scholarly journals A metabarcoding comparison of taxonomic richness and composition between the water column and the benthic boundary layer

2020 ◽  
Author(s):  
H E Parry ◽  
A Atkinson ◽  
P J Somerfield ◽  
P K Lindeque
Keyword(s):  
Boundary Layer ◽  
Water Column ◽  
Benthic Boundary Layer ◽  
Monitoring Site ◽  
Benthic Assemblages ◽  
Low Light ◽  
Operational Taxonomic Units ◽  
Shelf Seas ◽  
Term Monitoring

Abstract Zooplankton monitoring in shelf seas predominantly uses nets that miss the benthic boundary layer (BBL) just above the seabed. However, this boundary between pelagic and benthic assemblages can be faunistically rich, having its own distinct hyperbenthic fauna and acting as a low-light refuge for overwintering or dielly migrating zooplankton. To compare species richness and composition between pelagic and BBL habitats, we sampled a long-term monitoring site in the Western English Channel seasonally. Metabarcoding methods applied to vertical net samples (top 50 m in a ∼54-m water column) and those from a hyperbenthic sledge generated >100 000 sequences clustered into 294 operational taxonomic units. Of these, 215 were found in the BBL and 170 in the water column. Some key taxa (e.g. mysids) were native to the BBL; by contrast, other delicate taxa (e.g. ctenophores) seemed to avoid the BBL. The major contrasts in plankton composition related to the seasonal cycle rather than to pelagic-BBL differences, suggesting that the basic dynamics of the site are captured by our ongoing long-term weekly resolution monitoring. Overall, metabarcoding approaches, applied to both water column and BBL, provide an independent view of plankton dynamics, and augment existing traditional methods.

scholarly journals Aerosol optical depth retrievals in central Amazonia from a multi-filter rotating shadow-band radiometer calibrated on-site

2019 ◽  
Vol 12 (2) ◽  
pp. 921-934
Author(s):  
Nilton E. Rosário ◽  
Thamara Sauini ◽  
Theotonio Pauliquevis ◽  
Henrique M. J. Barbosa ◽  
Marcia A. Yamasoe ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spectral Response ◽  
Monitoring Site ◽  
Direct Normal Irradiance ◽  
Central Amazonia ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Band Radiometer

Abstract. Extraterrestrial spectral response calibration of a multi-filter rotating shadow band radiometer (MFRSR) under pristine Amazonian Forest atmosphere conditions was performed using the Langley plot method. The MFRSR is installed in central Amazonia as part of a long-term monitoring site, which was used in the context of the GoAmazon2014/5 experiment. It has been operating continuously since 2011 without regular extraterrestrial calibration, preventing its application to accurate monitoring of aerosol particles. Once calibrated, the MFRSR measurements were applied to retrieve aerosol particle columnar optical properties, specifically aerosol optical depth (AODλ) and Ångström exponent (AE), which were evaluated against retrievals from a collocated Cimel Sun photometer belonging to the AErosol RObotic NETwork (AERONET). Results obtained revealed that pristine Amazonian conditions are able to provide MFRSR extraterrestrial spectral response with relative uncertainty lower than 1.0 % in visible channels. The worst estimate (air mass =1) for absolute uncertainty in AODλ retrieval varied from ≈0.02 to ≈0.03, depending on the assumption regarding uncertainty for MFRSR direct normal irradiance measured at the surface. The obtained root mean square error (RMSE ≈0.025) from the evaluation of MFRSR retrievals against AERONET AODλ was, in general, lower than estimated MFRSR AODλ uncertainty, and close to the uncertainty of AERONET field Sun photometers (≈0.02).

Phanerozoic development of tiering in soft substrata suspension-feeding communities

Paleobiology ◽  
1986 ◽  
Vol 12 (4) ◽  
pp. 400-420 ◽  
Author(s):  
David J. Bottjer ◽  
William I. Ausich
Keyword(s):  
Boundary Layer ◽  
Benthic Boundary Layer ◽  
Suspension Feeding ◽  
Velocity Gradients ◽  
Phylogenetic Constraints ◽  
Recent Brachiopods ◽  
Shallow Subtidal ◽  
The Vertical Distribution ◽  
Sediment Interface

