Phanerozoic flysch trace fossil diversity—observations based on an Ordovician flysch ichnofauna from the Aroostook–Matapedia Carbonate Belt of northern New Brunswick

1980 ◽  
Vol 17 (9) ◽  
pp. 1259-1270 ◽  
Author(s):  
R. K. Pickerill
Keyword(s):  
New Brunswick ◽  
Deep Sea ◽  
Benthic Communities ◽  
Trace Fossil ◽  
Geological Time ◽  
Organic Detritus ◽  
Systematic Effort ◽  
Behavioural Diversity ◽  
Stratigraphic Range ◽  
Sufficient Oxygen

An Ordovician flysch trace fossil assemblage from the Aroostook–Matapedia Carbonate Belt, northern New Brunswick, consists of the following identifiable ichnogenera: Alcyonidiopsis, Asteriacites, Asterosoma, Belorhaphe, Bifasciculus, Buthotrephis, Chondrites, Cochlichnus, Cosmorhaphe, Diplichnites, Fucusopsis, Glockeria, Gyrochorte, Helminthoida, Helminthopsis, Neonereites, Paleodictyon, Planolites, Protopaleodictyon, Scalarituba, Spirodesmos, Spirorhaphe, and Taenidium. The stratigraphic range of six ichnogenera, viz. Glockeria, Gyrochorte, Helminthoida, Spirodesmos, Spirorhaphe, and Taenidium, is, therefore, now extended to rocks of Ordovician age.The diversity exhibited by the assemblage is inconsistent with currently proposed models of Phanerozoic flysch trace fossil diversity. It is suggested that existing models suffer from an inadequacy of sampling and systematic effort per period of geological time, as reflected by the limited number of post-Cambrian/pre-Cretaceous, particularly post-Carboniferous/pre-Cretaceous, adequately documented flysch ichnoassemblages. The assemblage described here clearly illustrates a significant radiation of deep-sea behavioural diversity in the Ordovician. This is possibly related to the development during the Ordovician of a sufficient oxygen concentration and supply of organic detritus in the deep sea or colonization of deeper-water habitats concomitant with the significant diversification of Ordovician shelf benthic communities.

scholarly journals Impacts of bottom trawling on benthic trophic status and meiofauna in a deep-sea sedimentary environment (Gulf of Castellammare, southwestern Mediterranean Sea)

2020 ◽  
Author(s):  
Antonio Pusceddu ◽  
Sarah Paradis ◽  
Davide Moccia ◽  
Pere Puig ◽  
Pere Masque ◽  
...  
Keyword(s):  
Community Composition ◽  
Deep Sea ◽  
Biochemical Composition ◽  
Benthic Communities ◽  
Sedimentary Environment ◽  
Sediment Cores ◽  
Organic Detritus ◽  
Bottom Trawling ◽  
Sedimentary Environments ◽  
The Impact

<p>The impacts of bottom trawling on the structure of benthic communities can be relatively non-selective, hitting biodiversity as a whole. This holds true also in the deep sea, where the impacts of trawling can be more severe and long-lasting than in shallow-waters, due to the reduced capacity for recovery and greater vulnerability of deep-sea organisms. For years, our knowledge of the impact of trawling on deep-water ecosystems has remained limited and has focused mainly on fish stocks and hard bottom systems. More recently, a number of studies have addressed the impacts of bottom trawling in the deep-sea sedimentary environments, and very few of them have focused on the impacts on meiofauna, though it is a key faunal component of deep-sea ecosystems.</p><p>We investigated the impact of bottom trawling on the quantity, biochemical composition and nutritional value of sedimentary organic matter and meiofauna along the Sicilian Margin (Gulf of Castellammare, southwestern Mediterranean) at ca. 550 m depth, during the summer of 2016. Amount, biochemical composition and freshness of sedimentary OM, as well as the abundance and community composition of meiofauna were determined in sediment cores taken at both trawled and untrawled grounds. The continuous erosive processes in the trawled site have led, generally, to the depletion of OM contents (20-60% lower than those in the untrawled site), as well as to statistically significant differences from the untrawled site in its biochemical composition. Nevertheless, the upper 2 cm of the trawled site consisted of recently accumulated sediments, enriched in phytopigments, and bulk OM contents similar to those in the untrawled one, interpreted as a very recent input of fresh OM from the upper water column. The abundance of meiofauna in trawled grounds was significantly higher than that in untrawled ones, whereas no differences were observed between trawled and untrawled grounds deeper in the sediment. Differences in the meiofaunal community composition among sediment layers in each site were larger than those among sites.</p><p>As previously reported, deep bottom trawling in the Gulf of Castellammare erodes large volumes of sediment, exposing old compacted sediment that is depleted in OM. This erosive action generally prevents the accumulation of fresh sediment. However, the episodic short-lived deposition of fresh organic detritus between hauls can lead to a temporary accumulation of fresh and bioavailable OM which, in turn, can induce a positive response in meiofauna abundance.</p><p>These results pinpoint the need of considering the impacts of bottom trawling on the benthic communities of deep-sea sedimentary environments at temporal scales shorter than previously done.</p>

