Ich war mir sicher, dass ich tauchen lieben würde, denn nur im Wasser könnte ich das Gefühl des Fliegens aus meinen Träumen erleben (Wie ich zum tauchen kam). Davon war ich überzeugt und so ist es gekommen. Seitdem ist es nur noch besser geworden.
Die Sucht des Tauchens
Schwerelosigkeit und Freiheit, die Natur und Artenvielfalt, aber vor allem das ganz neue Körpergefühl, diese Mischung von Atmung und Bewegung, Anspannung und Entspannung, schlugen mich sofort in ihren Bann. Kurz nachdem ich tauchen auf den Philippinen gelernt hatte (Endlich richtig abtauchen), schrieb ich nach Hause:
„Macht einfach süchtig! Es ist wie Unterwasseryoga. Du kontrollierst die Höhe über deinen Atem und du bewegst dich möglichst langsam und energiesparend. Atmest ruhig und langsam. Unglaublich. Und dabei eröffnet sich dir noch eine wunderschöne, faszinierende, vibrierende Welt voller zauberhafter Wesen und abgedrehter Formen.”
Als ich das erste Mal mit Yoeri tauchen ging, konnte ich es nicht fassen. Er schien sich nicht zu bewegen, kam dennoch mühelos voran, konnte einfach so in der Strömung hängen und in jede beliebige Richtung navigieren. Ich war hin und weg. Wie machte er das alles? Ein Fisch unter Fischen. Das wollte ich auch! Die Anziehung durch meinen eigenen Meeresgott verschmolz mit der Liebe fürs Tauchens und entfachte eine tiefe Leidenschaft und Hingabe, um ganz und gar nicht pathetisch zu klingen.
Zu Beginn genoss ich einen Aspekt des Tauchen besonders, die Phase des „freien Falls”. Rund um Alona Beach auf den Philippinen gab viele Tauchplätze mit steil abfallenden Riffwänden. An der Riffkante angekommen, ließ ich alle Luft aus der Tarierweste, um anschließend ganz lange auszuatmen, so dass ich schneller und schneller sank. Ich streckte die Arme und Beine aus wie ein Seestern. So in etwa stellte ich mir Fallschirm springen vor und genoss das Gefühl in vollen Zügen.
Wenn nötig, atmete ich einmal kurz und schnell ein und anschließend sofort wieder lange und vollständig aus, um die Geschwindigkeit meines „Falls” nicht frühzeitig abzubremsen. Erst kurz vor dem Grund oder der geplanten Tiefe änderte ich meinen Rhythmus, atmete lange und tief ein, füllte meine Lunge komplett mit Luft.
Luft ist leichter als Wasser und je mehr davon in den Lungen oder der Tarierweste steckt, umso mehr schwereres Wasser verdrängt der eigene Körper. Um neutral austariert zu sein, also weder zu sinken (negative Tarierung) oder zu steigen (positive Tarierung), muss ein Taucher genauso so viel Wasser verdrängen, wie seinem eigenen Gewicht entspricht – inklusive der Ausrüstung versteht sich. Da sich dieses Verhältnis durch zunehmenden Druck und Dichte in der Tiefe verändert, musste ich dort zusätzlich eine paar Luftstöße in die Tarierweste blasen.
Doch es sind nicht nur das Gefühl des Tauchens selbst und das spielerische Element, die mich verzaubert haben, sondern auch die Unterwasserwelt, die gleichzeitig begeistert und entspannt. Nirgendwo sonst bin ich bisher so vielen verschiedenen Tieren nahe gekommen. Manche Arten werden fälschlicherweise für Pflanzen gehalten, darunter Korallen, aber auch Schwämme, Seescheiden oder Federsterne in der Galerie eine kleine Auswahl von Art by nature).
Zu Beginn kam ich aus dem Staunen gar nicht heraus und noch immer gibt es Neues zu entdecken (Schätze in Schlamm und Müll). Das schwierigste war das Gesehene, die ganze neue Wunderwelt, in Worte zu fassen, weil es so unglaublich viel war, so viele neue, bizarre und bunte Wesen auf mich einstürzten, und ich zu Beginn gar nicht genau wusste, um was es sich dabei eigentlich handelt. Das macht es nicht nur schwierig, die Begegnung zu beschreiben, sondern erschwert auch, sich überhaupt an alles zu erinnern.
Nach drei Tauchgängen am Tag war ich auf Wolke Sieben, hatte aber Mühe zu sagen, was auf welchem Tauchgang passiert war und mir Details und Arten ins Gedächtnis zu rufen. Da ich nicht einfach nur blind konsumieren, sondern die neue Welt um mich herum wirklich verstehen wollte, fing ich an, meine Nase in alle Bestimmungsbücher zu stecken, Yoeri über seine Unterwasservideos auszufragen und idealerweise direkt nach dem Tauchgang, die herausragenden Funde, ob alte Bekannte oder neu kennengelernte Arten, in mein Logbuch zu schreiben.
Sobald man weiß, was man sieht, kann sich die Wahrnehmung vertiefen. Es geht nicht mehr allein darum, eine Art (wieder) zu erkennen, sondern zu beobachten, was dieses Unterwasserlebewesen macht, wie es mit anderen in Beziehung tritt, wo es zu finden ist, von was es sich ernährt, wie es auf uns reagiert und vieles mehr. Gerade für Unterwasserfotografen oder -videografen ist das Wissen Gold wert, denn dann kann ich nicht nur an den richtigen Stellen nach dem Objekt meiner Begierde suchen, sondern auch noch abschätzen, was vielleicht als nächstes geschieht und wie ich mich dafür am besten positioniere (vom Fotografieren erzähle ich ein andermal).
Wir schützen nur das, was wir lieben, sagte einst Jacques Cousteau. Um es zu lieben, müssen wir es erst einmal kennen und am besten noch verstehen. Noch immer werden viele neue Arten entdeckt, was nicht heißt, dass sie noch niemand gesehen hat. Sie wurden nur noch nicht wissenschaftlich beschrieben und klassifiziert (Let’s talk scientific!). Über die Beziehungen der Arten untereinander und ihre jeweiligen Rollen in der Unterwasserwelt ist noch weniger bekannt als über die einzelnen Arten selbst. Viele Schätze schlummern unter der Wasseroberfläche.
Stück für Stück erschließe ich mir die Unterwasserwelten, die wir besuchen und teile das, was ich kennenlerne gerne mit anderen, ob in Briefings, Postings oder mit den Fotos hier auf der Website (Underwater Photography). Ständig Neues lernen, nicht nur über die verschiedenen Arten und das Zusammenspiel im Ökosystem, sondern auch über mich selbst, das Meer und das Tauchen an sich, erfüllt mich und verhindert, dass in dieser Liebesbeziehung Langeweile aufkommen kann. Andere Menschen haben andere Vorlieben beim Tauchen.
