Fig 1.
Study area on the southern Brazilian coast.
(A) Patos Lagoon estuary where the experimental step was conducted. (B) “Concheiros Beach” where the samples were collected.
Table 1.
Categorical variables measured in this study.
Fig 2.
Zooplankton potential colonization on shells.
(A) Total occurrence frequency (%) of holoplankton, thycoplankton, and meroplankton in zooplankton samples. (B) Zooplankton potential on sampled colonizing shells. (C) Settled zooplankton (%) on shells.
Fig 3.
Zooplankton colonization on shells.
(A) The colonization density on the internal and external surfaces of different shells. (B) The richness of colonizers on internal and external surfaces. (C) Settled zooplankton composition (%) on different shells sides. The vertical lines denote the 95% confidence intervals (standard error*1.96), and the lowercase letters indicate similarities (the same letters) or significant differences (different letters) between the shells (Tukey test).
Fig 4.
(A) Bacterial biofilm density (bact cm-2) on different shells. (B) The relative size (FSC-A) and complexity (SSC-A) of the bacterial cells measured by a flow cytometer. Each point represents a bacterial cell. The lighter colors (central part) are related to higher density cells with a determined feature (size × complexity) being characterized as one population. (C) Microorganism communities stained with acridine orange under epifluorescence microscopy (1000X). The vertical lines denote the 95% confidence intervals (standard error*1.96), and the lowercase letters indicate similarities (the same letters) or significant differences (different letters) between the shells (Tukey test).
Table 2.
Categorical classification of external ornamentation, mineralogy (1 = calcite; 2 = aragonite; 3 = bimineralic) and frequency of occurrence (FO) data.
Fig 5.
Sclerobionts coverage on mollusks.
(A) Gastropoda genera: Ade.: Adelomelon, Buc.: Buccinanops, Cre.: Crepidula, Epi.: Epitonium, Oli.: Olivancillaria, Psa.: Psania, Sin.: Sinum. (B) Bivalvia genera: Ama.: Amalarillodesma, Ami.: Amiantis, Ana.: Anadara, Bra.: Brachidontes, Chls: Chlamys, Cra.: Crassostrea, Don.: Donax, Gly.: Glycymeris, Lae.: Laevicardium, Mac.: Mactra, Ost.: Ostrea, Per.: Perna, Pho.: Pholas, Pit.: Pitar. Und.: Unidentifiable.
Fig 6.
The occurrence of sclerobionts exposed to distinct life modes, sizes, and colors of the host substrates.
(A) Gastropod life modes. (B) Bivalvia life modes. (C) Gastropod sizes (D) Bivalvia sizes. (E) Gastropod color. (F) Bivalvia color. Und.: Unidentifiable. The vertical lines denote the 95% confidence intervals (standard error*1.96), and the lowercase letters indicate similarities (the same letters) or significant differences (different letters) between the factors evaluated (Tukey test).
Fig 7.
The occurrence of sclerobionts exposed to distinct ornamentation and mineralogy of the host substrates.
(A) Gastropod external ornamentation. (B) Bivalvia external ornamentation. (C) Bivalvia internal ornamentation. (D) Bivalvia mineralogy. Und.: Unidentifiable. The vertical lines denote the 95% confidence intervals (standard error*1.96), and the lowercase letters indicate similarities (the same letters) or significant differences (different letters) between the factors (Tukey test).
Table 3.
Spearman rank correlations between the shell factors evaluated (Table 1), and the total taphonomic grade (TTG) (see also S1 Table).
Fig 8.
Sclerobiont occurrence on different shell size.
(A) Encrustation occurrence on Gastropoda. (B) Bioerosion occurrence on Gastropoda. (C) Encrustation occurrence on Bivalvia. (D) Bioerosion occurrence on Bivalvia.
Fig 9.
Some examples of sclerobionts that colonized molluscan shells gathered from Concheiros Beach, on the Southern coast of Rio Grande do Sul, Brazil.
(A) The inside of a Buccinanops gastropod that contained sclerobionts, such as serpulid polychaete, bryozoans, and an oyster. On the external side of the shell, there is evidence of bioerosion by Spionidea polychaeta (arrow). (B) A gastropod shell with a sand structure made by the polychaete Phagmatopoma caudata. (C) A gastropod covered by bryozoans. (D) A fragment of a gastropod that was fouled by eggs of the bivalve Stramonita haemastoma (arrow). (E) An external view of a Pholas bivalve shell with encrusting Ostreidae and bryozoans and a sediment-tube made by a polychaete (arrow). (F) Internal view of another Pholas shell with several oysters (Ostrea equestris) and bryozoans. (G) External view of an Anadara brasiliana bivalve shell with a boring sponge. (H) Internal view of a Mactra bivalve shell encrusted by Ostreidae. The hole was made by a spionidea polychaete. Scale bars: 10 mm.