scholarly journals Some recent advances in the study of deep-sea foraminiferal biology and their palaeoecological significance

1992 ◽  
Vol 6 ◽  
pp. 111-111
Author(s):  
Andrew J. Gooday
Keyword(s):  
Deep Sea ◽  
Large Scale ◽  
Regional Distribution ◽  
Euphotic Zone ◽  
Ocean Floor ◽  
Biological Research ◽  
Turbidity Currents ◽  
Geological Time ◽  
Foraminiferal Assemblage ◽  
Organic Detritus

During the past two decades, biologists have become increasingly aware of the diversity and abundance of foraminifera in marine benthic ecosystems. These protists are probably the most important eukaryotes present in ocean floor communities. In some areas, particularly central oceanic regions, foraminiferal assemblages are dominated by newly discovered, soft-bodied forms with morphologies quite unlike those of “conventional” foraminifers and with little fossilisation potential. However, despite the presumed loss of these delicate forms from the fossil record, foraminiferal tests are still the only microfossils to occur commonly in ancient deep-sea sediments. Thus, they are a focus of attention for both geologists and biologists. This presentation will concentrate on two main areas of biological research which have palaeontological significance.Foraminiferal microhabitats. Recent research indicates that particular species tend to live infaunally (deep or shallow), epifaunally or suprabenthically. Growth above or below the sediment-water interface has major implications for the stable isotope chemistry of calcareous tests, an important tool in palaeooceanography. Other species inhabit organic detritus composed of phytoplankton material rapidly sedimented from the euphotic zone. This “phytodetritus” arrives suddenly on the ocean floor following the spring bloom and is quickly colonized by foraminiferal species which feed on it, reproduce and rapidly develop large populations. These populations collapse when the food source is exhausted. The direct consumption of phytodetritus (and other organic matter inputs) by benthic foraminifers may be a widespread phenomenon which influences their population dynamics, regional distribution patterns and isotope chemistry.Recolonization. The defaunation of large tracts of ocean floor by turbidity currents or anoxic events must have happened on countless occasions over geological time, particularly along ocean margins and in basinal areas. Evidence from sediment tray experiments suggests that it may take several years for a stable community (including foraminifers) to become reestablished in small areas of defaunated sediment. Large devastated areas may require substantially longer to recover. However, on the Madeira Abyssal Plain, a normal foraminiferal assemblage occurs on the surface of a turbidite deposited several hundred years ago, suggesting that large-scale recolonization may occupy decades rather than centuries. The fossil foraminiferal assemblages present in deep-water flysch sequences are presumably the product of similar recolonization (?successional) events.These and other biological processes often operate on time scales (days, months, years) which usually can not be resolved in the stratigraphic record. This inevitably complicates the application of biological research to palaeontology.

In situ Enclosure Experiment Using a Benthic Chamber System to Assess the Effect of High Concentration of CO2 on Deep-Sea Benthic Communities

2005 ◽  
Vol 61 (5) ◽  
pp. 835-843 ◽  
Author(s):  
Hiroshi Ishida ◽  
Yuji Watanabe ◽  
Tatsuo Fukuhara ◽  
Sho Kaneko ◽  
Kazushi Furusawa ◽  
...  
Keyword(s):  
Deep Sea ◽  
Benthic Communities ◽  
Chamber System ◽  
High Concentration ◽  
Enclosure Experiment ◽  
Benthic Chamber

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 CHONDRITES-CLADICHNUS ICHNOCOENOSIS FROM THE DEEP-SEA DEPOSITS OF PIERFRANCESCO (CRETACEOUS; ITALY): OXYGEN- OR NUTRIENT-LIMITED?

