Tag: coral reef

  • Palm Jumeirah and Dubai’s Artificial Islands: The Land That Needs a Software Update

    Dubai’s beaches lose between 10,000 and 15,000 cubic meters of sand per year to natural erosion. The Palm Jumeirah — 5.72 square kilometers of artificial land, 94 million cubic meters of dredged marine sand, shaped into a palm tree visible from orbit — has accelerated that rate by disrupting the natural alongshore sediment transport that used to feed sand from one beach to the next. The island blocks the current. The sand that would have traveled east piles up on the western side. The beaches to the east starve. Simultaneously, the Palm’s own fronds lose sand to wave action and tidal currents, requiring continuous replenishment — over 3.5 million cubic meters in a single major maintenance operation. NASA satellite data showed the island sinking at approximately 5 millimeters per year. The breakwater that protects the fronds from storm waves also traps water inside the lagoons, reducing circulation, which produces stagnant zones where algal blooms generate the “unpleasant smell” that tourists have been reporting since the island opened. Dubai has spent millions armoring its coastline with hard structures — seawalls, groynes, rock revetments — to prevent the erosion the island caused on adjacent beaches. The Palm Jumeirah is not a piece of land that was built and then exists. It is a piece of land that was built and must be continuously rebuilt, replenished, armored, and circulated — or it dissolves back into the Persian Gulf it was dredged from. Every other piece of infrastructure in this course sits on stable ground. The Palm Jumeirah is the ground, and the ground is temporary.

    What was built

    Between 2001 and 2006, Nakheel Properties — the real estate development arm of the Dubai government — dredged sand from the Persian Gulf seabed and sprayed it into the shape of a palm tree off the coast of Jumeirah Beach. No concrete foundation. No seawall at the base. The island is sand and rock — sand forming the fronds and the trunk, rock forming the protective crescent breakwater that shields the fronds from open-ocean wave action. The breakwater alone required 7 million tonnes of rock, quarried and barged from the Hajar Mountains 100 kilometers away. The total construction cost was approximately $12 billion. The island added 78 kilometers of coastline to Dubai — which was the economic point: more coastline means more beachfront property, and beachfront property in Dubai commands premiums that inland real estate does not.

    The Palm Jumeirah was Phase I of a three-phase plan that included Palm Jebel Ali (50% larger, shelved during the 2008 financial crisis, relaunched in 2023 with a $4.6 billion loan) and Palm Deira (the largest, later redesigned as the smaller “Deira Islands”). Simultaneously, Nakheel constructed The World — 300 islands arranged in the shape of a world map, 4 kilometers off the coast, intended for private island ownership by the global ultra-wealthy. The 2008 crash killed The World’s momentum. For a decade, the archipelago sat mostly empty — visible on satellite imagery as a dissolving world map, the sand slowly returning to the sea. A Monaco-themed hotel opened in 2022. A Sweden Island resort is under development. The pattern is clear: development happens island by island, slowly, without the coordinated buildout the original vision imagined. Individual island owners are responsible for their own shoreline protection — a cost that runs into millions of dirhams annually per island, which explains why most islands remain undeveloped.

    The maintenance physics

    The Delta Works protect land that exists naturally but would flood without intervention. The Palm Jumeirah is different — it protects land that doesn’t exist naturally and would vanish without intervention. The Netherlands fights the sea to keep existing land dry. Dubai fights the sea to keep manufactured land from dissolving. The maintenance is not optional. It is existential. If the sand replenishment stops, the fronds erode. If the breakwater degrades, storm waves enter the lagoons. If the circulation pumps fail, the water stagnates. If the seawalls on adjacent beaches aren’t maintained, the coastline retreats at rates of up to 10 meters per year in some sections.

    The dredged marine sand that forms the island is particularly susceptible to erosion because it lacks the binding properties of naturally deposited coastal sand — the shell fragments, organic matter, and compaction that give natural beaches structural cohesion. The Falkirk Wheel was built from steel and concrete to last 120 years. The Schwebebahn was built from structural steel to last 125 years and counting. The Palm Jumeirah was built from sand — a material that water is specifically good at moving — and its longevity depends entirely on how much money and energy Dubai commits to putting the sand back faster than the sea takes it away.

