Sponges

Abstract

Coral reefs are known to be among the most biodiverse marine ecosystems and one of the richest in terms of associations and species interactions, especially those involving invertebrates such as corals and sponges. Despite that, our knowledge about cryptic fauna and their ecological role remains remarkably scarce. This study aimed to address this gap by defining for the first time the spatial ecology of the association between the epibiont hydrozoan Nemalecium lighti and the Porifera community of shallow coral reef systems at Bonaire. In particular, the host range, prevalence, and distribution of the association were examined in relation to different sites, depths, and dimensions of the sponge hosts. We report Nemalecium lighti to be in association with 9 out of 16 genera of sponges encountered and 15 out of 16 of the dive sites examined. The prevalence of the hydroid–sponge association in Bonaire reef was 6.55%, with a maximum value of over 30%. This hydrozoan has been found to be a generalist symbiont, displaying a strong preference for sponges of the genus Aplysina, with no significant preference in relation to depth. On the contrary, the size of the host appeared to influence the prevalence of association, with large tubular sponges found to be the preferred host. Although further studies are needed to better understand the biological and ecological reason for these results, this study improved our knowledge of Bonaire’s coral reef cryptofauna diversity and its interspecific associations. View Full-Text

Abstract

A paramount challenge in coral reef ecology is to estimate the abundance and composition of the communities residing in such complex ecosystems. Traditional 2D projected surface cover estimates neglect the 3D structure of reefs and reef organisms, overlook communities residing in cryptic reef habitats (e.g., overhangs, cavities), and thus may fail to represent biomass estimates needed to assess trophic ecology and reef function. Here, we surveyed the 3D surface cover, biovolume, and biomass (i.e., ash-free dry weight) of all major benthic taxa on 12 coral reef stations on the island of Curaçao (Southern Caribbean) using structure-from-motion photogrammetry, coral point counts, in situ measurements, and elemental analysis. We then compared our 3D benthic community estimates to corresponding estimates of traditional 2D projected surface cover to explore the differences in benthic community composition using different metrics. Overall, 2D cover was dominated (52 ± 2%, mean ± SE) by non-calcifying phototrophs (macroalgae, turf algae, benthic cyanobacterial mats), but their contribution to total reef biomass was minor (3.2 ± 0.6%). In contrast, coral cover (32 ± 2%) more closely resembled coral biomass (27 ± 6%). The relative contribution of erect organisms, such as gorgonians and massive sponges, to 2D cover was twofold and 11-fold lower, respectively, than their contribution to reef biomass. Cryptic surface area (3.3 ± 0.2 m2 m−2planar reef) comprised half of the total reef substrate, rendering two thirds of coralline algae and almost all encrusting sponges (99.8%) undetected in traditional assessments. Yet, encrusting sponges dominated reef biomass (35 ± 18%). Based on our quantification of exposed and cryptic reef communities using different metrics, we suggest adjustments to current monitoring approaches and highlight ramifications for evaluating the ecological contributions of different taxa to overall reef function. To this end, our metric conversions can complement other benthic assessments to generate non-invasive estimates of the biovolume, biomass, and elemental composition (i.e., standing stocks of organic carbon and nitrogen) of Caribbean coral reef communities.

Abstract

Sponges are a diverse phylum of sessile filter-feeding invertebrates that are abundant on Caribbean reefs and provide essential ecological services, including nutrient cycling, reef stabilization, habitat, and food for a variety of fishes and invertebrates. As prominent members of the benthic community, and thus potential food resources, factors determining the biochemical and energetic content of sponges will affect their trophic contributions to coral reef ecosystems. In order to evaluate the influence of geographic variation on biochemical composition and energetic content in the tissue of sponges, we collected several common and widespread species (Agelas conifera, Agelas tubulata, Amphimedon compressa, Aplysina cauliformis, Niphates amorpha, Niphates erecta, and Xestospongia muta) from multiple shallow reefs in four countries across the Caribbean Basin, including Belize, Curaçao, Grand Cayman, and St. Croix, U.S. Virgin Islands. In addition, we correlated inherent species-level traits, including the production of antipredator chemical defenses and the relative abundance of microbial symbionts, with biochemical and energetic content. We found that energetic content was higher in sponges with antipredator chemical defenses, and was significantly correlated with the concentration of chemical extracts from these sponges. We also noted that sponges with high microbial abundance contained significantly more soluble protein than sponges with low microbial abundance. Finally, both biochemical and energetic content varied significantly among sponges from different locations; sponges from Grand Cayman had the highest lipid and energetic content, whereas sponges from Belize had the highest carbohydrate content but lowest energetic content. Despite similar environmental conditions at these sites, our results demonstrate that biochemical and energetic content of sponges exhibits geographic variability, with potential implications for the trophic ecology of sponges throughout the Caribbean Basin.

