Arsenic distribution and species in two Zostera capricorni seagrass ecosystems, New South Wales, Australia

2011 ◽  
Vol 8 (1) ◽  
pp. 9 ◽  
Author(s):  
William A. Maher ◽  
Simon D. Foster ◽  
Anne M. Taylor ◽  
Frank Krikowa ◽  
Elliot G. Duncan ◽  
...  
Keyword(s):  
Food Web ◽  
Nitrogen Isotopes ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Trophic Levels ◽  
Marine Animals ◽  
South Wales ◽  
Arsenic Distribution ◽  
Seagrass Ecosystems ◽  
Zostera Capricorni

Environmental context Arsenic concentrations and species were determined in seagrass ecosystems where the food web was established using carbon and nitrogen isotopes. There was a clear increase in the proportion of arsenobetaine in tissues of higher trophic level organisms, which is attributed to an increasing arsenobetaine content of the diet and the more efficient assimilation and retention of arsenobetaine over other arsenic species. The results provide an explanation for the prominence of arsenobetaine in higher marine animals. Abstract Arsenic concentrations and species were compared in biota from two Zostera capricorni ecosystems. Mean arsenic concentrations were not significantly different for non‐vegetative sediment, rhizosphere sediment, Z. capricorni blades, roots, rhizomes, epiphytes, amphipods, polychaetes, molluscs, crustaceans and fish, but were significantly different in detritus. Sediments and plant tissues contained mostly inorganic arsenic and PO4–arsenoriboside. Detritus contained mostly PO4–arsenoriboside. Fish tissues contained predominately arsenobetaine. Other animals had lower proportions of arsenobetaine and variable quantities of minor arsenic species. Bioconcentration but not biomagnification of arsenic is occurring with no evidence of arsenic hyper accumulation. The proportion of arsenobetaine increases through the food web and is attributed to a shift from a mixed diet at lower trophic levels to animals containing mostly arsenobetaine at higher trophic levels and the more efficient retention of arsenobetaine, compared to other arsenic species.

Distribution of arsenic species in an open seagrass ecosystem: relationship to trophic groups, habitats and feeding zones

2012 ◽  
Vol 9 (1) ◽  
pp. 77 ◽  
Author(s):  
A. Price ◽  
W. Maher ◽  
J. Kirby ◽  
F. Krikowa ◽  
E. Duncan ◽  
...  
Keyword(s):  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Trophic Levels ◽  
Arsenic Content ◽  
Trophic Groups ◽  
Marine Systems ◽  
Seagrass Ecosystem ◽  
High Concentrations ◽  
Species Specific ◽  
Arsenic Source

Environmental contextAlthough arsenic occurs at high concentrations in many marine systems, the influencing factors are poorly understood. The arsenic content of sediments, detritus, suspended particles and organisms have been investigated from different trophic levels in an open seagrass ecosystem. Total arsenic concentrations and arsenic species were organism-specific and determined by a variety of factors including exposure, diet and the organism physiology. AbstractThe distribution and speciation of arsenic within an open marine seagrass ecosystem in Lake Macquarie, NSW, Australia is described. Twenty-six estuarine species were collected from five trophic groups (autotrophs, suspension-feeders, herbivores, detritivores and omnivores, and carnivores). Sediment, detritus, epibiota and micro-invertebrates were also collected and were classified as arsenic source samples. There were no significant differences in arsenic concentrations between trophic groups and between pelagic and benthic feeders. Benthic-dwelling species generally contained higher arsenic concentrations than pelagic-dwelling species. Sediments, seagrass blades and detritus contained mostly inorganic arsenic (50–90 %) and arsenoribosides (10–26 %), with some methylarsonate (9.4–14.6 %) and dimethyarsinate (7.9–9.7 %) in seagrass blades and detritus. Macroalgae contained mostly arsenoribosides (40–100 %). Epibiota and other animals contained predominately arsenobetaine (63–100 %) and varying amounts of dimethyarsinate (0–26 %), monomethyarsonate (0–14.6 %), inorganic arsenic (0–2 %), trimethylarsenic oxide (0–6.6 %), arsenocholine (0–12 %) and tetramethylarsonium ion (0–4.5 %). It was concluded that arsenic concentrations and species within the organisms of the Lake Macquarie ecosystem are species-specific and determined by a variety of factors including exposure, diet and the physiology of the organisms.

