Figure 1.
Box 1 shows different treatments A to D, in 4: A) Simulation of kelp forest canopy with seawater and kelp blade; B) Kelp blade and filtered seawater to remove phytoplankton and control for TEP produced in seawater; C) Synthetic kelp blade and filtered seawater to control for EPS on blade and TEP in seawater; D) Filtered seawater to control for surrogate loss due to settling or attachment to surfaces of jar. Box 2 indicates where and when measurements were taken and box 2.1. shows steps to measure parameters on kelp blade biofilm. Box 3 shows parameters measured and box 4 indicates methods used for each parameter.
Figure 2.
Benthic diatoms (predominantly Cocconeis spp.) in snail fecal pellet (A) and in gel-like EPS matrix scraped from surface of giant kelp blades on which snails were feeding (B); DAPI-stained bacteria (C) and different genera of benthic diatoms (D) also in gel-like EPS matrix from kelp blade surfaces from Experiment 1. Scale bars 10 µm.
Figure 3.
Kelp blade cross-section with diatom (white arrow) ‘trapped’ in EPS fibers, stained with alcian blue (Experiment 1).
Scale bar 50 µm. Panel B represents a higher magnification of A, showing benthic diatom in kelp EPS. Scale bar 10 µm.
Figure 4.
Percentages (mean ± SD) of T. gondii oocyst surrogates suspended in the water at samples taken following 6 and 12 hrs during Experiment 2 (N = 9 per treatment, except at t = 6 hrs for treatments C and D where N = 6).
Table 1.
Mann-Whitney (or Test U) results shows the significant decrease in the percentage of surrogates of T. gondii measured in the water at t = 6 hrs and t = 12 hrs in all treatments.
Figure 5.
Percentages (mean ± SD) of T. gondii surrogates suspended in water and present in kelp scrapings at the termination of Experiment 2 (12 hrs) (N = 9 per treatment).
Figure 6.
EPS concentrations (mean ± SD) on the kelp blades’ surface at the end of Experiment 2 (t = 12 hrs) (N = 9 per treatment).
Nd = not detected.
Figure 7.
TEP (A) and chlorophyll a (B) (mean ± SD) measured in water at t = 0, 6 and 12 hrs in 4 different treatments (N = 9 per treatment) used in Experiment 2.
LOD on (A) indicates TEP limit of detection. Nd indicates that TEP and chlorophyll a were not detected in treatments B, C, and D.
Table 2.
Mann-Whitney results showing significant difference between the percentage of surrogates associate with kelp blades and suspended in the water in all treatments and at the end of the experiment (t = 12 hrs).
Figure 8.
Concentration (mean ± SD) of diatoms on the surface of the kelp blades (N = 3) from Experiment 2 after 12 hrs.
Nd = not detected.
Figure 9.
A) Benthic diatoms scraped from the surface of kelp blades analyzed in Experiment 2 showing alcian blue staining of EPS. B) Same image as in A, but observed simultaneously with transmitted light showing both EPS, surrogates of T. gondii oocysts (white arrows) and benthic diatoms fluorescing red. C) Same image as in A and B, but observed using 50 W light source and a chlorophyll filter set showing surrogates (white arrows) and chlorophyll (red fluorescence) from benthic diatoms. Scale bars 100 µm.