https://doi.org/10.1111/ivb.12341

The cryptobiontic (cavity-dwelling) sponges from 32 growth framework reef cavities were collected over the depth range 12 m to 43 m along the leeward side of Bonaire, Netherlands Antilles. Thc resulting sample of 1,245 specimens comprised 92 species, which showed a peak in species diversity at about 18m depth. Of the 79 species that show significant restriction of their depth rangcs in this study, most are known elsewhere to have different or greater depth ranges. However, 17 eryptobiontic sponge species in Bonaire appear to be depth restricted. This suggests that there may be a depth zonation of some cryptobiontic sponges, and opens up the possibility that with more study, cryptobiontic sponges may be of some use in ancient reefs as a paleoenvironmental tool. The presence of 10 species of endolithic sponge over a broad depth range shows that sponge erosion in the cavities is widespread, although it does not appear to be intensive. Based upon the amount of preservable skeletal material produced by sponges in these reef cavities, it appears that as much as 97% of the cryptobiontic sponge sample would be lost during fossilization, leading to the conclusion that the fossil record of cryptobiontic sponges may be a very poor representation of their actual importance in fossil reef cavity systems.

Marine organism are often kept, cultured, and experimented on in running seawater aquaria. However, surprisingly little attention is given to the nutrient composition of the water owing through these systems, which is generally assumed to equal
in situ conditions, but may change due to the presence of biofouling organisms. Signi cantly lower bacterial abundances and higher inorganic nitrogen species (nitrate, nitrite, and ammonium) were measured in aquarium water when biofouling organisms were present within a 7-year old inlet pipe feeding a tropical reef running seawater aquaria system, compared with aquarium water fed by a new, biofouling-free inlet pipe. These water quality changes are indicative of the feeding activity and waste production of the suspension- and lter-feeding communities found in the old pipe, which included sponges, bivalves, barnacles, and ascidians. To illustrate the physiological consequences of these water quality changes on a model organism kept in the aquaria system, we investigated the in uence of the presence and absence of the biofouling community on the functioning of the lter-feeding sponge Halisarca caerulea, by determining its choanocyte ( lter cell) proliferation rates. We found a 34% increase in choanocyte proliferation rates following the replacement of the inlet pipe (i.e., removal of the biofouling community). This indicates that the physiological functioning of the sponge was compromised due to suboptimal food conditions within the aquarium resulting from the presence of the biofouling organisms in the inlet pipe. This study has implications for the husbandry and performance of experiments with marine organisms in running seawater aquaria systems. Inlet pipes should be checked regularly, and replaced if necessary, in order to avoid excessive biofouling and to approach in situ water quality. 

This study explores the competitive and allelopathic interactions of native sponges and the non-native ascidian, Trididemnum solidum, in the space-limited coral reef environments of Bonaire, NA. The study had two main goals: (1) to identify native sponge species and provide estimates of sponge and T. solidum percent cover, and (2) investigate the allelopathic and overgrowth responses of native sponges and T. solidum when they are engaged in spatial competition with each other. Belt transects and modified nearest-neighbor methods were used to quantify abundance, species diversity, and interactions between native sponges and T. solidum at the Karpata dive site on Bonaire. Overall, it was found that percent cover of sponges significantly increased with depth while percent cover of T. solidum varied among depths, reaching a maximum at 11 – 15 m. Twenty-two species of sponges were recorded with species composition and abundance varying among depths while diversity among depths was not significantly different (p = 0.880). It was found that percent cover of T. solidum had a significant effect on the number of contact interactions. A closer look at contact interactions revealed that T. solidum frequently (87.5 % - 100.0%) overgrew sponges and caused tissue necrosis but was itself never observed to be overgrown. Staged interactions between two abundant encrusting sponges (Ulosa ruetzleri and Halisarca sp.) and T. solidum showed that native sponge growth is impaired by the ascidian and that T. solidum uses allelopathy when expanding its colonies. As described by this study, the success of T. solidum in its expanded range may provide support for two additional hypotheses: the evolution of increased competitive ability hypothesis, which attributes the success of non-native species to their increased ability to overgrow native organisms, and the novel weapons hypothesis which explains that non-native species are successful because they harbor allelopathic chemicals that native organisms have not evolved defenses for.

This student research was retrieved from Physis: Journal of Marine Science V (Spring 2009)19: 2-9 from CIEE Bonaire.

