DOI: 10.5061/dryad.cn5kh5m
title: Data from: Identifying areas prone to coastal hypoxia – the role of topography

description: Hypoxia is an increasing problem in marine ecosystems around the world.
 While major advances have been made in our understanding of the drivers of
 hypoxia, challenges remain in describing oxygen dynamics in coastal
 regions. The complexity of many coastal areas and lack of detailed in situ
 data have hindered the development of models describing oxygen dynamics at
 a sufficient spatial resolution for efficient management actions to take
 place. It is well known that the enclosed nature of seafloors and reduced
 water mixing facilitates hypoxia formation, but the degree to which
 topography contributes to hypoxia formation and small-scale variability of
 coastal hypoxia has not been previously quantified. We developed simple
 proxies of seafloor heterogeneity and modeled oxygen deficiency in complex
 coastal areas in the northern Baltic Sea. According to our models,
 topographical parameters alone explained ∼80 % of hypoxia occurrences. The
 models also revealed that less than 25 % of the studied seascapes were
 prone to hypoxia during late summer (August–September). However, large
 variation existed in the spatial and temporal patterns of hypoxia, as
 certain areas were prone to occasional severe hypoxia (O2 &lt; 2 mg
 L−1), while others were more susceptible to recurrent moderate hypoxia
 (O2 &lt; 4.6 mg L−1). Areas identified as problematic in our study
 were characterized by low exposure to wave forcing, high topographic
 shelter from surrounding areas and isolation from the open sea, all
 contributing to longer water residence times in seabed depressions.
 Deviations from this topographical background are probably caused by
 strong currents or high nutrient loading, thus improving or worsening
 oxygen status, respectively. In some areas, connectivity with adjacent
 deeper basins may also influence coastal oxygen dynamics. Developed models
 could boost the performance of biogeochemical models, aid developing
 nutrient abatement measures and pinpoint areas where management actions
 are most urgently needed.
description: Original hypoxia
 dataOriginal data used in:
 Identifying areas prone to coastal hypoxia - the role of topography,
 Virtanen, Elina A., Norkko, Alf, Nyström Sandman, Antonia, Viitasalo,
 Markku. The file contains original hypoxia data, with mean and minimum
 oxygen concentration, hypoxia frequencies, and binary hypoxia (hypoxia
 present/absent) observations based on thresholds in the publication.
 Predictor variables are excluded due to national
 restrictions.Hypoxia_data.7zScript for reproducing hypoxia modelsScript here is an example script for reproducing the hypoxia models. Parameters listed in the script are for the occasional hypoxia (&lt;4.6 mg L -1) model. Hypoxia data which R script suggests, is a modified version due to national restrictionshypoxia_models.RScripts for reproducing the plotsScripts for reproducing the plots as in the publication. Results of models (areas in km2 affected, predictor importances, percent correctly classified, AUC) are averaged across different model versionsScripts_for_reproducing_plots.7z