An Invasive Mussel (Arcuatula senhousia, Benson 1842) Interacts with Resident Biota in Controlling Benthic Ecosystem Functioning

The invasive mussel Arcuatula senhousia has successfully colonized shallow soft sediments worldwide. This filter feeding mussel modifies sedimentary habitats while forming dense populations and efficiently contributes to nutrient cycling. In the present study, the density of A. senhousia was manipulated in intact sediment cores taken within an intertidal Zostera noltei seagrass meadow in Arcachon Bay (French Atlantic coast), where the species currently occurs at levels corresponding to an early invasion stage. It aimed at testing the effects of a future invasion on (1) bioturbation (bioirrigation and sediment mixing) as well as on (2) total benthic solute fluxes across the sediment–water interface. Results showed that increasing densities of A. senhousia clearly enhanced phosphate and ammonium effluxes, but conversely did not significantly affect community bioturbation rates, highlighting the ability of A. senhousia to control nutrient cycling through strong excretion rates with potential important consequences for nutrient cycling and benthic–pelagic coupling at a broader scale. However, it appears that the variability in the different measured solute fluxes were underpinned by different interactions between the manipulated density of A. senhousia and several faunal and/or environmental drivers, therefore underlining the complexity of anticipating the effects of an invasion process on ecosystem functioning within a realistic context.

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A new device to mount portable energy-dispersive X-ray fluorescence spectrometers (p-ED-XRF) for semi-continuous analyses of split (sediment) cores and solid samples

Geoscientific Instrumentation Methods and Data Systems ◽

10.5194/gi-6-93-2017 ◽

2017 ◽

Vol 6 (1) ◽

pp. 93-101 ◽

Cited By ~ 4

Author(s):

Philipp Hoelzmann ◽

Torsten Klein ◽

Frank Kutz ◽

Brigitta Schütt

Keyword(s):

Spatial Resolution ◽

Atlantic Coast ◽

Sediment Cores ◽

Ccd Camera ◽

Energy Dispersive ◽

Solid Samples ◽

Industrial Property ◽

X Ray ◽

New Device ◽

Sample Chamber

Abstract. Portable energy-dispersive X-ray fluorescence spectrometers (p-ED-XRF) have become increasingly popular in sedimentary laboratories to quantify the chemical composition of a range of materials such as sediments, soils, solid samples, and artefacts. Here, we introduce a low-cost, clearly arranged unit that functions as a sample chamber (German industrial property rights no. 20 2014 106 048.0) for p-ED-XRF devices to facilitate economic, non-destructive, fast, and semi-continuous analysis of (sediment) cores or other solid samples. The spatial resolution of the measurements is limited to the specifications of the applied p-ED-XRF device – in our case a Thermo Scientific Niton XL3t p-ED-XRF spectrometer with a maximum spatial resolution of 0.3 cm and equipped with a charge-coupled device (CCD) camera to document the measurement spot. We demonstrate the strength of combining p-ED-XRF analyses with this new sample chamber to identify Holocene facies changes (e.g. marine vs. terrestrial sedimentary facies) using a sediment core from an estuarine environment in the context of a geoarchaeological investigation at the Atlantic coast of southern Spain.

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Estuarine Macrofauna Affects Benthic Biogeochemistry in a Hypertrophic Lagoon

Water ◽

10.3390/w11061186 ◽

2019 ◽

Vol 11 (6) ◽

pp. 1186 ◽

Cited By ~ 5

Author(s):

Tobia Politi ◽

Mindaugas Zilius ◽

Giuseppe Castaldelli ◽

Marco Bartoli ◽

Darius Daunys

Keyword(s):

