A sea sponge is a type of marine invertebrate that belongs to the phylum Porifera. Sea sponges are among the simplest and oldest animals on Earth, with a fossil record dating back to the Cambrian period. There are approximately 5,000 known species of sea sponge, which can be found in all oceans of the world at depths ranging from the intertidal zone to over 10,000 meters.
Sea sponges are characterized by their porous bodies and ability to filter water for food using specialized cells called choanocytes. Choanocytes line the inner chambers of a sponge and beat their whip-like flagella to create water currents that bring food and oxygen into the Sponge through its tiny pores. The majority of sea sponges are sessile, meaning they attach themselves to substrates on the seafloor and do not move throughout their lifetime.
Sea sponges come in a wide variety of shapes and sizes, from small encrusting growths less than 2 centimeters in diameter to massive barrel-shaped sponges over 2 meters tall. The vast majority of sea sponges are hermaphrodites, meaning they have both male and female reproductive organs, but some species are gonochoristic (either male or female). Sponges reproduce both sexually and asexually depending on environmental conditions; when conditions are favorable they will reproduce sexually by releasing eggs and sperm into the water where fertilization occurs. Asexual reproduction occurs via fragmentation; when a piece of sponge breaks off it can grow into an entirely new individual Sponge.
Despite being simple animals, sea sponges play an important role in marine ecosystems as both primary producers and detritivores. As primary producers, they provide food and shelter for other organisms in their community through photosynthesis performed by symbiotic algae living within their tissues. As detritivores ,they consume large amounts of dissolved organic matter (DOM) which would otherwise accumulate in seafloor sediments . This consumption helps maintain water quality by preventing DOM build up ,and also enriches sediments with nutrients essential for benthic communities .