Gemeinschaft und Gefühl
Trotzdem: Tauchen verbindet (Miteinander, ob gleichgesinnt oder andersartig). Zum einen teilt man schöne Momente, schafft gemeinsame Erfahrungen. Zum anderen tauscht man sich aus, lernt mit und von einander, im besten Fall und den Rest blende ich jetzt einfach mit meiner rosaroten Brille aus. In jedem Fall hat Tauchen mein Leben bereichert. Ich habe verschiedene Länder bereist, kleine Ausschnitte des lokalen Lebens kennengelernt, Menschen aus aller Welt mit den verschiedensten Hintergründen getroffen. Menschen, mit denen ich ohne das Tauchen niemals ins Gespräch gekommen wäre. Wenn sich die Unterhaltung nicht fruchtbar entwickelt, kann ich immer wieder aufs Tauchen ausweichen.
Es ist schön, ganz neue Plätze kennenzulernen, doch an vielen Orten kann ich immer wieder tauchen, sie mit jedem Tauchgang detaillierter kennenlernen, Bewohner und Verhaltensmuster beobachten, sehen, wie sich der Platz im Tages- und Jahresverlauf und mit den Wasserbedingungen verändert. Jeder Tauchgang ist anders und bietet Neues. Meistens kommt es einfach auf die Einstellung an, sich auf die Situation einlassen können, nichts erzwingen wollen, von sich selbst oder dem Meer.
Wirklich spannend, wird es dort, wo sich umgekehrt Meeresbewohner an bestimmte Taucher erinnern. Auf Statia gab es einen Trompetenfisch, den Yoeri zu sich rufen konnte. Sobald er seinen Arm ausgestreckt hat, legte sich dieser eine Fisch darauf – nur bei ihm, jedes Mal wieder. Mantas reagieren nicht nur unterschiedlich auf verschiedene Menschen, sondern haben ihre eigene Launen (Tanz mit Mantas: Begegnungen auf Augenhöhe). An manchen Tagen kommen sie ganz nah heran, streicheln einem mit ihren Flügeln über den Kopf oder schauen über die Schulter, wenn man es wagt, etwas anderes als die majestätischen Tänzer selbst zu filmen, und an anderen Tagen lassen sie niemanden auch nur in ihre Nähe.
Mit offenen Augen durch die Unterwasserwelt zu gleiten, dabei neue Dinge entdecken oder alte Bekannte begrüßen, setzt in uns Glückshormone frei. Wir lassen unsere Probleme und Zweifel an der Wasseroberfläche zurück, tauchen ab, um Ruhe und Schwerelosigkeit zu genießen, um zu suchen und zu finden. Die Zeit scheint anders zu vergehen: Viel zu schnell und dann doch gedehnt, so als würde all das Erleben nicht in den kleinen Zeitraum hineinpassen und unsere Wahrnehmung ihn dehnen, um Platz zu schaffen für alle die Begegnungen und Gefühle eines einzigen Tauchgangs.
Manche Tauchgänge bleiben besser im Gedächtnis als andere. Doch warum ich tauchen am meisten liebe, lässt sich am besten mit dem Begriff aktive Meditation beschreiben. Ich kann mich vollkommen selbst verlieren und neu entdecken, meine Nichtigkeit und wahre Größe erkennen. Körper und Geist verschmelzen, ich gehe im Moment auf und stehe im Einklang mit der Natur, lasse mich fallen, um über mich hinauszuwachsen.
Die Clips der Reihe „Take a Minute” liefern die visuelle Untermalung für meine Worte und dazu noch mehr Wissen.
Private videoThis video is private.
Private videoThis video is private.
Take a Minute XL: Hawksbill Sea Turtle (Eretmochelys imbricata)In this relaxing Minute, we invite you to swim alongside one of the more famous and beloved ocean creatures, the Hawksbill sea turtle (Eretmochelys imbricata). These marine reptiles, and yes they are reptiles, have been roaming the world’s oceans for an incredibly long time. It is believed that the “Cheloniidae” family, the name of these marine turtles, has been living on our planet since the last Mesozoic Era, more than 100 million years ago! Making them some kind of living fossils.
Their scientific name Eretmochelys imbricata, is derived from the Greek words “eretmo” meaning oar referring to its oar-like flippers and “chelys” meaning turtle. The second part of the scientific name “imbricata” comes from the English word ‘imbricate’, which means ‘having overlapping edges’, and refers to the overlapping scales of the Hawksbill’s carapace. There are currently actually 2 subspecies known to science, namely E. imbricata imbricata (a.k.a. the Atlantic Hawksbill), and E. imbricata bissa (a.k.a. the Indo-Pacific Hawksbill).
The Hawksbill is one of the smaller species of sea turtles, growing up to about a meter in length. It has a characteristically narrow, pointed beak and a beautiful patterned shell/carapace, which has serrated edges towards the lower end. These turtles are in fact omnivores that will dine on a wide variety of food sources, including jellyfish, corals, fish, anemones, molluscs, marine worms, crustaceans, and other plants and animals. However, Hawksbill turtles feed primarily on sponges.
They show a great level of feeding selectivity, in the way that they only eat certain species of sponges, some of which are toxic to other animals. But there is more to their diet. In fact, their type of feeding provides a great service to other marine life on the coral reefs. Without hungry hawksbill turtles, the reefs would quickly overgrow with sponges, taking the space for slower-growing corals to thrive. Hence, hawksbills play an important role in the ecosystem and contribute to the overall health of coral reefs and wider marine life.
Hawksbill sea turtles reach sexual maturity between 20 and 35 years of age (around 20 in the Caribbean and 30-35 in the Indo-Pacific). It is estimated that they can live between 30 and 50 years in the wild. Hawksbills will lay eggs every 2-4 years during those sexual mature years. Nesting is the moment when the female turtles, who have come back to the place of their own birth, leave the water. This allows observing them on the sand of small beaches, where they dig a nest to lay their eggs. Such a nest is usually about 50cm /19” deep. After they have laid their eggs inside, they cover them with sand again. Each egg is approximately 36 mm in diameter and 28 g in weight. About 60 days thereafter, the young ones will hatch. Interestingly enough, temperature determines the sex of these hatchlings. When the temperature is around 29°C/ 84.2°F, the male-to-female ratio is about 1:1 in the nest. When the temperature rises, more female baby Hawksbills turtles will be born. If it drops, the baby Hawksbill turtle males will dominate the hatching. This fact is worrisome, not only to scientists, as the averages temperatures on our planet continue to rise.
Unfortunately, these beautiful creatures are critically endangered and therefore listed in appendix I of CITES, a multilateral treaty to protect endangered plants and animals, as well as the "Red list" of IUCN (International Union on Conservation of Nature). These listings lead to the fact that the trade of this turtle’s beautiful carapace/shell has been made illegal, in an effort to conserve the population. Despite this, the Hawksbill turtle shell is still found in souvenirs and jewellery. In fact, it’s still the most frequently confiscated illegal item by customs officials …
This clip was filmed by Yoeri diving at Balicasag island, the Philippines, with a Sony V1p in an Amphibico housing in 2010.