Tiering is the vertical distribution of organisms within the benthic boundary layer. Primary tierers are suspension-feeding organisms with a body or burrow that intersects the seafloor. Secondary tierers are suspension-feeders that maintain positions above or below the sediment-water interface as either epizoans on primary tierers and plants or by living in the burrows of primary tierers. Different primary tierers from soft substrata, nonreef, shallow subtidal shelf and epicontinental sea settings have had different tiering histories, resulting largely from contrasting constructional and phylogenetic constraints. Primary colonial tierers generally occupied lower epifaunal tiers during the Paleozoic and Mesozoic, but since the Cretaceous they have been dominant in the highest tier (+ 20 to +50 cm). Primary echinoderm tierers have been almost exclusively epifaunal, and from the Paleozoic through the Jurassic they were present throughout the epifaunal tiered structure. Although primary bivalve tierers have been both epifaunal and infaunal, they have occupied only lower epifaunal tiers, whereas they have adapted to all levels of the infaunal tiering structure, particularly from the late Paleozoic through the Recent. Brachiopods have lived primarily in tiers directly above or below the water-sediment interface and have not contributed significantly to tiering complexity.Of the numerous physical and biotic processes and constraints that affect shallow marine benthos, a few have contributed more significantly to changes in tiering patterns. Trends for increasing body size could have accounted for most of the development of tiering complexity up to +50 cm and down to –12 cm. Development of tiering above +50 cm could have been due to processes which would have yielded greater feeding capability, such as competitive interactions for a place from which to feed or adaptations to velocity gradients in the hydrodynamic boundary layer. The most significant process for development of infauanl tiering below –12 cm appears to have been as an adaptive response for predator avoidance.Unlike infaunal tiering, which never declined after it developed, epifaunal tiering has undergone a general reduction twice. Reduction in epifaunal tiering at the end of the Paleozoic appears to have been the result of the mass extinction at this time, whereas long-term biotic processes seem to have been more important for the tiering decline at the end of the Mesozoic. Tiering structure through the Phanerozoic was thus produced through interactions of a number of physical and biotic factors, tempered by constructional and phylogenetic constraints of each primary tierer group.

scholarly journals Aerosol Optical Depth retrievals in Central Amazonia from a Multi-Filter Rotating Shadow-band Radiometer on-site calibrated

2018 ◽  
Author(s):  
Nilton E. Rosário ◽  
Thamara Sauini ◽  
Theotonio Pauliquevis ◽  
Henrique M. J. Barbosa ◽  
Marcia A. Yamasoe ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Spectral Response ◽  
Monitoring Site ◽  
Direct Normal Irradiance ◽  
Central Amazonia ◽  
Mean Square Errors ◽  
Term Monitoring ◽  
Band Radiometer

Abstract. Extraterrestrial spectral response calibration of a Multi-Filter Rotating Shadow band Radiometer (MFRSR) under Amazonian Forest atmosphere pristine conditions using the Langley plot method was performed and evaluated. The MFRSR is installed in central Amazonia as part of a long-term monitoring site, which was used in the context of the GoAmazon2014/5 Experiment. It has been operating continuously since 2011 without regular extraterrestrial calibration, preventing its application to accurate monitoring of aerosol particles. Once calibrated, the MFRSR measurements were applied to retrieve aerosols particles columnar optical properties, specifically Aerosol Optical Depth (AODλ) and Ångström Exponent (AE), which were evaluated against retrievals from a collocated CIMEL sunphotometer belonging to the AErosol RObotic NETwork (AERONET). Results obtained revealed that Amazonian pristine conditions are able to provide MFRSR extraterrestrial spectral response with relative uncertainty lower than 1.0 % at visible channels. The worst estimate (air mass = 1) for absolute uncertainty in AODλ retrieval varied from ~ 0.02 to ~ 0.03, depending on the assumption regarding uncertainty for MFRSR direct-normal irradiance measured at the surface. Obtained Root Mean Square Errors (RMSE ~ 0.025) from the evaluation of MFRSR retrievals against AERONET AODλ were, in general, lower than estimate MFRSR AODλ uncertainties, and close to AERONET field sunphotometers (~ 0.02).

scholarly journals From Water into Sediment—Tracing Freshwater Cyanobacteria via DNA Analyses

2021 ◽  
Vol 9 (8) ◽  
pp. 1778
Author(s):  
Ebuka Canisius Nwosu ◽  
Patricia Roeser ◽  
Sizhong Yang ◽  
Lars Ganzert ◽  
Olaf Dellwig ◽  
...  
Keyword(s):  
Water Column ◽  
High Throughput Sequencing ◽  
Surface Sediments ◽  
Environmental Changes ◽  
Sediment Traps ◽  
Sequence Variant ◽  
Sediment Record ◽  
Term Monitoring ◽  
Taphonomic Processes

