Tag Archives: sea creatures

Friday Fellow: Brown Mussel

by Piter Kehoma Boll

Until now, the mollusks featured here included a chiton, a cephalopod and two gastropods. So it is time to bring a bivalve. And what would be better than showing you a common mollusk from the South Atlantic Ocean?

Living on rocky shores around South America and Africa, our fellow is called Perna perna, or populary brown mussel. In places where it lives, it can be found in great concentrations, sometimes covering large areas of rocks. It usually measures about 90 mm in length, but some larger specimens may reach up to 120 mm. The increased surface area on the rocks they occupy attract other rock-living marine species, such as barnacles, limpets, snails and algae.

Perna_perna

Some specimens of Perna perna growing on an oyster in South Africa. Photo by Bernadette Hubbart.*

The brown mussel is a filter feeder, as most bivalves, feeding on suspended organic matter, as well as on small microrganisms, such as phytoplankton and zooplankton. As a prey, it is eaten by a variety of animals, such as sea birds, crustaceans and mollusks. Humans also consume it in both South America and Africa. Its ingestion, however, must be cautious, as it may contain toxins from dinoflagellates that it ingested, as well as heavy metals from water pollutants.

Spread through the world by humans after attaching itself on ships, the brown mussel has become invasive in other parts, especially in the Gulf of Mexico, and it continues to increase its occupied area. This can have deleterious effects both ecologically and economically, as it may displace native species and also cause damage to human equipments. It is, therefore, one more species that became a problem due to us, humans. And the damage will not be easy to be repared.

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References:

Ferreira, A. G.; Machado, A. L. S.; Zalmon, I. R. (2004) Temporal and spatial variation on heavy metal concentrations in the bivalve Perna perna (LINNAEUS, 1758) on the northern coast of Rio de Janeiro State, Brazil. Brazilian Archives of Biology and Technology 47(2): 319–327. http://dx.doi.org/10.1590/S1516-89132004000200020

Holland, B. S. (2001) Invasion without a bottleneck: microsatellite variation in natural and invasive populations of the brown mussel Perna perna (L). Marine Biotechnology 3, 407–415. https://dx.doi.org/10.1007/s1012601-0060-Z

Wikipedia. Perna perna. Available at: < https://en.wikipedia.org/wiki/Perna_perna >. Access on October 21, 2017.

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Friday Fellow: Common Latticed Sponge

by Piter Kehoma Boll

Let’s go back to the sea and to our distant animal relatives, the sponges. Today I’m bringing a calcareous sponge with a nice appearance, Clathrina clathrus, who I decided to call “the common latticed sponge”.

Found in the Mediterranean Sea and the European coast of the Atlantic Ocean, the common latticed sponge has a yellow color and about 10 cm in diameter. It is formed by a tangle of tubes that somewhat resemble a twisted lattice or something like that.

450px-clathrina_clathrus_scarpone_055

A specimen of Clathrina clathrus with its latticed appearance. Photo by Wikimedia user Esculapio.*

The shape and size of the specimens is quite variable, changing in a matter of hours by expansion, contraction and folding of structures and cells. In the same way, specimens often fragment into smaller ones or merge into larger ones, so that individuality is a dynamic process.

Recently, the common latticed sponge has revealed to contain some compounds, known as clathridimines, that show antimicrobial activities against Gram-positive and Gram-negative bacteria, as well as against the yeast Candida albicans. These compounds may be produced by the diverse community of bacteria that live in close association with this sponge, a community that is yet very little known.

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References:

Gaino, E.; Pansini, M.; Pronzato, R.; Cicogna, F. (1991) Morphological and structural variations in Clathrina clathrus (Porifera, Calcispongiae). In.: Reitner, J.; Keupp, H. (Eds.) Fossil and Recent Sponges. Springer-Verlag, Berlin. pp. 360-371.

Quévrain, E.; Roué, M.; Domart-Coulon, I.; Bourguet-Kondracki, M.-L. (2014) Assessing the potential bacterial origin of the chemical diversity in calcareous sponges. Journal of Marine Science and Technology 22(1): 36-49.

Roué, M.; Domart-Coulon, I.; Ereskovsky, A.; Djediat, C.; Perez, T.; Bourguet-Kondracki, M.-L. (2010) Cellular localization of clathridimine, an antimicrobial 2-aminoimidazole alkaloid produced by the Mediterranean calcerous sponge Clathrina clathrusThe Journal of Natural Products 73(7): 1277–1282.

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Friday Fellow: Hummingbird Bobtail Squid

by Piter Kehoma Boll

If you are digging through the sand at the bottom of the clear tropical waters around Indonesia and the Philippines, you may end up finding a colorful little creature, the hummingbird bobtail squid, Euprymna berryi, also known as Berry’s bobtail squid.

Euprymna_berryi

A beautiful specimen photographed in East Timor. Photo by Nick Hobgood.*

Measuring about 3 cm if male or 5 cm if female, the humminbird bobtail squid is actually more closely related to cuttlefish than to true squids. Its body has a translucent skin marked by many black chromatophores, and to the human eye the animal seems to have a color pattern formed by a blend of black, electric blue and green or purple dots.