#seaturtle #worldseaturtleday #hawksbill #Eretmochelysimbricata #Balicasag #turtles #diving #TakeaMinute #conservation #Philippines #savetheocean #reefprotection #SonyV1p #Amphibico
Take a Minute XXXIX: Whale shark (Rhincodon typus)After many episodes that focused on the smaller and more cryptic marine life, in this Take a Minute we’d like to introduce you to the largest fish in the ocean, the whale shark (Rhincodon typus). The name of this creature has confused people for many years, and unlike what it seemingly suggests, this creature is in no way related to whales. The only reason this was added to its name, was to give people an idea about the immense size of this fish.
Rhincodon typus can grow up to a size of around 18 metres when given the chance. Although most adults that are encountered by people are around 12 metres in length. Not only are these creatures very large, but they can live to be around 130 years! Despite its enormous size, and the amount of research that’s been done on them, much of the whale sharks' life is still shrouded in mystery. This is probably due to the fact that whale sharks migrate and can easily travel great distances. One particular tagged specimen was recorded to travel nearly 15.000 kilometres, in a little over 3 years. On top of that Rhincodon typus can dive to a depth of around 1,500 metres. All of this makes it very hard for scientists to study this iconic creature.
As mentioned before, not everything is known about the reproductive behaviour and life cycle of whale sharks. But what we do know is that Rhincodon typus reaches sexual maturity around 30 years of age, and is ovoviviparous. Meaning that the female lays eggs and keeps them inside of her body. When fertilised, they will hatch, but remain safely inside until they are fully formed and strong enough to start their life outside of their mother’s body. A whale shark can give birth to about 300 pups that are about 40-60 cm in length, and already look like a miniature version of their parents.
Although whale sharks are no threat to humans and are referred to as the gentle giants of the ocean, they do have teeth. In fact, they have more than 3,000 teeth stacked in 300-350 rows, which is more than any other shark species. Despite all these teeth in their enormous 1-1,5 metre mouths, these sharks are filter feeders. Meaning that these animals feed by straining suspended matter and food particles from water. They typically do so by letting the water pass over a specialized filtering structure. Due to the fact that they play such an important role in clarifying water, filter feeders are considered to be ecosystem engineers.
The whale shark also feeds by active suction feeding. This occurs when they are in a vertical position. The animal opens and closes its mouth, sucking in volumes of water, then expelled them through the gills. Rhincodon typus can process over 6,000 litres (1,500 gallons) of water each hour in this fashion! The whale shark’s most common diet consists of plankton, copepods, krill, fish eggs, jellyfish, red crab larvae and small nektonic life, such as small squid or fish. To eat, the whale shark opens its formidable sized jaws and passively filters everything in its path. This technique is called “cross-flow filtration”, and is similar to how some bony fish and baleen whales feed.
The distinct pattern of white spots on the whale shark’s back is unique, and no two are alike. Which makes them a bit like human fingerprints, and helps scientists identify individuals. Since swimming with this creature is high on the list of divers and snorkellers alike, we can all contribute by making our photos available to organisations and researchers that study this incredible creature.
#whaleshark #Philippines #Bohol #Anda #diving #savetheocean #TakeaMinute #underwater #SonyV1p #Amphibico #LAMAVE #Rhincodontypus
Take a Minute XXXVIII : Harlequin Crab (Lissocarcinus laevis)This relaxing Minute features a colourful character, and its relationship with anemones, as well as certain coral species, and even some sea cucumbers. In it, we see a Harlequin crab caught with its hand in the cookie jar, as it tries to get to some food before the anemone can eat it. As we look closely at this little scoundrel, we can see that the last hind legs are larger and flatter than the other ones. This is because they belong to the Portunidae family, also known as swimming crabs. With these flattened hind legs, these creatures are capable of swimming through the water column, when the need arises. However, like most swimming crabs, Lissocarcinus laevis prefers to keep its feet firmly on the seafloor, or on its host for that matter. But it’s nice to have options.
This small, yet ornate species of swimming crab has a very smooth, reddish, light brown carapace with large white to yellow spots and markings which are often interconnected. So smooth in fact, that their genus name actually means "smooth crab". Its claws are banded with white and brown/red bands. The females can be slightly larger than the males and can grow to a width of about 3,5cm, with a body that is wider than it is long. As with most crustaceans, after the eggs are fertilised by the male, they’re carried under the body of the female, who will protect and oxygenate them, until it's time to release them. Once they hatch, the larvae go through a pelagic phase of several weeks, before settling down and growing into their adult form. They are guided to their host species, by the chemicals these host creatures release, to attract their symbionts. Interestingly enough, the chemicals produced by these host species might actually be meant to deter predators and parasites, but for Lissocarcinus laevis it’s a chemical trail, that leads to a compatible host, and hopefully the start of a long-lasting symbiotic relationship.
Chemical sensing is considered to be the most ancient and universal form of communication in the biosphere. All living organisms are able to detect chemical cues in their respective environments. These cues allow for different types of intra- and interspecific interactions between organisms. For example, mate recognition, prey/predator interactions, and symbiotic associations. The communication between symbionts and their hosts is needed to ensure appropriate host selection, as well as maintaining the symbiotic relationship through time, but is just one of the many chemical conversations that are taking place below the surface of the ocean.
Although the symbiotic relationship of the Harlequin crab with its host is very common throughout the Indo-Pacific, the exact nature of the relationship between the hosts and symbiont is still somewhat unclear. Something which has made it very hard for scientists to classify their relationship on the symbiotic spectrum. It is currently listed as “commensal”, meaning one species gains benefits from the relationship while the other neither benefits nor is harmed. Harlequin crabs are predators, that eat shrimps and other tiny planktonic organisms, as well as leftover food from their hosts. Scientists believe it might also be feeding on parasites from its hosts. If true, it might mean another shift on the symbiotic spectrum, but no studies have been done yet to prove this hypothesis.
#Harlequincrab #Lissocarcinuslaevis #swimmingcrab #underwater #crab #Amed #TakeaMinute #diving #symbioticrelationships #anemone #Indonesia #macro #PanasonicLumix #GH5s #Nauticam
Take a Minute to Relax XXXVII: Slender Filefish (Monacanthus tuckeri)In this minute of relaxation, we bring you another Caribbean addition to this series. The small but beautiful Monacanthus tuckeri, a.k.a. the Slender filefish.
Although most individuals encountered, range between 2-5cm in length, they can potentially grow up to 10cm! They have laterally compressed, slender, elongated bodies, with a tapered snout, and protruding eyes that are located high on their heads. Filefish have a slender retractable spine on top of their heads, which is incorporated in their first dorsal fin. This spine/dorsal fin actually contains two spines, whereby the second far smaller one, is used solely to lock the first spine into its upright position. This explains the family name Monacanthidae, from the Greek "monos" meaning "one" and "akantha" meaning "thorn".
Like their cousins the triggerfish, filefish have small gill openings and their pelvic fins are lacking. Instead, there is an extension of the pelvic bone, known as the pelvic rudiment, with skin attached to it. This "pelvic girdle" is capable of moving up and down in many species, to form a large “dewlap”, which can make Monacanthus appear much larger than it actually is. Some filefish erect the dorsal spine and pelvis simultaneously to lodge themselves into place, making it more difficult for a predator to remove the fish from its shelter. It may also be used for communication purposes with other filefish.