    The 1.2 square kilometers of coral reef destroyed during dredging operations compounded the problem. Coral reefs function as natural breakwaters — they dissipate wave energy before it reaches the shore. By destroying the reef to build the island, the construction removed the natural coastal defense that would have reduced the erosion the island now experiences. The Chicago River Reversal solved a water quality problem and created an ecological one. The Palm Jumeirah solved a real estate problem and created a coastal one — the reef that used to protect the coast was buried under the island that now needs protection from the coast.

    The ecological inventory

    The sediment plume from dredging operations buried coral reefs and oyster beds under a 5-centimeter layer of silt across a wide radius. Seagrass beds — critical habitat for dugongs, sea turtles, and juvenile fish — were smothered. Turbidity from suspended sediment reduced light penetration, killing photosynthetic organisms. The conflict minerals extracted from ungoverned supply chains leave environmental damage that the extracting party is not positioned to remediate. Dubai’s artificial islands leave marine damage that the developer remediates partially and voluntarily — artificial reef structures have been installed along the breakwater, and some marine recovery has been documented — but the net ecological balance is negative, and the remediation is cosmetic relative to the scale of the original destruction.

    The stagnant water problem persists. The breakwater’s crescent shape, designed to protect the fronds from storm waves, also prevents natural tidal flushing. Engineers deepened channels and installed circulation infrastructure to move water through the lagoons, but the system is only partially effective. The Barcelona vacuum garbage system moves waste through sealed pipes by pressure differential. Dubai moves seawater through manufactured lagoons by engineered circulation — the same challenge of forcing flow through an environment that would naturally be stagnant, using infrastructure to create the conditions that nature would have provided if the island hadn’t been built.

    Palm Jebel Ali: the sequel

    In 2023, Nakheel relaunched Palm Jebel Ali — the second palm, 50% larger than Jumeirah, shelved since the 2008 crash. The redesigned masterplan includes 80 hotels, homes for 35,000 families, six marinas, and theme parks including SeaWorld Aquatica and Busch Gardens. Jan De Nul Dredging was awarded an AED 810 million contract for marine works — dredging, reclamation, beach profiling, and sand placement. The first eight fronds were scheduled to be site-ready by early 2025, with a revised completion target of 2027. The project is aligned with the Dubai 2040 Urban Master Plan and backed by Dubai Holding’s institutional support. Every lesson the Schwebebahn teaches about infrastructure precision and the dabbawalas teach about operational resilience is inverted at Palm Jebel Ali: the infrastructure is not precise, it is approximate (sand shaped into a landform), and the resilience depends not on human systems but on the continuous expenditure of capital to counteract erosion that will never stop.

    The China parallel

    Dubai builds artificial islands for real estate. China builds them for military projection. The seven artificial islands China has constructed in the Spratly Islands in the South China Sea — dredged coral and sand piled on reefs — host fighter jet hangars, missile systems, radar installations, and 3,000-meter runways. The autonomous weapons and loitering munitions that represent the cutting edge of military capability are deployed from islands that, like Dubai’s, are sand formations in open water subject to the same erosion physics. The difference is that Dubai’s islands are luxury real estate whose maintenance is funded by property premiums. China’s islands are military installations whose maintenance is funded by defense budgets. Both are land that exists only because a government decided to build it, and both will dissolve if that government stops maintaining them. The Great Man-Made River depletes an aquifer that will never refill. Dubai’s islands erode sand that must be continuously replaced. Both are infrastructure that consumes a finite resource — fossil water in Libya, dredged marine sand in Dubai — and both depend on the willingness of a government to keep paying the bill indefinitely.

    The Mexico City Gran Canal was built on a lakebed that is sinking. The NYC steam system was built on pipes that are aging. The qanats were built above aquifers that are depleting. Dubai’s islands were built on the sea — and the sea, which was there before the sand and will be there after it, is patient, and the sand is not, and the infrastructure that looks like land from a satellite photograph is, at the molecular level, a temporary arrangement between Dubai’s construction budget and the Persian Gulf’s tidal currents — an arrangement that must be renegotiated, in sand and rock and millions of dirhams, every year, for as long as the island exists, which is exactly as long as the maintenance continues and not one day longer.

