Chicken Liver Sponge Survives Polluted Spanish Port

A resilient sea sponge has survived for over a year in the polluted waters of a Spanish harbour, raising hopes for a natural cleanup method. Scientist Manuel Maldonado and his team from the Spanish National Research Council transplanted several sponge species into Marina Palamós on the Costa Brava to test their hardiness.

Only one species, the chicken liver sponge (Chondrosia reniformis), endured the harsh conditions. Nearly 92% of its transplanted specimens survived the 15-month study. Some even reproduced asexually, increasing their numbers from 24 to 40.

Testing Survival in a Harsh Environment

The research aimed to prove sponges could live in harbours, among the world's most disturbed marine environments. Pollution from rubbish, oil, invasive species, and noise makes it difficult for marine life to thrive. Lead researcher Manuel Maldonado explained that they tested different Spanish species with the idea of finding some that could survive in a harbour environment.

The team selected five common coastal sponge species, chosen for their abundance and resilience. They were collected from a site roughly 18 miles (30km) south of the harbour. Co-author Carlota Escarré monitored their health through regular dives over 15 months.

One Clear Survivor Emerges

The results showed a stark contrast in survival rates. While other transplanted species shrank and died, the chicken liver sponge proved remarkably robust.

Carlota Escarré said the outcome was a surprise for all of them. The organism's success was followed by another promising sign: red starfish began settling in the area, suggesting the sponges could start attracting other marine life.

Potential for Bioremediation and Habitat Recovery

Sea sponges are ancient ecosystem engineers that filter pollutants and cycle nutrients. Their ability to enhance biodiversity by providing habitat for worms and crustaceans points to their potential for renaturalising ports. Independent marine biologist Andreu Santín Muriel endorsed this view, stating that sponges are excellent potential species for bioremediation and habitat recovery.

He contrasted the attention given to corals with the overlooked role of sponges. Santín Muriel noted that sponges provide more ecosystem services, yet they are not as attractive, so they have received way less money.

Cautions and Future Research

Experts caution that the findings, while promising, are localized. David Amptmeijer, a doctoral researcher not involved in the study, noted it is unclear if these organisms could survive in a harbour with a different climate, like one in Maine. He believes more research is needed to understand how they interact with specific pollutants.

Maldonado suspects the success of the chicken liver sponge is linked to its diverse microbiome, which allows it to process compounds like ammonium. His team plans to investigate this after the summer. They will continue monitoring the sponges for several years and have proposed a new project combining them with oysters, another powerful type of filter feeder. Santín Muriel noted that these animals have survived for over 600 million years through multiple mass extinctions, suggesting they may already possess natural solutions to modern pollution problems.