#marine sponge

[critter-of-the-day]

22nd of July 2025: Phorbas tenacior

We’re keeping with the marine theme, though now travelling to the Mediterranean: here is Phorbas tenacior, a type of sea sponge. They can found at around 25 metres depth [1], though the sublittoral zone with which they are generally associated [2] can reach depths of up to 150 or 300 m [3].

Their reproductive phase lasts for 6 months, beginning around April or May. This phase is however pretty evenly segmented between the release of egg cells, the development of embryos, and the existence of larvae. Unlike some other types of sponges, their larvae have non-directional swimming and are generally smaller, indicating a shorter larval lifespan [2].

Aside from one paper on their reproduction, the other research surrounding them seems to be more focussed on the bacteria that live within their thin, crusty layers [3][4] (note that their growth patterns have been described as ”thinly encrusting” [2]; I am not needlessly dissing them or anything).

Sources: [1] [2] [3] [4] [Image] 

[fuckyeahaquaria]

Bargibant’s Seahorse | Hippocampus bargibanti

[fuckyeahaquaria]

Pontohi Pygmy Seahorse | Hippocampus pontohi

The Pontohi Pygmy Seahorse was first discovered in 2003 by a local guide in Bunaken National Park in Indonesia and officially described in 2008 -- so it is a recently discovered species. While other pygmy seahorses prefer specific hosts, the Pntohi hangs out in between small algae and hydroids, which means basically everywhere along walls and rocks. 

[critter-of-the-day]

12th of August 2026:

The image above may or may not be of Clathria aruensis, as it was labelled as an unidentified species of Clathria. However the only more specific depiction I could find of them was a diagram of their spicules from 1912, so I think this image is a pretty good stand-in.

They are a sponge found in the Arafura Sea, which is the sea between Australia and New Guinea. While the exact location where they were first discovered is unknown, it was somewhere near the Aru Islands. They form a thin crust on small rocks, and are a yellow-ish grey colour when preserved in alcohol [1].

They are frequently associated with polychaetes, meaning they’re inhabited by bristled marine worms. These worms also appear to stimulate antibacterial activity within them. One study which compared them and five other sponge species in the area found C. aruensis to have the highest antibacterial activity among them, when inhibiting Escherichia coli, Staphylococcus aureus, and Pseudomonas aerophoba. The range at which they inhibited them (3-9 mm) still categorised it within the low to medium inhibition zone though [2].

Sources: [1] [2] [Image by Bernard Picton]

[critter-of-the-day]

24th of June 2026: Neopetrosia problematica

Okay I promise not all critters this week are marine invertebrates, but here is Neopetrosia problematica, a sponge from Monterey Bay in California, USA [1].

While they themselves feed through water filtration [2], they can easily fall prey to the nudibranch Diaulula sandiegensis, as indicated by faecal analysis [3].

In one study comparing how good different sponges were at growing from suspended cells back into full sponges, they performed the worst from the 7 sponges tested. They formed primary aggregates in fewer than half of the trials (all the other sponges had success rates of at least 70%), and formed no fully fledged sponges. The second criterion was rather uncommon though, with only 2 out of the 7 having any success there [4].

Despite my best efforts I haven’t actually been able to tell what makes these sponges problematic. One study did mention that their irregularity in shape meant their surface area and volume had to be estimated with triangles, rather than using a singular osculum and multiplying it by the number of oscula, as they had done with other sponges in the study [2]. However, their etymology seems to be reserved for the Stanford students and faculty who actually have access to Max Walker de Laubenfels’ doctoral thesis which originally described these guys in 1929 [5].

Sources: [1] [2] [3] [4] [5] [Image] 

[unbfacts]

[elizastudieslife]

Drawing of a Marine Sponge

12-01-2019

Started this up a little bit ago, and finally finished it! Took less than 3 hours, and I'm happy with how it turned out.

I'm so happy I decided to take marine biology this year.

[heycalacademy]

Venus' flower basket / CAS-IZ 173148

Scientific name: Euplectella aspergillum  Locality: PHILIPPINES: Negros Island Collector: Angel Alcala Identified by: R. Van Syoc 15 Nov 2005 Department: Invertebrate Zoology & Geology, image © California Academy of Sciences