Redundancy Analysis ◽

Coastal Lagoons ◽

Sediment Cores ◽

Benthic Macrofauna ◽

Benthic Respiration ◽

Solute Fluxes ◽

Wide Range ◽

Benthic Biogeochemistry ◽

Chemical Conditions ◽

Macrofauna Communities

Coastal lagoons display a wide range of physico-chemical conditions that shape benthic macrofauna communities. In turn, benthic macrofauna affects a wide array of biogeochemical processes as a consequence of feeding, bioirrigation, ventilation, and excretion activities. In this work, we have measured benthic respiration and solute fluxes in intact sediment cores with natural macrofauna communities collected from four distinct areas within the Sacca di Goro Lagoon (NE Adriatic Sea). The macrofauna community was characterized at the end of the incubations. Redundancy analysis (RDA) was used to quantify and test the interactions between the dominant macrofauna species and solute fluxes. Moreover, the relevance of macrofauna as driver of benthic nitrogen (N) redundancy analysis revealed that up to 66% of the benthic fluxes and metabolism variance was explained by macrofauna microbial-mediated N processes. Nitrification was stimulated by the presence of shallow (corophiids) in combination with deep burrowers (spionids, oligochaetes) or ammonium-excreting clams. Deep burrowers and clams increase ammonium availability in burrows actively ventilated by corophiids, which creates optimal conditions to nitrifiers. However, the stimulatory effect of burrowing macrofauna on nitrification does not necessarily result in higher denitrification as processes are spatially separated.

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Environmental Drivers of Benthic Flux Variation and Ecosystem Functioning in Salish Sea and Northeast Pacific Sediments

PLoS ONE ◽

10.1371/journal.pone.0151110 ◽

2016 ◽

Vol 11 (3) ◽

pp. e0151110 ◽

Cited By ~ 26

Author(s):

Rénald Belley ◽

Paul V. R. Snelgrove ◽

Philippe Archambault ◽

S. Kim Juniper

Keyword(s):

Ecosystem Functioning ◽

Benthic Flux ◽

Environmental Drivers ◽

Salish Sea ◽

Flux Variation ◽

Northeast Pacific

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Connecting pH with body size in the marine gastropod Trophon geversianus in a latitudinal gradient along the south-western Atlantic coast

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315416001557 ◽

2016 ◽

Vol 98 (3) ◽

pp. 449-456 ◽

Cited By ~ 3

Author(s):

Mariano E. Malvé ◽

Sandra Gordillo ◽

Marcelo M. Rivadeneira

Keyword(s):

Body Size ◽

Shell Length ◽

Large Scale ◽

Atlantic Coast ◽

Size Variation ◽

Environmental Drivers ◽

Shell Weight ◽

Western Atlantic ◽

Asymptotic Size ◽

The Impact

There is growing concern about the impact of contemporaneous ocean acidification on marine ecosystems, but strong evidence for predicting the consequences is still scant. We have used the gastropod Trophon geversianus as a study model for exploring the importance of oceanographic variables (sea surface temperature, chlorophyll a, oxygen, calcite and pH) on large-scale latitudinal variation in mean shell length and relative shell weight. Data were collected from a survey carried out in 34 sites along ~1600 km. Neither shell length nor relative shell weight showed any monotonic latitudinal trend, and the patterns of spatial variability were rather complex. After correcting for spatial autocorrelation, only pH showed a significant correlation with mean shell length and relative shell weight, but contrary to expectations, the association was negative in both cases. We hypothesize that this could mirror the negative effect of acidification on growth rate, which may cause larger asymptotic size. Latitudinal trends of body size variation are not easy to generalize using ecogeographic rules, and may be the result of a complex interaction of environmental drivers and life-history responses.

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Biogenic structures in the Arctic: an ecosystem functioning hotspot?