Runoff and sewage discharge present serious consequences if left unchecked in coral reef ecosystems. Eutrophication and the introduction of harmful chemicals to the environment can lead to the destruction of coral reefs. Phosphates and polycyclic aromatic hydrocarbons (PAHs) are well known components of runoff that are detrimental to the reef ecosystem. As such, the ability to monitor the concentration and spatial distribution of these chemicals is of great interest. These pollutants may be detected using bioindicators. Bioindicators are organisms that can be used to monitor the health of an ecosystem. In this study, sponges were assessed as bioindicators for phosphate and PAHs in coral reef environments. Holopsamma helwigi, Ircinia strobilina, and Pseudoceratina crassa are common Leuconoid sponges that were tested for pollutant contaminations using fluorometric analysis. The sponges were collected along a transect spanning the northern coast of Kralendijk, Bonaire. A known runoff site at ‘Kas di Arte’ (12° 9' 19.9362" N, 68° 16' 44.5434" W) was selected as the starting point for the transect. The sponges bioaccumulated both phosphates and PAH compounds. Concentrations of the pollutants were not found to decrease as the distance from the runoff site increased suggesting that sponges assessed here are not capable of showing short-term variation in spatial trends of pollutant concentration. In order to better understand how the sponges accumulate pollutants, a thorough exploration of the kinetics of pollution bioaccumulation should be pursued in future studies.

This student research was retrieved from Physis: Journal of Marine Science XV (Spring 2014)19: 45-51 from CIEE Bonaire.

Suspension feeders perform a crucial role in uniting the benthic and pelagic environments in coral reef ecosystems. Of suspension feeders, sponges are one of the most highly abundant, widespread, and efficient filter-feeding organisms. However, suspension feeding in sponges is not completely understood. Previous studies have looked at the effect of temperature on pumping rate as well as the effect of particle size on retention rate. The purpose of this study was to investigate the depth-dependence of pumping rates and filtration efficiencies in two Caribbean reef sponges, Aplysina archeri and Aplysina lacunosa, at two depth profiles. Videos were taken of sponges pumping fluorescein dye to obtain pumping rates, and turbidity measurements were taken of both inhalant and exhalant water samples that were collected in situ via syringes in order to estimate filtration efficiency. The results revealed a species-specific interaction with depth for both pumping rate and filtration efficiency. Aplysina lacunosa was found to have both a faster pumping rate and increased filtration efficiency at the shallower depth, while no differences were observed across depths for A. archeri. Additionally, correlations were found between pumping rate and filtration efficiency for both species, suggesting the development of distinct filter-feeding strategies. Aplysina lacunosa had a positive correlation between pumping rate and filtration efficiency, while the correlation in A. archeri was found to be negative. Understanding the effect of depth on the filter-feeding mechanism of sponges is important to understanding the greater implications of the benthic-pelagic coupling process of sponges and suspension feeders in general.

This student research was retrieved from Physis: Journal of Marine Science XVI (Fall 2014)19: 6-12 from CIEE Bonaire.

Marine sponges provide an important link between the benthic and pelagic environments of coral reef ecosystems, yet there is relatively little known about them. Past studies have indicated that depth and size could be contributing factors in tube sponge filter feeding strategies. This study investigated the effects of depth and size on pumping rate and filtering efficiency of Aplysina lacunosa, a common Caribbean reef sponge. At two different depths, several parameters of the sponges were measured: tube length, wall thickness, tissue volume, pumping rate (using fluorescein dye), and filtering efficiency (percent reduction in turbidity between the ostia and osculum). Water samples collected from the water column had similar food availabilities between the two depths. There was a positive relationship between sponge size and pumping rate but not filtering efficiency. Additionally, no relationship was found between depth and sponge pumping rate and filtering efficiency, which is consistent with my finding that food availability did not differ across depths. The filter feeding strategy of A. lacunosa may be unique in the context of other benthic filter feeders in that its pumping rate but not filtering efficiency is affected by size and that neither pumping rate nor filtering efficiency are affected by depth. Further investigations are needed to learn more about the biology of A. lacunosa and its significance to Caribbean coral reefs.

This student research was retrieved from Physis: Journal of Marine Science XVIII (Fall 2015)19: 40-46 from CIEE Bonaire.

Stressors causing coral reef degradation are making reefs susceptible to domination by other organisms. One documented phase-shift is increased macroalgal cover of deteriorated reefs. Sponges also have the potential to overtake reefs because of their tolerance for rising temperatures and ocean acidification, ability to outcompete corals for space, and tendency to grow on available substrate created by coral mortality. This study aimed to address gaps in the literature on sponge/coral relationships as well as simultaneously study the interactions between coral and both of its potential competitors. Percentage encrusting sponge cover, percentage algae cover, and encrusting sponge density were compared to percentage live, damaged, and dead coral cover to examine the interactions among coral, sponges, and algae. Sponge/coral interactions were also classified to assess sponge aggressiveness. Data was collected at Yellow Submarine dive site using belt transects and photoquadrats. Although no correlations were significant, most comparisons found that sponges and algae decreased with more live coral cover and increased with more dead coral cover. No significant differences among the abundance of sponge/coral interaction types were found on the reef slope, but there were significant differences present on the reef crest. In both locations, most interactions were not aggressive overgrowth interactions. The relationships among sponges, algae, and coral suggest that both sponges and algae tend to grow on substrate made available by coral death. By examining the interactions of both sponges and algae with coral, comparison of these relationships was possible, potentially prompting future work that also assesses multiple ecologically important interactions.

This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 42-51 from CIEE Bonaire.