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dariusmarineblog · 3 months ago

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Sea Sponges!!

Sea Sponges are a type of invertebrate that are a member of the phylum Porifera (meaning bearing pores in Latin). There are about 8,500 species of sponge known to scientists but there is an estimated total of 25,000 species! They are known to have existed for up to 600 million years; putting them around for the period of time where our Earth was known as 'Snowball Earth', as the entirety of the planet froze over. It is said that when the carbon levels rose to an inhabitable level among the surface, as the carbon cycle worked with the ocean, many say that sponges helped the oxygen level below the ocean rise to livable conditions, making way for the animals of the Ediacaran Period to take over and thrive.

Role of Sponges For Other Creatures:

Many different species of fish that reside among coral reefs use sponges, an example being the Giant Barrel Sponge (Xestospongia muta), many fish use this sponge to deposit their eggs within it. Crustaceans such as the Sponge Crab (Dromiidae) will tear up and mold a living sponge into a portable shelter for it to adhere to its' back. It is a living and exceedingly effective shelter which plays both roles as camouflage and a source of chemical protection against predators due to the unappealing toxins sponges make to protect themselves. This is also supposed to be a case of mutualism*. The mobility the crab gives to the sponge, allowing it a higher advantage over its' cousins, overcoming the limitations of having a sessile lifestyle. During the crabs movements, the sponge gains access to more nutrient-rich waters and currents.

*Mutualism - A symbiotic relationship in which both organisms benefit from one another.

Anatomy of Sponges:

There are 3 types of morphology among sea sponges, such as;

Asconoids - A vase-like structure with a central cavity.

Syconoids - These are similar to asconoids in shape but they have folds within the body wall, amplifying the surface area, allowing a larger intake of food.

Leuconoids - These are an interconnected system of chambers and canals obtaining the largest surface area.

Some sponges bore* themselves into rocks, for example, Cliona celata. This distinct sponge is found worldwide within coastal waters, typically areas around 200m deep. Within the marine ecosystem, sights of this sponge indicate signs of pollution zones around the area.

Photo: https://irishwestcoastsealife.com/species/cliona-celata/

*Boring - Sponges that fabricate holes or perforations in the material in which they reside.

Some encrust* on the sea floor, dispersing over a substantial area, making them harder to remove and unlikely to be predated. For example, Hemimycale columella. This particular specie is reportedly found in copious seas/oceans, such as the Atlantic Ocean, the English Channel and the Mediterranean Sea.

Photo: https://www.marlin.ac.uk/species/detail/15

*Encrusting - Sponges that encrust on the sediment by forming a firm flat layer against the surface to bind the material together.

Some sponges erect*, constructing a stem-like formation, allowing them access to a plethora of nutrients within the water; though these sponges are more vulnerable to predators due to their foundations. An example of this is Aplysina fistularis (Also known as 'Yellow Tube Sponge' or simply just 'Yellow Sponge'). This specie is found in bountiful amounts around the Caribbean. This sponge was first reported by Prussian zoologist in 1766 named, Peter Simon Pallas.

Photo: https://en.wikipedia.org/wiki/Aplysina_fistularis

*Erect - These are sponges that grow vertically from the sea floor, building a long stem for support.

It's important to note that Porifera are classed as animals, not plants!! Even though they reproduce and survive rather similarly to plants. Sea Sponges have no central nervous system, no digestive system, no circulatory system and no organs!

Cells:

Sclereocytes secrete sharp, indigestible bone-like spicules* that give the sponge shape and fend off predators. These spicules foretell the consistency, and texture of the sponge - whether a species will be soft, rock-like or skeletal.

*Spicules - They are hard crystals made from either calcium carbonate (CaCO₃) or silica (SiO₄).

Archaeocytes are great phagocytic cells that swallow food particles. They also permit a sponge to revitalise itself and regrow from minimal cells available.

Choanocytes bring in flow of water and pump it around the sponges' canals. Sieve-like structures filtrate food particles and small organisms to supply the sponge with its' necessary nutrients. After this process has completed the water is then expelled from the osculum.

