scholarly journals A Brief Description of Surface Structure and Composition of the Pseudo-Snail Shell Formed by a Sea Anemone Stylobates sp. Symbiotic with Hermit Crabs from the Deep-Sea Floor

2019 ◽  
Vol 36 (4) ◽  
pp. 284 ◽  
Author(s):  
Akihiro Yoshikawa ◽  
Shiori Nakazawa ◽  
Akira Asakura
Keyword(s):  
Surface Structure ◽  
Deep Sea ◽  
Sea Anemone ◽  
Hermit Crabs ◽  
Snail Shell ◽  
Sea Floor

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.

Large Plastic Debris Dumps: New Biodiversity Hot Spots Emerging on the Deep-Sea Floor

2021 ◽  
Author(s):  
Xikun Song ◽  
Mingxin Lyu ◽  
Xiaodi Zhang ◽  
Bernhard Ruthensteiner ◽  
In-Young Ahn ◽  
...  
Keyword(s):  
Deep Sea ◽  
Hot Spots ◽  
Plastic Debris ◽  
Sea Floor

scholarly journals CO2-driven decrease in pH disrupts olfactory behaviour and increases individual variation in deep-sea hermit crabs

2015 ◽  
Vol 73 (3) ◽  
pp. 613-619 ◽  
Author(s):  
Tae Won Kim ◽  
Josi Taylor ◽  
Chris Lovera ◽  
James P. Barry
Keyword(s):  
Ocean Acidification ◽  
Individual Variation ◽  
Deep Sea ◽  
Phenotypic Diversity ◽  
Hermit Crabs ◽  
Prey Detection ◽  
Stable Conditions ◽  
Living Species ◽  
Metabolic Performance ◽  
Olfactory Behaviour

Abstract Deep-sea species are generally thought to be less tolerant of environmental variation than shallow-living species due to the relatively stable conditions in deep waters for most parameters (e.g. temperature, salinity, oxygen, and pH). To explore the potential for deep-sea hermit crabs (Pagurus tanneri) to acclimate to future ocean acidification, we compared their olfactory and metabolic performance under ambient (pH ∼7.6) and expected future (pH ∼7.1) conditions. After exposure to reduced pH waters, metabolic rates of hermit crabs increased transiently and olfactory behaviour was impaired, including antennular flicking and prey detection. Crabs exposed to low pH treatments exhibited higher individual variation for both the speed of antennular flicking and speed of prey detection, than observed in the control pH treatment, suggesting that phenotypic diversity could promote adaptation to future ocean acidification.

Seasonal deposition of phytodetritus to the deep-sea floor

1986 ◽  
Vol 88 ◽  
pp. 265-279 ◽  
Author(s):  
A. L. Rice ◽  
D. S. M. Billett ◽  
J. Fry ◽  
A. W. G. John ◽  
R. S. Lampitt ◽  
...  
Keyword(s):  
Deep Sea ◽  
Benthic Communities ◽  
Time Lapse ◽  
Sediment Traps ◽  
Temporal Variations ◽  
Sea Floor ◽  
Porcupine Seabight ◽  
The Past ◽  
Sea Bed ◽  
Seasonal Deposition

SynopsisEvidence has accumulated over the past twenty years to suggest that the deep-sea environment is not as constant as was at one time thought, but exhibits temporal variations related to the seasonally in the overlying surface waters. Recent results from deep-moored sediment traps suggest that this coupling is mediated through the sedimentation of organic material, while observations in the Porcupine Seabight indicate that in this region, at least, there is a major and rapid seasonal deposition of aggregated phytodetritus to the sea-floor at slope and abyssal depths.This paper summarises the results of the Porcupine Seabight studies over the past five years or so, using time-lapse sea-bed photography and microscopic, microbiological and chemical analyses of samples of phytodetritus and of the underlying sediment. The data are to some extent equivocal, but they suggest that the seasonal deposition is a regular and dramatic phenomenon and that the material undergoes relatively little degradation during its passage through the water column. The mechanisms leading to the aggregation of the phytodetritus have not been identified, and it is not yet known whether the phenomenon is geographically widespread nor whether it is of significance to the deep-living mid-water and benthic communities.

scholarly journals Interannual variation in the epibenthic megafauna at the shallowest station of the HAUSGARTEN observatory (79° N, 6° E)

2012 ◽  
Vol 9 (12) ◽  
pp. 18039-18081 ◽  
Author(s):  
K. S. Meyer ◽  
M. Bergmann ◽  
T. Soltwedel
Keyword(s):  
Population Dynamics ◽  
Deep Sea ◽  
Interannual Variation ◽  
Suspension Feeding ◽  
Fram Strait ◽  
Population Densities ◽  
Camera System ◽  
Sea Floor ◽  
Time Period ◽  
Food Input

