Variety Of Sponges Research Articles

Gorgonians Are Foundation Species on Sponge-Dominated Mesophotic Coral Reefs in the Caribbean

Foundation species (FS) regulate ecological processes within communities often facilitating biodiversity and habitat complexity. Typically FS are dominant structure-forming taxa; but less dominant taxa having disproportionate ecological impacts to the community can also be FS. Mesophotic coral ecosystems (MCEs) are deep coral reef (∼30–150 m) communities, often dominated by emergent sponges in the Caribbean Basin. Despite the potential competitive advantage of sponges on MCEs, gorgonians are also common constituents of these reefs. Data from the Bahamas demonstrate increased biodiversity and densities of sponges on mesophotic reefs with gorgonians relative to reefs without these species. Drawing upon fifteen years of field surveys at five sites in the Caribbean Basin we assessed in situ interactions between gorgonians and sponges to quantify outcomes consistent with competition (i.e., tissue necrosis and overgrowth). Gorgonians were effective competitors against a variety of sponges, and two allelochemicals produced by Ellisella elongata were mechanistically important in interactions with Agelas clathrodes. We also examined invertebrate recruitment patterns near gorgonians to assess their role in facilitating MCE biodiversity. Our results indicate that live gorgonians, Antillogorgia bipinnata and E. elongata, facilitate biodiverse recruitment into MCEs, indicating that this process is governed by more than passive hydrodynamics. Collectively, these data indicate that these gorgonians exhibit both positive and negative ecological interactions (i.e., facilitation and competition, respectively) with sponges, and other taxa. Thus, these gorgonians are FS of MCE communities within the Caribbean Basin that display several traits contributing to the ecological structure of these understudied communities.

Flow phantom for contrast enhanced ultrasound research, device validation, and clinical training

Phantoms are an important part of ultrasound research, instrument development, and clinical training. There are, however, no standardized phantoms for contrast enhanced ultrasound. Phantoms typically include either tubes to mimic flow in larger vessels or dialysis tubing to mimic perfusion in the capillary bed. These approaches fail to mimic the full range of flow regimes and tissue scattering observed in the body during imaging. To address some of these limitations, we designed a phantom that integrates flow in both the macro- and microcirculation with physiological tissue backscatter, attenuation, and sound speed and that can be customized to simultaneously mimic flow in normal and malignant tissues. A variety of sponges and foams were considered. Acceptable materials were fit in a custom-built flow chamber and imaged with a commercially available ultrasound system. A polyvinyl alcohol (PVA) sponge was deemed to be a suitable phantom material. PVA has a sound speed of 1490 m/s and attenuation coefficient of 0.6 dB/cm/MHz. After introducing a contrast agent into the flow system, the agent could be visualized rapidly entering the flow inlets, perfusing slowly through the sponge, and rapidly exiting through the flow outlets. [Funded by Philips Ultrasound and the Life Sciences Discovery Fund No. 3292512.]Phantoms are an important part of ultrasound research, instrument development, and clinical training. There are, however, no standardized phantoms for contrast enhanced ultrasound. Phantoms typically include either tubes to mimic flow in larger vessels or dialysis tubing to mimic perfusion in the capillary bed. These approaches fail to mimic the full range of flow regimes and tissue scattering observed in the body during imaging. To address some of these limitations, we designed a phantom that integrates flow in both the macro- and microcirculation with physiological tissue backscatter, attenuation, and sound speed and that can be customized to simultaneously mimic flow in normal and malignant tissues. A variety of sponges and foams were considered. Acceptable materials were fit in a custom-built flow chamber and imaged with a commercially available ultrasound system. A polyvinyl alcohol (PVA) sponge was deemed to be a suitable phantom material. PVA has a sound speed of 1490 m/s and attenuation coefficien...