It is thought that sponges are able to pump 10,000 times of their own volume in water in just a single day! Within that same process, it provides a crucial service toward the ecosystem. They support with nutrient cycling, by making carbon (C), Nitrogen (N₂) and Phosphorous (P₄) bioavailable. They also play a supporting role in facilitating habitats for opposing marine life.

Sponges in The Deep:

Vast sponge gardens are distributed over the ocean floor, predominantly made up of the class Hexactinellida, also known as glass sponges. These fields of sponges aid in keeping deep sea creatures thriving. As much as they help other creatures, they also take away from them. Food is highly sparse within the deeps so the choanocytes have had to find new ways to adapt to these more difficult measures, finding ways of absorbing food more efficiently. An example being the Asbestopluma monticola*. This deep sea sponge has numerous microscopic hooks that line the skeleton. These hooks act almost like a spider's-web, capturing any small fish or crustaceans that get too close to its' proximity. Once the hooks have latched on and caught it, the sponge cells begin to engulf the food and digest it.

Photo: https://sanctuaries.noaa.gov/news/nov17/cataloguing-the-depths-of-monterey-bay-national-marine-sanctuary.html

* The Asbestopluma monticola is a carnivorous sponge that was discovered by scientists that work for the Monterey Bay Aquarium Research Institute back in 2014.

Another example is the harp sponge (Chondrocladia lyra), it has a very similar feeding pattern. This sponge is able to embed itself into the sea floor mud, using a root-like system called a Rhizoid.

Photo: https://reefbuilders.com/2012/11/06/chondrocladia-lyra/

Whilst these carnivorous sponges help support biodiversity by providing habitats and refugia, the sponges within the deep that continue their filter-feeding lifestyle execute a task called benthic-pelagic coupling*.

*Benthic-Pelagic Coupling - The exchange of energy, mass, or nutrients between benthic and pelagic habitats.

Sponges make this possible by suspension feeding; to achieve this they extend above the sea floor, and into the current flowing water; this is where they will consume plankton and create that specific link between the benthic zone and the midwater atop of it.

These deep water sponges cosmetics look very abnormal compared to their shallow equivalents. The reason for this is because each different class of sponge display depth-related contrasts to each other.

A simple example of this would be the Calcarea sponges as they are confined to the more shallow areas of the ocean because as you get deeper within the waters their calcium carbonate (CaCO₃) skeletal structures become too challenging to manufacture. The Hexactinellida skeletal species inhabit explicitly within the deeps. Residents of the Demospongiae species have a skeleton made entirely of silicon dioxide. This makes this species more plentiful than others. About 90% of all sponge species come from the Demospongiae class, as they colonize shallow and deep waters and also can be found thriving near chemosynthetic environments. Asbestopluma rickettsi is found flourishing around hydrothermal vents and clinging to rocks that surround them. This specific specie feeds on the chemosynthetic bacteria that bloom on the superheated vent fluids.

Threats:

There are a riot of threats that cause harm to these sea sponges, including, mass pollution, the rates of over-fishing, ocean acidification and of course, climate change. Many of these species are finding it strenuous and demanding to adapt, survive and reproduce through the rate at which the temperatures of the ocean are rising, disturbing the balance within the vast populations of Porifera. Sponge bleaching also can effect these species just the same as coral bleaching.

My Sources:

https://sigmaearth.com/climate-change-the-disappearing-sea-sponges/#:~:text=However%2C%20despite%20their%20ecological%20significance%20and%20fascinating%20biology%2C,temperatures%20and%20changing%20chemistry%20severely%20challenge%20their%20survival.

The Mysterious Realm of Deep Sea Sponges

How Earth's First, Unkillable Animals Saved the World

Interesting Facts About SEA SPONGES

https://www.inaturalist.org/taxa/131705-Aplysina-fistularis

https://european-marine-life.org/02/hemimycale-columella.php

https://www.inaturalist.org/taxa/117715-Cliona-celata

#biology #blog #climate change #marine biology #ocean life #marine animals #sea #porifera #sponges #sea sponge #first post #info

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