Sea Sponge Zooplankton

Sea sponges are widely distributed filter feeders in marine habitats, but scientists have only truly begun to understand the importance of zooplankton – tiny drifting creatures in the sea which form the foundation of the ocean’s food web – as part of the sponge’s diet. Zooplankton act as an important food source not only for sea sponges, but also for more charismatic species such as whales, sharks, turtles, dolphins and seabirds. In order to understand the impact of zooplankton on sponge populations, scientists have recently begun to conduct studies on the sponge-zooplankton interactions.

One notable study, conducted in 2014 by researchers from Florida Atlantic University, revealed that sea sponges filter food from the bottom environment by filtering zooplankton from the water column. This study showed that the presence of sponges increases the abundance of zooplankton.

Mikayla Culpepper, a marine biologist involved in the study, notes that it is likely that large numbers of sea sponges in an area causes an increase in nutrients that attract zooplankton and that the interaction between the two is an important part of food chain of the ocean and ecosystems. She explains that healthy populations of sponges are key to maintaining the health of the ocean and, if these species become too rare, the zooplankton populations would be impacted.

An additional study, conducted by the same research team, further revealed how sea sponges use zooplankton for food. It is believed that sea sponges use special catch-strategies – such as mucus nets or pumping – that allow them to capture and feed on large numbers of zooplankton at one time. Similarly, another study conducted in 2020 by The University of the Virgin Islands, St. Thomas, found that sea sponges harbor significant diversity of zooplankton, with many of the species having never been reported in previous studies. This suggests that a relationship between sponges and zooplankton exists beyond the predatory one, and that sponges also provide a safe environment for certain types of zooplankton.

Furthermore, a study conducted by a research team in 2018 in the North Atlantic revealed that sea sponges can significantly reduce zooplankton losses in areas near coral reefs, and that the sponge’s presence is related to higher zooplankton production associated with coral reefs. The research team suggests that more studies are needed to understand better these interactions and the full implications of changes in zooplankton levels for sponge populations.

Finally, a study conducted in 2020 by The University of North Carolina-Wilmington’s Marine Ecology and Fisheries Department concluded that up to 50% of a sponge’s daily food intake can include zooplankton, with the higher the densities of them in the environment, the more the sponge consumes. The study highlighted the importance of understanding the role of sponges in the ocean’s ecology.

Impact on Coral Reefs

Corals have a unique relationship with sponges that involves competition, commensalism, and predation. Corals compete for resources and prey upon sponges, while the sponges filter-feed on nutrients from the water column including zooplankton. The presence of sea sponges can drastically impact the coral reef ecosystem in which they inhabit. When sponges consume zooplankton, they reduce the amount of food available to the corals, which can lead to a decline in the growth of corals. Additionally, large amounts of filtering from sponges changes the composition of the water and can lead to algal blooms that can be toxic to corals.

In addition to competition for resources, sponges can also impact the health of coral reefs in other ways. For instance, sea sponges can produce toxins which harm corals and other species that inhabit the same environment. These chemicals can be released through their spicules ( tiny needle-like structures) or through their mucus which can stick to coral polyps. Furthermore, some sponges have been found to release antibiotics which can be detrimental to the health of coral reefs.

Coral reefs are among the most diverse and important ecosystems in the world. They are home to millions of species, from small invertebrates to large predators, provide food for coastal populations, and even protect shorelines from storms and erosion. For these reasons, the interactions between sponges and corals must be understood in order to ensure the health and longevity of coral reef ecosystems.

Threats to Sponge Populations

Sponges are some of the oldest complex animals on the planet, dating back about 600 million years. Despite their long history and importance to oceanic ecosystems, sea sponges are facing multiple threats that put their future at risk.

The most pressing threat to sponges is climate change. Rising sea temperatures can harm the delicate balance of sponge populations and could disrupt the sponge-zooplankton relationship. Furthermore, nutrient runoff from agricultural and industrial activity, ocean acidification, and over fishing of sponges for natural products are all potential threats. Additionally, habitat destruction caused by activities such as trawling, oil spills, coastal development, and dynamite fishing are all contributing to the decline in the number of sponges in oceanic ecosystems.

Moreover, the spread of invasive species can have a harmful effect on sponge populations. Invasive species can disrupt the balance between sponges and other marine organisms as they often compete for food and space. In some cases, these species may even prey upon sponges. For example, the red-tide organism, Ceratium furca, is known to feed on sponges and can quickly cause drastic declines in sponge populations.

The constant barrage of threats to sponge populations is making it more and more difficult for these species to survive. Scientists are striving to better understand the role that sponges play in oceanic ecology and the importance of zooplankton in the sponge’s diet in order to protect these important and ancient organisms.

Protection of Sponge Populations

Despite the threats to sponges, there are conservation efforts currently in place to protect these species. Organizations such as The Marine Conservation Institute are working to protect sponges through a variety of methods. These include identifying areas of high sponge diversity, mapping areas of natural sponge beds, and lobbying for increased protection of these areas.

Similarly, the International Union for Conservation of Nature (IUCN) has created a list of the highest priority locations for protection. These areas have been identified as having a large number of threatened or endangered sponges and other marine organisms, and are typically located in areas with high biodiversity. These locations are then used as the basis for the development of Marine Protected Areas (MPAs) which create legal protections to assure that sponges and other species are able to flourish.

In addition, research organizations such as The Deepwater Horizon Natural Resource Damage Assessment (DWH NRDA) have performed studies on the long-term effects of the Deepwater Horizon oil spill on sponge populations. The results of this research have been used to create plans to restore affected habitats and develop approaches to minimize long-term impacts to sponge and other marine organisms in the Gulf of Mexico.

Finally, The National Oceanic and Atmospheric Administration (NOAA) has developed a suite of informational and educational materials to help raise awareness about ocean life, and has also established reporting networks that allow anyone to report sightings of oil spills, ocean debris, or threatened species.

Conclusion

Given the complex relationship between sea sponges and zooplankton, it is clear that more research is needed on this relationship in order to fully understand the implications of changes in either species for oceanic ecology. Nevertheless, by taking action to preserve sponge populations and their habitats, scientists and conservationists alike can help protect our ocean’s biodiversity and ensure a healthy future for our planet.

Susie Romaine

Suzie S. Romaine is an experienced marine biologist and author specializing in sea sponges. When she isn’t researching or writing about sea sponges, Suzie enjoys swimming, diving, and playing with her pet seahorse, Squirtle.

Leave a Comment