The science pages use some jargon. Here's what each word means, without a biology degree.
If we've used a term anywhere and it isn't here, tell us and we'll add it.
Aragonite saturation (Ω, "omega-arag")
A measure of how easy it is for coral to build its stony skeleton from the seawater around it. Above
about 3.3 is good for growth; below that, building gets hard. River water carrying dissolved limestone can
raise it (helpful); pollution that adds carbon dioxide can lower it.
Bleaching
When heat-stressed coral expels the tiny algae living inside it, turning bone-white. Without the algae the
coral starves. Short bleaching can be survived; prolonged bleaching usually kills. Driven by heat and
bright light together, which is why shade matters.
Bistability / tipping point
A system that can settle into one of two very different stable states, here, "mostly coral" or "mostly
seaweed." Push it past a tipping point and it flips, and flipping back is hard. Grazing pressure is the knob.
Chlorophyll-a
The green pigment in plankton. Satellites measure it to estimate how much plankton (and therefore how many
nutrients) are in the water. High chlorophyll = nutrient-rich, often from farm runoff or sewage.
Degree Heating Weeks (DHW)
The standard heat-stress score for reefs, adding up how much and how long the water sat above the coral's
summer comfort limit. DHW over 4 = bleaching expected; over 8 = severe bleaching and death.
Banco Capiro hit ~14 in 2023 and survived.
Diadema antillarum(long-spined sea urchin)
A black, spiny urchin that grazes seaweed off reefs. A Caribbean-wide die-off in 1983 removed most of them,
which helped seaweed take over many reefs. Banco Capiro still has them in force, roughly 100× the regional density.
Elkhorn coral (Acropora palmata)
A large, branching, antler-shaped coral that used to build Caribbean reefs and is now critically endangered.
Banco Capiro / Cocalito has hundreds of colonies, part of what makes it special.
Eutrophication
Too many nutrients in the water (from sewage, fertilizer). Usually bad for reefs, it fuels seaweed and disease.
Part of this project's puzzle is why it isn't killing this reef.
Heterotrophy (coral "eating")
Corals get energy two ways: from their internal algae (like solar panels) and by catching plankton with their
tentacles (eating). In murky, plankton-rich water, eating matters more, and well-fed corals resist and recover
from bleaching better.
Kd490 / turbidity (water clarity)
How quickly light fades as you go deeper. High Kd490 = murky water, light disappears fast. It's how we measure,
from satellites, that Banco Capiro's water is ~2.5× murkier than nearby clear reefs.
Lagrangian particle model
A way to simulate where water carries things by releasing thousands of virtual particles into modeled ocean
currents and following each one. We used it to track river mud and see whether it reaches the reef.
Macroalgae (seaweed)
Large algae that compete with coral for space and can smother it. Grazers (fish, urchins) keep it in check.
When grazers vanish, seaweed can take over a reef.
Maximum Monthly Mean (MMM)
The temperature of the reef's warmest average month, its "summer normal." Heat stress is measured as how far
and how long the water climbs above this line.
Ocean reanalysis (GLORYS)
A best-estimate reconstruction of past ocean conditions (currents, temperature at depth) built by blending a
physics model with real measurements. We used the GLORYS product to study the bay's currents and any upwelling.
Resuspension
When waves or currents stir settled mud and sand back up into the water, making it briefly murkier. Useful here
because it can shade the coral exactly during calm, hot spells.
Sea-surface temperature (SST)
The temperature of the top layer of the ocean, measured by satellites. The basic input for tracking heat stress.
Secchi depth
A simple field measure of water clarity: lower a white disk until you can't see it, and note the depth.
A cheap, on-the-boat way to check the murkiness the satellites see.
The microscopic algae that live inside coral and feed it through photosynthesis. Different strains handle heat
differently, the strain called Durusdinium is unusually heat-tolerant. We suspect a tough strain helps
Banco Capiro, but confirming it needs genetic testing on the trip.
Upwelling / Ekman pumping
When deep, cooler water rises toward the surface, it can shield coral from heat. Winds and coastlines can drive
it. We tested whether it protects Banco Capiro, and found it doesn't here.
Missing a term? The Science page links each concept to its source, and
the Data & Researchers page has the full methods.