I found a super big dwarf cushion star (P. exigua) while doing some field work on intertidal molluscs at Long Bay, Malabar. Look at the second picture for size comparison (hand for scale)! Such cuties.
Also known as the Chocolate Chip or Knobbed Sea Star, the horned sea star is a species of oreasterid sea star that occurs in warm, shallow waters in the Indo-Pacific. Like many other sea stars P. nodosus is an opportunistic carnivore and will feeds mainly on sessile invertebrates and other slow moving invertebrates. The “horns” which give P. nodosus its common name are used mainly to deter potential predators by making it look less palatable.
MORE LOSERS THAN WINNERS IN FUTURE WARM ANTARCTICA
The waters of the Southern Ocean are projected to warm over the coming century, with potential adverse consequences for native cold-adapted organisms. An average warming of 0.4 of a degree is predicted by 2099, this warming will not be enough to allow any species from other neighbouring continents to invade or colonise Antarctica, it will cause the unique local species to change their distribution.
The seafloor animals of the Southern Ocean shelf have long been isolated by the deep ocean surrounding Antarctica and the Antarctic Circumpolar Current, with little scope for southward migration. How these largely endemic species will react to future projected warming is unknown British Antarctic Survey researchers examined the potential distribution of 963 species of seafloor marine invertebrates under a warming scenario produced by computer models. According to the study, while some species in some areas will benefit, 79% of the species native to the region will lose out, facing a significant reduction in suitable temperature habitat.
These findings highlight the species and regions most likely to respond significantly (negatively and positively) to warming and have important implications for future management of the region.
Photo: Antarctic Sea urchin (Sterechinus neumayeri), British Antarctic Survey (BAS)
Ocean acidification and the development of calcifying organisms
What is ocean acidification? Increased CO2 results in a lowering of pH in the ocean, making it more acidic. Since cold water absorbs CO2 more easily than warm water, polar regions are more at risk.
How does it impact calcifying organisms? It decreases the saturation state of CaCO3 (calcium carbonate), meaning that animals which produce calcium carbonate shells or skeletons (such as molluscs, echinoderms, and corals) will be severely impacted. Their skeletons and shells may become stunted, deformed, and more porous (see below).
Pictured Above: Echinoderm larvae from tropical, temperate and polar sea urchins under different pH levels (note: the lower the pH, the more acidic). This figure shows that increasing acidity significantly inhibits their development (Byrne et al., 2013). Scale bars = 200 µm.
Whats going to happen? - Species extinctions - A decrease in biodiversity, species richness, and biomass of coral reefs - Food webs will be simplified - Habitat complexity will be reduced - A shift from coral reefs to seagrass/algae based ecosystems in some areas
Also known as the Cookie Dough Sea Cucumber, the chocolate chip sea cucumber is a species of Stichopodid sea cucumber which is commonly encountered throughout the western Atlantic Ocean, occurring from North Carolina to the Caribbean and south to Brazil, individuals also occur in western-central Africa. Chocolate chip sea cucumbers typically occur in shallow waters with a wide variety of substrates (sand, mud, rock, etc..). Like most sea cucumbers, I. badionotus is a detritivore combing the sea floor for any detritus it encounters.
Field trip to Bodega Bay (1/26/14) Finale: My favorite pictures from the day
1) Bat Star and Pisaster right next to each other, with Pisaster’s tube feet visible. Pisaster was more prevalent where there more waves, since it mostly ate mussels, while the bat stars ate more algae, which grew with less waves, so it was cool to see them both right next to each other
2) Scyphozoan Jelly on the mudflats. The red spots are eyespots. We thought the fluffy tan things in the middle might be the oral arms retracted in for low tide. We also thought it (and all the others we found) were dead, but then we put them in a bucket and they were fine. (One thing I learned on this field trip was that cnidarians can in fact survive on the coast at low tides.)
…a species of Loveniid sea urchin which boasts a mostly cosmopolitan distribution. Where it occurs in temperate seas in the north Atlantic, west Pacific, around Australia and New Zealand, as well as South Africa. Sea potatoes are often seen on sandy sea beds, where they will bury themselves constructing small burrows which are lined by mucus secretions. Detritus and other nutrients will collect on these secretions, and made their way to the central area of the burrow, where the sea potato will feed on them. Sea potato burrows are known to house a wide range of commensals, especially the bivalve Tellimya ferruginosa.
Sand dollars are flattened and disk-shaped and have five rows of tube feet which allow for extremely slow locomotion. The narrow elongated holes in the sand dollar test (shell) are lunules, which serve as channels to help move food from the aboral surface to the oral surface and the mouth.
…is a species of Heliasterid sea star which is distributed around the Antarctic Peninsula, South Georgia and the South Sandwich Islands, where it occurs in the intertidal zone. Like other large starfish Labidiaster annulatusis a opportunistic predator and scavenger, feeding on a wide range of food items. It is known to feed by climbing to an elevated position (like the top of a rock or sponge) and extending its arms out like fishing rods, grabbing any prey items that swims by.
so my marine science teacher was a meme for every student that had him. he had my friend and i make shirts with tardigrades on them for an extra 30 points on the final “shell quiz”. he has a ridiculously huge collection of seashells and one time i witnessed him drop his only duck clam on the floor. it shattered and i swear that man was about to cry.
he also had this habit of over-pronouncing words and yelling random phyla. like we’d be watching a video and he’d yell “ECHINODERMATA” or “ECHINOIDEA” etc. he also showed us a video of a whale exploding, and a video of this guy screaming for a solid 30 seconds while he was shoulder deep in sand trying to find a snail.
boy oh boy i have so many stories