Gametogenesis and the reproductive cycle in the deep-sea anemone Paracalliactis stephensoni (Cnidaria: Actiniaria)

1990 ◽  
Vol 70 (1) ◽  
pp. 163-172 ◽  
Author(s):  
Michel Praet-Van
Keyword(s):  
Organic Matter ◽  
Shallow Water ◽  
Deep Sea ◽  
Phytoplankton Bloom ◽  
Sea Anemone ◽  
Bay Of Biscay ◽  
Sea Anemones ◽  
Spring Phytoplankton Bloom ◽  
Sea Floor ◽  
Ultrastructural Investigation

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.

scholarly journals Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

2013 ◽  
Vol 10 (5) ◽  
pp. 2945-2957 ◽  
Author(s):  
A. Dell'Anno ◽  
A. Pusceddu ◽  
C. Corinaldesi ◽  
M. Canals ◽  
S. Heussner ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Depth ◽  
Surface Waters ◽  
Deep Sea ◽  
Nutritional Value ◽  
Trophic State ◽  
Phytoplankton Bloom ◽  
Continental Margins ◽  
Organic C ◽  
Deep Sea Sediments

Abstract. The bioavailability of organic matter in benthic deep-sea ecosystems, commonly used to define their trophic state, can greatly influence key ecological processes such as biomass production and nutrient cycling. Here, we assess the trophic state of deep-sea sediments from open slopes and canyons of the Catalan (NW Mediterranean) and Portuguese (NE Atlantic) continental margins, offshore east and west Iberia, respectively, by using a biomimetic approach based on enzymatic digestion of protein and carbohydrate pools. Patterns of sediment trophic state were analyzed in relation to increasing water depth, including repeated samplings over a 3 yr period in the Catalan margin. Two out of the three sampling periods occurred a few months after dense shelf water cascading events. The benthic deep-sea ecosystems investigated in this study were characterized by high amounts of bioavailable organic matter when compared to other deep-sea sediments. Bioavailable organic matter and its nutritional value were significantly higher in the Portuguese margin than in the Catalan margin, thus reflecting differences in primary productivity of surface waters reported for the two regions. Similarly, sediments of the Catalan margin were characterized by significantly higher food quantity and quality in spring, when the phytoplankton bloom occurs in surface waters, than in summer and autumn. Differences in the benthic trophic state of canyons against open slopes were more evident in the Portuguese than in the Catalan margin. In both continental margins, bioavailable organic C concentrations did not vary or increase with increasing water depth. Overall, our findings suggest that the intensity of primary production processes along with the lateral transfer of organic particles, even amplified by episodic events, can have a role in controlling the quantity and distribution of bioavailable organic detritus and its nutritional value along these continental margin ecosystems.

scholarly journals Bioavailability of sinking organic matter in the Blanes canyon and the adjacent open slope (NW Mediterranean Sea)

2013 ◽  
Vol 10 (5) ◽  
pp. 3405-3420 ◽  
Author(s):  
P. Lopez-Fernandez ◽  
S. Bianchelli ◽  
A. Pusceddu ◽  
A. Calafat ◽  
A. Sanchez-Vidal ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Deep Sea ◽  
Phytoplankton Bloom ◽  
Statistical Tests ◽  
Sea Surface ◽  
Submarine Canyons ◽  
Entire Study ◽  
Sea Floor ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

Abstract. Submarine canyons are sites of intense energy and material exchange between the shelf and the deep adjacent basins. To test the hypothesis that active submarine canyons represent preferential conduits of available food for the deep-sea benthos, two mooring lines were deployed at 1200 m depth from November 2008 to November 2009 inside the Blanes canyon and on the adjacent open slope (Catalan Margin, NW Mediterranean Sea). We investigated the fluxes, biochemical composition and food quality of sinking organic carbon (OC). OC fluxes in the canyon and the open slope varied among sampling periods, though not consistently in the two sites. In particular, while in the open slope the highest OC fluxes were observed in August 2009, in the canyon the highest OC fluxes occurred in April–May 2009. For almost the entire study period, the OC fluxes in the canyon were significantly higher than those in the open slope, whereas OC contents of sinking particles collected in the open slope were consistently higher than those in the canyon. This result confirms that submarine canyons are effective conveyors of OC to the deep sea. Particles transferred to the deep sea floor through the canyons are predominantly of inorganic origin, significantly higher than that reaching the open slope at a similar water depth. Using multivariate statistical tests, two major clusters of sampling periods were identified: one in the canyon that grouped trap samples collected in December 2008, concurrently with the occurrence of a major storm at the sea surface, and associated with increased fluxes of nutritionally available particles from the upper shelf. Another cluster grouped samples from both the canyon and the open slope collected in March 2009, concurrently with the occurrence of the seasonal phytoplankton bloom at the sea surface, and associated with increased fluxes of total phytopigments. Our results confirm the key ecological role of submarine canyons for the functioning of deep-sea ecosystems, and highlight the importance of canyons in linking episodic storms and primary production occurring at the sea surface to the deep sea floor.

