Discover the remarkable marine animal forests found around Wellington’s coast, which are thriving biodiversity hotspots that play a crucial role in maintaining water quality and supporting the local marine food chain.
The Unexpected Oasis
Surprising find: Marine animal forests discovered in the shallows of Te Whanganui-a-Tara Wellington, around which overpass the motorways and rails go their way. Constructed by massive numbers of invertebrates — sponges, horse mussels, and brachiopods – they serve as a form of habitat creation that results in a veritable underwater garden resembling the richness found in many terrestrial forests.
These unique communities of organisms are now recognised globally as biodiversity hotspots, and are located right at the city’s doorstep, explained lead researcher Professor James Bell from Te Herenga Waka—Victoria University of Wellington. Using footage from Seascape Surveys, the research team led by Dr. Valerio Micaroni and Dr. Francesca Strano have discovered several animal forests in Wellington Harbour, some as shallow as 15 meters, alongside others along the Kāpiti Coast and Mana Island.
The Vital Role of Shallow-Water Ecosystems
What is also surprising about finding these animal-rich ecosystems in only 20 meters of water, is that this area normally contains seaweeds. Dr Micaroni said it was staggering that the scientists found one directly next to an urban area as they are usually in deeper, more remote locations.
The sponges that largely comprise these forests are essential to the health of the local marine ecosystem. They recognized a huge potato sponge (Suberites australiensis) growing to a diameter of more than 40 centimeters and forming dense beds. The fauna are represented by two species, 9 rich invertebrate groups, and four ecological invertebrate units, Mollusca: Gastropoda (12%) and Bivalvia (13%), Polychaeta Oligochaeta Hydrozoa Anthozoa Octocorallia Ascidiacea Bryozoa Porifera respectively taxonomic outline. including Rhodophyta red algae as well as one sponge new to the science.
Additionally, the sponge beds in the harbor total an area of 120,000m2 and can filter approximately 500 million to 1 billion liters of water per day. They play an important role in filtering the water column and transferring nutrients and organic matter from the water to the sediment, which contributes to overall water quality and supports benthic food web. Despite their ecological significance, these shallow water forests are, for the most part, unprotected or only weakly protected and have been subject to a range of threats including climate change (alterations in ocean circulation affecting water temperature), fisheries (dredging), on-land activities generating sediments that suffocate coral-dwelling sponges; pollution.
Conclusion
The research has identified these remarkable marine animal forests in the shallow waters around Wellington as important repositories for biodiversity and ecology from a relatively unknown and understudied group of fragile ecosystems. Although they are vital components that help to maintain water quality and the local marine food web, 75 percent of them have not been safeguarded and they are increasingly threatened due to human activities. This project highlights the pressing need to conserve these hidden gems and prevent the loss of biodiversity in forgetting/lost yet unique faunal communities.
