scholarly journals A preliminary study on the diversity of invertebrates associated with Corallina officinalis Linnaeus in southern Istrian peninsula

2019 ◽  
Vol 60 (2) ◽  
pp. 127-136
Author(s):  
Moira Buršić ◽  
Ljiljana Iveša ◽  
Andrej Jaklin ◽  
Milvana Arko Pijevac
Keyword(s):  
Physical Structure ◽  
Major Influence ◽  
Intertidal Area ◽  
Invertebrate Species ◽  
Sampling Locations ◽  
Corallina Officinalis ◽  
Preliminary Study ◽  
Invertebrate Assemblages ◽  
Abundance And Diversity ◽  
Algal Turfs

Red coralligenous algae Corallina officinalis provides shelter to many invertebrate species from wave actions, predation and desiccation stress in the intertidal area. Physical structure and complexity of the habitat have a major influence on biodiversity of this community. The aim of this preliminary study was to examine the diversity of invertebrate assemblages inside the red algae C. officinalis turf. Three sampling locations were chosen where algal cover range was above 90%. On each location sampling was done quantitatively by scraping off within 3 replicate quadrats 20 x 20 cm in size. A total of 30,518 specimens were isolated from all sampling locations. The prevalent groups were amphipod crustaceans, polychaetes, bivalves and gastropods that made a total of 86% of all macrofaunal groups associated with algal turfs. The most abundant group were amphipods that made 42% of the total separated individual invertebrates. Our study demonstrated that C. officinalis is a very important habitat with high abundance and diversity of invertebrate assemblages.

scholarly journals Patterns of mollusc distribution in mangroves from the São Marcos Bay, coast of Maranhão State, Brazil

2016 ◽  
Vol 46 (4) ◽  
pp. 391-400 ◽  
Author(s):  
Carlos A. L. RODRIGUES ◽  
Rannyele P. RIBEIRO ◽  
Nayara B. SANTOS ◽  
Zafira S. ALMEIDA
Keyword(s):  
Buenos Aires ◽  
Temporal Distribution ◽  
Temporal Variations ◽  
Line Transect ◽  
Intertidal Area ◽  
Water And Sediment ◽  
Diversity Gradient ◽  
Straight Line ◽  
Abiotic Variables ◽  
Abundance And Diversity

ABSTRACT The diversity and distribution of molluscs from the Amazon Coast of Maranhão State, Brazil, are poorly understood. The aim of this study was to investigate how molluscs in two mangrove creeks (Buenos Aires and Tronco) at the São Marcos Bay, coast of the Maranhão State, respond to spatial and temporal variations in the environment. Sampling was performed in the intertidal area along three zones established using a straight line transect of 100 m. Abiotic variables of water and sediment were measured at each creek. We found 5,912 specimens belonging to 23 species and 15 families of epifaunal and infaunal molluscs. The patterns of their distribution in the two creeks were different. Salinity, dissolved oxygen, and rainfall were the main variables that affected the temporal distribution of molluscs. We found low species richness in the overall mollusc composition. Diversity in the Buenos Aires Creek was lower than that observed in the Tronco Creek, possibly because of activities of a port located in proximity to the former. The spatial distribution of molluscs along the zones followed an abundance and diversity gradient, mainly influenced by exposure time during low tide. Port activities may influence the patterns of mollusc distribution in the surrounding mangroves, and we thus highlight the importance of management and monitoring of these areas.

Dissolved Carbohydrate Distribution and Dynamics in Two Southeastern United States Reservoirs

1988 ◽  
Vol 45 (2) ◽  
pp. 325-332 ◽  
Author(s):  
James J. Alberts ◽  
John W. Bowling ◽  
Mark Emmons
Keyword(s):  
United States ◽  
Aquatic Macrophytes ◽  
Southeastern United States ◽  
Physical Structure ◽  
Spatial And Temporal Variability ◽  
Vertical Profiles ◽  
Anaerobic Conditions ◽  
Sampling Locations ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

