Fig 1.
Map and photos of the study areas on Funen Island, Denmark.
Hatched areas indicate the studied eelgrass meadows in Dalby Bay (55°31ʹ07ʺ N, 10°37ʹ05ʺ E) and Kertinge Nor (55°26ʹ52ʺ N, 10°33ʹ30ʺ E) while photos illustrate differences in filamentous macroalgae, eelgrass shoot density, and jellyfish abundance. Encircled M shows location of monitoring stations for water column data. Contains data from the Map 10 data set of the Danish Geodata Agency, 2015.
Table 1.
Monitoring data for water column concentrations of nutrients, chlorophyll a, light attenuation and temperature.
Table 2.
Physical and biogeochemical sediment parameters (mean ± SEM) from DB and KN (n = 3–4).
Table 3.
Stable isotope δ13C and δ15N values (mean ± SEM) of primary sources and animal species associated to seagrass meadows in and Dalby Bay and Kertinge Nor in Denmark, June 2011.
Fig 2.
Zostera marina meadow characteristics in Dalby Bay and Kertinge Nor.
Values are mean ± SE. Asterisks indicate statistical significant differences based on t-tests (* = 0.05, *** = 0.001). For stacked columns the statistics refer to the summed value. (A) Z. marina and algal biomass. Numbers in columns are above to below ground biomass ratios. (B) Z. marina shoot density and leaf area index. (C) Z. marina above ground production.
Fig 3.
Faunal biomass (A) and abundance (B) in Dalby Bay and Kertinge Nor in June 2011.
Asterisks indicate significant difference between the two sites (t-test <0.05).
Fig 4.
The relative (%) species contribution to total fish biomass (AFDW m-2) in Dalby Bay (DB) and Kertinge Nor (KN) in June 2011.
Fig 5.
Stable isotope values of species associated to Zostera marina meadows in Dalby Bay (DB) and Kertinge Nor (KN) in Denmark, June 2011.
Mean δ13C vs. δ15N in (A) DB and (B) KN. Ascending mean δ15N values of consumer species in (C) DB and (D) KN. The dashed line indicates the convex hull. TA is the total area of the convex hull. A. aurita was excluded from the TA due its special position in the food web and lack of sampling in DB; See Table 3 for species abbreviations and isotopic signals.
Table 4.
Proportional (%) contribution of primary production food sources to selected benthic invertebrates in DB and KN in June 2011.
Table 5.
Proportional (%) contribution of food sources to selected consumers in Dalby Bay, Denmark.
Table 6.
Proportional (%) contribution of food sources to selected consumers in Kertinge Nor, Denmark.
Fig 6.
Biomass distribution at trophic levels of Zostera marina meadows in Dalby Bay and Kertinge Nor, Denmark, June 2011.
The biomass of each species is distributed across trophic levels (TL) 1–4 according to their diet, based on stable isotope mixing model results (Tables 5 and 6), gut contents (S3 Table), and literature data (S4 Table). Combined width of bars indicate biomass at each TL in (A) Dalby Bay and (B) Kertinge Nor. Note biomass value of TL1 in KN is divided by 5 for visual purposes. (C) Linear regression of TL 2–4 and log10biomass (DB: log10biomass = 1.416–0.374×TL, R2 = 0.99; KN: log10biomass = 0.683 + 0.017×TL, R2 = 0.24), with slope indicating overall shape of the consumer part of biomass pyramids in Fig 6A and 6B above.