  • Fish That Use Tools: The Species That Shattered Assumptions About What Fish Can Do

    In 2006, a diver named Scott Gardner was ascending from an 18-meter dive in the Keppel Islands region of the Great Barrier Reef when he heard a cracking noise. He looked over and saw a blackspot tuskfish hovering above a sand patch, holding a cockle shell in its jaws. The fish was rolling onto its side and slamming the shell against a rock—alternating left and right blows, aimed at the pointed section of the rock for maximum impact—until the shell cracked open. Scattered around the rock were broken shells from previous meals. This wasn’t an isolated event. It was a feeding station. The fish had a preferred anvil, and it had been using it long enough to accumulate a midden of shattered prey.

    Gardner photographed the sequence. The images were published in Coral Reefs in 2011, and the paper posed a question in its title that a generation of biologists had considered already answered: “Tool use in the tuskfish?” The question mark was doing heavy lifting. By the definitions that Jane Goodall had established—the use of an external object as a functional extension of mouth or hand in the attainment of an immediate goal—the tuskfish was using a tool. The external object was the rock. The goal was food. The behavior was deliberate, sequential, and repeated. The only reason anyone hesitated to call it tool use was that the animal doing it was a fish.

    Why this matters more than it should

    For most of the history of comparative cognition, the assumption was straightforward: fish are simple. They operate on instinct. They have small brains, short memories, and minimal behavioral flexibility. Tool use—the cognitive capacity to identify an external object, recognize its functional utility, and deploy it to achieve a goal—was reserved for the clever animals: primates, corvids, maybe elephants and sea otters. The hierarchy was implicit and rarely questioned. Mammals and birds think. Fish react.

    The tuskfish broke that hierarchy not by being unusually smart but by doing something that forced the definition of intelligence to either expand or become incoherent. If tool use is a marker of advanced cognition, and a fish uses tools, then either the fish is cognitively advanced or tool use isn’t the marker we thought it was. Both conclusions are uncomfortable for the framework that produced the hierarchy in the first place.

    The discomfort deepened as evidence accumulated. The tuskfish observation wasn’t a one-off. A 2025 study led by Macquarie University, published in Coral Reefs, documented anvil use in five species of Halichoeres wrasses across the western Atlantic—the first evidence of tool use for three of those species and the first video evidence for the other two. Through a citizen science initiative, researchers gathered 16 new observations of wrasses deliberately picking up hard-shelled prey and smashing them against rocks, corals, and other hard surfaces. The findings extended the known range of fish tool use from the Indo-Pacific to the Atlantic and from a handful of isolated observations to a pattern distributed across an entire fish family spanning 50 million years of evolution.

    Culum Brown, head of the Fish Lab at Macquarie University and one of the foremost researchers on fish cognition, suggested that wrasses may be fishes’ answer to primates among mammals and corvids among birds—a lineage with a disproportionate number of examples of cognitive complexity relative to the broader group. Researchers at the Paris-Saclay Institute of Neuroscience found that wrasses have a larger telencephalon and forebrain region compared to other teleost fish, including a substantially enlarged inferior lobe—a brain structure with no direct analog in mammals or birds—that shows unique connectivity to the pallium, a region already linked to higher-order cognition in other animals.

    The physics problem fish solved

    The reason tool use is rare in fish isn’t necessarily cognitive. It’s physical. Water is 800 times denser than air. Try swinging a hammer underwater and you’ll understand the constraint immediately. The momentum required to crack a shell with an object held in your mouth, while suspended in a fluid medium that resists rapid movement in every direction, is orders of magnitude harder to generate than doing the same thing on land. A chimpanzee cracking a nut with a rock is operating in an environment that cooperates with the physics of impact. A fish is operating in an environment that actively resists it.

    The tuskfish solved this by inverting the relationship: instead of swinging a tool against a stationary target, it swings the target against a stationary tool. The rock is the anvil, fixed in the substrate. The shell is the projectile, gripped in the fish’s jaws and slammed against the anvil through rapid body rotation. This isn’t just tool use. It’s tool use adapted to an environment where the conventional approach—wielding a hammer—is physically impossible. The fish engineered a workaround.

