What determines sclerobiont colonization on marine mollusk shells?

Area of Science:

• Marine Biology
• Paleoecology
• Invertebrate Zoology

Background:

• Empty mollusk shells serve as substrates for sclerobionts, but factors influencing colonization are not fully understood.
• Colonization patterns on modern and fossilized shells require further investigation to bridge ecological and paleontological perspectives.

Purpose of the Study:

• To investigate the key factors affecting sclerobiont colonization on mollusk shells.
• To compare colonization patterns on modern shells with their preservation in death assemblages.
• To understand the role of bacterial biofilms in sclerobiont settlement.

Main Methods:

• Experimental and field studies comparing sclerobiont colonization on three bivalve species with varying shell textures.
• Evaluation of host characteristics (mode of life, size, color, ornamentation, mineralogy) influencing colonization on dead mollusk shells.
• Comparison of modern invertebrate settlements with their representation in molluscan death assemblages.

Main Results:

• Sclerobiont settlement is enhanced by high bacterial biofilm density, heterogeneous shell surfaces, shallow infaunal/attached epifaunal modes, colorful/oxidized surfaces, specific shell sizes, and calcitic mineralogy.
• Bacterial biofilm density, shell size, and texture were identified as the most significant factors.
• Colonization patterns observed in modern settings showed similar trends in molluscan death assemblages, particularly on textured bivalve shells.

Conclusions:

• Bacterial biofilms play a crucial role in influencing sclerobiont colonization on mollusk shells.
• Ecological relationships observed in modern marine organisms are relevant for interpreting the fossil record of sclerobionts.
• Shell characteristics significantly mediate the colonization process, impacting both current ecosystems and paleontological interpretations.