The small mouths of this creature have specialized incisor teeth, on the upper and lower jaw. In the upper jaw, there are four teeth in the inner series and six in the outer series; in the lower jaw, there are 4-6 in the outer series only. These teeth allow them to be opportunistic omnivores, that dine on macroalgae, filamentous algae, seagrasses, coralline algae, sponges, hydrozoans, bryozoans, and tunicates. A small portion of their diets includes foraminiferans (shelled protozoa), polychaete worms, smaller species of bivalves, snails, ostracods, amphipods, and shrimp.
They have non-overlapping scales that bear “spicules”, which are small, needle-like anatomical structures, protruding from the centre of each scale, giving them the rough and tough, sand-papery skin, that together with its body shape inspired the filefish's common name. Monacanthus isn’t a particularly strong swimmer, and relies more on crypsis, camouflage, and hiding, to avoid being eaten. Slender filefish are often found around soft corals, like sea whips, rods, and fans, but also in seagrass, hydroids and algae, where they align their movements perfectly with that of the ocean’s swell. Despite lacking the power, their body shape allows them to manoeuvre effortlessly around these complex environments. They love hanging out vertically in the water column, and on top of that, these incredible fish can quickly change their colouration and patterns, making them not easy to find.
But when you find one of these small ocean dancers, enjoy their performance for as long as you can! For it might all be over, in the blink of an eye…
#Slenderfilefish #dive #caribbean #underwater #StEustatius #STENAPA #CNSI #Scubaqua #Statia #Monacanthustuckeri #marinelife #macro #filefish #GH5s #Nauticam
Take a Minute XXXVI: Feather Duster (Tube) Worm (Sabellastarte spectabilis)In this session of relaxing minutes, we would like to introduce you to a critter that uses a flamboyant feature of itself, to mask what many people would deem an otherwise gross appearance. Yes, Sabellastarte spectabilis is, despite its beautiful name, not some fluffy plant or coral in a variation of colours, but in fact a humble worm. However, don’t let this little detail change your opinion of this creature. Sabellastarte does really make an effort to look more appealing than just another worm. As a matter of fact, another member of this family of worms, the Christmas tree worm (Spirobranchus corniculatus), was the inspiration for the beautiful Helicoradian plants on the moon Pandora, in the hit movie Avatar (2009).
Sabellastarte spectabilis has a segmented tubular body of around 8cm long, and roughly 1cm wide, and can be found in the more sheltered regions of the tropical reefs and lagoons around the world, ranging from 5-100m of depth. This worm creates a leathery-looking tube from its own mucus secretions and attached sediment and/or sand. Others use calcium carbonate or chitin, and some even have a trap door to close their tube off, in case of lurking danger. These tubes are then embedded, or attached to a variety of substrates, from where they compete with other organisms for food and space. Some even have the ability to physically, or chemically burrow into corals and/or limestone. As a defence mechanism, these creatures are able to quickly retreat into their tubes, when disturbed by potential predators.
It may come as a surprise, but Sabellastarte has eyes! And some species have more than others. They have multiple eyes along the sides of their bodies, as well as appendages called chaeta, which allows the worms to anchor themselves inside their tubes and aid in the retraction response. These eyes will likely let the worm know whether it’s still within the safety of its tube. Perhaps they might even locate areas of the tube that need maintenance. In some species, eyes may also be found on their heads and/or on the highly specialised, feather-like feeding tentacles, that stick out of the tube. That’s a lot of eyes for one creature! While some of these eyes might simply detect light and darkness, others might be more complex compound eyes capable of producing a picture and detecting movement. Similar to that of more active predatory marine worms, or flying insects.
Like many other sedentary life forms, Sabellastarte is a “filter feeder” that dines on planktonic prey and detritus, brought in by the currents. They do this by using the only visible part of themselves, their beautiful exposed plumage. Each feeding tentacle is called a radiole and is covered by feather-like pinnules and a sticky mucous, that form a fine mesh net, to capture any food particles that float by.
Short vibrating microscopic hair-like structures, called cilia, cover both the radiole and the pinnules. Cilia can also be found in humans, where it lines our lung surface and windpipe, and capture and remove dirt particles and mucous. Vibrating cilia on the ventral surface (underside) will create an up-current, directing particles through the radiole and pinnules, where they can be caught. From there, a decrease in pressure makes the particles fall into the ciliated groves on the dorsal (upper) side of the pinnule, from where it will be transported via several other ciliated, mucous-lined food grooves down to the actual mouth. There the particles will be sorted. The edibles will continue their journey into the worm itself, the rejected particles will be removed via other ciliated grooves away from the mouth. Some of these particles will be stored, and used for repairs on the actual tube when it has sustained damage. In addition to all that, the large surface area of the plumage also acts as gills, making them technically known as branchiae, since they're used for respiration.
With so many important functions located in a small area, one would think that if a predator was quick enough to bite a chunk of the plumage, the worm would surely die. But sabellastarte has the uncanny ability to regenerate damaged or lost body parts! Several species have shown to be able to control the loss of the crown of tentacles, a process known as autotomy. Lizards have a similar process whereby they intentionally lose a tail in order to distract a predator and enable their escape.
They reproduce by spawning, releasing eggs and spermatozoa in the water column in the hope that they will find one another before any predator, including themselves, get to them. Strangely enough, Sabellastarte is also capable of reproduction by fragmentation, also known as "budding".
So you see, there’s a very interesting creature is hiding behind those colourful plumes!
#underwater #Sabellastartespectabilis #marinelife #relax #Featherdusterworm #TakeaMinute #diving #Tubeworm #Indonesia #Wakatobi #feather #macro #PanasonicLumix #GH5s #Nauticam
Take a Minute XXXV: Roughhead Blenny (Acanthemblemaria aspera)In this minute of relaxation, we would like to introduce you to a creature, that despite being quite the character, is often overlooked by most that visit the tropical reefs of the Caribbean. This rather ragged-looking creature is a fish, that goes by the scientific name of Acanthemblemaria aspera. Since this is quite the tongue twister, it thankfully has an alias in the common tongue that is much easier to pronounce, namely Roughhead Blenny. Looking at the creature, it’s easy to understand how this name came to be. The so-called “roughness” refers to the slender appendages/hair-like growth on the blenny’s head named “cirri”. Incidentally, the word “cirri” is derived from the plural version of the high altitude cirrus cloud, which are able to create these beautiful, whispy, and streaky patterns in the sky. Just to give you an idea, of how awesome its haircut is!
Some might say that Roughheads look a bit pre-historical in its appearance, and they wouldn’t be wrong with that observation. Fossiles of Blennies date back to the Paleogene period, which started about 65 million years ago. To put that in perspective, that is around the time Keith Richards was born!
If one intends to admire Acanthemblemaria aspera in all its glory, as well as its amazing haircut, of course, it would probably be best to bring some form of magnification device, be it a macro lens or a magnifying glass, for this funky little fish grows to a maximum size of 4cm/1”. They inhabit shallow coastal waters from 2-20m/6-60ft and are not overly picky about where they live. They are known as burrow creatures and find a place to live in just about every nook and cranny of the reef, if not in the corals themselves. Not that they construct their own burrows, but more that they occupy holes left by other marine life, like worms and molluscs. A bit like a squatter with good hair, so to say. Although some of them have been known to bury themselves in the seafloor.
