Sea Sponge Survives Polluted Spanish Port
A 'chicken liver' sponge species thrived and reproduced in a polluted Spanish harbor, suggesting it could be a natural tool for cleaning ports.
A humble sea sponge has survived for 15 months in the polluted waters of Marina Palamós harbour on Spain's Costa Brava. The finding, from a study led by sponge biologist Manuel Maldonado of the Spanish National Research Council, suggests these ancient animals could help clean up some of the world's most degraded marine environments.
Only one of five tested sponge species endured the harbour's harsh conditions. The chicken liver sponge, also known as the kidney sponge, saw nearly 92% of its transplanted specimens survive. Researcher Carlota Escarré, who monitored the organisms, called the result a surprise. Some of the transplanted individuals even reproduced asexually, increasing their numbers from 24 to 40.
Testing Survival in a Harsh Environment
The research team began their work nearly two years ago to test if these filter feeders could live in a harbour. Ports accumulate pollutants like oil and rubbish, host invasive species, and suffer from noise, making it hard for marine life to thrive. Maldonado's team selected five common coastal species known to be resilient. The scientist noted that you don't want to use a very sensitive or protected species; it has to be something you can handle and transport.
The organisms were collected from a site about 18 miles south of the harbour. Escarré then conducted regular dives over 15 months to check on them using underwater photography. The survival rates varied dramatically between species.
A Potential Tool for Bioremediation
Sea sponges are filter feeders, capable of processing enormous volumes of water. They can remove pollutants and cycle nutrients. Their structures also enhance biodiversity by providing habitat for other marine creatures like worms and crustaceans. The arrival of red starfish in the study area after the transplantation hints at this effect.
Andreu Santín Muriel, a marine biologist at the University of Porto not involved in the study, says the research confirms what experts have long believed. He argues that these animals provide more ecosystem services than corals but receive far less attention and funding.
Cautious Optimism and Future Research
Experts urge caution, noting the study's limited scope. David Amptmeijer, a doctoral researcher at Helmholtz-Zentrum Hereon, pointed out it is unclear if the same organisms would survive in a very different harbour, such as one in Maine. While he sees potential, he says more research is needed to understand how they interact with specific pollutants.
Maldonado suspects the successful species' success is linked to its diverse internal community of symbiotic microorganisms, which may help it process pollutants like ammonium. His team plans to investigate this after the summer. They will continue monitoring the transplanted animals for several years and have proposed a new project combining them with oysters, another powerful filter feeder.
Santín Muriel reflects on the ancient lineage of these creatures. He noted they have survived at least five mass extinctions. This history suggests they may already possess natural solutions to modern pollution problems. The biologist added that we tend to look more to technology to solve environmental pollution, but marine organisms most likely have already developed toolkits that could help us clean the oceans.