10.7287/peerj.preprints.26738v1 ◽

2018 ◽

Author(s):

Marie Pierrejean ◽

Philippe Archambault ◽

Barbara Neves ◽

Evan Edinger ◽

Christian Nozais

Keyword(s):

Ecosystem Functioning ◽

Cold Water ◽

Sediment Cores ◽

Three Dimensional ◽

Ammonium Phosphate ◽

The Arctic ◽

Benthic Fluxes ◽

Bare Sediment ◽

Biogenic Structures ◽

Associated Species

In deep-sea environments, resources availability and habitat complexity drive the distribution of benthic organisms. Biogenic structures such as cold-water corals and sponges create a three-dimensional habitat that facilitate sediment and resources accumulation and therefore show a high abundance of the associated species compared to bare sediments. However, the functions of these biodiversity hotspots in the ecosystem functioning are still poorly known. In this study, we addressed three main questions: 1) do benthic fluxes vary according to their position within patches and bare sediment? 2) are infaunal communities similar in biogenic structure and bare sediment patches? and finally, 3) which variables explain benthic fluxes in these patches? Infaunal communities and benthic fluxes were examined in Arctic regions presenting two types of biogenic structures: corals (Keratoisis sp.) and arborescent sponges. To compare ecosystem functioning between the biogenic structure versus bare sediment patches, sediment cores were collected to quantify benthic fluxes (nitrate, nitrite, ammonium, phosphate and silicate) and the diversity, abundance and composition of infauna. Multivariate analyses suggested that biogenic structure and bare sediment patches exhibited different infaunal assemblage and a spatial pattern for the benthic fluxes even with a distance of 100 m between the type of patches.

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Coral and Seawater Metagenomes Reveal Key Microbial Functions to Coral Health and Ecosystem Functioning Shaped at Reef Scale

10.21203/rs.3.rs-600995/v1 ◽

2021 ◽

Author(s):

Laís Farias Oliveira Lima ◽

Amanda Alker ◽

Bhavya Papudeshi ◽

Megan Morris ◽

Robert Edwards ◽

...

Keyword(s):

Microbial Community ◽

Nutrient Cycling ◽

Ecosystem Functioning ◽

Environmental Changes ◽

Coral Host ◽

Shotgun Metagenomics ◽

Patch Reefs ◽

Coral Microbiome ◽

Gene Functions ◽

Coral Health

Abstract Background The coral holobiont is comprised of a highly diverse microbial community that provides key services to corals such as protection against pathogens and nutrient cycling. The coral surface mucus layer (SML) microbiome is very sensitive to external changes and tied to ecosystem functioning, as it constitutes the direct interface between the coral host and the environment. The functional profile of microbial genes in the coral SML is underexplored and the use of shotgun metagenomics is relatively rare among coral microbiome studies. Here we investigate whether the bacterial taxonomic and functional profiles in the coral SML are shaped by the local reef zone and explore their role in coral health and ecosystem functioning. Results The analysis was conducted using metagenomes and metagenome assemble genomes (MAGs) associated with the coral Pseudodiploria strigosa and the water column from two naturally distinct reef environments in Bermuda: inner patch reefs exposed to a fluctuating thermal regime and the more stable outer reefs . Our results showed that the microbial community structure is simultaneously selected by the host medium (i.e., coral SML versus water) and the local environment (i.e., inner reefs versus outer reefs), both at taxonomic and functional levels. The coral SML microbiome from inner reefs provides more gene functions that are involved in nutrient cycling (e.g., photosynthesis, phosphorus metabolism, sulfur assimilation) and that are related to higher levels of microbial activity, competition, and stress response, such as dimethylsulfoniopropionate (DMSP) breakdown. In contrast, the coral SML microbiome from outer reefs contained genes indicative of a carbohydrate-rich mucus composition found in corals exposed to less stressful temperatures and showed high proportions of microbial gene functions that play a potential role in coral disease, such as degradation of lignin-derived compounds and sulfur oxidation. Conclusion The fluctuating environment in the inner patch reefs of Bermuda could be driving a more beneficial coral SML microbiome; potentially increasing holobiont resilience to environmental changes and disease. Our results reveal microbial taxa and functions selected at reef scale in the coral SML microbiome that can leverage disease management, microbiome engineering, and microbial eco-evolutionary theories.