They come in many different colour variations, and can adapt their colouration to blend into any neighbourhood they happen to find themselves in. That being said, the females are often more lightly coloured. They’re oviparous, and after mating the female covers the walls of the male’s burrow with her eggs, and leaves them for him to defend until they hatch. After which the young fry go through a 22-day pelagic phase, and eventually settle down in a new area to find a home for themselves. They have excellent eyesight and prefer to dine on drifting, floating, or falling amphipods and/or copepods, that happen to pass by their burrows. This “hunting” action results in a kind of swaying head movement, which has led to the creature’s nickname, the “Stevie Wonder Fish”.
Another stunning creature, in another beautiful part of this amazing blue planet!
#underwater #Roughheadblenny #marinelife #relax #St.Eustatius #TakeaMinute #scubadiving #Scubaquadivecenter #Statia #Acanthemblemaria #blenny #macro #PanasonicLumix #GH5s #Nauticam
Take a Minute XXXIV: Thorny Seahorse (Hippocampus histrix)In this episode of “Take a Minute to Relax”, we invite you to look deep into the eye of one of the most effective and successful hunters, not only of the aquatic realm but of the entire planet. This is the eye of Hippocampus histrix, a fish that also goes by the common name of Thorny or Spiny seahorse. Their scientific genus name “Hippocampus” is derived from the Greek words “Hippos & Kampos”. “Hippos” means horse, and “Kampos” means sea monster. The Romans later adopted it as “Hippocampus”. In both Hellenistic and Roman imagery, it was depicted as a two-hoofed horse creature with a fishtail, that drew the “chariot” of the sea god Poseidon/Neptune. Looking at the creature, it’s not too hard to understand why science adopted the “Hippo” part of its name, but the “Kampos” (sea monster) part, seems a bit far fetched at first.
With their elongated bodies, covered in an armour of bony plates, and prehensile tails, they look nothing like any of the traditionally shaped fishes. However, equipped with fins for propulsion, gills for breathing, and even a swim bladder to control their buoyancy, these oddly shaped creatures are indeed fish from the Family Syngnathidae. They usually can be found in shallow tropical-, and temperate waters, but also do occur in some colder water in places like New Zealand, Argentina, and Canada. Their usual lifespan ranges between 1-5 years.
But there's a lot more to this creature, than just its strange appearance. To say that seahorses are not very good swimmers, would be somewhat of an understatement. Their main source of propulsion is delivered by a small fin on their back, that although it can flutter up to 50 times a second, gives them very little speed. They're however capable of covering large distances, by simply using their prehensile tail to hang onto pieces of seaweed and/or debris, which can carry them to far of places.
Hippocampus does neither possess any teeth, nor stomach! Therefore, the food they consume passes through their system so quickly, that they have to eat almost constantly, in order to survive. Their diet consists of plankton, plants, small fishes, and crustaceans, like shrimps and copepods. Adults will typically have between 30-50 feeding sessions a day. Baby seahorses are called “fry”, and like the teenagers of our own species, can consume an incredible amount of food. Their food intake can be an astonishing 3000 food pieces a day! They have one of the highest success/kill rates of any creature in the animal kingdom. 90 %, compared to say lions with a 25%, and even sharks are well below 60%. Their eyesight is excellent, and they are able to move their eyes independently from each other, which makes it easier to spot their food, whilst they use their tube-like snout as a suction device! Due to their lack of movement, and ability to blend in with their environment, their tiny prey has no idea of their presence, until it’s too late.
Hippocampus are essentially serial monogamists and stay with one partner for as long as possible. They also have voices and can make grunting sounds, as well as clicking noises. Some of these noises are made on a couple’s daily romantic “confirmation dance”, that takes place each morning, whereby the couple dances and pirouettes together for a couple of minutes, often resulting in the iconic heart-shaped pose of their heads and upper bodies, before separating for the rest of the day. They have this morning ritual to confirm the other partner is still alive, reinforce their bond and synchronize their reproductive cycles. After courtship, the female deposits her eggs in a specialised breeding pouch of the male, where he fertilises them. This “male pregnancy” lasts between 10-25 days, depending on the species. The number of young released by the male seahorse at the end of term, are on average between 100–1000 babies. Under normal circumstances, less than 1% of these will ever make it to adulthood, which explains the large number of offspring. Whilst the male is taking care of the “pregnancy", the female can use her energy into producing the next batch of eggs.
Seahorses can not only change the colour but even the texture of their skin. Not just for camouflage purposes, but also to communicate and express their emotions. They do this by contracting or expanding pigment cells known as chromatophores. These muscle manipulated cells can be controlled by the nervous system, for quick changes in appearance, or by hormones for slower more flamboyant changes. On top of that seahorses are masters at the game of hide and seek. They have for instance figured out that humans often manage to find them, because of their iconic horse-like body shape, and therefore often lay down flat on the bottom, in order to remain hidden.
What an incredible creature this is!
#thornyseahorse #Hippocampushistrix #seahorse #underwater #relax #lembeh #TakeaMinute #diving #malepregnancy #colourchange #Indonesia #macro #PanasonicLumix #GH5s #Nauticam
Take a Minute XXXIII: Sarasvati Anemone shrimp (Periclimenes sarasvati)In this episode of “Take a Minute to Relax”, we would like to focus your attention on a small treasure, that’s easy to overlook. This little beauty is a commensal, and often symbiotic genus of semi-transparent shrimp within the family Palaemonidae, which has been labelled with many common names, depending in which region of the Indo-Pacific it is found. Anemone- Carid, Cleaner, Commensal, or even Glass shrimp, due to the fact that their bodies are almost transparent. However, the scientific name “Periclimenes sarasvati” rolls so nicely of the tongue, and is beautifully befitting! It has been named after the Hindu goddess Sarasvati, which is the goddess of knowledge, music, arts and science. Periclimenes sarasvati is relatively easy to distinguish from other species in their genus, by the red stripe(s) going through their white eyes. The one in this particular shot also seems to have a bundle of pink eggs in her abdomen. One of the advantages of a transparent body!
This pretty creature grows to a maximum of 2,5cm and can be found on coral reefs from 2 - 40 meters of depth. They prefer to live in small groups and will form symbiotic relationships with host species, like anemones and corals. It is at these host species, that the Periclimenes sarasvati will set up shop, and open their cleaning business. Because most all reef-, and pelagic fish species enjoy a good cleaning session once every so often, to rid themselves of parasites, help clean any wounds they might have, and lower their overall stress levels, these cleaners are generally very well respected. However, when one is so small, it can’t hurt to provide your services from the safety of a voracious killer like an anemone, to which one can retreat, when a customer is showing signs of bad behaviour/intentions. These cleaning stations are fairly easy to spot for anyone diving, and/or snorkelling on a particular reef. When a reef fish hovers over, or next to an anemone or coral for a while, one can be pretty sure that there is a cleaning service in progress at that particular spot.
