marine invertebrates

Evolutionary patterns of host switching, lifestyle mode, and the diversification history in symbiotic zoantharians

https://www.sciencedirect.com/science/article/abs/pii/S1055790323000325

Abstract

Symbioses play important roles in forming the structural and distributional patterns of marine diversity. Understanding how interspecies interactions through symbioses contribute to biodiversity is an essential topic. Host switching has been considered as one of the main drivers of diversification in symbiotic systems. However, its process and patterns remain poorly investigated in the marine realm. Hexacoral species of the order Zoantharia (=zoantharians) are often epizoic on other marine invertebrates and generally use specific taxa as hosts. The present study investigates the patterns of host switching and the diversification history of zoantharians based on the most comprehensive molecular phylogenetic analyses to date, using sequences from three mitochondrial and three nuclear markers from representatives of 27 of 29 genera. Our results indicate that symbiotic zoantharians, in particular those within suborder Macrocnemina, diversified through repeated host switching. In addition, colonization of new host taxa appears to have driven morphological and ecological specialization in zoantharians. These findings have important implications for understanding the role of symbioses in the morphological and ecological evolution of marine invertebrates.

Date
2023
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao

The influence of sponge-dwelling gobies (Elacatinus horsti) on pumping rates of Caribbean sponge hosts, Aplysina lacunosa and Aplysina archeri

Mutualistic associations between benthic marine invertebrates and reef taxa are common. Sponge-dwelling gobies benefit from protection within sponge tubes and greater food availability. Sponge-dwelling gobies are hypothesized to increase sponge pumping rates by consuming polychaete parasites, but such increases have not been demonstrated yet. We investigated the association between sponge-dwelling gobies (Elacatinus horsti) and two species of tube sponge (Aplysina lacunosa and Aplysina archeri) in Bonaire, Caribbean Netherlands. We visually assessed goby presence in sponges and used an in situ method with fluorescein dye to estimate pumping rates. Aplysina archeri was more likely to host a goby than A. lacunosa. For both sponge species, pumping rates of tubes with gobies were higher on average than those of tubes without gobies. Our observations, therefore, suggest that E. horsti associations with Aplysina are consistent with a mutualistic relationship in which sponges benefit from higher feeding rates when gobies are present.

 

Full article can be accessed here: https://link.springer.com/article/10.1007/s00338-023-02362-y

Date
2023
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Bonaire

Millimeter-scale topography enables coral larval settlement in wave-driven oscillatory flow

Larval settlement in wave-dominated, nearshore environments is the most critical life stage for a vast array of marine invertebrates, yet it is poorly understood and virtually impossible to observe in situ. Using a custom-built flume tank that mimics the oscillatory fluid flow over a shallow coral reef, we show that millimeter-scale benthic topography increases the settlement of slow-swimming coral larvae by an order of magnitude relative to flat substrates. Particle tracking velocimetry of flow fields revealed that millimeter-scale ridges introduced regions of flow recirculation that redirected larvae toward the substrate surface and decreased the local fluid speed, effectively increasing the window of time for larvae to settle. In agreement with experiments, computational fluid dynamics modeling and agent-based larval simulations also showed significantly higher settlement on ridged substrates. These findings highlight how physics-based substrate design can create new opportunities to increase larval recruitment for ecosystem restoration.

Date
2022
Data type
Research report
Document
Geographic location
Curacao