore’s unmistakable pink tentacles and translucent body. Fascinatingly, their studies revealed that the siphonophore feeds on fish larvae, with one specimen even being recorded preying on a chaetognath, a predatory marine worm.
This discovery is pivotal not only for the species itself but also for understanding the rich tapestry of biodiversity endemic to the Benguela Ecosystem. The presence of R. eysenhardtii in False Bay might indicate shifts in the distribution of marine species, potentially driven by ocean currents or environmental changes that merit further investigation.
Researchers stress the urgency of studying siphonophores and other small marine invertebrates to better comprehend their roles within ocean ecosystems. Habitats such as the Great African Seaforest must be protected to sustain these species and the essential ecological services they provide.
This study forms part of the 1001 Seaforest Species initiative, a collaborative effort with the Save Our Seas Foundation. The project aims to document 1001 species, intertwining marine biology research with environmental storytelling to raise local and global awareness about biodiversity's critical role in human survival and the Great African Seaforest's status as a global biodiversity beacon.
Landschoff encapsulates the essence of this research: “Our findings underscore the need to safeguard marine biodiversity and improve documentation of rarely observed species."
As scientists continue to delve deeper into the ocean’s mysteries, discoveries like that of Rhizophysa eysenhardtii remind us of the breathtaking complexity of marine life waiting to be uncovered.