Female sponges have a chance occurrence of pulling sperm from the same species, leading to reproduction.
Natural predators of sponges are scarce despite their soft-bodied structure and nitrogen-rich tissue that can be an attractive food source.
Predators are deterred by the sponge's chemical defenses.
Sponges have evolved toxins over 600 million years to fend off these predators.
Sponges pass large volumes of water through their bodies, filtering out pathogens and particulates.
A sponge can filter the equivalent volume of a room's water in one day.
This constant water flow exposes them to pathogens, necessitating advanced chemical protections.
Sponges are chemically rich, leading to significant interest in pharmaceutical bioprospecting.
More medicinal compounds have been sourced from sponges than from all other marine organisms combined.
Some sponges host symbiotic microbes that aid in filtering out harmful materials, preventing digestion of beneficial organisms like their own species' sperm.
Sponges provide insights into the evolution of immune systems due to their filtering mechanisms and interactions with pathogens.
Sponges are vulnerable to specific pathogens and environmental stressors such as:
Low/high salinity levels
Temperature fluctuations
Excess phytoplankton which can clog their filtration systems
Physical damage from storms
Jellyfish, which possess stinging cells, are generally avoided by most sponges, and their high water content makes them less concerning in terms of detoxification.
Sea turtles feed on a select few types of sponges, particularly those with silica spicules instead of toxic chemicals.
Their digestive systems are tolerant of this roughage, but they do not consume most sponge species.
Instances of illness in South Pacific villages after eating sea turtles may suggest consumption of toxic sponges accumulated within the turtles, although this remains anecdotal.
Sponge species display specific temperature tolerances based on their native environment, e.g., Antarctic sponges cannot survive if relocated to coral reefs or other drastically different temperatures.