Dissolved carbohydrate concentrations were measured in the waters of two southeastern United States reservoirs (Pond B and Par Pond) in 1982 and 1983 with attention to the influence of rooted aquatic macrophytes, spatial and temporal variability, and depth. Mean concentrations for all sampling locations were 2.86 ± 1.01 mg∙L−1 in Pond B and 1.72 ± 1.24 mg∙L−1 in Par Pond. There were no consistent spatial or temporal differences within a reservoir, nor were there consistent differences between macrophyte beds and open waters in either impoundment. Dissolved carbohydrate concentrations increased in both reservoirs during the day, reaching maxima in late afternoon, with an accompanying decrease in the dissolved organic carbon (DOC). The dissolved carbohydrates comprised 5.8–20.2% of the DOC in Par Pond and 25.7–42.3% of the DOC in Pond B. In both reservoirs, vertical profiles show the presence of carbohydrates at all depths during aerobic and anaerobic conditions. Midwater concentration maxima were present in Par Pond during periods of holomixis and stratification. The maxima were coincident with an intense pycnocline during periods of stratification; but during holomixis, the maximum was apparently unsupported by physical structure.

scholarly journals Chetoui Olive Cultivar Rhizosphere: Potential Reservoir for Exoenzymes and Exopolysaccharides Producing Bacteria

2020 ◽  
Vol 14 (4) ◽  
pp. 2569-2575
Author(s):  
Ben Amar Cheba ◽  
H.M.A. Abdelzaher
Keyword(s):  
Bacterial Abundance ◽  
Geographical Origin ◽  
Enteric Bacteria ◽  
Biotechnological Applications ◽  
Olive Cultivar ◽  
Potential Reservoir ◽  
Olive Cultivars ◽  
Preliminary Study ◽  
Abundance And Diversity ◽  
Bacterial Groups

Rhizospheric soils from cultivated olive (Olea europaea) trees of Chemlali, Chetoui, Quaissi, and Djalat cultivars were assessed for their bacterial abundance and diversity and were further screened for production of exopolysaccharides and exoenzymes (cellulase, chitinase, amylase, protease, lipase, and peroxidase). The results of the present study indicate that Chetoui cultivar revealed higher diversity, followed by Chemlali > Quaissi > Djalat, wherein, bacilli, enteric bacteria, and pseudomonads were abundantly present as specific bacterial groups associated with the Chetoui rhizosphere. Moreover, the exopolysaccharide (EPS)-producing bacteria of Chetoui cultivar (68.4%) presented the highest efficiency, followed by Djalat (23.5%) > Chemlali (7 %) > Quaissi (1%). These results revealed that the Chetoui cultivar presented highest enzyme activities, followed by Chemlali > Djalat > Quaissi, with a distinct abundance of peroxidase- and chitinase-producing bacteria, which may play a pivotal role in adapting olives to the environmental stresses. From this preliminary study, we confirmed that olive rhizosphere microbial diversity is essentially driven by the geographical origin and genotype of olive cultivars. Furthermore, we recommended the Chetoui olive cultivar rhizosphere as a potential reservoir for exoenzyme- and EPS-producing bacteria useful for future biotechnological applications.

scholarly journals How and to What Degree Does Physical Structure Differ Between Natural and Artificial Habitats? A Multi-Scale Assessment in Marine Intertidal Systems

2021 ◽  
Vol 8 ◽  
Author(s):  
Ferrante Grasselli ◽  
Laura Airoldi
Keyword(s):  
Construction Material ◽  
Structural Complexity ◽  
Physical Structure ◽  
Physical Habitat ◽  
Ecological Value ◽  
Natural Habitats ◽  
Artificial Habitats ◽  
The North ◽  
Ecological Consideration ◽  
Abundance And Diversity

Marine infrastructures are increasing, generating a variety of impacts and introducing artificial habitats which have low ecological value and support assemblages that differ significantly from those on natural rocky coasts. While in the past there was little ecological consideration as to how artificial structures were built, now the trend is to look for “greener” designs inspired by or mimicking nature. These greening efforts have had a strong focus on enhancing physical habitat structure to support more diverse assemblages, driven by the untested assumption that artificial habitats lack the physical structure proper to natural habitats. We tested this assumption by comparing five descriptors of physical structure (inclination; exposure; roughness; abundance, and diversity of surface morphological microelements) across a combination of natural and artificial habitats of regular and irregular morphologies (seawalls = artificial regular; cliffs = natural regular; breakwaters = artificial, irregular; and boulder fields = natural irregular) in the North Adriatic Sea. Most structural descriptors were similar between artificial and natural habitats. Only inclination was consistently steeper in the artificial than in the natural habitats. Other minor differences in roughness or in the abundance of some surface microelements were related to the general morphology (regular or irregular) of the habitat rather than to its artificial or natural identity. The outcomes challenge the widespread assumption that artificial habitats lack the physical structure proper to natural habitats and stimulate renewed consideration about other structural and non-structural elements that could enhance the performance and sustainability of artificial marine structures, such as construction material, environmental setting or maintenance. They also encourage a wider reflection about what makes an artificial building surface “greener”: structural complexity is an important ecological parameter, and its deliberate increase will lead to responses in the biota, however, this may not necessarily match “more natural” conditions.

