Dr. John Bruno introduced me to NOAA’s Coral Reef Watch website last year. It’s a online tool for tracking global sea surface temperature data in real-time. But, really, all you need is an affinity for color scales to find it useful. Reddish areas on the map mean corals beware; temperatures are unusually high. For sleep deprived master’s students, pretty colors are easier on the eyes that plotted regressions.
But what about temperatures, say, a quarter mile beneath the surface? There are no user-friendly websites or pretty maps for tracking anomalous temperatures in deeper waters. Little light reaches to this depth and it is nearly impossible for satellites to gather data. Perhaps that’s why awareness of climate-induced changes in the mesopelagic environment is only recently gaining ground.
Last week, NPR’s Science Friday hosted Dr. William Gilly of Stanford’s Hopkins Marine Lab. His lab is investigating the recent population increase and geographic spread of the deep-water Humbolt Squid up the California coast. This tropical jumbo-sized squid has even been spotted in Sitka, Alaska!
Why are there more and why are they moving? One theory suggests that their mesopelagic habitat is changing, and the squid are following new temperature and oxygen gradients. New science does conclude that oxygen levels off California are changing at about 1000m depth. But very little is known about how mesopelagic creatures are responding
The full NPR interview is worth a listen for those of you interested in new indicators of mesopelagic environmental change. The deep deserves attention, too.
Best headline ever: “Attack of the giant squids: Terror as hundreds of 5ft long creatures of the deep invade Californian coastline” (thanks to the Daily Mail). Turns out the backstory behind this one is even more interesting: the squid at hand (the humboldt squid) have envaded the San Diego coastline en masse due to unknown reasons (apparently global warming, shortage of food, predator avoidance and even underwater earthquakes have been cited as possible explanations). These squid are huge – up to 2m in length an weighing ~50kg, and school in numbers upto 1200.
Sounds relatively harmeless, right? Here’s how Scott Cassell, a commercial diver out of La Jolla described his experience diving with the Humboldt squid:
The monstrous squid remains motionless just ten feet away. Emotions gave way to cognitive thought and I trained my camcorder on him and begin to record. Almost on cue, he begins his approach. Then, with blinding acceleration, he lurches onto me with a powerful “thud crackle”. He slams into my chest. The impact was incredibly powerful, knocking the wind out of me. His huge arms envelope my complete upper body and camera and I can feel my chest plate move as his beak grinds against it. The crackle and scratching of thousands of chitenous ring teeth against my fiberglass/kevlar chest plate is unmistakable. (Read more)
The rest of Cassell’s article is fascinating:
The beak of a Dosidicus gigas is large and very powerful. The edges are assharp as trauma shears and are capable of gouging out an orange-sized chunk of flesh, regardless of tissue make up. I have seen a five-foot Dosidicus gigas bite through the thick bone of a tuna head, skull and all, with minimal effort removing fist-sized portions with each bite.
To hold their prey item firmly, this squid has about 2,000 suction disks; each lined with chitenous ring teeth. Chitin is a material similar to that of fingernails and that of beetle exoskeletons (A polysaccharide). These chitenous ring teeth are needle sharp and very effective. Every suction disk has up to 36 of these teeth. That means a Humboldt squid employs as many as 72,000 teeth upon its hapless victims. Prey has little chance of escaping a Humboldt squid’s deadly embrace.
Thousands of ring teeth cut into the flesh of their prey so deeply, you can hear it. When they drag their victim away with pulses from their massive jet funnel, the sounds of their hapless victim being ripped apart fills the water. It sounds a bit like heavy duty Velcro being pulled apart underwater. Then the beak can be heard, that huge knife-edged beak. The gouging of bone and tissue sound like the shredding of cabbage combined with that of hacking apart coconuts with a machete.
But to cut to the chase – skip to around 1.40 onwards in the video below for the footage (2.22 is also pretty freaky).