Environmental drivers of benthic communities and habitat heterogeneity on an East Antarctic shelf

2016 ◽  
Vol 29 (1) ◽  
pp. 17-32 ◽  
Author(s):  
Alexandra L. Post ◽  
Caroline Lavoie ◽  
Eugene W. Domack ◽  
Amy Leventer ◽  
Amelia Shevenell ◽  
...  
Keyword(s):  
Water Depth ◽  
Habitat Heterogeneity ◽  
Marine Protected Area ◽  
Regional Distribution ◽  
Benthic Fauna ◽  
Environmental Drivers ◽  
Brittle Stars ◽  
Sea Bed ◽  
Sessile Invertebrates ◽  
Antarctic Shelf

AbstractThis study presents the first analysis of benthic megafauna and habitats from the Sabrina Coast shelf, encompassing a proposed Marine Protected Area. Sea bed imagery indicated an abundant benthic fauna compared to other parts of the Antarctic shelf, dominated by brittle stars, polychaete tubeworms, and a range of other sessile and mobile taxa. The distribution of taxa was related (ρ=0.592, P<0.001) to variations in water depth, latitude, substrate type and phytodetritus. High phytodetritus cover was associated with muddy/sandy sediments and abundant holothurians and amphipods, while harder substrates hosted abundant brachiopods, hard bryozoans, polychaete tubeworms, massive and encrusting sponges, and sea whips. Brittle stars, irregular urchins and anemones were ubiquitous. Variations in substrate largely reflected the distribution of dropstones, creating fine-scale habitat heterogeneity. Several taxa were found only on hard substrates, and their broad regional distribution indicated that the density of dropstones was sufficient for most sessile invertebrates to disperse across the region. The hexactinellid sponge Anoxycalyx joubini and branching hydrocorals exhibited a more restricted distribution, probably related to water depth and limited dispersal capability, respectively. Dropstones were associated with significant increases in taxa diversity, abundance and biological cover, enhancing the overall diversity and biomass of this ecosystem.

scholarly journals SEA-BED CONFIGURATION IN RELATION TO BREAKWATER STABILITY

1972 ◽  
Vol 1 (13) ◽  
pp. 81 ◽  
Author(s):  
J.H. Van Oarschat ◽  
A. Wevers
Keyword(s):  
The Netherlands ◽  
Present Article ◽  
Water Depth ◽  
Systematic Study ◽  
Public Works ◽  
Irregular Waves ◽  
Sea Bed ◽  
Hydraulic Conditions ◽  
Overall Stability ◽  
The Stability

Stability tests on the Europoort breakwaters, situated on a shallow foreshore, clearly demonstrated the effect of the foreshore configuration on the overall stability. The present article gives a descriptionof the stability experiments and the interpretation leading to general conclusions regarding foreshore effects in combination with hydraulic conditions such as wave period, water depth and wave height. Both regular and irregular waves have been used. The experiments, carried out in commission of the Netherlands Government Department of Public Works (Rijkswaterstaat) were of an applied nature and were not directed primarily to the systematic study of foreshore effects.

Taxonomic Dependency of Beta Diversity for Bacteria, Archaea and Fungi in a Semi-Arid Lake

2021 ◽  
Author(s):  
Haijun Yuan ◽  
Weizhen Zhang ◽  
Huaqun Yin ◽  
Runyu Zhang ◽  
Jianjun Wang
Keyword(s):  
Water Depth ◽  
Beta Diversity ◽  
Species Turnover ◽  
Environmental Drivers ◽  
Ecological Processes ◽  
Environmental Selection ◽  
Community Variation ◽  
Taxonomic Groups ◽  
Semi Arid ◽  
Total Beta