Sedimentary ancient DNA-based studies have been used to probe centuries of climate and environmental changes and how they affected cyanobacterial assemblages in temperate lakes. Due to cyanobacteria containing potential bloom-forming and toxin-producing taxa, their approximate reconstruction from sediments is crucial, especially in lakes lacking long-term monitoring data. To extend the resolution of sediment record interpretation, we used high-throughput sequencing, amplicon sequence variant (ASV) analysis, and quantitative PCR to compare pelagic cyanobacterial composition to that in sediment traps (collected monthly) and surface sediments in Lake Tiefer See. Cyanobacterial composition, species richness, and evenness was not significantly different among the pelagic depths, sediment traps and surface sediments (p > 0.05), indicating that the cyanobacteria in the sediments reflected the cyanobacterial assemblage in the water column. However, total cyanobacterial abundances (qPCR) decreased from the metalimnion down the water column. The aggregate-forming (Aphanizomenon) and colony-forming taxa (Snowella) showed pronounced sedimentation. In contrast, Planktothrix was only very poorly represented in sediment traps (meta- and hypolimnion) and surface sediments, despite its highest relative abundance at the thermocline (10 m water depth) during periods of lake stratification (May–October). We conclude that this skewed representation in taxonomic abundances reflects taphonomic processes, which should be considered in future DNA-based paleolimnological investigations.

scholarly journals Temporal and Spatial Variations of Geodia cydonium (Jameson) (Porifera, Demospongiae) in the Mediterranean Confined Environments

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 615
Author(s):  
Maria Mercurio ◽  
Cataldo Pierri ◽  
Frine Cardone ◽  
Giuseppe Corriero
Keyword(s):  
Spatial Variations ◽  
Benthic Assemblages ◽  
Temporal And Spatial Variations ◽  
Mar Piccolo Of Taranto ◽  
Geodia Cydonium ◽  
Temporal And Spatial ◽  
The Mediterranean ◽  
Changes Over Time ◽  
Term Monitoring

Confined marine environments are particularly susceptible to climate change and anthropic pressures. Indeed, the long-term monitoring of benthic assemblages in these environments allows us to understand the direction of changes over time. The demosponge Geodia cydonium is a suitable study case, since it is widely represented in many Mediterranean environments, while being a long-living and important habitat-forming species. Here, we report the results of a descriptive study on temporal and spatial variations of this demosponge in three semi-enclosed environments along the Italian coast: Marsala Lagoon, Porto Cesareo Bay, and Mar Piccolo of Taranto. At Marsala and Porto Cesareo, the study compares the present data with those reported by the literature at the end of the 1990s. Caused by the modification of its preferential habitats, the data indicated the loss and a remarkable regression of this species at Porto Cesareo and Marsala, respectively. In addition, we hypothesized that the increase in severe weather phenomena in the small Bay of Porto Cesareo recorded during the last 20 years may have had a marked impact on water mass, thus affecting the sponge assemblages. At Taranto, despite a remarkable environmental degradation, G. cydonium has appeared stable and persistent in the last 45 years, thus representing one of the richest and most well-preserved populations in the Mediterranean Sea.

Structure and taxonomic composition of subtidal nematode and macrofauna assemblages at four stations around the UK coast

2004 ◽  
Vol 84 (2) ◽  
pp. 315-322 ◽  
Author(s):  
M. Schratzberger ◽  
P. Whomersley ◽  
R. Kilbride ◽  
H.L. Rees
Keyword(s):  
Geographical Location ◽  
Taxonomic Composition ◽  
Benthic Assemblage ◽  
Benthic Assemblages ◽  
Marine Monitoring ◽  
Long Term Monitoring ◽  
The Uk ◽  
Term Monitoring ◽  
Water Depths

The diversity and structure of meiobenthic nematodes and macrobenthic infauna were studied at four widely spaced subtidal sites around the UK coast in relation to a number of measured environmental variables. The stations were situated on soft sediments at water depths of 53 to 95 m and are intended as long-term monitoring locations as part of the UK National Marine Monitoring Programme. Similar benthic assemblages were encountered in comparable environmental conditions. The distribution of nematode and macrofauna species was mainly governed by the geographical location of the habitat and the granulometric composition of the substrate. There was no evidence of any adverse effect on the measures of benthic assemblage structure arising from trace metal concentrations in the sediment, indicating the relatively unpolluted nature of the offshore locations under investigation. Nematode and macrofauna assemblages exhibited stable patterns over time periods of three years.

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