Distribution and Speciation of Arsenic in Temperate Marine Saltmarsh Ecosystems

2005 ◽  
Vol 2 (3) ◽  
pp. 177 ◽  
Author(s):  
Simon Foster ◽  
William Maher ◽  
Anne Taylor ◽  
Frank Krikowa ◽  
Kristy Telford
Keyword(s):  
Arsenic Concentration ◽  
Negative Relationship ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Total Arsenic ◽  
Marine Animals ◽  
Visceral Mass ◽  
Arsenic Uptake ◽  
Significant Negative Relationship ◽  
Root Tissues

Environmental Context. The pathways by which arsenic is accumulated and transferred in aquatic ecosystems are relatively unknown. Examination of whole marine ecosystems rather than individual organisms provides greater insights into the biogeochemical cycling of arsenic. Saltmarshes with low ecological diversity are an important terrestrial–marine interface about which little is known regarding arsenic concentrations and species distribution. This study examines the cycling of arsenic within Australian saltmarsh ecosystems to further understand its distribution and trophic transfer. Abstract. This paper reports the distribution of total arsenic and arsenic species in saltmarsh ecosystems located in south-east Australia. We also investigated the relationship between arsenic, iron, and phosphorus concentrations in saltmarsh halophytes and associated sediment. Total mean arsenic concentrations in saltmarsh plants, S. quinqueflora and S. australis, for leaves ranged from 0.03 ± 0.05 to 0.67 ± 0.48 μg g−1 and 0.03 ± 0.02 to 0.08 ± 0.06 μg g−1, respectively, and for roots ranged from 2 ± 2 to 6 ± 12 μg g−1 and 0.39 ± 0.20 to 0.57 ± 1.06 μg g−1 respectively. Removal of iron plaque from the roots reduced the arsenic concentration variability to 0.40–0.79 µg g−1 and 0.95–1.05 µg g−1 for S. quinqueflora and S. australis roots respectively. Significant differences were found between locations for total arsenic concentrations in plant tissues and these differences could be partially attributed to differences in sediment arsenic concentrations between locations. For S. quinqueflora but not S. australis there was a strong correlation between arsenic and iron concentrations in the leaf and root tissues. A significant negative relationship between arsenic and phosphorus concentrations was found for S. quinqueflora leaves but not roots. Total mean arsenic concentrations in salt marsh animal tissues (7 ± 2–21 ± 13 µg g−1) were consistent with those found for other marine animals. The concentration of total arsenic in gastropods and amphipods could be partially explained by the concentration of total arsenic in the dominant saltmarsh plant S. quinqueflora. Of the extractable arsenic, saltmarsh plants were dominated by arsenic(iii), arsenic(v) (66–99%), and glycerol arsenoribose (17–35%). Arsenobetaine was the dominant extractable arsenic species in the gastropods Salinator soilda (84%) and Ophicardelus ornatus (89%) and the crab Neosarmatium meinerti (89%). Amphipods contained mainly arsenobetaine (44%) with some phosphate arsenoribose (23%). Glycerol trimethyl arsonioribose was found in both gastropods (0.7–0.8%) and the visceral mass of N. meinerti (0.1%). These results show that arsenic uptake into plants from uncontaminated saltmarsh environments maybe dependent on plant iron uptake and inhibited by high phosphorus concentrations. Arsenic in saltmarsh plants is mainly present as inorganic arsenic, but arsenic in animals that eat plant detritus is present as organo arsenic species, primarily arsenobetaine and arsenosugars. The presence of glycerol trimethyl arsonioribose poses the question of whether trimethylated arsonioriboses are transitory intermediates in the formation of arsenobetaine.

Ecological factors affecting the accumulation and speciation of arsenic in twelve Australian coastal bivalve molluscs

2018 ◽  
Vol 15 (2) ◽  
pp. 46 ◽  
Author(s):  
William Maher ◽  
Joel Waring ◽  
Frank Krikowa ◽  
Elliott Duncan ◽  
Simon Foster
Keyword(s):  
Food Webs ◽  
De Novo ◽  
Ecological Factors ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Dry Mass ◽  
Water Soluble ◽  
Trophic Levels ◽  
Bivalve Molluscs ◽  
Deposit Feeders

Environmental contextKnowledge of the pathways by which arsenic is accumulated and transferred in marine ecosystems is scarce. Molluscs are important keystone organisms providing a link between primary producers (micro and macroalgae) and higher trophic levels such as fish. The present study examines the accumulation and species of arsenic in common bivalve molluscs from south-east Australia to understand the cycling of arsenic in marine food webs. AbstractThe present paper reports the whole-tissue total arsenic concentrations and water-soluble arsenic species in 12 common coastal Australian bivalve mollusc species. Mean arsenic concentrations ranged from 18 to 57 µg g−1 dry mass. Planktivores had significantly less arsenic (20–40 µg g−1; 22 ± 3 µg g−1) than did suspension and deposit feeders (36–57 µg g−1; 43 ± 7 µg g−1), with those associated with fine clay–silt sediments (49 ± 7 µg g−1) having significantly more arsenic than those associated with sand substrates (31 ± 11 µg g−1 ). Most planktivores and suspension feeders had similar arsenic species, with high proportions of arsenobetaine (AB) (64–92 %) and relatively low proportions of other arsenic species (0.55–15.8 %). Lower proportions of AB (13–57 %) and larger proportions of inorganic arsenic (6–7 %) were found in deposit feeders, reflecting increased exposure to inorganic arsenic in sediments. The study indicated that at lower trophic levels, organisms feed on algae and suspended matter containing a range of arsenic species including arsenosugars and AB. The implications for arsenic cycling are that as all bivalve molluscs accumulate AB and are a source of AB in benthic food webs. Because all bivalve molluscs also contained appreciable concentrations of arsenoriboses, precursors are present for the de novo synthesis of AB. As well, deposit feeders have higher proportions of inorganic arsenic that can be metabolised to different end products when ingested by higher trophic organisms

