Exceptional preservation of two new early rossellid sponges: the dominant species in the Hirnantian (Late Ordovician) Anji Biota of China

2020 ◽  
Vol 177 (5) ◽  
pp. 1025-1038
Author(s):  
Joseph P. Botting ◽  
Dorte Janussen ◽  
Yuandong Zhang ◽  
Lucy A. Muir
Keyword(s):  
Deep Water ◽  
Soft Tissues ◽  
Water Environment ◽  
Common Species ◽  
Nepheloid Layer ◽  
Exceptional Preservation ◽  
Unique Character ◽  
Bedding Planes ◽  
Superficial Similarity ◽  
Water Ecosystems

The Anji Biota of Zhejiang Province, South China, is an exceptionally preserved, sponge-dominated fauna from the latest Ordovician interval, representing a deep-water environment and containing more than 100 sponge species. Herein a complex of two common species that together dominate the deepest-water sponge assemblages within the sequence are described: Shouzhispongia coronata gen. et sp. nov. and Shouzhispongia prodigia gen. et sp. nov. The complex taphonomic pathway for sponge preservation is critical to interpretation of the fossils: prostalial hypodermal pentactins (a unique character of the hexactinellid family Rossellidae) were originally present and are locally visible, but many have been lost taphonomically because spicules are primarily preserved as moulds within soft tissues. The choanosomal skeleton is composed dominantly of very small hexactins and other triaxon spicules rather than diactins, suggesting an early branching position within the family stem group. Despite their abundance in the Anji Biota, and superficial similarity to certain extant rossellid genera such as Bathydorus, no closely similar sponges have yet been described. This highlights the extremely incomplete fossil record of truly deep-water ecosystems. Preservational alignment patterns of the sponges on bedding planes support previous ideas of nepheloid-layer collapse as the primary burial mechanism.

scholarly journals Monsoonal forcing of cold-water coral growth off southeastern Brazil during the past 160 kyr

2020 ◽  
Vol 17 (23) ◽  
pp. 5883-5908
Author(s):  
André Bahr ◽  
Monika Doubrawa ◽  
Jürgen Titschack ◽  
Gregor Austermann ◽  
Andreas Koutsodendris ◽  
...  
Keyword(s):  
Organic Matter ◽  
Continental Slope ◽  
Deep Water ◽  
Cold Water ◽  
Southeastern Brazil ◽  
Nepheloid Layer ◽  
Saturation State ◽  
The Past ◽  
Water Ecosystems ◽  
The Impact

Abstract. Cold-water corals (CWCs) constitute important deep-water ecosystems that are under increasing environmental pressure due to ocean acidification and global warming. The sensitivity of these deep-water ecosystems to environmental change is demonstrated by abundant paleorecords drilled through CWC mounds that reveal characteristic alterations between rapid formation and dormant or erosive phases. Previous studies have identified several central parameters for driving or inhibiting CWC growth such as food supply, oxygenation, and the carbon saturation state of bottom water, yet there are still large uncertainties about the relative importance of the different environmental parameters. To advance this debate we have performed a multiproxy study on a sediment core retrieved from the 25 m high Bowie Mound, located at 866 m water depth on the continental slope off southeastern Brazil, a structure built up mainly by the CWC Solenosmilia variabilis. Our results indicate a multifactorial control on CWC growth at Bowie Mound during the past ∼ 160 kyr, which reveals distinct formation pulses during northern high-latitude glacial cold events (Heinrich stadials, HSs) largely associated with anomalously strong monsoonal rainfall over the continent. The ensuing enhanced runoff elevated the terrigenous nutrient and organic-matter supply to the continental margin and likely boosted marine productivity. The dispersal of food particles towards the CWC colonies during HSs was facilitated by the highly dynamic hydraulic conditions along the continental slope that prevailed throughout glacial periods. These conditions caused the emplacement of a pronounced nepheloid layer above Bowie Mound, thereby aiding the concentration and along-slope dispersal of organic matter. Our study thus emphasizes the impact of continental climate variability on a highly vulnerable deep-marine ecosystem.

scholarly journals Monsoonal forcing controlled cold water coral growth off south-eastern Brazil during the past 160 kyrs

2020 ◽  
Author(s):  
André Bahr ◽  
Monika Doubrawa ◽  
Jürgen Titschack ◽  
Gregor Austermann ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Organic Matter ◽  
Continental Slope ◽  
Deep Water ◽  
Cold Water ◽  
Nepheloid Layer ◽  
High Northern Latitude ◽  
South Eastern ◽  
The Past ◽  
Eastern Brazil ◽  
Water Ecosystems