Antarctic deep-sea meiofauna and bacteria react to the deposition of particulate organic matter after a phytoplankton bloom

2011 ◽  
Vol 58 (19-20) ◽  
pp. 1983-1995 ◽  
Author(s):  
Gritta Veit-Köhler ◽  
Katja Guilini ◽  
Ilka Peeken ◽  
Oliver Sachs ◽  
Eberhard J. Sauter ◽  
...  
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Deep Sea ◽  
Phytoplankton Bloom

Transformations of biogenic particles during sedimentation in the northeastern Atlantic

1995 ◽  
Vol 348 (1324) ◽  
pp. 179-189 ◽  
Keyword(s):  
Organic Matter ◽  
Deep Sea ◽  
Vertical Flux ◽  
Biological Pump ◽  
Sea Floor ◽  
The North ◽  
Sea Bed ◽  
Attached Bacteria ◽  
North Eastern ◽  
Break Up

The vertical flux and transformation of biogenic particles are im portant processes in the oceanic carbon cycle. Changes in the magnitude of the biological pump can occur in the north eastern Atlantic on both a seasonal and interannual basis. For example, seasonal variations in vertical flux at 47° N 20° W are linked to seasonal ocean productivity variations such as the spring bloom. The size and organic and inorganic content of phytoplankton species, their development and succession also play a role in the scale and composition of the biological pump. The majority of flux is in the form of fast sinking aggregates. Bacteria and transparent exopolymer particle production by phytoplankton have been implicated in aggregate production and mass flux events. Zooplankton grazing and faecal pellet production, their size and composition and extent of their vertical migration also influence the magnitude of vertical flux. Aggregates are formed in the upper ocean, often reaching a maximum concentration just below the seasonal thermocline and can be a food resource to mesozooplankton as well as to the high concentrations of attached bacteria and protozoa. Attached bacteria remineralize and solubilize the aggregate particulate organic carbon. The degree of particle solubilization is likely to be affected by factors controlling enzyme activity and production, for example temperature, pressure or concentration of specific organic molecules, all of which may change during sinking. Attached bacterial growth is greatest on particulate organic matter collected at 500 m which is the depth where studies of 210 Po reveal that there is greatest break-up of rapidly sinking particles. Break-up of particles by feeding zooplankton can also occur. The fraction of sinking POC lost between 150-3100 m at one station in the north eastern Atlantic could supply about 90% of the bacterial carbon demand. Some larger, faster sinking aggregates escape solubilization and disaggregation in the upper 1000 m and arrive in the deep ocean and on the deep-sea bed. Seasonally varying rates of sedimentation are reflected at the deep-sea floor by deposition of phytodetrital material in summer. Approximately 2-4% of surface water primary production reaches the sea floor in 4500 m depth at 47° N 20° W after a sedimentation time of about 4-6 weeks. In this region, concentrations of chloroplastic pigments increased in summer by an order of magnitude, whereas seasonal changes in activity or biomass parameters were smaller. Breakdown of the generally strongly degraded organic matter deposited on deep-sea sediments is mainly accomplished by bacteria. Rates of degradation and efficiency of biomass production depend largely on the proportion of biologically labile material which decreases with advancing decay. It is likely that different levels of organic matter deposition influence the bioturbation rates of larger benthos, which has an effect on transport processes within the sediment and presumably also on microbial degradation rates.

scholarly journals A Deep-Sea Sponge Loop? Sponges Transfer Dissolved and Particulate Organic Carbon and Nitrogen to Associated Fauna

