A Sea of Glass Page 6
Highly esteemed Sir,
On receiving your favour I thank you most kindly for your pleasing and clarifying answer. Your announcement that you intend to come to Dresden next summer and to visit us as well pleases us very much, and we request you to grant us the honour of your attendance certainly. Of your new splendid work, Das System der Medusen is the first volume already in our possession, and we do rejoice in being able to order immediately the second volume, when it is published, because your works are for our aims in replication both in description and in figures the most excellent and suitable among all books.
Again friendly thanking and hoping that we see you soon in person,
I remain with friendly greetings from my father and myself,
With most excellent respect,
Your devoted
Rudolf Blaschka
The strong influence of Haeckel also turns up in the Blaschkas’ fascination with siphonophores. For example, take the Blaschkas’ Portuguese-man-of war, complete with attached swimming bells and the dangling lures that are modified polyp stages (page 42). In addition to his interest in the developmental sequences of animals, Haeckel had an unusual interest in the division of labor that some groups like the siphonopohores and the hydrozoans show. Our glass collection includes representations of both themes, illustrated by the siphonophores. We have several series in glass showing different developmental stages, but the siphonophore version stands out in depicting stages that I’ve never seen before and that would not be easy to find in the wild. Each of the tiny sculptures in the series represents one of five stages in the siphonophore’s development, from tiny ciliated larvae to the process of budding the different polyp types that produce the multiformed adult jellyfish.
The Blaschkas also designed models to show the complex variations in the division of labor within each animal. The Apolemia must be the most stunning glass in our collection, both for its size, complexity, and sheer compositional brilliance. The glass figure of Rosacea, however, comes closest to showing the actual nematocyst lures dangling down from the feeding and reproductive polyps (page 47). The models of Rosacea, Velella, Halistemma, and man-of-war all show spectacular examples of division of labor; one can see the specialization of each individual zooid, or unit within the colony, that is responsible for the animal’s defense, feeding, or reproduction (Mapstone 2014). A watercolor of Halistemma rubrum depicts the basic form of a living siphonophore—the large swimming bell that is the powerhouse for fast movement and the long dangling tentacles that are the deathtraps for all manner of small shrimp and even fish, each tentacle capped with a deadly, red-tipped, neurotoxin-loaded harpoon. The differences between the flotilla of propulsive, swimming bells and the vast trailing armature of tentacles is easy to see, but harder to make out are the feeding polyps, nestled amid the warrior and reproductive polyps.
The beauty of these creatures aside, there is a darker part to Haeckel’s interest in siphonophores. For him, a siphonophore’s physiological organization also represented a model of the hierarchy of social systems; a siphonophore should not be viewed as an individual, but as a social unit, a “state.” In German, the word for “state” is Staat, hence the name Staatsquallen, or “state jellyfish” (Reiling 1998). In a “state,” all of the differentiated polyps and medusae contributed to the benefit of the whole: some specialized in feeding, others in reproduction or floating, and still others evolved for defense, with a stiff armature of stinging capsules. Haeckel presented the Blaschkas with a signed copy of his 1869 lecture on this subject, which addressed the division of labor in nature and in human society. This lecture laid the groundwork for the further development of Social Darwinism, a controversial philosophy that posits that persons and races are subject to the same laws of natural selection as those Charles Darwin described for plants and animals. This theory was the basis for promoting the idea that the white European race was superior to others and should rule over them. The chilling crux of the idea was Haeckel’s argument that a society’s level of culture stood in direct relation to the extent of its division of labor. According to Haeckel, primitive societies were characterized by “little division of labor” (Haeckel 1900). These ideas are believed to have catalyzed Germany to support an authoritarian state power and a rigid belief in eugenics that culminated in the horrific genocide carried out by the Nazis (Gasman 2007). We do not know how important these ideas were to the Blaschkas, or whether they shared Haeckel’s political as well as scientific philosophies. We are left only with the stories that history and art tell us.