Abstract. Cold-water corals (CWC) constitute important deep-water ecosystems that are increasingly under environmental pressure due to ocean acidification and global warming. The sensitivity of these deep-water ecosystems to environmental change is demonstrated by abundant paleo-records drilled through CWC mounds that reveal a characteristic alteration between rapid formation and dormant or erosive phases. Previous studies have identified several parameters such as food supply, oxygenation, and carbon saturation state of bottom water as central for driving or inhibiting CWC growth, yet there is still a large uncertainty about the relative importance of the different environmental parameters. To advance this debate we have performed a multi-proxy study on a sediment core retrieved from the 25 m high Bowie Mound, located in 866 m water depth on the continental slope off south-eastern Brazil, a structure built up mainly by the CWC Solenosmilia variabilis. Our results indicate a multi-factorial control on CWC growth and mound formation at Bowie Mound during the past ~160 kyrs, which reveals distinct formation pulses during glacial high northern latitude cold events (Heinrich Stadials, HS) largely associated with anomalous continental wet periods. The ensuing enhanced run-off elevated the terrigenous nutrient and organic matter supply to the continental margin, and might have boosted marine productivity. The dispersal of food particles towards the CWC colonies during HS was facilitated by the highly dynamic hydraulic conditions along the continental slope that prevailed throughout glacial periods. These conditions caused the emplacement of a pronounced nepheloid layer above Bowie Mound aiding the concentration and along-slope dispersal of organic matter. Our study thus demonstrates a yet unrecognized impact of continental climate variability on a highly vulnerable deep-marine ecosystem.

scholarly journals pH up-regulation as a potential mechanism for the cold-water coral <i>Lophelia pertusa</i> to sustain growth in aragonite undersaturated conditions

2015 ◽  
Vol 12 (23) ◽  
pp. 6869-6880 ◽  
Author(s):  
M. Wall ◽  
F. Ragazzola ◽  
L. C. Foster ◽  
A. Form ◽  
D. N. Schmidt
Keyword(s):  
Deep Water ◽  
Cold Water ◽  
Isotope Analysis ◽  
Lophelia Pertusa ◽  
Ambient Seawater ◽  
Skeletal Morphology ◽  
Composition And Structure ◽  
Ph Conditions ◽  
Water Ecosystems ◽  
Water Coral

Abstract. Cold-water corals are important habitat formers in deep-water ecosystems and at high latitudes. Ocean acidification and the resulting change in aragonite saturation are expected to affect these habitats and impact coral growth. Counter to expectations, the deep water coral Lophelia pertusa has been found to be able to sustain growth even in undersaturated conditions. However, it is important to know whether such undersaturation modifies the skeleton and thus its ecosystem functioning. Here we used Synchrotron X-Ray Tomography and Raman spectroscopy to examine changes in skeleton morphology and fibre orientation. We combined the morphological assessment with boron isotope analysis to determine if changes in growth are related to changes in control of calcification pH. We compared the isotopic composition and structure formed in their natural environment to material grown in culture at lower pH conditions. Skeletal morphology is highly variable but shows no distinctive differences between natural and low pH conditions. Raman investigations found no difference in macromorphological skeletal arrangement of early mineralization zones and secondary thickening between the treatments. The δ11B analyses show that L. pertusa up-regulates the internal calcifying fluid pH (pHcf) during calcification compared to ambient seawater pH and maintains a similar elevated pHcf at increased pCO2 conditions. We suggest that as long as the energy is available to sustain the up-regulation, i.e. individuals are well fed, there is no detrimental effect to the skeletal morphology.

Exceptional preservation in the Jurassic of Osteno

1985 ◽  
Vol 311 (1148) ◽  
pp. 171-180 ◽  
Keyword(s):  
Calcium Phosphate ◽  
Organic Material ◽  
Soft Tissues ◽  
Taxonomic Diversity ◽  
Cellular Level ◽  
Metasomatic Process ◽  
Exceptional Preservation ◽  
Sea Bottom ◽  
Colloidal Calcium Phosphate ◽  
Sediment Interface

The Sinemurian deposit of Osteno, discovered in 1964, is remarkable for the exceptional preservation of its fossils. They are almost exclusively non-calcareous organisms such as fishes, crustaceans, polychaetes and nematodes. Their exceptional fossilization is due to a metasomatic process implying a molecule-for-molecule replacement of the organic material by colloidal calcium phosphate, a process that has permitted the preservation of the soft tissues of the organisms in some cases even to cellular level. The Osteno deposit formed on a poorly oxygenated sea bottom inhabited by fauna with a low taxonomic diversity, in some cases monotypic. Infaunal organisms are not found in the deposit since the H 2 S-O 2 boundary was probably situated slightly below the water-sediment interface.

scholarly journals Deciphering the preservation of fossil insects: a case study from the Crato Member, Early Cretaceous of Brazil

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2756 ◽  
Author(s):  
Gabriel Ladeira Osés ◽  
Setembrino Petri ◽  
Bruno Becker-Kerber ◽  
Guilherme Raffaeli Romero ◽  
Marcia de Almeida Rizzutto ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Soft Tissues ◽  
Three Dimensional ◽  
Size Variation ◽  
Northeastern Brazil ◽  
Geochemical Data ◽  
Fossil Insects ◽  
Exceptional Preservation ◽  
Zn And Cu In ◽  
Crato Member