2022 ◽  
Vol 128 (1) ◽  
Author(s):  
ANDREA BAUCON ◽  
GIROLAMO LO RUSSO ◽  
CARLOS NETO DE CARVALHO ◽  
FABRIZIO FELLETTI
Keyword(s):  
Late Cretaceous ◽  
Deep Sea ◽  
Trace Fossils ◽  
Northern Apennines ◽  
Trace Fossil ◽  
Ecological Succession ◽  
Rhythmic Pattern ◽  
Low Oxygen ◽  
Fossil Assemblage

The Italian Northern Apennines are acknowledged as the place where ichnology was born, but there is comparatively little work about their ichnological record. This study bridges this gap by describing two new ichnosites from the locality of Pierfrancesco, which preserve an abundant, low-disparity trace-fossil assemblage within the Late Cretaceous beds of the M. Cassio Flysch. Results show that lithofacies and ichnotaxa are rhythmically organized. The base of each cycle consists of Megagrapton-bearing calciclastic turbidites, which are overlain by marlstone beds with an abundant, low-disparity assemblage of trace fossils. This includes Chondrites intricatus, C. patulus, C. targionii, C. recurvus and Cladichnus fischeri. The cycle top consists of mudstones with no distinct burrows. The rhythmic pattern of Pierfrancesco reflects a deep-sea ecological succession, in which species and behaviour changed as turbidite-related disturbances altered the seafloor. This study opens the question of whether the Chondrites-Cladichnus ichnocoenosis represents low-oxygen or nutrient-poor settings.

scholarly journals Evidence for benthic-pelagic food web coupling and carbon export from California margin bamboo coral archives

2014 ◽  
Vol 11 (2) ◽  
pp. 2595-2621 ◽  
Author(s):  
T. M. Hill ◽  
C. R. Myrvold ◽  
H. J. Spero ◽  
T. P. Guilderson
Keyword(s):  
Primary Production ◽  
Deep Sea ◽  
Benthic Communities ◽  
California Current ◽  
Strong Relationship ◽  
Nitrogen Isotope ◽  
Carbon Export ◽  
Carbon And Nitrogen ◽  
Pelagic Food Webs

Abstract. Deep-sea bamboo corals (order Gorgonacea, family Isididae) are known to record changes in water mass chemistry over decades to centuries. These corals are composed of a two-part skeleton of calcite internodes segmented by gorgonin organic nodes. We examine the spatial variability of bamboo coral organic node 13C/12C and 15N/14N from thirteen bamboo coral specimens sampled along the California margin (37–32° N; 792 to 2136 m depth). Radiocarbon analyses of the organic nodes show the presence of the anthropogenic bomb spike, indicating the corals utilize a surface-derived food source (pre-bomb D14C values of ∼ −100‰, post-bomb values to 82‰). Carbon and nitrogen isotope data from the organic nodes (13C = −15.9‰ to −19.2‰ 15N = 13.8‰ to 19.4‰) suggest selective feeding on surface-derived organic matter or zooplankton. A strong relationship between coral 15N and habitat depth indicate a potential archive of changing carbon export, with decreased 15N values reflecting reduced microbial degradation (increased carbon flux) at shallower depths. Using four multi-centennial length coral records, we interpret long-term 15N stability in the California Current. Organic node 13C values record differences in carbon isotope fractionation dictated by nearshore vs. offshore primary production. These findings imply strong coupling between primary production, pelagic food webs, and deep-sea benthic communities.

scholarly journals Deep-sea benthic communities in the largest oceanic desert are structured by the presence of polymetallic crust

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Juliette Delavenne ◽  
Louise Keszler ◽  
Magalie Castelin ◽  
Pierre Lozouet ◽  
Philippe Maestrati ◽  
...  
Keyword(s):  
Deep Sea ◽  
Benthic Communities