scholarly journals The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

2014 ◽  
Vol 79 (7) ◽  
pp. 815-828 ◽  
Author(s):  
Nikola Ilic ◽  
Slavica Lazarevic ◽  
Vladana Rajakovic-Ognjanovic ◽  
Ljubinka Rajakovic ◽  
Djordje Janackovic ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Arsenic Removal ◽  
Ph Value ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Deionized Water ◽  
Order Kinetic ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 ?C through batch studies. The influence of the initial pH value, the initial As concentrations, the contact time and types of water on the sorption capacity was investigated. Two types of water were used, deionized and groundwater. The maximal sorption capacity for As(III) from deionized water was observed at initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, and the significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g?1 for As(III) and 4.2 mg g?1 for As(V) in deionized water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results show that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has a potential for the application in water purification processes.

Functional diversity alters the effects of a pulse perturbation on the dynamics of tritrophic food webs

2021 ◽  
Author(s):  
Ruben Ceulemans ◽  
Laurie Anne Myriam Wojcik ◽  
Ursula Gaedke
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Functional Diversity ◽  
Feedback Loop ◽  
Environmental Changes ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Nutrient Pulse ◽  
Trade Offs ◽  
Food Web Model

Biodiversity decline causes a loss of functional diversity, which threatens ecosystems through a dangerous feedback loop: this loss may hamper ecosystems' ability to buffer environmental changes, leading to further biodiversity losses. In this context, the increasing frequency of climate and human-induced excessive loading of nutrients causes major problems in aquatic systems. Previous studies investigating how functional diversity influences the response of food webs to disturbances have mainly considered systems with at most two functionally diverse trophic levels. Here, we investigate the effects of a nutrient pulse on the resistance, resilience and elasticity of a tritrophic---and thus more realistic---plankton food web model depending on its functional diversity. We compare a non-adaptive food chain with no diversity to a highly diverse food web with three adaptive trophic levels. The species fitness differences are balanced through trade-offs between defense/growth rate for prey and selectivity/half-saturation constant for predators. We showed that the resistance, resilience and elasticity of tritrophic food webs decreased with larger perturbation sizes and depended on the state of the system when the perturbation occured. Importantly, we found that a more diverse food web was generally more resistant, resilient, and elastic. Particularly, functional diversity dampened the probability of a regime shift towards a non-desirable alternative state. In addition, despite the complex influence of the shape and type of the dynamical attractors, the basal-intermediate interaction determined the robustness against a nutrient pulse. This relationship was strongly influenced by the diversity present and the third trophic level. Overall, using a food web model of realistic complexity, this study confirms the destructive potential of the positive feedback loop between biodiversity loss and robustness, by uncovering mechanisms leading to a decrease in resistance, resilience and elasticity as functional diversity declines.

scholarly journals Arsenic speciation in food chains from mid-Atlantic hydrothermal vents

2012 ◽  
Vol 9 (2) ◽  
pp. 130 ◽  
Author(s):  
Vivien F. Taylor ◽  
Brian P. Jackson ◽  
Matthew R. Siegfried ◽  
Jana Navratilova ◽  
Kevin A. Francesconi ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Arsenic Speciation ◽  
Inorganic Arsenic ◽  
Food Sources ◽  
Arsenic Compounds ◽  
Marine Animals ◽  
Δ13c And Δ15n ◽  
Organic Arsenic

Environmental contextArsenic occurs in marine organisms at high levels and in many chemical forms. A common explanation of this phenomenon is that algae play the central role in accumulating arsenic by producing arsenic-containing sugars that are then converted into simpler organic arsenic compounds found in fish and other marine animals. We show that animals in deep-sea vent ecosystems, which are uninhabited by algae, contain the same organic arsenic compounds as do pelagic animals, indicating that algae are not the only source of these compounds. AbstractArsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge hydrothermal vents. The shrimp species, Rimicaris exoculata, the vent chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (δ13C and δ15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the vent chimneys covered with microbial mat, which is a presumed food source for many vent organisms, contained high levels of total As, but organic species were not detectable. The formation of arsenosugars in pelagic environments is typically attributed to marine algae, and the pathway to arsenobetaine is still unknown. The occurrence of arsenosugars and arsenobetaine in these deep sea organisms, where primary production is chemolithoautotrophic and stable isotope analyses indicate food sources are of vent origin, suggests that organic arsenicals can occur in a foodweb without algae or other photosynthetic life.

