Importance of land-based sampling in marine dissolved organic matter research

Many traditional conservation approaches treat marine and terrestrial ecosystems separately, failing to account for the interconnection between land and sea. Pollutants enter marine environments through surface runoff (e.g. from intense rainfalls) and subsurface groundwater discharge, affecting coastal ecosystems. Research highlights that anthropogenic pollutants (e.g. pharmaceuticals, pesticides or human metabolites) are of growing concern due to their potential cumulative and unnoticed effects on aquatic organisms. In this study we are joining fluorescence spectroscopy and untargeted metabolomics (LC-MS/MS) of dissolved organic matter, to assess the influx of pollutants from land on nearshore reef systems, in regards to seasonal rainfall events. By integrating both land-based and coastal water samples we can identify pollutants of terrestrial origin as some substances are naturally occurring in one system that might be identified as potential pollutants in another. Field data showed  significant seasonal variability in anthropogenically derived pollutants, with increased abundance linked to higher precipitation, mainly from human metabolites and personal care products. Pollutant levels in the wet season of 2022 were more than 3.6 times higher than in the dry season of 2022 or wet season of 2021, corresponding to rainfall more than double that of 2021. This study recommends taking samples along the land-sea continuum and highlights rain events derived pollution of coastal waters with potential detrimental impact on coral reefs.

Presentation Preference: Oral

Primary Presenter: Lisa Schellenberg, Royal Netherlands Institute for Sea Research (lisa.schellenberg@nioz.nl)

Authors:

Lisa Schellenberg, Royal Netherlands Institute for Sea Research  (lisa.schellenberg@nioz.nl)

Daniel Petras, University of Tuebingen, Germany / University of California Riverside, USA  (dpetras@ucr.edu)

Mark Vermeij, CARMABI Foundation, Curaçao / University of Amsterdam, the Netherlands  (carmabilog@gmail.com)

Corina Brussaard, Royal Netherlands Institute for Sea Research / University of Amsterdam, the Netherlands  (corina.brussaard@nioz.nl)

Andreas Haas, Royal Netherlands Institute for Sea Research  (andi.haas@nioz.nl)