° ° °
What I really hoped yet also feared to see on our dive in Liguria were Portuguese man-of-wars. Like others within the siphonophore group, man-of-wars are fish-eaters and can pack a punch strong enough to level a diver. In fact, a student of mine was injured during a dive fifteen years ago on the Yucatán Peninsula in Mexico. We were documenting coral reef health at a remote site near Akumal; we’d surfaced from a drift dive on one of our deeper reef sites when she began screaming that she’d been hit. A brightblue tentacle was draped across her arm, torn from the Portuguese man-of-war that had stung her. I peeled it off, hoping she didn’t have other stings and would not go into allergic shock. It was a stormy, wind-filled day and in the high seas it was hard for our boat to find us. It felt like hours that I looked for the boat while calming her and hoping like I had never hoped before that she would not get worse or we would not get hit by other tentacles, invisibly deployed around us. We finally hauled her aboard the boat and poured vinegar on the sting, hoping the acidity would deactivate the neurotoxin protein. She was lucky. Other than a hugely swollen arm and a terrifying experience for us all, she was okay. In regions like Australia and the Mediterranean, an average of ten people a day are sent to the emergency room with life-threatening allergic reactions to the neurotoxin, and over 10,000 people a year are stung in Australia.
Despite the dangers they pose, these are complex and beautiful creatures. Unlike the living version, our man-of-war in glass provides a safe opportunity to look closely at the parts that make up these very successful superorganisms. In contrast to many of the smaller transparent siphonophores, the man-of-war is unusual in having a bright-blue float that gives the animal buoyancy. It is also distinct in having three-to-five-foot blue tentacles that stretch from the bell and pinkish polyps that dangle from the gas-filled float. A close look reveals the collection of attached polyps, medusae, and poison-tipped defensive tentacles that make up the superorganism we call a siphonophore.
It was only after our second Mediterranean dive, in the no-fishing preserve of Portofino, that I understood how over-fished most regions of the Mediterranean are and how this favors jellyfish. The waves were down when we reached the preserve, an hour’s motor around the headland. Anchored at the edge of a deep rocky reef, we slipped into water clear and sharp with high visibility. Big fish, little fish, red fish, blue fish! Fish of all sizes and colors surrounded us. As we descended to the bottom, Marco, the divemaster, flashed the hand signal for grouper, and there it was, nearly the size of Nathan. We were in an underwater fairyland, with rock walls carpeted with the Blaschka matches precious red coral (Corallium rubrum) and purple gorgonian (Paramuricea clavata). We swam through vast schools of anchovy and at least four other species of common plankton-loving fish. This small preserve is what the entire over-fished Mediterranean is supposed to be like! I can’t say for sure which of these fish might prey on larval or adult jellyfish, but there were definitely no mauve stingers at this site. Because plankton are notoriously patchy, I’d be a poor scientist if I argued that there had been lots of jellyfish the day before due to the lack of predatory fish at the shipwreck site and none today at this site because of the presence of fish. There could be several other explanations, including weather and chance, but the pattern did get me thinking about the widespread effects of over-fishing as a likely cause of jellyfish blooms.
Ecologists describe increases in jellyfish blooms as a sign of a changin
g ocean. Jellyfish are one Blaschka group that will likely do well in warming oceans with fewer fish and turtles to control their numbers. But of course, they will not increase uniformly as a group with their diversity intact; rather, as with birds, some of the fairly common nuisance species—the jellyfish equivalent of starlings—will do well, and other examples of spectacular diversity will dwindle. So while there has been a lot of press about the danger of jellyfish taking over our oceans, I still contend diversity within this group will decline, while the population of particular species, like the mauve stinger in the Mediterranean, will increase. Fernando Boero, jellyfish expert and organizer of Jellyfish Watch, estimates that nuisance species have increased in the Mediterranean (Boero et al. 2008; De Donno et al. 2014). Many of our Blaschka pieces reside in this group.
In the Pacific Northwest, Claudia Mills from the Friday Harbor Labs has studied the pelagic jellies her entire career. This region of the Pacific Northwest, tucked in protected waters near the junction of both northern and southern ranges of some species, is home to some of the world’s most diverse gelatinous zooplankton fauna. Some of us who have long worked at the labs remember well the days in the early 1980s when Osamu Shimomura was studying the Green Fluorescent Protein (GFP) that gives jellyfish their glow. Between 1961 and 1988, he hired fleets of kids to pull up bucketfuls of the crystal jelly (Aequorea victoria), a Blaschka match, from our docks. GFP is the glowing magic that is responsible for bioluminescence in many of the cnidarians and is particularly abundant in the crystal jelly, which used to dominate our plankton and still sails our seas. Shimomura and colleagues won a Nobel prize for the work done with the GFP of the crystal jellyfish. Claudia estimates that the crystal jelly is rarer now and would not support the level of research effort that was needed for Shimomura’s discovery. Claudia and others also observe that many other jelly species have declined, although it is tough to track their status (Condon et al. 2012; Dong et al. 2010). Our red-eye medusa, Polyorchis penicillatus, a tall-belled hydromedusa and stunning Blaschka match (above), has also declined in the waters off Washington State (Mills 2001), although we were delighted to see a few in the summer of 2015. Further afield, many of the hydromedusae in the northern Adriatic Sea have declined, including two of the five species in the family Polyorchidae.