2021 ◽  
Vol 8 ◽  
Author(s):  
Martijn C. Bart ◽  
Meggie Hudspith ◽  
Hans Tore Rapp ◽  
Piet F. M. Verdonschot ◽  
Jasper M. de Goeij
Keyword(s):  
Organic Matter ◽  
Coral Reefs ◽  
Shallow Water ◽  
Deep Sea ◽  
Cold Water ◽  
Trophic Levels ◽  
Sponge Species ◽  
Sponge Tissue ◽  
Associated Fauna ◽  
Brittle Stars

Cold-water coral reefs and sponge grounds are deep-sea biological hotspots, equivalent to shallow-water tropical coral reefs. In tropical ecosystems, biodiversity and productivity are maintained through efficient recycling pathways, such as the sponge loop. In this pathway, encrusting sponges recycle dissolved organic matter (DOM) into particulate detritus. Subsequently, the sponge-produced detritus serves as a food source for other organisms on the reef. Alternatively, the DOM stored in massive sponges was recently hypothesized to be transferred to higher trophic levels through predation of these sponges, instead of detritus production. However, for deep-sea sponges, the existence of all prerequisite, consecutive steps of the sponge loop have not yet been established. Here, we tested whether cold-water deep-sea sponges, similar to their tropical shallow-water counterparts, take up DOM and transfer assimilated DOM to associated fauna via either detritus production or predation. We traced the fate of 13carbon (C)- and 15nitrogen (N)-enriched DOM and particulate organic matter (POM) in time using a pulse-chase approach. During the 24-h pulse, the uptake of 13C/15N-enriched DOM and POM by two deep-sea sponge species, the massive species Geodia barretti and the encrusting species Hymedesmia sp., was assessed. During the subsequent 9-day chase in label-free seawater, we investigated the transfer of the consumed food by sponges into brittle stars via two possible scenarios: (1) the production and subsequent consumption of detrital waste or (2) direct feeding on sponge tissue. We found that particulate detritus released by both sponge species contained C from the previously consumed tracer DOM and POM, and, after 9-day exposure to the labeled sponges and detritus, enrichment of 13C and 15N was also detected in the tissue of the brittle stars. These results therefore provide the first evidence of all consecutive steps of a sponge loop pathway via deep-sea sponges. We cannot distinguish at present whether the deep-sea sponge loop is acting through a detrital or predatory pathway, but conclude that both scenarios are feasible. We conclude that sponges could play an important role in the recycling of DOM in the many deep-sea ecosystems where they are abundant, although in situ measurements are needed to confirm this hypothesis.

The influence of organic matter diagenesis on CaCO3 dissolution at the deep-sea floor

1994 ◽  
Vol 58 (13) ◽  
pp. 2799-2809 ◽  
Author(s):  
Richard A. Jahnke ◽  
Deborah B. Craven ◽  
Jean-Francois Gaillard
Keyword(s):  
Organic Matter ◽  
Deep Sea ◽  
Sea Floor

scholarly journals Facultative chemosynthesis in a deep-sea anemone from hydrothermal vents in the Pescadero Basin, Gulf of California

2020 ◽  
Author(s):  
Shana K Goffredi ◽  
Cambrie Motooka ◽  
David A. Fike ◽  
Luciana C Gusmão ◽  
Ekin Tilic ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Deep Sea ◽  
Gulf Of California ◽  
Hydrothermal Vents ◽  
Prey Capture ◽  
Sea Anemone ◽  
Sea Anemones ◽  
Bacterial Phyla ◽  
Marine Habitats ◽  
Chemosynthetic Bacteria