Abstract Microbial beta diversity has been recently studied along the water depth in aquatic ecosystems, however its turnover and nestedness components remain elusive especially for multiple taxonomic groups. Based on the beta diversity partitioning developed by Baselga and Local Contributions to Beta Diversity (LCBD) partitioning by Legendre, we examined the water-depth variations in beta diversity components of bacteria, archaea and fungi in surface sediments of Hulun Lake, a semi-arid lake in northern China, and further explored the relative importance of environmental drivers underlying their patterns. We found that the relative abundances of Proteobacteria, Chloroflexi, Euryarchaeota and Rozellomycota increased towards deep water, while Acidobacteria, Parvarchaeota and Chytridiomycota decreased. For bacteria and archaea, there were significant (P < 0.05) decreasing water-depth patterns for LCBD and LCBDRepl (i.e., species replacement), while increasing patterns for total beta diversity and turnover, implying that total beta diversity and LCBD were dominated by species turnover or LCBDRepl. Further, bacteria showed a strong correlation with archaea regarding LCBD, total beta diversity and turnover. Such parallel patterns among bacteria and archaea were underpinned by similar ecological processes like environmental selection. Total beta diversity and turnover were largely affected by sediment total nitrogen, while LCBD and LCBDRepl were mainly constrained by water NO2−-N and NO3−-N. For fungal community variation, no significant patterns were observed, which may be due to different drivers like water nitrogen or phosphorus. Taken together, our findings provide compelling evidences for disentangling the underlying mechanisms of community variation in multiple aquatic microbial taxonomic groups.

Characteristics of Naturally Occurring and Pollutant Hydrocarbons in Marine Sediments

1973 ◽  
Vol 1973 (1) ◽  
pp. 205-213 ◽  
Author(s):  
M. Tissier
Keyword(s):  
Marine Sediments ◽  
Benthic Fauna ◽  
Chloroform Extract ◽  
Alkyl Chains ◽  
Marine Food Chain ◽  
Naturally Occurring ◽  
Sea Bed ◽  
Polycyclic Aromatic ◽  
The Difference

ABSTRACT Hydrocarbons spilled on the sea may, naturally or by sinking agent, settle on the sea bed and pollute marine muds which are the substratum of the benthic fauna and flora. They may be absorbed by these organisms which are the basis of the nutrition for a large part of the aquatic fauna. This hydrocarbon pollutants will enter by this way in the marine food chain and raise the problem of long term toxicity. Therefore it is important to measure the quantity of hydrocarbons in the marine sediments in order to know the level of pollution. We must, however, be able to make the difference between indigenous hydrocarbons and crude-oil derived hydrocarbons. Both contain, n and iso-alkanes, cyclo-alkanes and aromatics, but their quantity, the percentage of each type of compounds and the distribution of some specific molecules are often very particular. A detailed analysis of the chloroform extract of the sediment by chromatography, mass spectrometry and U. V. fluorescence can discriminate between unpolluted and polluted sediments even in the case of low level pollution. The samples which have been analysed, were collected on the French coast of the English channel in Normandie and in the Seine Bay. It has been noted in the unpolluted samples a higher percentage of heavy products (resins and asphaltènes), a more important odd carbon dominance in the n-alkanes distribution than in the polluted ones. The aromatic fraction of the indigenous hydrocarbons is mainly composed of polycyclic aromatic hydrocarbons without alkyl chains whereas polluted samples show many types of alkylaromatics.

scholarly journals Benthic fauna distribution over different seamounts in the Mozambique Channel, from towed camera data

2018 ◽  
Author(s):  
Marion Boulard ◽  
Inge Van Den Beld ◽  
Julie Tourolle ◽  
Olivier Soubigou ◽  
Stephan Jorry ◽  
...  
Keyword(s):  
Preliminary Analysis ◽  
Biological Sample ◽  
Benthic Fauna ◽  
Local Scale ◽  
Brittle Stars ◽  
Still Images ◽  
Mozambique Channel ◽  
Ongoing Work ◽  
Taxonomic Groups ◽  
Upper Slope

Seamounts in the Mozambique Channel host rich but potentially vulnerable ecosystems. A towed camera survey was used to assess the composition, vulnerability and resilience of four seamounts: Glorieuses, Sakalaves, Bassas da India, and Hall Bank. This six dive survey, between 300 and 1,000 m depth recorded > 40 hours of videos, > 6000 still images, covering > 200,000 m². Over 70,000 individuals were observed and 400 morphospecies identified. The main taxonomic groups were sponges, corals, crustaceans, echinoderms, and fish. Preliminary analysis based on morphotypes suggests that composition, densities and diversity of these groups varied significantly between seamounts. Variability has also been observed at a local scale, between the peak and upper slope of a seamount. Glorieuses is a muddy terrace dominated by three sponge morphotypes. Sakalaves’ plateau is dominated by brittle stars and corals, while the upper slopes are mainly dominated by fish and urchins, sponges and crabs. The contrary pattern was observed on Bassas da India and Hall Bank, where the peak is dominated by fish, and the upper slopes by sponges and corals. Relief and substrate appear to be the two main drivers of faunal community distribution. Ongoing work with taxonomists will verify image-based morphotypes with biological sample identifications.

