UDTR Global Rights of Nature Radar

Amino acid compound-specific isotope analysis reveals island mass effect subsidies in reef-associated Hawaiian zooplankton

Identification

Public canonical key

radar:r-00d2d93f633fbfdaf8eee46b6d2b60df

Authors

Blake Stoner-Osborne · R. García-Seoane · Christopher B. Wall · Natalie J. Wallsgrove · Jeffrey C. Drazen · Brian N. Popp

Reported year

2026

Reported language

en

Source type

article

First detected

2026-11-14T02:03:11.218239+00:00

Last metadata observation

2026-11-14T02:03:11.218239+00:00

Last HTTP verification

Not checked

Institutions reported by the source

University of Hawaiʻi at Mānoa · Instituto Español de Oceanografía · Centro Oceanográfico de A Coruña

Reported affiliation countries

ES · US

Documentary abstract — original language

The Island Mass Effect (IME) is the nearshore enhancement of primary productivity around islands and atolls relative to offshore waters. Although its physical and biogeochemical drivers are well characterized, the IME’s influence on the diets and distributions of consumers remains poorly resolved. We applied amino acid compound-specific stable isotope analysis (AA-CSIA) to Hawaiian zooplankton sampled across nearshore–offshore and surface–deep gradients to test whether island-derived production alters isotopic composition and trophic structure in reef-associated assemblages relative to offshore counterparts across sites, seasons, and years. Essential amino acid δ 13 C values (δ 13 C EAA ) normalized to their mean values displayed contrasting nearshore–offshore patterns: lysine and threonine δ 13 C values increased with distance from shore, whereas phenylalanine and valine values decreased. These patterns likely reflect shifts in zooplankton diet and the amino acid biosynthetic pathways of their primary producer prey along the coastal–oceanic gradient. Source amino acid δ 15 N values (δ 15 N SAA ) declined offshore for lysine and phenylalanine but increased with depth, indicating spatial variation in nitrogen sources and greater reliance on microbially reworked organic matter at depth. Trophic position estimates based on δ 15 N values of glutamic acid and alanine relative to phenylalanine increased offshore and with depth, consistent with longer food webs and additional microzooplankton trophic steps in offshore waters. Multivariate analysis integrating δ 13 C EAA and δ 15 N SAA values clearly distinguished reef, offshore surface, and offshore deep zooplankton assemblages, revealing a conservative isotopic tracer of island-derived production in reef communities. These results demonstrate AA-CSIA’s utility for tracing island-derived productivity to consumers and clarifying biogeochemical connectivity between coastal and open-ocean food webs.

Identifiers

OPENALEX

https://openalex.org/W7159855522

DOI

10.7717/peerj.21076

PMID

https://pubmed.ncbi.nlm.nih.gov/42079739

PMCID

https://www.ncbi.nlm.nih.gov/pmc/articles/13135334

Documentary context

Documentary family

article

Source-reported types

article

Publishers

PeerJ, Inc.

Entity mentions are not evidence of legal recognition. Jurisdiction studied is separate from author affiliation country.

Sources

OpenAlex · Record 1

• Document · https://doi.org/10.7717/peerj.21076

Documentary status

Relevance pending

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