Costas españolas donde podría haber tiburones: ¿cuáles son las especies más comunes?
La Caracola - Diario de Información del Mar
Here are black worms I found in my mountain pond sample! I put them under polarized light to make them glow as if they were in rave 😂 They’re mainly found in North America and Europe in freshwater ponds, lakes and marshes especially in shallow water in sediments or decaying leaves. They’re known to be decomposers as they feed on organic matter but they also nom on microbes!
Black worms belong to the annelid worm group and more precisely the oligochaete worms, just as earthworms! Oligochaete worms are segmented animals, meaning that their body is made of small repetitive units and all of them possess a pair of primitive kidneys and components of circulatory and nervous system. Primitive kidneys are essential to remove wastes from blood and the body cavity. The different segments also bear a pair of bristles, called setae, which are use to anchor the worm when moving around. But to move around so easily by crawling on surfaces also means muscles are needed! Circular and longitudinal muscles are here to help these worms to lengthen and contract all of their segments to be able to stretch forward and eat all of the food!
The vascular system of these worms is composed of one dorsal and one ventral blood vessel that goes from one end to the other. The blood is pumped by the dorsal blood vessel but also by modified transverse vessels located at the front of the worm and acting as muscular hearts! I’ll make another video where we can actually see the red blood being pumped 🩸
Most aquatic oligochaete worms possess dissolved red blood pigments called erythrocruorin that are responsible for oxygen transport all over the body in different tissues. For oxygen to enter blood vessels, it first needs to diffuse inside the worm through their thin skin. Erythrocruorin pigments are sometimes called giant hemoglobin although their affinity for oxygen is a bit weaker than most hemoglobine!
Soundtrack is a courtesy of @tondal_ 🐛
Video taken with my iPhone mounted on a BA310E Motic microscope with an @ilabcam adapter 🔬
This beautiful video of a Small Tooth Sawfish is from @singlefinphoto. A very rare encounter of this fish as this sawfish is critically endangered.
☠️ JELLYFISH HUNTER ☠️
This is Phylliroe, a pelagic nudibranch who’s body plan and locomotion resembles that of fish!
This nudibranch is an open ocean hunter which preys upon unexpecting jellyfish through use of its rhinophores!
The nudibrach’s resemblance with fish is an example of convergent evolution, which is when different organisms independently evolve similar traits!
Elcano ya está en Santander
El buque estará en la capital cántabra hasta el viernes junto al Centro Botín. Las entradas gratuitas pueden solicitarse por internet
Look at these beautiful algae!
The one that looks like a chain of beads is an Anabaena. These are cyanobacteria and they have cell specialization! Two roundish cells in the chain are called the heterocyts and they convert nitrogen gas into ammonia.
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Even though 70-something percent of our atmosphere is nitrogen gas, most plants cannot use the nitrogen gas to create nitrogen requiring compounds. However the plants can use the nitrogen products cyanobacteria manufacture, so it’s extremely important for the environment that cyanobacteria fix nitrogen.
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There are also many cute Mallomonas in the clip, they look like golden seeds with spikes on them. There are some tiny green algae that I don’t even try to identify, they are the smallest ones that buzz around. And some brownish looking Trachelomonas, some green Phacus! It’s just a drop of pond water, and it has so much diversity!
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If you enjoy my videos you can support me for as little as $1/month on Patreon. And I’ll be uploading some printable photos of the clip here. The link in my bio! ❤️
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Thank you so much for reading!
Best,
James Weiss
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This is an obligate symbiosis because the Chlorella can no longer survive on their own. The algae has lost its ability to uptake nitrogen naturally from its environment, and instead receives its nitrogen from the hydra via the amino acid glutamine. Each Chlorella is stored in its own compartment called a “symbiosome” and the algae is directly passed down from each generation of the Hydra.
This is a mutualistic symbiosis because the algae give the Hydra energy and fixed carbon from photosynthesis, and the Hydra gives the algae its source of nitrogen as well as protection from the environment. Having this symbiosis means that the green Hydra can withstand much longer periods of food scarcity than its non-photosynthetic counterparts.
Source:
Mayuko Hamada, Katja Schröder, Jay Bathia, Ulrich Kürn, Sebastian Fraune, Mariia Khalturina, Konstantin Khalturin, Chuya Shinzato, Nori Satoh, Thomas CG Bosch (2018) Metabolic co-dependence drives the evolutionarily ancient Hydra–Chlorella symbiosis eLife 7:e35122
https://doi.org/10.7554/eLife.35122
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