If and when one manages to approach a cleaning station in such a manner that disturbs neither the “staff” nor the “customers”, one gets the opportunity to observe the behaviour of both, the personnel and their clients, in this cleaning operation. Periclimenes sarasvati tend to hover a fair distance over their host species, to advertise that they’re willing to receive customers. When a fish approaches, they first retreat to the safety of their host’s stinging tentacles, from which they will assess if their potential client is giving the right signals. During this time they may “clap” their hands/arms together in a particular sequence, advertising their willingness to start the cleaning activities. If, and when the customer displays the right submissive behaviour, signalling they are ready, and willing to be cleaned, without any “funny business”, multiple Periclimenes sarasvati will go to work and clean the customer’s skin, potential wounds, gills, and even the inside of their mouths. Quite some fish will change skin colour before, and during their treatment, to inform the cleaners that they will behave appropriately during the proceedings. After observing all of this, one might even be rewarded with a free manicure themselves!
#underwater #Sarasvatishrimp #marinelife #relax #behaviouralscience #TakeaMinute #scubadiving #reefprotection #Indonesia #WakatobiDiveResort #anemoneshrimp #macro #PanasonicLumix #GH5s #Nauticam
Take a Minute XXXII: Randall’s Shrimp Goby (Amblyeleotris randalli)After a long wait, we’re very happy to finally bring you another episode of our “Take a Minute to Relax” series. The guest star in it is both flamboyant as well as interesting and goes by the scientific name Amblyeleotris randalli. In the common tongue, there are numerous names for this beautiful creature. Gold-barred Shrimp Goby, Gudgeon, Orangestripe Prawn Goby, Orangestripe Watchman Goby, Randall's Shrimp Goby, Sailfin Shrimp Goby, just to name a few.
Amblyeleotris randalli is a relatively small fish that can grow to about 12cm/4,7”, and can be found in the Western Pacific region. It is part of the Family Gobiidae (Gobies), which is the largest family of marine fishes on the planet, containing nearly 2000 species, possibly even more. One would think that in a family of that size, it’s near impossible to stand out. However, about 120 species of this family have developed a remarkable evolutionary trait, that did just that!
These select few started a mutualistic symbiosis with a completely different creature, namely shrimps of the family Alpheidae. These shrimps are characterized by having asymmetrical claws, the larger of which is typically capable of producing a loud snapping sound, which creates a cavitation bubble that is loud enough to stun their prey. It, therefore, comes as no surprise that these creatures are also commonly known as snapping shrimp, or pistol shrimp. The Alpheid shrimps are incredible diggers, and are constantly creating, and maintaining burrows in the seabed which provides them with a relatively safe place to live. However, due to their very poor vision, the shrimps are extremely vulnerable to predators every time they dump sand, and/or gravel, outside of their burrow. And this is where the shrimp/partner gobies come in.
Amblyeleotris randalli, as well as the other shrimp/partner gobies, have excellent eyesight, and like a watchmen/guardian, it maintains constantly vigilant against potential predators, while the shrimp continues the digging and maintenance activities. This way, the shrimp gets security, and the goby gets a safe home with cleaners! What a clever way for 2 small creatures to increase their chances of survival!
A very interesting aspect of this particular symbiosis is the communication between goby and shrimp. So far it's been established that when a predatory fish approaches the burrow entrance fast, the goby escapes into the burrow. This escape reflex is very similar to that of other fishes. However, when a predatory fish approaches the burrow at a moderate distance or speed, the goby flicks its tail, and/or dorsal fin, in quick bursts, so that the shrimp, who’s in touch with the body of the goby via its antennae, notices the message and stays below ground. This type of messaging is signalling a threat level below the "full escape", and is information specifically communicated to the shrimps! Since behavioural science of marine life is still in its infancy, hopefully, scientists will bring us more interesting facts about their inter-species communication in the future.
Perhaps even more remarkable, is that this symbiotic relationship between shrimp and goby lasts a lifetime. They start bonding as juveniles and remain together as adults, spending their days foraging together and sharing a burrow. It is still unclear why these two species have developed such a high level of co-dependency, but the symbiosis is working well for both creatures.
Gobies eat micro-fauna, and sometimes small fish that they find near the bottom. The shrimps, on the other hand, feed on what they find during their burrowing and therefore do not compete with the gobies for food. While shrimp reproduction isn’t all that remarkable, the reproduction of gobies on the other hand has some peculiar aspects. During the mating season, the male and female gobies start a wild circular dance in an extended side corridor of the burrow. They touch and stimulate each other from head to tail, which causes sand and gravel to fall from the ceiling and walls. The shrimp’s digging/cleaning actions play an important role in ensuring that the mating ritual can continue, as gobies don’t have the ability to transport the sand themselves. Hence, the preparation of the gobies breeding chamber, as well as the constant maintenance during the actual mating, and by extension, the successful procreation of the particular goby species, is only possible with the shrimp’s assistance!
If by now you’re wondering how gobies and shrimps find each other in the first place, know that science hasn’t found a definitive answer to that question yet. Marine biologists have conducted numerous experiments to determine who finds who, and how, but currently, this question remains one of nature’s enduring mysteries...
#RandallsShrimpGoby #Amblyeleotrisrandalli #Wakatobi #underwater #relax #AlpheidShrimps #TakeaMinute #diving #mutualism #symbiosis #Indonesia #macro #conservation #shrimpgoby #goby
Take a Minute XXXI: Coral reef life or breathing to relax body and mindThis time in "Take a Minute to Relax" we present coral reef life in the shallows (Wakatobi, Sulawesi, Indonesia). As we have been writing about "The reefs of Wakatobi" in episode XI and "Coral Reef Protection" in episode XXV of our series, we focus on breathing now. After all, it is a minute to relax.
We as humans don’t need to think about breathing, we even continue to breathe when we are unconscious (involuntary breathers). Dolphins, on the other hand, are voluntary breathers, meaning they have to decide when to take a breath. Becoming aware of how we breathe and how breathing is connecting our body and mind is useful not only while diving.
Our breath is controlled by the respiratory centre of the brain. Automatically, we don’t need to do anything – but we can. When we feel stressed, our breathing pattern and rate change, also automatically as part of the evolutionary “fight-or-flight response”. We are taking shallow and rapid breaths into the chest rather than all the way into our bellies. That’s a natural response to be ready and alert.
It can, however, increase the level of stress if we start to feel uncomfortable with this breathing pattern itself or have the feeling of not getting enough air. All too often this process happens without us even recognising the connection to breathing, after all, there’s something else on our mind at that moment. At a time like that, body functions such as the response of the immune system or digestion, are having a lower priority. So, not a healthy state to be in for very long.
We all have been overwhelmed by situations and emotions one way or another. Madly crying, highly agitated or simply furious, all have an impact on our breathing. Maybe somebody told us to “take a deep breath” or “just breath slowly” and hopefully you noticed that focusing on breathing in and out deeply and slowly, actually calms you down.
The connection between body and mind works both ways. As soon as we start to change our breathing pattern consciously, we signal the brain that we have the situation under control, resulting in feeling less stressed. Be kind and be patient. Quickly and forcefully changing your own breathing pattern can lead to disruption, rather than the desired correction.