Exceptionally well-preserved three-dimensional insects with fine details and even labile tissues are ubiquitous in the Crato Member Konservat Lagerstätte (northeastern Brazil). Here we investigate the preservational pathways which yielded such specimens. We employed high resolution techniques (EDXRF, SR-SXS, SEM, EDS, micro Raman, and PIXE) to understand their fossilisation on mineralogical and geochemical grounds. Pseudomorphs of framboidal pyrite, the dominant fossil microfabric, display size variation when comparing cuticle with inner areas or soft tissues, which we interpret as the result of the balance between ion diffusion rates and nucleation rates of pyrite through the originally decaying carcasses. Furthermore, the mineral fabrics are associated with structures that can be the remains of extracellular polymeric substances (EPS). Geochemical data also point to a concentration of Fe, Zn, and Cu in the fossils in comparison to the embedding rock. Therefore, we consider that biofilms of sulphate reducing bacteria (SRB) had a central role in insect decay and mineralisation. Therefore, we shed light on exceptional preservation of fossils by pyritisation in a Cretaceous limestone lacustrine palaeoenvironment.

scholarly journals Hyperparasitism in caves: bats, bat flies and ectoparasitic fungus

2018 ◽  
Vol 1 ◽  
Author(s):  
Katrine Jensen ◽  
Luísa Rodrigues ◽  
Thomas Pape ◽  
Anders Garm ◽  
Sergi Santamaria ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Natural Populations ◽  
Common Species ◽  
Unique Case ◽  
Male And Female ◽  
Entire Life ◽  
Bat Flies ◽  
Starting Point ◽  
Bat Fly ◽  
Peculiar Case

Bat flies (Nycteribiidae) of the order Diptera are highly specialized bloodsucking ectoparasites living on bats. The life-cycle of the bat flies emphasizes their obligate relationship with their hosts as they spend almost their entire life on bats. Upon mating, the female bat fly carries the larvae internally until the 3rd-instar when it deposits the larvae on the ceiling of the roost occupied by bats. The larvae then form a puparium. After 3-4 weeks the adult bat fly emerges from the puparium and starts searching for a host bat to colonize. Some of these ectoparasitic bat flies themselves are infected with an ectoparasitic fungus of the genus Arthrorhynchus (Laboulbeniales). Ascospores of the fungi attach themselves to the cuticle of the bat fly and develop a very conspicuous haustorium that penetrates into the soft tissues from where it presumably extract nutrition from the hemolymph of the bat flies. This interaction converts the fungus into a hyperparasite. Both the parasite and hyperparasite are obligates and cannot live separate from their hosts. This peculiar case of hyperparasitism remains highly unknown. The bat flies were collected in caves of Portugal, in maternity and hibernation bat seasons, and in the autumn migration period. The most common species of cave-dwelling bat species in Portugal is Miniopterus schreibersii, frequently parasitized with Nycteribia schmidlii and Penicillidia conspicua bat flies. We have studied the prevalence of the Laboulbeniales of the genus Arthrorhynchus in natural populations of bat flies. The site and position of the fungus on male and female bat flies unveils the mechanism of fungal transmission among bat flies, indicating that it occurs during mating behavior. This study is the starting point towards the understanding of this unique case of fungus-insect-vertebrate hyperparasitism interaction. See Suppl. material 1.

scholarly journals A Depth-Bistatic Bottom Reverberation Model and Comparison with Data from an Active Triplet Towed Array Experiment

2020 ◽  
Vol 10 (9) ◽  
pp. 3080
Author(s):  
Youngcheol Jung ◽  
Woojae Seong ◽  
Keunhwa Lee ◽  
Seongil Kim
Keyword(s):  
Time Series ◽  
Deep Water ◽  
Water Environment ◽  
Ray Theory ◽  
Reverberation Time ◽  
Environment Model ◽  
Line Array ◽  
Model Predictions ◽  
Towed Array ◽  
Good Agreement

In this paper, a depth-bistatic bottom reverberation model that employs the ray theory is presented. The model can be applied to an active towed array in the ocean. The reverberation time series are modeled under the depth-bistatic assumption and their Doppler shift is calculated based on the actual source–receiver geometry. This model can handle N × 2D range-dependent bathymetry, the geometry of a triplet array, and the Doppler motion of the source, targets, and receiver. The model predictions are compared with the mid-frequency reverberation data measured by an active triplet towed array during August 2015 in the East Sea, Korea. These data are collected with a variable depth source at mid-frequency and the triplet line array in a deep-water environment. Model predictions of the beam time series and its spectrogram are in good agreement with the measurement. In particular, we discuss the effects of the source and receiver depths on the reverberation in deep water observed in both the measured and modeled results.

scholarly journals Morphological divergence between three Arctic charr morphs – the significance of the deep‐water environment

2015 ◽  
Vol 5 (15) ◽  
pp. 3114-3129 ◽  
Author(s):  
Sigrid Skoglund ◽  
Anna Siwertsson ◽  
Per‐Arne Amundsen ◽  
Rune Knudsen
Keyword(s):  
Deep Water ◽  
Arctic Charr ◽  
Water Environment ◽  
Morphological Divergence
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