Coral Bleaching & Acidification
Explain the mutualistic symbiosis between coral polyps and photosynthetic zooxanthellae; describe how heat stress causes bleaching (corals expel zooxanthellae and turn white); explain ocean acidification chemistry: CO2 dissolves in seawater to form carbonic acid, lowering pH and dissolving calcium carbonate skeletons; connect reef loss to the collapse of habitat for ~25% of marine species; evaluate current reef restoration efforts
Lesson
Set out your lesson
“Many reef-building corals host photosynthetic algae, called zooxanthellae. Algae supply sugars; corals supply shelter and resources. Heat stress can cause algae loss and bleaching. Bleached does not mean dead. Acidification is a separate chemical change; lower pH does not necessarily mean pH below seven. Safety: No seawater, acids, shells, live organisms or reef visits. Stop: Stop at paper paths and evaluation. Do not mix acids, test shells or touch coral.”
Bring to the table
- Paper
- Pencil
Extra for the adult
Worked example. I choose B for the supplied comparison because it addresses a local stress and checks survival, not just the number transplanted. I would need survival and reproduction records over time. Bleaching concerns algae loss; acidification concerns seawater chemistry and skeleton-building conditions.
Optional challenge. Why can a transplanted coral survive initially yet fail to establish a reproducing reef population? Adult key: Initial survival does not show later breeding, recruitment or resilience to repeated stress.
What to notice. Keep the coral sketch and proposal answer. Note help with chemistry terms or the chosen criterion.
Share and support
Family records and proof options
Keep a record of your learning
Save photos, notes, and attendance. Export a proof packet for compliance or portfolio reviews.
Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
NASA Climate Kids · Practice link — not the full lesson
Ocean
Before you open · source notes
Ocean supports Coral Bleaching & Acidification. An adult previews and guides; this is a learning page, not a scored quiz.
Free educational page, no sign-in required for the tested path.
Before you openAsk the learner one fact they learned and one question they still have.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public NASA Climate Kids page. An anonymous GET on 2026-11-12 returned HTTP 200 with no login or payment prompt for this URL. Opening the link does not save practice or assess mastery. An adult should preview and guide the learner.
NASA Climate Kids. “Ocean.” External page; Gakuva does not copy, host, embed, or redistribute materials.
Unknown — link only
Check understanding
No checks listed
“Has your child heard of coral bleaching? Can they explain what's actually happening to the coral — what breaks down between the coral and the tiny algae living inside it, and why warmer or more acidic water triggers this?”
Curriculum record
- Type
- Conceptual
- Subject
- Science
- Domain
- Ocean Life
- Age range
- Ages 12–13