Red-eye medusa (Polyorchis penicillatus) in Blaschka watercolor (left) and alive. This jellyfish has declined in the last decade in the San Juan Islands (Mills 2001), although we were pleased to see several in summer 2015. Watercolor courtesy of the Rakow Research Library, Corning Museum of Glass, BIB ID: 122338; photo by Susan Middleton.
What do we stand to lose? If we look to the Mediterranean, ground zero in our search for Blaschka matches, we know that marine vertebrates—back-boned animals like turtles, marine mammals, and fish (including bluefin tuna, sea bass, and hake)—are in danger of extinction from over-fishing, habitat degradation, and pollution, according to a report from the International Union for Conservation of Nature (see www.iucnredlist.org). More than forty species of Mediterranean fish are endangered (see chapter 8). Although we know that certain species of jellyfish are disappearing, and the diversity is diminished, it will be a long time before we have estimates on how many rare and spectacular jellyfish we are losing. Why? Pelagic animals like the jellies are difficult to catalogue because they are broadly distributed throughout the open ocean. This challenge has prompted a new global effort to track changing gelatinous zooplankton populations (Lucas et al. 2014). In the meantime, the species that are dangerous or prone to blooms, such as the mauve stinger, moon jelly, and Portuguese man-of-war, continue to sound the alarm that our oceans are out of balance. One thing is certain: the oceanic food webs that thrived 160 years ago, when Leopold Blaschka first encountered the magic of jellyfish on a nighttime sojourn across the sea, would have had far more predators on jellyfish, like octopuses, squid, and turtles, and enough sharks to have kept us out of the water.
4.
WORMS
Ecosystem Engineers Undercover
The tentacled tubeworm (Pista cretacea). Inside its burrow, with only a few tentacles stretched across the sand or mud of its home, this worm would be easily overlooked. This glass rendition of a worm shows the full mass of feeding tentacles and bright red gills and the long line of bristles running the length of the body. Photo by Claire Smith.
ON A STILL DAY like this, the cliffed shore of Appledore Island in Maine is a fine perch for early dawn coffee, with a soft-pinked ocean stretching west nine miles to the Portsmouth, New Hampshire, bridge. I’m teaching at the Shoals Marine Lab, a field station for the study of marine biology jointly run by Cornell and the University of New Hampshire. Although within sight of the mainland, it’s actually pretty remote; the RV John M. Kingsbury, a sturdy sixty-foot green and tan fishing boat, is our only way to reach the mainland. I see it bouncing ready at the dock. The big question is, will our band of twenty-something students be ready for a 6:00 a.m. departure? Last night, we’d reviewed the plan for the upcoming low-tide worm hunt at Creek Farm. The early departure was not a selling point for the millennials, but I hoped the prospect of hot showers and post-worm-hunt breakfast would tip the scales. There was certainly no danger of my oversleeping; I had gotten a 5:00 a.m. wake-up call from on-duty gulls outside my window, enthusiastically announcing to any of their brethren within earshot that the sun was rising. As I reached the dock, it was still devoid of students. I worried the tide might not wait for us and considered going after them, but then I saw the shuffling band of sleepy Cornell undergrads, buckets in hand, crest the hill—not alert, but with good-natured smiles, a bonus that early in the morning. Once again, the world felt good; we were about to embark on a muddy adventure to search out new frontiers of worm diversity from one end of a great tidal mudflat to the other.
It’s easy to appreciate how the aesthetic appeal of a sea star or a jellyfish might inspire a person to capture it on canvas or in glass, but the true test of a great artist is to render the improbable as art. The Blaschkas did nothing less when they transformed a tubeworm into a mesmerizing object of art (page 68). The magic of their work lies in their artistic sense of design, coupled with a passion for natural history and the biology of form, as seen in the rendering of the tube-dwelling worm with red gills. Another example is the Serpula feather duster worm, which they re-created in both glass and watercolor (page 84), capturing perfectly the bright red tentacle crown and the red-striped operculum, a trapdoor that snaps shut to secure the closed tube. The even bigger prize for transforming the normal into extraordinary should go to their model of the burrowing lugworm Arenicola, since in glass it’s the normal worm that benefits most from an artistic eye. In their watercolor and eventually glass, the Blaschkas captured just the right curves and green body color to maximize the impact of the red gills and the signature dorsal blood vessel showing through the body, exactly as it does in a live worm (page 78). We know they thought deeply about the internal form as they worked, because in one Blaschka drawing of the lugworm, it is laid open to show a rare vision of how the external structures match up with the internal anatomy, showing the matched muscles, gills, and nephridia, which function as kidneys.