Верхнепермские рифы Южного Китая – последние рифы палеозоя

Subject of research . The upper Permian reefs of the Yangtze block of southern China are considered. Among them there are two species which differ in location in the basin and the nature of the internal structure. Methods and results. On the basis of geological and lithological methods of research it is shown that the main rift builders were a variety of sponges, whith a lesser extent bryozoans and wide development of non-carcass organisms. Along with relatively simple buildings (biostromes), the reefs in the strict sense of this term are also established. The beginning of reef formation is fixed by the accumulation of detritus of echinoderms with micro-grain cemented material. Reef formation ended until the end of Permian, before bulk biota extinction on the border of Permian and Triassic although potentially reef-building organisms still existed. Conclusion. The events that led to the great mass extinction were preceded by certain changes, which primarily destroyed the system of reef biocenosis, which led to the cessation of the formation of reefs with the continued existence of individual groups of organisms.

Characterization of macrofaunal assemblages associated with sponges and tunicates collected off the southeastern United States

Abstract. Sponges can serve as hosts to invertebrate assemblages that live and reproduce within them. Sponges also constitute a major part of the benthic epifaunal community on the continental shelf of the southeastern United States; however, little is known about these sponges and the assemblages they harbor. In this study, the associated fauna from a variety of sponges and one species of tunicate collected by submersible from the continental shelf and slope of the southeastern United States at depths in the range 18–875 m were examined. Seventeen sponges, comprising eight species (Ircinia campana, Topsentia sp., Geodia sp., Characella sp., Erylus sp., Apylsina archeri, Cliona sp., and Pheronema carpenteri), and three tunicate colonies (Didemnidae) were fully dissected and all associated organisms were identified and counted. Additionally, the sponges Pheronema annae (951 m) and P. carpenteri (770 m) represent new records for the region. The diversity (H′) and density of associates varied considerably among hosts; the densities of associates ranged 0.4–11,684 per 1 L of host volume. Polychaete worms were the most common organisms found, with one species, Haplosyllis spongicola, being especially abundant in I. campana, Topsentia sp., and Cliona sp. The amphipods Ericthonius punctatus and Leucothoe cf. spinicarpa, as well as decapods such as snapping shrimp (Synalpheus sp.) and crabs (e.g., Pilumnus floridana, Micropanope urinator), were also common. The number of symbiont taxa did not significantly increase as the sponge size increased. However, weak positive trends were found between the diversity of associates and increasing canal diameter. Sponges and tunicates were judged to represent legitimate ecological communities harboring a complete food web as well as gravid and juvenile individuals.

The impact of Dictyota spp. on Halimeda populations of Conch Reef, Florida Keys

Species of the brown alga Dictyota dominate the reef tract in the Florida Keys. In surveys during summer and fall months between 1994 and 2001, Dictyota occupied as much as 70% of the benthos on Conch Reef. Dictyota spp. were found growing epiphytically on Halimeda tuna, Halimeda opuntia, Lobophora variegata, Galaxura sp., fire coral, hard corals, soft corals, bryozoans and a variety of sponges on Conch Reef. From 1994 to 2001, the percent coverage of Halimeda spp. declined from 15% to 3% on the same reef. In Aug. 1999, 2000 and 2001, on average, 56% of two Halimeda species on Conch Reef had >50% of their thalli covered by Dictyota menstrualis and Dictyota pulchella. To address the impact of Dictyota on Halimeda, short-term growth of unepiphytized and heavily epiphytized (>50% Dictyota cover) H. tuna were compared with unepiphytized H. tuna to which a Dictyota mimic was attached. The number of new segments per plant ranged from 1 to 174 over 9 days. Halimeda thalli with >50% Dicytota cover and thalli covered with Dictyota mimic grew significantly slower than unepiphytized thalli. A second short-term experiment addressed the impact of neighboring Dictyota on the growth and metabolism of unepiphytized H. tuna. Augmenting or clearing epilithic Dictyota around but not in contact with H. tuna had no impact on growth or metabolism of H. tuna. Unepiphytized and heavily epiphytized H. tuna were also collected for studies of metabolism. This work indicated that epiphytic Dictyota negatively impacts metabolic rates of H. tuna in part by shading H. tuna thalli. This negative impact was also in part chemically mediated, as exposure to Dictyota-conditioned water elevated respiration rates in the same manner as seen in the metabolic studies of naturally epiphytized H. tuna.