scholarly journals Food-web modification in the eastern Gulf of Finland after invasion of Marenzelleria arctia (Spionidae, Polychaeta)

NeoBiota ◽  
2021 ◽  
Vol 66 ◽  
pp. 75-94
Author(s):  
Sergey Golubkov ◽  
Alexei Tiunov ◽  
Mikhail Golubkov
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Food Chain ◽  
Native Species ◽  
Isotope Analysis ◽  
Marine Species ◽  
Trophic Levels ◽  
Benthivorous Fish ◽  
Neva Estuary ◽  
The Baltic

The paucity of data on non-indigenous marine species is a particular challenge for understanding the ecology of invasions and prioritising conservation and research efforts in marine ecosystems. Marenzelleria spp. are amongst the most successful non-native benthic species in the Baltic Sea during recent decades. We used stable isotope analysis (SIA) to test the hypothesis that the dominance of polychaete worm Marenzelleria arctia in the zoobenthos of the Neva Estuary after its invasion in the late 2000s is related to the position of this species in the benthic food webs. The trend towards a gradual decrease in the biomass of Marenzelleria worms was observed during 2014–2020, probably due to significant negative relationships between the biomass of oligochaetes and polychaetes, both of which, according to SIA, primarily use allochthonous organic carbon for their production. The biomass of benthic crustaceans practically did not change and remained very low. The SIA showed that, in contrast to the native crustacean Monoporeia affinis, polychates are practically not consumed either by the main invertebrate predator Saduria entomon, which preys on M. affinis, oligochaetes and larvae of chironomids or by benthivorous fish that prefer native benthic crustaceans. A hypothetical model for the position and functional role of M. arctia in the bottom food web is presented and discussed. According the model, the invasion of M. arctia has created an offshoot food chain in the Estuary food webs. The former dominant food webs, associated with native crustaceans, are now poorly developed. The lack of top-down control obviously contributes to the significant development of the Marenzelleria food chain, which, unlike native food chains, does not provide energy transfer from autochthonous and allochthonous organic matter to the upper trophic levels. The study showed that an alien species, without displacing native species, can significantly change the structure of food webs, creating blind offshoots of the food chain.

scholarly journals Mesoscale variations in the assemblage structure and trophodynamics of mesozooplankton communities of the Adriatic basin (Mediterranean Sea)

2021 ◽  
Author(s):  
Emanuela Fanelli ◽  
Samuele Menicucci ◽  
Sara Malavolti ◽  
Andrea De Felice ◽  
Iole Leonori
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Mediterranean Sea ◽  
Environmental Variables ◽  
Complex Structure ◽  
Assemblage Structure ◽  
Trophic Levels ◽  
Ecosystem Functions ◽  
Food Web Structure ◽  
Adriatic Basin

Abstract. Zooplankton are critical to the functioning of ocean food webs because of their utter abundance and vital ecosystem roles. Zooplankton communities are highly diverse and thus perform a variety of ecosystem functions, thus changes in their community or food web structure may provide evidence of ecosystem alteration. Assemblage structure and trophodynamics of mesozooplantkon communities were examined across the Adriatic basin, the northernmost and most productive basin of the Mediterranean Sea. Samples were collected in June–July 2019 along coast-offshore transects covering the whole western Adriatic side, consistently environmental variables were also recorded. Results showed a clear separation between samples from the northern-central Adriatic and the southern ones, with a further segregation, although less clear, of inshore vs. off-shore stations, the latter mostly dominated in the central and southern stations by gelatinous plankton. Such patterns were mainly driven by chlorophyll-a concentration (as a proxy of primary production) for northern-central stations, i.e. closer to the Po river input, and by temperature and salinity, for southern ones, with the DistLM model explaining 46 % of total variance. The analysis of stable isotopes of nitrogen and carbon allowed to identify a complex food web characterized by 3 trophic levels from herbivores to carnivores, passing through the mixed feeding behavior of omnivores, shifting from phytoplankton/detritus ingestion to microzooplankton. Trophic structure also spatially varied according to sub-area, with the northern-central sub-areas differing from each other and from the southern stations. Our results highlighted the importance of environmental variables as drivers of zooplanktonic communities and the complex structure of their food webs. Disentangling and considering such complexity is crucial to generate realistic predictions on the functioning of aquatic ecosystems, especially in high productive and, at the same time, overexploited area such as the Adriatic Sea.

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