Where does bleaching collide?

In marine ecology, bleaching is the breakdown of the symbiosis between a reef-building coral and the photosynthetic zooxanthellae living in its tissue: under thermal or light stress the coral expels or loses the algae that give it both colour and most of its food, turning the colony white and leaving it liable to starve or die if the stress persists. Glynn's 1993 Coral reef bleaching: Ecological perspectives synthesised the phenomenon across reefs, and Hoegh-Guldberg's 1999 projection tied mass bleaching to warming sea-surface temperatures. The referent is a stress response in a living symbiosis, tracked by the loss of pigment and symbiont density across a reef, nothing to do with a word losing meaning or a tooth being whitened.[1][2]

Unit

Loss of symbiont (zooxanthellae) density and pigment in coral tissue

Recovery means

Corals can re-acquire symbionts and recover pigment if the thermal stress eases before the colony starves

Measured by

Assessed by symbiont (zooxanthellae) counts, chlorophyll/pigment loss, colony colour scores, and bleaching extent across a reef

In historical linguistics, semantic bleaching is the loss or thinning of a word's specific lexical meaning as it is recruited into a more abstract, grammatical role: the way English will faded from 'to want' into a bare future marker, or going to lost its literal motion meaning. Hopper and Traugott's Grammaticalization treats bleaching as one of the hallmark processes by which content words drift toward function words over time. The referent is a change in a word's meaning across the history of a language, observed through shifting distribution and the stripping away of concrete semantic content, unrelated to a pale coral or a whitened tooth.[3]

Unit

Reduction in the specific lexical content a form carries over historical time

Recovery means

Not applicable

Measured by

Traced through historical and corpus evidence of a form's widening distribution and loss of concrete meaning