Island in the Stream: Oceanography and Fisheries of the Charleston Bump

2001 ◽  
Keyword(s):  
South Carolina ◽  
Geological Structure ◽  
Live Coral ◽  
Community Members ◽  
Long Distance ◽  
Fine Sediments ◽  
Invertebrate Species ◽  
Local Relief ◽  
Abundance And Diversity ◽  
Charleston Bump

<em>Abstract</em>.—The geological structure and characteristic community members of four relatively distinct benthic habitats, and their associated subhabitats, are described on the upper- and middle-continental slope just north of the Charleston Bump and below the deflection of the Gulf Stream eastward. The predominant habitats, identified from submersible surveys, included moderate-relief capped mounds, moderate-relief coral mounds, low-relief substrates and cohesive-mud substrates. Moderaterelief capped-mound habitats (185–220 m) due east of Charleston, South Carolina, were characterized by high local relief (about 20 m) outcroppings having abundant and diverse fish and sessile invertebrate communities. Moderate-relief coral-mound habitats, at depths of 503–555 m southeast of Charleston, consisted of mounds of dead coral fragments with a local relief of 15–23 m. Associated with the coral mounds was a depauperate assemblage of live coral and rare fish species. Yet, this habitat had a more diverse biological community than most of the low-relief subhabitats. Low–relief habitats at 293–567 m southeast of Charleston primarily consisted of fine sediments distributed in current generated patterns. Although epibenthic fish and invertebrate species were associated with this habitat, their abundance and diversity was relatively low. Cohesive-mud habitats at 150–250 m were distributed along depth contours for a long distance. Many of the species found here were associated with widely distributed tilefish <em> Lopholatilus chamaeleonticeps </em>burrows that impart negative relief to large areas of this flat habitat.

COMPOSITIONAL CHANGES IN DISPERSED CRUDE OIL IN THE WATER COLUMN DURING A NEARSHORE TEST SPILL

1985 ◽  
Vol 1985 (1) ◽  
pp. 521-530
Author(s):  
David S. Page ◽  
Edward S. Gilfillan ◽  
Judith C. Foster ◽  
Erin Pendergast ◽  
Linda Gonzalez ◽  
...  
Keyword(s):  
Crude Oil ◽  
Water Samples ◽  
American Petroleum Institute ◽  
Maximum Depth ◽  
Gravimetric Analysis ◽  
Intertidal Area ◽  
High Concentration ◽  
Near Surface ◽  
Dispersed Oil ◽  
Sampling Locations

ABSTRACT As part of the American Petroleum Institute sponsored tidal area dispersant project involving two test spills of Murban crude oil in Long Cove, Searsport, Maine in August, 1981, water samples were collected. This paper deals with the analytical results for the analyses of water samples collected for analysis of non-volatile hydrocarbons by: infrared spectrophotometric quantitation of total CCl4 extractables, and gravimetric analysis of aliphatic and aromatic hydrocarbon fractions followed by capillary gas chromatography. In the dispersant-treated oil discharge area, there were two primary water sampling locations during the discharge phase of the experiment: an upper intertidal area (maximum depth = 2 meters) and a lower intertidal area (maximum depth = 3.5 meters). The gas chromatographic data for the water samples were treated numerically to obtain parameters whose values reflect the extent of dispersed oil weathering. For the aliphatics, the peak area ratio for n C14/n C18 was calculated for each sample. For the aromatics, the ratio for the peak area sum of the mono, di, and trimethyl naphthalenes to that for the mono, di, tri, and tetramethyl dibenzothiophenes was determined for each sample. At both sampling locations, dispersed oil in water sampled 10 cm off the bottom consistently had a smaller fraction of lower boiling aliphatic and aromatic hydrocarbons than water sampled at the same place and the same time ½ meter below the surface. In addition, the data show that there is a 12–50 fold decrease in hydrocarbon concentration on going from near surface to near bottom at any given time, even in water as shallow as 2 meters. The data indicate that the primary mechanism for hydrocarbon loss involves volatilization of hydrocarbon fractions. Analyses of water samples taken from submerged plumes of dispersed oil outside the sampling areas demonstrated slower loss of low boiling components consistent with the importance of atmospheric exchange in the weathering process. In the chemical dispersal of an oil spill, it may be most advantageous to use mixing methods that minimize vertical mixing in order to maintain a high concentration of emulsified oil in the upper ½ meter water layer. This will maximize the extent of loss of lower boiling hydrocarbon components into the atmosphere and thus minimize the toxicity of any dispersed oil fractions that diffuse downward and interact with benthic communities.

