Sponges: Pollution's Unseen Victims And Their Fight

Sponges are filter feeders that play a crucial role in maintaining the health of aquatic ecosystems. However, their presence is sensitive to water conditions, indicating that they are vulnerable to pollution. Sponges can absorb and accumulate various pollutants, including pesticides, lead, bacteria, and microparticles such as microplastics and textile fibres. This accumulation occurs through their filter-feeding behaviour, which can lead to high concentrations of pollutants in their tissues. The impact of pollution on sponges is a growing concern, especially with the increasing presence of microparticulate pollutants in our oceans. The ability of sponges to absorb and retain these pollutants makes them potential candidates for biomonitoring and bioremediation, where they can be used to assess pollution levels and restore water quality.

Sponges can absorb pesticides, lead and bacteria

Sponges can absorb pesticides, lead, and bacteria, and they are being considered for use in cleaning up Europe's coastline. Sponges are filter feeders, and they can filter between two and 20 cubic metres of water per kilogram of body weight every day. This makes them very effective at absorbing contaminants.

Sponges are being studied for use in a process called bioremediation, where organisms are used to remove pollutants. They can absorb pesticides, lead, and dangerous bacteria, and they can also filter out specific bacteria that kill shellfish, such as E. coli and Vibrio aestuarianus.

Sponges are also being considered for use in biomonitoring, which is when local organisms are collected and analysed to determine their level of exposure to pollutants. Sponges can withstand high levels of pollution and can live in contaminated environments, making them ideal bioindicators for persistent pollutants.

In addition, sponges can help protect other organisms from certain pollutants. For example, a bacteria that lives inside the sponge Theonella swinhoei protects the sponge from arsenic poisoning by converting the toxic metal into a non-harmful substance. This process also stops the arsenic from building up in animals that eat the sponges.

Sponges can be used to soak up pollutants on an industrial scale

Sponges are incredibly versatile, having been used by humans for thousands of years for cleaning, painting, and even as contraceptive devices. They are also highly effective at absorbing and accumulating pollutants, which makes them ideal for use in tackling pollution on an industrial scale.

Sponges are filter feeders, meaning they can filter a large volume of water and are therefore able to accumulate pollutants from the environment. This makes them useful bioindicators of pollution levels. For example, sponges can be used to indicate the presence of polycyclic aromatic hydrocarbons (PAHs), which are produced by the incomplete combustion of organic matter, such as fossil fuels and wood. PAHs are among the most frequently detected persistent organic pollutants in marine coastal areas. Sponges can also indicate the presence of heavy metals and other contaminants in the water.

The ability of sponges to absorb and accumulate pollutants means they could be used on an industrial scale to soak up pesticides, lead, and even dangerous bacteria from Europe's coastline. This process is known as bioremediation, where organisms are used to remove pollutants. Sponges are particularly effective at filtering out lead and biological agents, including the bacteria E. coli and Vibrio aestuarianus, which kill shellfish.

In addition to natural sponges, scientists have also developed synthetic sponges that are effective at soaking up microplastics. These biodegradable sponges are made from starch and gelatin and can remove up to 90% of microplastics in tap water and seawater. The structure of the sponge can be adjusted to make it more or less porous, which affects the size of the particles it can collect. These synthetic sponges could be used in wastewater treatment plants or food production facilities to filter out microplastics.

Overall, sponges have a high capacity for absorbing and accumulating pollutants, making them ideal candidates for use in industrial-scale pollution cleanup efforts.

Sponges are bioindicators of microparticulate pollutants

Sponges were analysed using traditional histological methods, advanced light microscopy, and Raman spectroscopy. The results showed that sponges accumulated and embedded very fine sediment fractions, absent in the surrounding sand. This indicates that sponges can act as efficient sediment traps, recording the diversity of matter in the ambient water.

Sponges were found to have accumulated a range of different particles, including degraded man-made products such as polystyrene, cotton, titanium dioxide, and blue-pigmented particles. The uptake of particles by sponges appears to be independent of the material type, suggesting that the fluctuation in material ratios is due to the spatial variation of surrounding microparticles.

Sponges have a strong potential to biomonitor microparticulate pollutants. They can provide a unique estimate of local micro-pollution applicable to the immediate fauna. This makes them ideal bioindicators as they are sessile animals with a wide geographic spread.

Sponges can be used to monitor man-made pollution in marine environments

Sponges are also able to filter large volumes of water. One kilogram of sponges can process over 24,000 litres per hour. This means that they can be used to monitor the levels of pollutants in the water. For example, sponges have been used to monitor the levels of polycyclic aromatic hydrocarbons (PAHs) in the water. PAHs are a class of compounds with more than 100 different forms, and they are found naturally in petroleum products and are also produced from the incomplete combustion of organic matter, such as fossil fuels and wood. PAHs are among the most frequently detected persistent organic pollutants in marine coastal areas and, as such, warrant consistent monitoring.

Sponges can also be used to monitor heavy metal pollution. They invariably filter a large volume of seawater and potentially accumulate heavy metals and other contaminants from the environment. As sponges can live in the same location for many years, they have the capability to accumulate anthropogenic pollutants such as metals over long periods.

In addition, sponges can be used to monitor pollution from pesticides, medicines, and nanoparticles. They have been found to absorb these substances better than oysters in laboratory tests. This suggests that it would be possible to reduce the accumulation of certain chemical and biological pollutants in marine sediments and water through bioremediation by sea sponges.

Sponge-associated bacteria can indicate heavy metal pollution

Sponges are filter feeders that can filter a large volume of water and accumulate heavy metals and other contaminants from the environment. They are sessile marine invertebrates with a modular body organization, meaning they can live in the same location for many years and thus have the ability to accumulate anthropogenic pollutants such as metals over long periods.

Sponges host a large number of microorganisms within their tissues, and bacteria in seawater have been established as biological indicators of contamination. A study by Joseph Selvin et al. investigated the heavy metal resistance pattern of sponge-associated bacteria to develop suitable biological indicators. The bacteria associated with the marine sponge Fasciospongia cavernosa were evaluated as potential indicator organisms. The bacteria showed resistance against tested heavy metals, with Cd and Hg being the most resistant heavy metal pollutants in the Gulf of Mannar biosphere reserve.

Another study by Adi Lavy et al. examined the potential roles of microorganisms in arsenic and barium cycles in the sponge Theonella swinhoei, which is known to accumulate high levels of these metals. The study found that a single sponge symbiotic bacterium, Entotheonella sp., is responsible for arsenic and barium accumulation within the host. These bacteria mineralize both elements on intracellular vesicles, potentially acting as a detoxifying organ for the sponge.

Sponge-associated bacteria can, therefore, indicate heavy metal pollution by accumulating and resisting heavy metals, making them suitable candidates for biomonitoring and developing indicator models for pollution studies.

Frequently asked questions