    The sixbar wrasse took the same approach in captivity. Given food pellets too large to swallow and too hard to break with its jaws, the wrasse carried the pellets to a rock in its aquarium and smashed them. The researcher who observed it, Łukasz Paśko at the University of Wrocław, watched the wrasse perform the behavior 15 times and described it as “remarkably consistent” and “nearly always successful.” The behavior only appeared after many weeks in captivity, suggesting the fish learned it through individual experience rather than instinct—it tried other approaches first, found them inadequate, and developed a new strategy.

    Anvils, middens, and long-term site fidelity

    A 2023 study on graphic tuskfish in New Caledonia found that specific anvils showed evidence of being used by one or more tool-using fish for years. The anvils accumulated debris. Other fish species learned to recognize the visual and auditory cues of tool use in progress—the body movements, sand clouds, and the “clack” sound of shell hitting rock—and gathered as scavengers. In 94 percent of observed tool-use events, attendant fish from six different families showed up to pick up fragments: surgeonfishes, triggerfishes, butterflyfishes, wrasses, angelfishes, and damselfishes. The tuskfish’s tool use had created a micro-ecosystem around its feeding station—a social and ecological structure generated by a fish banging a clam on a rock.

    The wrasses also showed flexibility in their tool use, selecting different types of anvils for different prey and sometimes switching anvils mid-session when the first choice wasn’t working. This isn’t stereotyped behavior—the kind of fixed action pattern that “instinct” describes. It’s decision-making under uncertainty, adapted in real time to the properties of the specific prey item and the available tools.

    The archerfish problem

    The wrasses aren’t the only fish that complicate the tool-use question. Archerfish—four-inch tropical marksmen from estuaries and mangroves between India and the Philippines—hunt by shooting precisely aimed jets of water at insects sitting on vegetation above the water’s surface, knocking them into the water where they can be eaten. The archerfish accounts for refraction at the water’s surface, adjusts for the target’s distance and position, and can hit prey up to three meters above the waterline. Researchers have demonstrated that archerfish can learn to recognize human faces and can be trained to hit specific targets, showing a capacity for visual discrimination and precision that wouldn’t be out of place in a primate cognition lab.

    Whether the water jet constitutes a “tool” depends on how strictly you define the term. The archerfish isn’t wielding an external object—it’s producing a projectile from its own body, more analogous to a spider’s web than a chimpanzee’s stick. But the functional outcome is the same: an organism using a mechanism beyond its own body to obtain food that would otherwise be inaccessible. The boundary between tool and technique blurs when the organism in question can’t hold anything in its hands, because it doesn’t have hands.

    What 600 species of wrasse haven’t told us yet

    There are over 600 species of wrasses worldwide. The Macquarie University team’s citizen science initiative is explicitly calling for divers and snorkelers to report observations of anvil use, acknowledging that the documented cases almost certainly represent a fraction of the actual prevalence. Brown put it directly: “For a long time, tool use was thought to be exclusive to primates and birds. We are still far from knowing how many species of wrasses use tools.” The field of fish cognition itself is young—69 percent of published studies used captive-reared subjects, only 9 percent conducted experiments on wild fish in their natural environment—meaning we’ve been studying fish cognition primarily by watching captive fish in artificial environments and then drawing conclusions about what fish can’t do.

    The tuskfish cracking a cockle on a rock doesn’t prove that fish are as smart as chimps. It proves that the cognitive hierarchy we built—mammals on top, birds below them, everything else at the bottom—was a projection of our anatomy onto our definition of intelligence. An animal that solves the same problem a primate solves, in a medium 800 times denser than air, without hands or arms, using a body plan that hasn’t shared a common ancestor with primates in over 400 million years, isn’t failing to be smart. It’s being smart in a way we weren’t looking for.

    We cover fish cognition alongside dolphin communication, elephant memory, and primate social intelligence across our Animal Culture & Knowledge course—including why the most important discoveries in comparative cognition keep coming from the species we assumed had nothing to teach us.