Fig 1.
I: Map of Denmark with location of study area (red circle: 55.574°N, 10.140°E) indicated. II: Gyldensteen Coastal Lagoon area in its original state (upper) redrawn from a 1780 map; just after land reclamation in 1871 (middle) with locations of the 2014 soil sampling sites: uncultivated (UC) and cultivated (C); and the area after flooding in 2014 (lower) with indications of macrofaunal sampling stations: outside west (OW), west (W), outside east (OE) and east (E) stations.
Table 1.
Water content, density, porosity and loss on ignition (LOI) in control cores from uncultivated (UC) and cultivated (C) soils.
Table 2.
Number and biomass (wet weight) of Marenzelleria viridis (Mar), Nereis diversicolor (Ner) and Scoloplos armiger (Sco) added to uncultivated (UC) and cultivated (C) soil cores.
Recovery of polychaetes, maximum depth of burrows, area- and weight-specific bioirrigation rates for the three species of polychaetes observed by the end of the experiment.
Fig 2.
Depth profiles of Br- in uncultivated (UC) and cultivated (C) soils (upper and lower graphs, respectively) without (Con) or with polychaetes added (Mar: Marenzelleria viridis, Ner: Nereis diversicolor and Sco: Scoloplos armiger).
Dashed lines indicate the sediment-water interface. Error bars indicate standard error (n = 3).
Fig 3.
Depth profiles of porewater SO42- in uncultivated soil (UC) and cultivated soil (C) flooded with seawater, without (Con) or with polychaetes added (Mar: Marenzelleria viridis, Ner: Nereis diversicolor and Sco: Scoloplos armiger).
Error bars indicate standard error (n = 3).
Fig 4.
Sediment O2 uptake (SOU) and exchange of TCO2 and DIN in flooded uncultivated (UC) and cultivated (C) soil without (Con) and with added polychaetes (Mar: Marenzelleria viridis, Ner: Nereis diversicolor and Sco: Scoloplos armiger, respectively).
Left and middle panels show temporal patterns and right panels show averages (from time of polychaete addition [t = 0] to end). Error bars indicate SE (n = 3). Capital and lower case letters in right panels represent the grouping of data obtained by 2-way ANOVA followed by Tukey post hoc analysis. Capital letters indicate significant difference between UC and C. Lower case letters indicate significant difference between core treatments (Con, Mar, Ner and Sco). * indicates significant interaction between the factors soil type and core treatment.
Table 3.
Flux increase (%) for treatments with polychaetes added (Mar: Marenzelleria viridis, Ner: Nereis diversicolor and Sco: Scoloplos armiger) in relation to defaunated controls (Con).
Fig 5.
Colonization of benthic infauna at the Western (W) and Eastern (E) stations after flooding of the Gyldensteen Coastal Lagoon.
March 29, 2014 is point of origin for all graphs. X-axis tick marks indicate start of March (M), June (J), September (S) and December (D).
Fig 6.
Two-dimensional plots of MDS outputs based on Bray-Curtis similarity matrix.
Panel (a): distribution of fauna dataset indicated by time and station. Time is represented as month by the two first letters and year by the two last numbers. Sampling months: February, April, May, July, August, September, and October. Sampling years: 2013 to 2015. Sampling stations: Western site inside the lagoon (W), Eastern site inside the lagoon (E), Western site outside the lagoon (OW), and Eastern site outside the lagoon (OE). The dashed ellipses indicate the groups of stations tested by ANOSIM analysis: Group Out composed of stations located outside the lagoon and Group In composed of stations inside the lagoon. Panels (b), (c) and (d): spatial and temporal abundance of species tested in the laboratory experiment.
Table 4.
Abundance, average similarity (Av. Sim.) and contribution (Cont.) of the most important species to the similarity within Group Out and Group In based on SIMPER analysis.
Fig 7.
Linear regressions between the relative stimulation of TCO2 efflux and sediment O2 uptake (SOU) and bioirrigation intensity in flooded uncultivated (UC) and cultivated (C) soils with polychaetes added (Mar: Marenzelleria viridis, Ner: Nereis diversicolor and Sco: Scoloplos armiger).