A simulation study to identify the sea water depth for the presence of air waves in sea bed logging

2012 ◽  
Author(s):  
Muhammad Abdulkarim ◽  
Afza Shafie ◽  
Noorhana Binti Yahya ◽  
Radzuan Razali ◽  
Wan Fatimah Wan Ahmad
Keyword(s):  
Water Depth ◽  
Simulation Study ◽  
Sea Water ◽  
Sea Bed

The benthic fauna of the Rockall Trough: regional distribution and bathymetric zonation

1986 ◽  
Vol 88 ◽  
pp. 159-174 ◽  
Author(s):  
J. D. Gage
Keyword(s):  
Water Mass ◽  
Regional Distribution ◽  
Benthic Fauna ◽  
Bathymetric Range ◽  
Northeast Atlantic ◽  
Faunal Change ◽  
Rockall Trough ◽  
Juvenile Stages ◽  
Species Recruitment ◽  
Cumulative Curves

SynopsisMore than 300 bottom samples taken in the Rockall Trough and neighbouring areas (Northeast Atlantic) since 1973 provide an opportunity to study the distributions of the commoner megafaunal species. These include 131 species of echinoderms, for the most abundant of which the bathymetric and regional distributions are defined. Analysis of samples by means of the coincidence-of-range method along a bathymetric transect shows peaks-in the first and last occurrences of species at the 800–1200m and 1800 m levels. Cumulative curves of the recruitment of all echinoderm species with increasing depth show step-like increases in the rate of species recruitment with depth. These maxima in rate of faunal change are related to water–mass structure, particularly the depth of the seasonal and permanent thermoclines. A considerably broader bathymetric range is shown by post-larvae and juvenile stages compared to adults.

scholarly journals First data on ostracods and foraminifera living in Cystoseira associations in western Ionian Sea

2018 ◽  
Vol 18 (3) ◽  
pp. 393
Author(s):  
FRANCESCO SCIUTO ◽  
ANTONIETTA ROSSO ◽  
ROSSANA SANFILIPPO ◽  
GIUSEPPINA ALONGI ◽  
MARCELLO CATRA ◽  
...  
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Protected Area ◽  
Marine Protected Area ◽  
Ionian Sea ◽  
Sea Bottom ◽  
Three Samples ◽  
The Family ◽  
First Time ◽  
The City

For the first time ostracod and foraminifera populations living on infralittoral algae were analysed from three different localities near the Ciclopi Islands Marine Protected Area along the Etnean Ionian coast of Sicily, few km N of the city of Catania. Six series of samples, each of three samples, were collected at 5, 10 and 26 m water depth in sea bottom areas where the Biocoenosis of the Infralittoral Algae is developed. Some samples were collected inside the Ciclopi Islands Marine Protected Area (CIMPA) and some outside it.In all the samples the ostracod association is characteristically constituted by a mixture of true shallow water phytal taxa and and infralittoral sediment-dwelling taxa. The family Xestoleberididae is markedly dominant, mainly in the shallowest samples. Xestoleberis dispar represents more than 60% of all the specimens, followed by X. communis and X. dispar. The families Paradoxostomatidae (with Paradoxostoma rarum, P. simile, P. parallelum, P. intermedium, P. atrum and P. caecum), Hemicytheridae (with Aurila prasina and A. convexa), Bairdidae (with Neonesidea mediterranea, N. corpulenta, and N. Longevaginata) follow. Loxoconchidae (with Loxoconcha rhomboidea), Pontocyprididae (with Pontocypris mediterranea and Pontocypris pirifera) and Cytheruridae (with very few specimens of Semicytherura spp.) are subordinate.Foraminifera are represented almost exclusively by phytal benthic taxa. Between them the the family Miliolidae is markedly prevalent, mostly represented by Quinqueloculina species, followed by the family Rotaliidae with Elphidium crispum, E. depressum, E. aculeatum, and Elphidium spp. Discorbidae, with Rosalina spp.; Cibidididae, largely represented by Cibicides refulgens and C. advenum; Planorbulinidae with Planorbulina mediterranensis, are also present.