Abstract. Epibenthic megafauna play an important role in the deep-sea environment and contribute significantly to benthic biomass, but their population dynamics are still understudied. We used a towed deep-sea camera system to assess the population densities of epibenthic megafauna in 2002, 2007 and 2012 at the shallowest station (HG I, ~ 1300 m) of the deep-sea observatory HAUSGARTEN, in the eastern Fram Strait. Our results indicate that the overall density of megafauna was significantly lower in 2007 than in 2002, but was significantly higher in 2012, resulting in overall greater megafaunal density in 2012. Different species showed different patterns in population density, but the relative proportions of predator/scavengers and suspension-feeding individuals were both higher in 2012. Variations in megafaunal densities and proportions are likely due to variation in food input to the sea floor, which decreased slightly in the years preceding 2007 and was greatly elevated in the years preceding 2012. Both average evenness and diversity increased over the time period studied, which indicates that HG I may be food-limited and subject to bottom-up control. The varying dynamics of different species may have been caused by differential capacities of populations to respond to increased food input through either recruitment or migration.

scholarly journals Are seamounts refuge areas for fauna from polymetallic nodule fields?

2019 ◽  
Author(s):  
Daphne Cuvelier ◽  
Pedro A. Ribeiro ◽  
Sofia P. Ramalho ◽  
Daniel Kersken ◽  
Pedro Martinez Arbizu ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Deep Sea ◽  
Soft Sediment ◽  
Sea Floor ◽  
Polymetallic Nodule ◽  
Refuge Area ◽  
Clipperton Fracture Zone ◽  
Clarion Clipperton Fracture Zone ◽  
Refuge Areas ◽  
Hard Substrata

Abstract. Seamounts are abundant and prominent features on the deep-sea floor and intersperse with the nodule fields of the Clarion-Clipperton Fracture Zone (CCZ). There is a particular interest in characterising the fauna inhabiting seamounts in the CCZ because they are the only other ecosystem in the region to provide hard substrata besides the abundant nodules on the soft sediment abyssal plains. It has been hypothesised that seamounts could provide refuge for organisms during deep-sea mining actions or that they could play a role in the (re-)colonisation of the disturbed nodule fields. This hypothesis is tested by analysing video transects in both ecosystems, assessing megafauna composition and abundance. Nine video transects (ROV dives) from two different license areas and one Area of Particular Environmental Interest in the eastern CCZ were analysed. Four of these transects were carried out as exploratory dives on four different seamounts in order to gain first insights in megafauna composition. The five other dives were carried out in the neighbouring nodule fields in the same areas. Variation in community composition observed among and along the video transects was high, with little morphospecies overlap on intra-ecosystem transects. Despite these observations of considerable faunal variations within each ecosystem, differences between seamounts and nodule fields prevailed, showing significantly different species associations characterising them, thus questioning their use as a possible refuge area.

scholarly journals FORAMINÍFEROS BENTÓNICOS RECIENTES EN LAS AGUAS PROFUNDAS DE LA CUENCA DE PANAMÁ: ECOLOGÍA Y SU POSIBLE RELACIÓN CON LAS CORRIENTES DE FONDO

2016 ◽  
Vol 42 (1) ◽  
Author(s):  
Germán David Patarroyo Camargo ◽  
José Ignacio Martínez Rodríguez
Keyword(s):  
Benthic Foraminifera ◽  
Deep Sea ◽  
Lower Surface ◽  
Sea Floor ◽  
Bottom Currents ◽  
High Productivity ◽  
Surface Productivity ◽  
Sea Currents ◽  
The Relationship ◽  
Foraminíferos Bentónicos

The relationship between recent benthic foraminifera and bottom currents in the Panama basin (Colombian Pacific) is examined, and the main ecological variables which control the distribution of benthic foraminifera are discussed. The benthic foraminiferal study of 24 core top samples and the integration with previous reports, support the view that in upwelling areas or under high terrigenous influx, the assemblages are dominated by infaunal forms such as Uvigerina, Bolivina, Globobulimina, and Chilostomella, beside common forms such as Uvigerina peregrina Cushman and Epistominella spp., which are indicative of high productivity. In contrast, epifaunal forms such as Cibicidoides, Laticarinina, and Hoeglundina are more common on the flanks of the Cocos and Carnegie Ridges indicating a lower surface productivity and a larger content of dissolved oxygen on the sea floor. Infaunal foraminifera are dominated by Siphouvigerina proboscidea (Schwager). In addition, several proxy taxa of the intensity of deep sea currents were detected in the analyzed assemblages. From these taxa, Cibicides wuellerstorfi (Schwager) has the best proxy potential for the reconstruction of intense bottom currents in sediments from the Cocos and Carnegie Ridges for the Holocene.

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