During the day, the hummingbid bobtail squid remains most of the time buried in the sand, coming out at night to capture small crustaceans, which it hunts using a bioluminescent organ in its gill cavity.

In some areas around its distribution, the hummingbid bobtail squid is captured and sold in small fisheries, but as the data on the distribution and population dynamics of this species are very poorly known, there is no way to say whether it is vulnerable or endangered in any way. As a result, it is listed as Data Deficient in the IUCN Red List.

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ResearchBlogging.orgReferences:

Barratt, I., & Allcock, L. (2012). Euprymna berryi The IUCN Red List of Threatened Species DOI: 10.2305/IUCN.UK.2012-1.RLTS.T162599A925343.en

Wikipedia. Euprymna berryi. Available at <https://en.wikipedia.org/wiki/Euprymna_berryi&gt;. Access on March 8, 2017.

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Friday Fellow: Branching Vase Sponge

by Piter Kehoma Boll

A fascinating group of animals that has not yet joined the Friday Fellows are the sponges. Different from all other animals, sponges have a unique body structure that behaves more like a plant or fungus. They grow in irregular or radial ways and are usually branched. More than that, they have thousands of small mouths along their bodies, called pores, that suck water from the environment in order to filter food from it.

But let’s talk about our species. Living in the Caribbean Sea, its name is Callyspongia vaginalis, commonly known as branching vase sponge. Its usual shape is that of a tube or set of tubes, sometimes branched, that may reach several centimeters in length and usually abour 3 cm in diameter. The color may vary from pink or lavender to duller colors, such as brown or gray.

callyspongia_vaginalis

A lavender pipe of Callyspongia vaginalis. Photo by Mark Rosenstein*.

As most sponges, the branching vase sponge feeds on small particles and microorganisms that it filters from water. As the concentration of particles in the water increases with depth, organisms growing deeper usually grow faster due to the higher food availability.

The main predators of the branching vase sponge are fishes. They actually act more like herbivores eating plants, as they don’t eat the whole sponge and usually do not kill it, but bite its surface, taking off pieces.

callyspongia_vaginalis2

A large and branched individual of the branching vase sponge. Photo by Paul Asman and Jil Lenoble.**

Bristlestars, especially of the genus Ophiothrix, such as Ophiothrix lineata, are frequently found living inside the main cavity of the sponge. There, these animals find shelter from predators and, at night, when the environment is safer, they extend their arms outside and clean the sponge from large organic particles, feeding on them. It’s a mutually benefitial association.

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ResearchBlogging.orgReferences:

EOL – Encyclopedia of Life. Callyspongia vaginalis. Available at <http://eol.org/pages/1163688/overview&gt;. Access on January 12, 2017.

Hendler, G. (1984). The Association of Ophiothrix lineata and Callyspongia vaginalis: A Brittlestar-Sponge Cleaning Symbiosis? Marine Ecology, 5 (1), 9-27 DOI: 10.1111/j.1439-0485.1984.tb00304.x

Hoppe, W. (1988). Growth, regeneration and predation in three species of large coral reef sponges Marine Ecology Progress Series, 50, 117-125 DOI: 10.3354/meps050117

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Friday Fellow: Royal sea star

ResearchBlogging.orgby Piter Kehoma Boll

In order to celebrate the 5oth Friday Fellow, which was posted today, I decided to bring you an extra Friday Fellow! Afterall, there are plenty of interesting lifeforms to be shown.

As I have never presented you any echinoderm, I thought it would be interesting to start the second group of 50 FFs with one of them. So I’ve chosen the royal sea star (Astropecten articulatus).

Beautiful colors, don't you think? Photo by Mark Walz.*

Beautiful colors, don’t you think? Photo by Mark Walz.*

Found in waters from 0 to 200 m deep the West Atlantic coast from New Jersey to Uruguay, the royal sea star may reach around 20 cm in diameter and is easily identified by its color. Dorsally it has a series of dark blue to purple granulose papilae and is lined by orange marginal plates with supermarginal white spines that give it a comb-like appearence, hence the name “Astropecten“, meaning “star-comb”.

As most starfishes, the royal starfish is a predator. It feeds mainly on small and medium-sized mussels and ingests the prey intact, digesting it inside its mouth. As it is unable to digest food extraorally (outside its mouth) it cannot feed on anything that cannot be ingested whole.

Most of its activity occurs at dawn and dusk, which may be inversely related to the activity of predatory fish, as those are usually more active during the day.

Being a considerably common starfish, you may easily find one while walking on the beach, provided that the beach is at the right place.

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References:

Beddingfield, S., & McClintock, J. (1993). Feeding behavior of the sea star Astropecten articulatus (Echinodermata: Asteroidea): an evaluation of energy-efficient foraging in a soft-bottom predator Marine Biology, 115 (4), 669-676 DOI: 10.1007/BF00349375

Wikipedia. Astropecten articulatus. Availabe at: <https://en.wikipedia.org/wiki/Astropecten_articulatus >. Access on July 28, 2016.

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