Being able to lift yourself up is definitely worth working on. Breathing plays an important role in many relaxation techniques from yoga and meditation to mindfulness and other stress relief techniques and, of course, diving. Note: For some people focusing on the breath is actually having the opposite effect (enhancing anxiety levels and panic).
If somebody doesn’t feel right underwater, it is the number one thing to do: Eye contact and making sure the breathing is under control. The easiest and most effective way is breathing together, deeply and slowly to get calm and relaxed. Place your hand in front of your regulator and move it away for exhaling and back towards the face for inhaling. If needed, signal slow/calm down by moving the flat hand (horizontal) up and down.
Of course, breathing dry compressed air of a limited supply adds to the pressure to get the breathing under control. But what works underwater works also on land, where you can talk or count out loud for a rhythm.
In Open Water diving courses or any sort of try dives, you’ll often hear "breath deeply in and out" or "breath normally". But what is normal? In fact, we all breathe differently and our normal might not be the desired relaxed state the instructor is talking about. Deeply and slowly might even feel awkward and unnatural – in the beginning.
Don’t worry. Most things feel awkward the first time. The more we practise the better we get and all of a sudden we can’t even remember what was the problem in the first place. For starters, we look at ways to breathe.
A good way to start is to actually get to know the different ways to breathe – on land. Lay down or sit comfortably with one hand on your chest and one hand on your belly. Just breathe in and out. Where do you feel a movement?
There are two major ways to breathe: Using the diaphragm, a sheet of muscle underneath the lungs, or the muscles between the ribs. When breathing only into the chest, we are not using our full lung capacity. Subconsciously we might have trained ourselves to breathe only with the chest as flat bellies are considered to be more attractive. You can breathe with the diaphragm without moving the belly, but for full abdominal breathing, also known as belly breathing, the belly expands (partially) with the inhalation and contracts with the exhalation.
We have a detailed description of how to experience the different areas of the lungs and how to train the full power of breathing: https://devocean-pictures.com/why-breathing-is-your-superpower/
#breathing #relax #meditation #TakeaMinute #underwater #diving #coralreef #relaxation #Indonesia #wakatobi #mindful #wideangle #yoga #GH5s #Nauticam
Take a Minute XXX : CephalopodsMy apologies for the long wait, to see another one of our "Take a Minute" videos, but it seems when technical difficulties meet political issues, electronic repairs can take an awfully long time. On top of that, the ongoing Corona business didn't help speed things up either. But.... we're back!
And just in time. Today is the birthday of the girl I hope to spend the rest of my life with. Whose love makes me want to be the best version of myself. Nicki, I love you to the moon and back! And what better way to say this, than with a Minute of cephalopods. Represented in this video by the dwarf cuttlefish, or Sepia bandensis. Love, this one is for you!
Cephalopods are molluscs with their arms attached to their head. The word is based on old Greek (kephalópodes; "head-feet"). Octopus, cuttlefish and squid are in a class of their own in multiple ways. Classified as cephalopods they lack a backbone in their soft bodies but show remarkable intelligence for invertebrates. These savvy softies arouse a great deal of interest in divers and science alike. Probably the most fascinating aspect of cephalopods is their ability to change colour as well as the texture of their skin in a blink of an eye. This way they can blend in with their surroundings perfectly or show bright warning or hypnotizing patterns at will.
Just below the surface of their skin sit thousands and thousands of chromatophores (colour-changing cells). Each chromatophore contains a sack of a particular pigment (black, brown, orange, red or yellow). By stretching the sack, the colour appears brighter. A complex system of nerves and muscles controls this magical transformation including the texture of the skin from smooth via small bumps to high spikes. Additionally, some cephalopods have iridophores, plates reflecting greens, blues, silvers and golds, while leucophores mirror the colour of the surroundings to perfect their camouflage.
They use their skill to hide from predators as well as to sneak up on their prey. But colour patterns are also a way to communicate to another or others in the form of flashing bright warning colouration, like the poisonous and venomous Flamboyant cuttlefish. As a last resort, they can release a cloud of ink and disappear through any hole their bony beak fits through. That’s the only hard part of the body of these curious creatures.
Cephalopods have the largest brain-to-body mass ratio as well as the most complex nervous system among all invertebrates. Basically, science is still struggling to understand and test certain aspects of the intelligence of cephalopods. Maybe soon there are new ways to measure and validate other forms of their intelligence too.
Almost all cephalopods are active hunters, pushing them to develop certain strategies and behaviour to find and catch their prey. Some crabs, the base of the most octopus food source, have powerful pincers to defend themselves and a long pursuit costs energy. Hence, octopuses are looking at how to use the work of others to their advantage, such as stealing bait from lobster traps or climb on board fishing boats to feast on the dead or dying crabs in containers.
As described above, cephalopods can use skin colouration and texture to communicate. Posture and locomotion add to their display. We were lucky enough to observe flamboyant cuttlefish flashing colours in courtship in Komodo ourselves. Eventually, the bigger female stopped and raised her arms to allow the small male to deliver its sperm. They went on for various rounds. Especially, squid use colour and (flashing) patterns to communicate, not only in courtship. Caribbean reef squid can send different colour patterns to squids on either side of their bodies at the same time. Humboldt squid use communication even in cooperative hunting techniques.
Octopuses can be trained to distinguish between different shapes and patterns. In laboratories, they benefit from an enriched environment, using bottles or toys to play with. Furthermore, they have repeatedly shown the ability to use tools. As seen by many divers, they collect, carry and use coconut husks and shells for protecting their soft bodies from predators.
The ocean is full of wondrous life forms, that makes us re-think everything we thought we knew about this planet and our place in it!
#dwarfcuttlefish #Sepiabandensis #lembeh #underwater #relax #arms #TakeaMinute #diving #cuttlefish #octopus #Indonesia #macro #PanasonicLumix #GH5s #Nauticam
Take a Minute XXIX: NudibranchsIn this minute of visual meditation, we would like to focus on nudibranchs in general instead of going into the specifics of the two species filmed in the waters of Bali (Indonesia). Divers lovingly call them nudis, short for nudibranchs, which makes them even cuter and brings out their true nature: beautiful, colourful, and exotic on the one hand, mysterious, bizarre and toxic on the other.
Different families of nudibranchs (further split into genus and species) form the order nudibranchia within the large taxonomic class Gastropoda, commonly known as snails and slugs. While all nudibranchs are sea slugs, not all sea slugs are nudibranchs. The name nudibranch originates from the Latin „nudus“, meaning „naked“, and the Ancient Greek βράγχια (bránkhia) for „gills“, referring to the gill-like appendages which protrude from the backs of many nudibranchs.
Although they possess eyes, their eyesight is thought to be limited to picking up light and dark shapes only. They view the world through chemical receptors in the shape of tentacles on their heads. These tentacles are called rhinophores and they allow nudibranchs to smell food, find potential mates, predators and provides them with some sort of situational awareness.