scholarly journals Environmental Drivers of Mesophotic Echinoderm Assemblages of the Southeastern Pacific Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Ariadna Mecho ◽  
Boris Dewitte ◽  
Javier Sellanes ◽  
Simon van Gennip ◽  
Erin E. Easton ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Benthic Fauna ◽  
Distinct Species ◽  
Environmental Drivers ◽  
Environmental Predictors ◽  
Management Tools ◽  
Large Spatial Scale ◽  
Southeastern Pacific ◽  
Remote Zone ◽  
Physical Barriers

Mesophotic ecosystems (50–400 m depth) of the southeastern Pacific have rarely been studied because of the logistical challenges in sampling across this remote zone. This study assessed how oxygen concentrations and other environmental predictors explain variation in echinoderm assemblages at these mesophotic systems, where this group is among the predominant fauna. We compiled data on echinoderm taxa at 91 sampling stations, from historical and recent surveys (between 1950 and 2019), covering a longitudinal gradient of approximately 3,700 km along with the Nazca, Salas y Gómez, and Juan Fernández ridges. Uni- and multivariate model-based tools were applied to analyze the patterns of benthic fauna in relation to environmental factors. Our results indicate a significant positive relationship between echinoderm species richness and depth, oxygen, and salinity. Changes in echinoderm community composition were significantly explained by oxygen, longitude, and chlorophyll-a. We observed notable species turnovers at ∼101 and ∼86°W, where assemblages tend to be more variable across stations. This turnover possibly reflects the effects of physical barriers to dispersion (e.g., currents) and habitat changes. Echinoderm assemblages observed around Easter and Desventuradas Islands presented a high occurrence of potentially endemic taxa and distinct species assemblages. This study is the first to assess the structure of mesophotic echinoderm assemblages of the southeastern Pacific Ocean along a large spatial scale. The information reported here could help design appropriate management tools for the vast, recently created, marine protected areas in the southeastern Pacific.

scholarly journals In-situ Image Analysis of Habitat Heterogeneity and Benthic Biodiversity in the Prince Gustav Channel, Eastern Antarctic Peninsula

2021 ◽  
Vol 8 ◽  
Author(s):  
Peter M. Almond ◽  
Katrin Linse ◽  
Simon Dreutter ◽  
Susie M. Grant ◽  
Huw J. Griffiths ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Habitat Heterogeneity ◽  
Environmental Changes ◽  
Marine Ecosystem ◽  
Habitat Type ◽  
Benthic Fauna ◽  
Ice Shelf ◽  
Camera System ◽  
Underwater Camera ◽  
Hard Substrates

Habitat heterogeneity is important for maintaining high levels of benthic biodiversity. The Prince Gustav Channel, on the Eastern Antarctic Peninsula, is characterized by an array of habitat types, ranging from flat, mud-dominated sheltered bays to steep and rocky exposed slopes. The channel has undergone dramatic environmental changes in recent decades, with the southern end of the channel permanently covered by the Prince Gustav Ice Shelf until it completely collapsed in 1995. Until now the marine benthic fauna of the Prince Gustav Channel has remained unstudied. A shallow underwater camera system and Agassiz trawl were deployed at different locations across the channel to collect information on habitat type and heterogeneity, benthic community composition and macrofaunal biomass. The texture of the seafloor was found to have a significant influence on the benthos, with hard substrates supporting higher abundances and diversity. Suspension and filter feeding organisms, including porifera, crinoids, and anthozoans, were strongly associated with hard substrates, with the same being true for deposit feeders, such as holothurians, and soft sediments. Habitat heterogeneity was high across the Prince Gustav Channel, particularly on a local scale, and this was significant in determining patterns of benthic composition and abundance. Other physical variables including depth and seafloor gradient played significant, interactive roles in determining composition potentially mediated through other processes. Sites that were once covered by the Prince Gustav Ice Shelf held distinct and unique communities, suggesting that the legacy of the ice shelf collapse may still be reflected in the benthos. Biomass estimations suggest that critical thresholds of vulnerable marine ecosystem indicator taxa, as defined by the Commission for the Conservation of Antarctic Marine Living Resources, have been met at multiple locations within the Prince Gustav Channel, which has implications for the future establishment of no take zones and marine protected areas within the region.

Sign in / Sign up

Export Citation Format

Share Document