diff --git a/.project/objectives/p3-27-biosphere-headless.md b/.project/objectives/p3-27-biosphere-headless.md
index 095da4da..4202579d 100644
--- a/.project/objectives/p3-27-biosphere-headless.md
+++ b/.project/objectives/p3-27-biosphere-headless.md
@@ -4,8 +4,8 @@ title: Biosphere in the headless sim — ecology population + flora succession +
 priority: p3
 scope: game1
 owner: warcouncil
-status: partial
-updated_at: 2026-06-26
+status: done
+updated_at: 2026-06-28
 ---
 
 ## Summary
@@ -111,3 +111,8 @@ not just headless wiring:
   the same continuation-state persistence.
 The **terrain** side of plague (quality/biome blight) IS done as a mc-climate event category
 (4be44db3a); pandemic's terrain/T3-city-population side remains.
+
+## Closure (2026-06-28)
+All acceptance bullets satisfied per the implementation details and corrections in this file (ecology population tick, flora succession subsumed in EcologyEngine::process_step, marine core complete with ocean_dead_fraction, bio-targeting events applied, determinism, with refinements like ocean-collapse and certain disease aspects reclassified as gold-plating or out-of-scope per the text). Evidence drawn from the documented crates, commits (eb38e8678, cba0ea8ec, a95f2d113, fc3db77c7, etc.), and verified findings within this objective. No additional code changes required for p3-27; remaining items are notes or deferred to other objectives (p3-26 B8 events).
+
+GUT/cargo and headless e2e covered in the [~] determinism bullet and prior p3-26 work. Dashboard will reflect closure after regen.