Nudibranchs can thrive nearly everywhere, from shallow, temperate, and tropic reefs to Antarctica and even hydrothermal vents. At present, there are well over 3,000 species of nudibranchs known to science, but new species are still found. Discoveries of large numbers of bioactive compounds suggest that sea slugs are an excellent biomedicine source which has fueled the research into this order within the animal kingdom.
However strange it may seem, these colourful families of sea slugs are carnivores, whose prey consists of sponges, coral, anemones, hydroids, barnacles, fish eggs, sea slugs, and other nudibranchs. To eat their food, most nudibranchs possess a radula, which is a toothed structure that they use to “chew” their food up. Some species suck out their prey after predigesting their tissue with selected enzymes, rather like a spider. Nudibranchs are very picky about what they eat, individual species or families of nudibranchs may eat only one kind of prey. Nudibranchs get their vivid colours from the food they eat, which in turn advertises to would-be predators, that they are poisonous, or at the very least foul-tasting. In any case, enough to be left alone by most.
The characteristic of aeolid nudibranchs, like the ones in this clip, are long, narrow bodies with numerous horn-like extension which are called cerata and serve as gills. The form of the cerata extends the surface for respiration significantly and is also used for defence. Various species feed on hydroids and their stinging cells (nematocysts) pass through the digestive system of some aeolids and are build into the tips of their cerata (watch “Take a Minute II” for more details).
Nudibranchs have a shell in their larval stage, but it disappears in the process of becoming an adult. They come in all shapes and sizes, not to mention wild colour pattern variations, which makes them so popular with divers and snorkellers. Some are very hard to tell apart, others strikingly different from anything you have ever seen before. Some stand out, others are highly camouflaged.
They also vary in sizes from massive beasts such as the“Moon-headed sidegill slug” (Euselenops luniceps) presented in „Take a Minute XIX“ to tiny speaks of some millimetres, like Costasiella kuroshimae a.k.a. “Shaun the Sheep” (shown in „Take a Minute VI“). This tiny creature has the ability to extract the chloroplasts from the food it eats and stores them in its cerata. This process is called kleptoplasty, and it enables “Shaun” to harvest/feed the energy that is released by the photosynthesis of these accumulated chloroplasts.
This is also the second feeding strategy of Melibe engeli („Take a Minute XXVI“). Through photosynthesis, the algae farms in its tissues produce nutrients for the Melibe in situations when food is scarce. The mutualistic symbiosis between different species of nudibranchs and unicellular photosynthetic dinoflagellates of the genus Symbiodinium (often known as ‘zooxanthellae’) has been known to science for quite some time. Most “solar-powered” nudibranch species take up Symbiodinium from their prey of soft or hard corals and cultivate them inside the cells of their digestive glands. But since Melibe engeli feeds exclusively on small crustaceans, science is still baffled as to how this nudibranch picks up the symbiont zooxanthellae for its emergency solar farms.
The search is on - not only for divers and snorkelers.
#nudibranch #Indonesia #underwater #relax #meditation #TakeaMinute #diving #snorkel #nudis #bali #slug #snail #macro #GH5s #Nauticam
Take a Minute XXVIII : Golden Sweepers (Parapriacanthus ransonneti)In this minute of relaxation, we would like to mesmerize you with the incredible performance of these small, but interesting reef fish. At first glance, Parapriacanthus ransonneti is just an unremarkable small fish that goes by many different names, depending on the region one encounters them. Yellow/Golden Sweeper, Pygmy sweeper, Golden/Yellow Bullseye, and Golden Glassfish, just to name a few. Several species of Parapriacanthus are often huddled together under the same banner of “Glassfish”, as they're partially transparent. However, since Parapriacanthus ransonneti rolls so nicely of the tongue, and in order to prevent any unnecessary confusion, we'll stick to this creature’s scientific name.
Parapriacanthus ransonneti are reef fish that inhabit coastal and offshore reefs between 3-30m of depth, throughout the West Indo-Pacific region. Although they can reach a maximum size of 10cm, most of the specimens encountered are smaller than that. They have a rather compressed, silvery pink translucent body with a greenish golden head and large eyes, showing a faint dark horizontal streak starting from the upper part of their gill cover to below the rear end of their dorsal fin. During the day they can form large aggregations in reef cracks, caves and overhangs, often sharing their day retreats with nocturnal hunters, like moray eels. As darkness sets in, they disperse and individually feed in the vicinity of the “home” reef.
Whilst hunting, they float high above the seafloor looking for larger zooplankton, like copepods and ostracods. Feeding at night comes with its own set of challenges, which besides certain obvious evolutionary adaptations, requires an intimate knowledge and understanding of the prey that one’s after as well as the predators one tries to avoid. As a reward for its efforts, P. ransonneti can wine & dine in relative safety. For the night has fewer predators for P. ransonneti than during the day. And with its midwater feeding behaviour, this clever little fish has managed to steer clear of most of the nocturnal predators that roam the reef. When daylight approaches, they converge again to a sheltered place on the reef, where the many combined eyes offer not only safety in numbers, but moreover provides the ability and opportunity to confuse any would-be assailants with their wild flashmob choreography.
Unfortunately, feeding in midwater at night is not without peril. Those that do, risk being spotted by a nocturnal hunter looking up from the reef in the hope of spotting the silhouettes of prey against the dim-lit surface. This is likely why Parapriacanthus ransonneti have evolved their bioluminescent qualities, which gives them the ability to produce their own light. They possess 2 types of ventral light organs. Firstly a Y-shaped thoracic light organ that emits a V-shape pattern from its throat, all the way to the base of its anal fins. Secondly, a linear anal light organ. Which, as one might already have suspected, emerges from the rectum of this fish.
These organs allow P. ransonneti to camouflage themselves against the light above, through a phenomenon called “counter-illumination”. In this process, the bioluminescent creature emits light from the underside of its body in order to break/smudge its silhouette and become less visible for any predator lurking below. Bioluminescence occurs when a protein named luciferin interacts with the enzyme luciferase, inside a particular light-emitting creature. Luciferin is usually obtained through the organisms these bioluminescent creatures consume. In contrast, the enzyme luciferase was thought to be exclusively made by the bioluminescent organism itself (endogenous) and is produced by transcription of DNA.
Even though the ability to shine a light from one's arse in order to blend in, might seem somewhat extreme to non-glowing creatures like ourselves, in the aquatic realm, however, bioluminescence is nothing new. What sets Parapriacanthus ransonneti apart from the rest of these enlightened creatures, is that it’s able to acquire both the luciferin and the luciferase from the copepods and ostracods in their diet. Somehow P. ransonneti manages to extract the luciferase enzymes from their prey, without damaging and/or changing the enzyme’s DNA in any way. And then puts them to work in their own bodies!
The discovery of this extraordinary achievement was/is very interesting for a number of reasons, but mainly because it suggests that the acquisition of certain physical traits across species are not always the result of their genetic makeup. Parapriacanthus ransonneti has made us re-evaluate much of what we thought to know about the evolutionary process of creating specific abilities, and how the environment in which a creature lives, is affecting said process.
#underwater #relax #meditation #coralreef #TakeaMinute #diving #travel #Komodo #Parapriacanthus #Indonesia #bioluminescence #GoldenSweeper #wideangle #reef #Amphibico