scholarly journals Functional interactions between post-translationally modified amino acids of methyl-coenzyme M reductase in Methanosarcina acetivorans

2019 ◽  
Author(s):  
Dipti D Nayak ◽  
Andi Liu ◽  
Neha Agrawal ◽  
Roy Rodriguez-Carerro ◽  
Shi-Hui Dong ◽  
...  
Keyword(s):  
Amino Acids ◽  
Methanogenic Archaea ◽  
Physical Structure ◽  
Major Influence ◽  
Methanosarcina Acetivorans ◽  
Coenzyme M ◽  
Phenotypic Analysis ◽  
And Function ◽  
Methyl Coenzyme M Reductase

AbstractMethyl-coenzyme M reductase (MCR) plays an important role in mediating global levels of methane by catalyzing a reversible reaction that leads to the production or consumption of this potent greenhouse gas in methanogenic and methanotrophic archaea. In methanogenic archaea, the alpha subunit of MCR (McrA) typically contains four to six post-translationally modified amino acids near the active site. Recent studies have identified genes that install two of these modifications (thioglycine and 5-(S)-methylarginine), yet little is known about the installation and function of the remaining post-translationally modified residues. Here, we provide in vivo evidence that a dedicated SAM-dependent methyltransferase encoded by a gene we designated mcmA is responsible for formation of S-methylcysteine in Methanosarcina acetivorans McrA. Phenotypic analysis of mutants incapable of cysteine methylation suggests that the S-methylcysteine residue plays an important role in adaptation to a mesophilic lifestyle. To examine the interactions between the S-methylcysteine residue and the previously characterized thioglycine, 5-(S)-methylarginine modifications, we generated M. acetivorans mutants lacking the three known modification genes in all possible combinations. Phenotypic analyses revealed complex, physiologically relevant interactions between the modified residues, which alter the thermal stability of MCR in a combinatorial fashion that is not readily predictable from the phenotypes of single mutants. Surprisingly, high-resolution crystal structures of the various unmodified MCRs were indistinguishable from the fully modified enzyme, suggesting that interactions between the post-translationally modified residues do not exert a major influence on the physical structure of the enzyme, but rather serve to fine-tune the activity and efficiency of MCR.

scholarly journals Meta-analyses of insect temporal trends must account for the complex sampling histories inherent to many long-term monitoring efforts

2020 ◽  
Author(s):  
Ellen A R Welti ◽  
Anthony Joern ◽  
aaron ellison ◽  
David C. Lightfoot ◽  
Sydne Record ◽  
...  
Keyword(s):  
Temporal Trends ◽  
Sampling Effort ◽  
Ecological Research ◽  
Complex Sampling ◽  
Sampling Locations ◽  
Long Term Ecological Research ◽  
History Of ◽  
Abundance And Diversity ◽  
Meta Analyses

In an article recently published in Nature Ecology &amp; Evolution (Crossley et al. 2020 “No net insect abundance and diversity declines across US Long Term Ecological Research sites”), sampling effort within Long-Term Ecological Research (LTER) datasets was assumed to be consistent across years. Given the complex history of many long-term datasets at LTER sites, this assumption does not often hold and we believe this assumption led to errors in Crossley et al.’s analysis. Here we first use the Konza Prairie grasshopper dataset as an example of how changes in sampling locations and effort can cause errors when data are assumed to be collected with invariant sampling. Second, we describe similar and additional errors in data use from 7 of the 13 LTER sites included in Crossley et al. (2020)’s analysis.

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