Deep-sea foraging pathways: an analysis of randomness and resource exploitation

Paleobiology ◽  
1979 ◽  
Vol 5 (2) ◽  
pp. 107-125 ◽  
Author(s):  
Jennifer A. Kitchell
Keyword(s):  
Deep Sea ◽  
Trace Fossil ◽  
Empirical Modeling ◽  
The Arctic ◽  
Foraging Strategies ◽  
Foraging Efficiency ◽  
Resource Exploitation ◽  
Foraging Patterns ◽  
Risk Of Predation ◽  
Random Behavior

The foraging paradigm of trace fossil theory has historically accorded random behavior to non-food-limited deposit-feeders and non-random behavior to food-limited feeders. A series of randomness measures derived from empirical modeling, simulation modeling, stochastic modeling and probability theory applied to foraging patterns observed in deep-sea bottom photographs from the Arctic and Antarctic yielded a behavioral continuum of increasing non-randomness. A linear regression of trace positions along the continuum to bathymetric data did not substantiate the optimal foraging efficiency-depth dependence model of trace fossil theory, except that all traces exhibited a greater optimization than that of simulated random foraging. It is hypothesized that optimization as evidenced by non-random foraging strategies represents maximization of the cost/benefit ratio of resource exploitation to risk of predation and that individual foraging patterns reflect an exploration response to the morphometry of a patchily distributed food resource. Differential predation and competition may account for the co-occurrence of random and non-random strategies within the same bathymetric zone.

A NEW TEICHICHNOID TRACE FOSSIL SYRINGOMORPHA CYPRENSIS FROM THE MIOCENE OF CYPRUS

Palaios ◽  
2019 ◽  
Vol 34 (10) ◽  
pp. 506-514 ◽  
Author(s):  
OLMO MIGUEZ-SALAS ◽  
FRANCISCO J. RODRÍGUEZ-TOVAR ◽  
ALFRED UCHMAN
Keyword(s):  
Deep Sea ◽  
Trace Fossil ◽  
Taxonomic Group ◽  
Energy Conditions ◽  
Bottom Current ◽  
Lower Paleozoic ◽  
Shallow Marine ◽  
Current Flows

ABSTRACTA new teichichnoid trace fossil, Syringomorpha cyprensis from the Miocene of Cyprus, is proposed as a vertical burrow composed of an arcuate-like tube with horizontal parts to subhorizontal distally and vertical to subvertical parts proximally and triangular spreiten in the inner corner of the tube. Previously, this ichnogenus was represented only by the lower Paleozoic, shallow marine S. nilssoni, which disappeared after the Cambrian. Syringomorpha cyprensis marks the reappearance of similar behavior, in a deep-sea environment with pelagic, contouritic, and turbiditic sedimentation, influenced by frequent turbiditic and bottom current flows. Both ichnospecies of Syringomorpha could be produced by the same taxonomic group of probable worm like organisms (polychaetes?). Energy conditions were a stronger influence on the distribution of S. cyprensis tracemaker rather depth.

The Diversity of Nematode Communities in the Southern North Sea

1974 ◽  
Vol 54 (1) ◽  
pp. 251-255 ◽  
Author(s):  
C. Heip ◽  
W. Decraemer
Keyword(s):  
North Carolina ◽  
North Sea ◽  
Deep Sea ◽  
Benthic Communities ◽  
Nematode Communities ◽  
Diversity Measure ◽  
Southern North Sea ◽  
The North ◽  
Harpacticoid Copepods ◽  
Logarithmic Series

Diversity is one of the most important parameters used in the description of a community; several theories relating diversity to other phenomena as predation, competition and stability have been proposed (Pianka, 1966). As a result of the increasing interest in diversity a number of studies have appeared during recent years, but the meiofauna has until recently been almost completely neglected, rather surprisingly when one considers the importance of this group of organisms in all marine benthic communities. Coull (1972) studied recently the diversity of harpacticoid copepods, with nematodes the major meiobenthic component, along the North Carolina shelf and in the deep sea. Warwick & Buchanan (1970) appear to be the only ones to have studied diversity in nematode communities, using α of the logarithmic series (Fisher, Corbett & Williams, 1943) as a diversity measure. The paucity of data seems primarily to be due to the taxonomic difficulties encountered in studying nematodes.

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