scholarly journals Methodological Studies on Estimates of Abundance and Diversity of Heterotrophic Flagellates from the Deep-Sea Floor

2016 ◽  
Vol 4 (1) ◽  
pp. 22 ◽  
Author(s):  
Alexandra Schoenle ◽  
Alexandra Jeuck ◽  
Frank Nitsche ◽  
Paul Venter ◽  
Dennis Prausse ◽  
...  
Keyword(s):  
Deep Sea ◽  
Heterotrophic Flagellates ◽  
Sea Floor ◽  
Abundance And Diversity ◽  
Methodological Studies

Organic and siliceous protistan scales in north-east Atlantic abyssal sediments

2006 ◽  
Vol 86 (4) ◽  
pp. 679-688 ◽  
Author(s):  
Andrew J. Gooday ◽  
Genoveva F. Esteban ◽  
Ken J. Clarke
Keyword(s):  
Deep Sea ◽  
Small Samples ◽  
Heterotrophic Flagellate ◽  
Heterotrophic Flagellates ◽  
East Atlantic ◽  
Sea Floor ◽  
North East ◽  
The North ◽  
Marine Habitats ◽  
Deep Sea Sediments

We report the occurrence of a high diversity of minute (∼1 μm diameter) organic and siliceous protistan scales in small samples (total volume ∼35 μl) of superficial sediment from the Porcupine Abyssal Plain (PAP), north-east Atlantic (4850 m water depth). Many exhibit characters by which they can be identified to species. The organic scales belong to the haptophyte genera Chrysochromulina (8–9 species), Chrysocampanula and Dolichomastix (1 species each). The siliceous scales belong to the chrysophytes Paraphysomonas vestita and Meringosphaera sp. and to the heterotrophic flagellate genus Thaumatomastix (T. dybsoeana, T. formosa, Thaumatomastix sp.). As far as we are aware, this is the first time that non-calcareous protistan scales have been observed in deep-sea sediments (although siliceous skeletal plates and cysts are reported). All scales probably originated from the upper water column and were delivered to the deep-sea floor on rapidly sinking detrital aggregates. However, naked heterotrophic flagellates are known to thrive in abyssal sediment habitats and so the possibility that some scale-bearing protists also live in benthic deep-sea environments cannot be eliminated. Many species identified at the PAP site are common in coastal marine waters around Europe; some occur as far afield as Tasmania and New Zealand. Five Chrysochromulina species are known from central oceanic areas, including parts of the North Atlantic, while another species, C. pringsheimii, is reported from a British freshwater lake. We retrieved ∼15% of the 55 named Chrysochromulina species (∼8% of the estimated total number of species in this diverse group) in the ∼35 μl of abyssal sediment. Because the scales can persist and be identified after cell death, they may provide useful time- and space-averaged information about the distribution of protist species in marine habitats. The long-term fate of the scales on the sea-floor is unknown. It is possible that at least some of the organic scales are preserved as microfossils in deep-sea sediments.

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

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 Relative Abundance and Diversity of Bacterial Methanotrophs at the Oxic–Anoxic Interface of the Congo Deep-Sea Fan

2017 ◽  
Vol 8 ◽  
Author(s):  
Sandrine Bessette ◽  
Yann Moalic ◽  
Sébastien Gautey ◽  
Françoise Lesongeur ◽  
Anne Godfroy ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Deep Sea ◽  
Abundance And Diversity ◽  
Sea Fan

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.

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