S
seaclean
Guest
When a sea urchin dies, does it omit a deadly gas into the tank making it possible to kill all the fish and coral.
florida joe
Well-Known Member
This is part of an article on sea cucumbers by Rob Toonen it explains how cukes can nuke a tank
The final and most drastic response possible is when a stressed cuke expels its Cuvierian tubules. These tubules are a series of long, spaghetti-like tubes which are associated with the hind gut of certain sea cucumbers, and are thought to be primarily defensive in function. Not all species possess these defensive structures, and even those that do, generally do not eject them without dire provocation. The Cuvierian tubules are located near the anus, and branch off from the base of the respiratory tree (the branched ‘gills’ of a sea cucumber). Now, if you’re reading this carefully, you should be wondering why the ‘gills’ of a sea cucumber are so near to its butt. Well, the answer is simple, although unusual – sea cucumbers actually breathe through their anus! That’s right – many people make the mistake of watching a sea cucumber breathe (it is quite obvious as the anus opens to allow water to flow in and then pinches down as the animal ‘exhales’ the water it just ‘inhaled’) and thinking that the opening that they are watching is the mouth. In cucumbers however, respiration is done through the anus, and the respiratory tree is associated with the other end of the digestive system. Why does any of this matter? Because when a cucumber is really threatened (it thinks it is about to be eaten), it can respond by inhaling a bunch of water and physically rupturing (literally exploding) the hind gut to expel these tubules and a soup of defensive chemicals that are intended to prevent the predator from ever wanting to mess with a sea cucumber again. The amount of defensive chemistry and the specific combination of chemicals that are produced varies by species from just under two to nearly three and one-half percent of the dry weight of the cucumber (Bryan et al. 1997). In general, the chemicals which appear to protect the sea cucumbers from being eaten are saponins (soap-like compounds) which are derived from triterpenoids (Ponomarenko et al. 2001; Stonik and Elyakov 1988). These chemicals usually work well to discourage many generalist predators, and unfortunately are also likely to seriously impact, and potentially even wipe out all their tankmates in a reef aquarium (the so-called ‘cuke-nuke’).
The final and most drastic response possible is when a stressed cuke expels its Cuvierian tubules. These tubules are a series of long, spaghetti-like tubes which are associated with the hind gut of certain sea cucumbers, and are thought to be primarily defensive in function. Not all species possess these defensive structures, and even those that do, generally do not eject them without dire provocation. The Cuvierian tubules are located near the anus, and branch off from the base of the respiratory tree (the branched ‘gills’ of a sea cucumber). Now, if you’re reading this carefully, you should be wondering why the ‘gills’ of a sea cucumber are so near to its butt. Well, the answer is simple, although unusual – sea cucumbers actually breathe through their anus! That’s right – many people make the mistake of watching a sea cucumber breathe (it is quite obvious as the anus opens to allow water to flow in and then pinches down as the animal ‘exhales’ the water it just ‘inhaled’) and thinking that the opening that they are watching is the mouth. In cucumbers however, respiration is done through the anus, and the respiratory tree is associated with the other end of the digestive system. Why does any of this matter? Because when a cucumber is really threatened (it thinks it is about to be eaten), it can respond by inhaling a bunch of water and physically rupturing (literally exploding) the hind gut to expel these tubules and a soup of defensive chemicals that are intended to prevent the predator from ever wanting to mess with a sea cucumber again. The amount of defensive chemistry and the specific combination of chemicals that are produced varies by species from just under two to nearly three and one-half percent of the dry weight of the cucumber (Bryan et al. 1997). In general, the chemicals which appear to protect the sea cucumbers from being eaten are saponins (soap-like compounds) which are derived from triterpenoids (Ponomarenko et al. 2001; Stonik and Elyakov 1988). These chemicals usually work well to discourage many generalist predators, and unfortunately are also likely to seriously impact, and potentially even wipe out all their tankmates in a reef aquarium (the so-called ‘cuke-nuke’).
blackjacktang
Active Member
I saw a 220g sps display and it about 4 of those really colorful cukes. I just thought in my head, if all those die, your screwed.