Category: Ecology

Summary: Estimating when stronger detrital-nursery exchange creates a reactive mode that links marsh subsidy, estuarine nursery retention, and offshore export instead of staying marsh-confined.

Estuarine nursery habitats connect marsh production, detrital subsidies, and coastal food webs, but it is not obvious when that exchange simply strengthens local nursery support and when it reorganizes the whole system. This experiment asks for the threshold where a reactive mode stops being confined to marsh-associated structure and instead bridges riverine subsidy, nursery retention, and offshore export.

The script builds dense disordered community matrices for an estuary-like system and increases the strength of detrital-nursery exchange while carrying a threshold bracket across larger matrix sizes. It uses repeated eigensolves to detect when the dominant reactive pattern becomes bridge-localized across the land-sea interface rather than concentrated in the marsh compartment.

That makes the project a structural transition study of estuarine food-web organization, not just a stability calculation. The aim is to identify when nursery-detrital coupling changes the geography of reactivity itself, producing a system-spanning takeover mode that standard descriptive studies do not directly map.

Method: Dense non-symmetric eigensolves with iterative deepening and bisection on detrital-nursery exchange strength across N=64 to 2048 disordered estuarine community matrices.

What is measured: Critical exchange threshold, localization of the dominant reactive mode, bridge-versus-marsh concentration, leading eigenvalue behavior, and bracket width.