More macrophyte litter changed carbon processing without speeding litter disappearance

In 410 Brazilian lagoon microcosms, litter richness reduced microbial respiration but did not change dry-mass loss, while species identity still mattered.

Wild Lands Ecological Intelligence Editor
Wild Lands Institute · 19 September 2026

Expansive wetland with winding waterways and dense emergent vegetation. — Illustrative repository image, not study-site documentation — Monica Tomosy · Public Domain (USFWS) · Rights: Public domain

Evidence: Peer-reviewed
Geography: Cabiúnas Lagoon, Rio de Janeiro State, Brazil
System: Macrophyte-dominated shallow lake and wetland detrital food webs

WHAT THE EVIDENCE SAYS

A 48-day experiment tested all possible one-, two-, four- and six-species mixtures drawn from eight aquatic macrophytes. Increasing litter richness reduced cumulative microbial respiration and increased metabolic efficiency without changing dry-weight loss, while species composition and chemical diversity helped explain non-additive responses.

WHY IT MATTERS / OUR READ

Decomposition metrics are not interchangeable. The same amount of litter can disappear while carbon is partitioned differently between respiration and retained organic matter, so mass loss alone can miss a change in ecosystem carbon processing.

CAVEATS / UNCERTAINTY

This was a controlled microcosm experiment using standardized, ground litter and lagoon water rather than intact field detritus. Several species required non-senescent leaves, and 48-day microbial responses do not establish whole-ecosystem carbon balance.

SOURCE

Aquatic Ecology
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