AbstractBackgroundNumerous deep-sea invertebrates have formed symbiotic associations with internal chemosynthetic bacteria in order to harness inorganic energy sources typically unavailable to most animals. Despite success in nearly all marine habitats and their well-known associations with photosynthetic symbionts, Cnidaria remain one of the only phyla without a clear dependence on hydrothermal vents and reliance on chemosynthetic bacterial symbionts specifically.ResultsA new chemosynthetic symbiosis between the sea anemone Ostiactis pearseae (Daly & Gusmão, 2007) and intracellular bacteria was discovered at ~3700 m deep hydrothermal vents in the southern Pescadero Basin, Gulf of California. Unlike most sea anemones observed from chemically-reduced habitats, this species was observed in and amongst vigorously venting fluids, side-by-side with the chemosynthetic tubeworm Oasisia aff. alvinae. Individuals of O. pearseae displayed carbon, nitrogen, and sulfur tissue isotope values (average δ13C −29.1‰, δ15N 1.6‰, and δ34S −1.1‰) suggestive of a distinct nutritional strategy from conventional Actiniaria suspension feeding or prey capture. Molecular and microscopic evidence confirmed the presence of intracellular SUP05-related bacteria housed in the tentacle epidermis of O. pearseae specimens collected from 5 hydrothermally-active structures within two vent fields ~2 km apart. SUP05 bacteria dominated the O. pearseae bacterial community (64-96% of the total bacterial community based on 16S rRNA sequencing), but were not recovered from other nearby anemones, and were generally rare in the surrounding water (< 7% of the total community). Further, the specific Ostiactis-associated SUP05 phylotypes were not detected in the environment, indicating a specific association. Two unusual candidate bacterial phyla (the OD1 and BD1-5 groups) also appeared to associate exclusively with O. pearseae and may play a role in symbiont sulfur cycling.ConclusionOstiactis pearseae represents the first member of Cnidaria described to date to have a physical and nutritional alliance with chemosynthetic bacteria. The facultative nature of this symbiosis is consistent with the dynamic relationships formed by both the SUP05 bacterial group and Anthozoa. The advantages gained by appropriating metabolic and structural resources from each other presumably contribute to their striking abundance in the Pescadero Basin, at the deepest known hydrothermal vents in the Pacific Ocean.

New Synaptidae (Holothuroidea: Apoda) from the Rockall Trough

1985 ◽  
Vol 65 (1) ◽  
pp. 255-261 ◽  
Author(s):  
J. D. Gage
Keyword(s):  
Shallow Water ◽  
Deep Sea ◽  
Coastal Areas ◽  
Bay Of Biscay ◽  
The North ◽  
Unknown Species ◽  
North Eastern ◽  
Rockall Trough ◽  
Deposit Feeding ◽  
Benthic Sampling

Apart from isolated records of species of the genus Protankyra and a brief reference to a ‘Leptosynapta sp.’ from 1985 to 2360 m depth from the northern Bay of Biscay (Sibuet, 1977), the holothurian family Synaptidae is unknown in the deep sea. Yet this family of small, deposit-feeding forms are often numerous in soft sediments of shallow water. The present paper describes two previously unknown species of synaptid discovered from recent benthic sampling in the Rockall Trough (N.E. Atlantic). These species belong to the genus Labidoplax, four other species of which have been described from coastal areas in the north eastern Atlantic.

Two New Deep-Sea Cirripedia (Ascothoracica and Acrothoracica) From the Atlantic

1974 ◽  
Vol 54 (2) ◽  
pp. 437-456 ◽  
Author(s):  
William A. Newman
Keyword(s):  
New Species ◽  
Calcium Carbonate ◽  
Shallow Water ◽  
Deep Water ◽  
Deep Sea ◽  
Life Histories ◽  
The Other ◽  
Bay Of Biscay ◽  
Southwest Atlantic ◽  
Highly Evolved

Two new deep-sea barnacles (Cirripedia) are described. The first, from approximately 5200 m in the Southwest Atlantic, belongs to the most generalized genus of the order Ascothoracica, Synagoga. The two previously known species, S. mira from the Mediterranean and S. metacrinicola from Japan, are from relatively shallow water. The new species is not only more generalized than either of these, but it exceeds previous depth records for any ascothoracican by more than 1000 m. It is apparently a sequentially protandric hermaphroditic ectoparasite, knowledge of which helps clarify difficulties in interpreting the life histories of certain more highly evolved endoparasitic forms. On the other hand, its markedly generalized features bear heavily on considerations of the origin of the Maxillopoda.The second new species, from approximately 1500 m in the Bay of Biscay, belongs to the most generalized genus of the order Acrothoracica, Weltneria. It is closely related to W. hessleri known from 1000 m off Bermuda and the two are unique in being the only true deep water members of the order. The new species is remarkable in inhabiting a friable, clayey substrate - all other acrothoracicins are known to burrow only in relatively solid forms of calcium carbonate. However, both have a calcified rostral plate, and this indicates that the Acrothoracica stem from scalpellid rather than cyprilepadid or iblid Lepadomorpha.

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