Soft corals (Cnidaria, Alcyonacea) from the Gulf of Nicoya estuary, Pacific of Costa Rica: a checklist

Introduction: The Gulf of Nicoya is the most important estuary on the Pacific coast of Costa Rica. Information on the presence of soft corals is scattered in the literature and in museum collections. Objective: To provide a list of soft corals reported for the estuary. Methods: We compiled the literature (2002-2020) and of the specimens deposited at the Museum of Zoology, University of Costa Rica. Results: Thirty species have been reported for the estuary (Clavulariidae, Gorgoniidae and Plexauridae). Most were collected on the eastern coast of the Nicoya Peninsula, and several species were described based on estuary specimens. Conclusion: The 30 species represent 79 % of those reported for Costa Rica. Despite this relatively high percentage, the sampling effort has been modest and other sites within the estuary should be explored.

A comparison of food sources of nudibranch mollusks at different depths off the Kuril Islands using fatty acid trophic markers

Gastropod molluscs such as nudibranchs are important members of deep-sea benthic ecosystems. However, data on the trophic ecology and feeding specialization of these animals are limited to date. The method of fatty acid trophic markers (FATM) was applied to determine the dietary preferences of nudibranchs off the Kuril Islands. Fatty acid (FA) compositions of Dendronotus sp., Tritonia tetraquetra, and Colga pacifica collected from deep waters were analyzed and compared with those of Aeolidia papillosa and Coryphella verrucosa from the offshore zone. The high level of FATM such as 22:5n-6 and C20 monounsaturated FAs indicated that Dendronotus sp. preys on sea anemones and/or anthoathecates hydroids similarly to that of shallow-water species A. papillosa and C. verrucosa. The high percentage of tetracosapolyenoic acids and the ratio 24:6n-3/24:5n-6 indicated that T. tetraquetra preys on soft corals such as Gersemia and/or Acanella at a depth of 250 m, but soft corals of the family Primnoidae may be the main item in the diet of T. tetraquetra at a depth of 500 m. The high content of Δ 7,13-22:2 and 22:6n-3 shows that C. pacifica can feed on bryozoans. In C. pacifica, 22:5n-6 may be synthesized intrinsically by the mollusks, whereas odd-chain and branched saturated FAs originate from associated bacteria.

Diversity of Benthic Organisms on Artificial Reef Structure

One of the methods of a marine rehabilitation program to accelerate the recovery of damaged coral reefs is to make artificial reefs as a new coral growth substrate. Interestingly, many benthic invertebrates overgrowth the artificial reef structures. The purpose of this study was to investigate the benthic organisms encrusting the artificial reefs including the cement and iron substrates. In June 2018, 10 artificial reef structures were deployed in 7-8m depth around Putri Island, Belinyu, Bangka Regency. The artificial reef structures were made in the form of an iron frame with a cement concrete weight. Colonization of sessile benthic organisms is generally marine invertebrates; Scleractinia corals, sponges, bivalves, hydrozoa, bryozoa, soft corals, gastropoda, crinoid, ascidian, and gorgonian. Natural recruited coral Pocillopora sp. was found in all artificial reef structures with colony sizes 3-8cm and surprisingly only coral pocillopora found adhered in iron frames and sinkers. The other benthic organisms are sponge, crinoid, and bryozoa with the number of densities are 2 organism/m2. Meanwhile, the lowest benthic density are groups of Mollusc and Ascidian with organism/m2. The type of succession that occurs in this research was likely a primary succession. The preference of benthic organisms among reefs appeared to be related to the proximity of natural hard-bottom habitat and type of iron and coating materials.

Recent updates on Sinularia soft coral

: Marine organisms are recognized as a rich source of bioactive secondary metabolites. The remarkable abundance and diversity of bioactive small molecules isolated from soft corals displayed their essential role in drug discovery for human diseases. Sterols and terpenes, particularly cembranolides, 14-membered cyclic diterpene, demonstrated numerous biological activities, such as antitumor, antimicrobial, antiviral, antidiabetic, anti-osteoporosis and anti-inflammatory. Accordingly, continuous investigation of marine soft corals will be the way for the discovery of a plentiful number of chemical diverse natural products with various biological potentials for prospective pharmaceutical industrial applications. Such review affords plenary inspection of the total secondary metabolites isolated from the Sinularia, from 2008 until 2020, besides their natural sources as well as bioactivities whenever possible.