The Blaschkas shape a surprising diversity of species, depicting even rare worms—or at least ones I didn’t initially recognize, like Pherusa plumosa. Pherusa, a sand-dwelling burrower, normally encrusted with sand grains or mud from eyespots to pygidium, is unrecognizable shimmering in glass. A more common worm, Perinereis cultrifera, the absolutely dirt-common clam worm, is majestic in its glass likeness. Nonetheless, the most arresting piece in our collection is a tube-dwelling terebellid worm, with its red glass gills and long winding feeding tentacles, which its living counterpart splays across the mud in search of food (page 68). Once again, we see the Blaschkas’ masterful ability to convey something more than the static animal. Here, they show the shimmering nature of the muscles playing underneath the transparent, flexible cuticle of the worm, each segment set off with t
iny, red-studded parapodia, projecting like the stubby legs of a millipede. On each parapodium are small hooks in set rows, all facing backward, to hold tight to the burrow sides in case a predatory fish tries to pull the worm out. In all three of these worms, you can see the signature characteristic of marine worms—the projecting and elaborately ornamented appendages protruding from each body segment. The Blaschkas used mixes of colored glass on only a few of the glass animals, including the red gills of this worm, so that those who don’t have microscopes or time to look carefully can still appreciate that they are beautiful, surprising animals.
Take my students. Some initially think worms are mud-dull, so it’s fun to see them sit up with interest when I share the range of worm biodiversity that exists. My lecture begins with the very consistent, logical layout of the long snake-like worm body plan, but then it’s juxtaposed against the shocking variations on this simple theme. I compare the variations in massive jaws and huge bristly appendages of the vicious, mobile, predatory bloodworms, and then we consider the differences of the array of sedentary tubeand burrow-dwelling worms. Some great families of mobile worms depicted by the Blaschkas include the clam worms, bloodworms, and bristle worms. To see the mighty, rather horrific curved black teeth at the end of the bloodworm’s proboscis, and to know they are armed with venom glands, makes you very glad these mobile predators are smaller than we are. However, some of the clam worms can reach two feet in length and have big jaws. The diet of these mobile worms includes other worms, corals, and small crustaceans, with some plant matter mixed in.
Sedentary tube- or burrow-dwelling worms, on the other hand, are less ferocious but come in stunning colors and tentacle shapes. These worms are of several types, depending on whether they filter plankton from the water column with bright plumes of tentacles, or dredge through the sand and mud with ciliated strand-like tentacles that can stretch three feet across the bottom, or simply eat and process mud, like the lugworm. The Blaschka watercolor of Spirorbis spirorbis, a very diminutive plumed worm no bigger than a ladybug, magnifies it to the scale of a tiger. Spirorbis builds a hard, white, spiraled tube and is so tiny that most people wouldn’t even notice it in nature. Yet this is no ordinary earthworm—like the serpulid tubeworm, Spirorbis is topped with a spectacular red plume of tentacles used to filter plankton from the sea. When the tide is out, the tentacles are withdrawn, and only the innocuous white spiral is seen attached to rocks throughout the Gulf of Maine or even in the harbors of Boston and San Francisco. The Blaschkas’ watercolor shows the worm pulled from its tube, revealing more than the brilliant tentacles and tiny hooks that hold it in place within the tube, and the eyespots that cause the tentacles to flicker in and out with shadows. The watercolor also shows the eggs and frilled, eyed larvae that are brooded by each mother worm inside her tube. I am impressed that the Blaschkas knew these details of the tiniest worm, holding close her brood of squirming larvae inside delicately sculpted porcelain tubes. Our glass model of the sand worm, Pista cristata, is quite sensational, showing both the diminutive tentacled tubeworm and its gem-like case made of glass sand grains (below). Sally Woodin, a professor at the University of South Carolina and one of the world’s experts on the ecology of burrowing worms, tells me this worm can form large beds in places like Coos Bay, Oregon, with emergent ends of the tubes marking each burrow.