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Heat stress destabilizes symbiotic nutrient cycling in corals

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2022653118 ◽

2021 ◽

Vol 118 (5) ◽

pp. e2022653118 ◽

Cited By ~ 3

Author(s):

Nils Rädecker ◽

Claudia Pogoreutz ◽

Hagen M. Gegner ◽

Anny Cárdenas ◽

Florian Roth ◽

...

Keyword(s):

Heat Stress ◽

Nutrient Cycling ◽

Energy Demand ◽

Metabolic Energy ◽

Environmental Drivers ◽

Coral Host ◽

Stylophora Pistillata ◽

Coral Holobiont ◽

Algal Symbiosis ◽

Energy Limitation

Recurrent mass bleaching events are pushing coral reefs worldwide to the brink of ecological collapse. While the symptoms and consequences of this breakdown of the coral–algal symbiosis have been extensively characterized, our understanding of the underlying causes remains incomplete. Here, we investigated the nutrient fluxes and the physiological as well as molecular responses of the widespread coral Stylophora pistillata to heat stress prior to the onset of bleaching to identify processes involved in the breakdown of the coral–algal symbiosis. We show that altered nutrient cycling during heat stress is a primary driver of the functional breakdown of the symbiosis. Heat stress increased the metabolic energy demand of the coral host, which was compensated by the catabolic degradation of amino acids. The resulting shift from net uptake to release of ammonium by the coral holobiont subsequently promoted the growth of algal symbionts and retention of photosynthates. Together, these processes form a feedback loop that will gradually lead to the decoupling of carbon translocation from the symbiont to the host. Energy limitation and altered symbiotic nutrient cycling are thus key factors in the early heat stress response, directly contributing to the breakdown of the coral–algal symbiosis. Interpreting the stability of the coral holobiont in light of its metabolic interactions provides a missing link in our understanding of the environmental drivers of bleaching and may ultimately help uncover fundamental processes underpinning the functioning of endosymbioses in general.

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Trophic interactions among the heterotrophic components of plankton in man-made peat pools

Journal of Limnology ◽

10.4081/jlimnol.2017.1594 ◽

2017 ◽

Author(s):

Michał Niedźwiecki ◽

Malgorzata Adamczuk ◽

Tomasz Mieczan

Keyword(s):

Carbon Flux ◽

Ecosystem Functioning ◽

Trophic Levels ◽

Environmental Drivers ◽

Heterotrophic Nanoflagellates ◽

Peat Bogs ◽

Trophic Groups ◽

Comprehensive Knowledge ◽

Different Types ◽

Freshwater Habitats

<p>Man-made peat pools are permanent freshwater habitats developed due to non-commercial man-made peat extraction. Yet, they have not been widely surveyed in terms of ecosystem functioning, mainly regarding the complexity of heterotrophic components of the plankton. In this study we analysed distribution and trophic interrelations among heterotrophic plankton in man-made peat pools located in different types of peatbogs. We found that peat pools showed extreme differences in environmental conditions that occurred to be important drivers of distribution of microplankton and metazooplankton. Abundance of bacteria and protozoa showed significant differences, whereas metazooplankton was less differentiated in density among peat pools. In all peat pools stress-tolerant species of protozoa and metazoa were dominant. In each peat pool five trophic functional groups were distinguished. The abundance of lower functional trophic groups (bacteria, heterotrophic nanoflagellates (HNF) and ciliates feeding on bacteria and HNF) was weakly influenced by environmental drivers and was highly stable in all peat pool types. Higher fu<span style="text-decoration: underline;">n</span>ctional trophic groups (naupli, omnivorous and carnivorous ciliates, cladocerans, adult copepods and copepodites) were strongly influenced by environmental variables and exhibited lower stability. Our study contributes to comprehensive knowledge of the functioning of peat bogs, as our results have shown that peat pools are characterized by high stability of the lowest trophic levels, which can be crucial for energy transfer and carbon flux through food webs.</p>

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Hidden similarities in the dynamics of a weakly synchronous marine metapopulation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1910964117 ◽

2019 ◽

Vol 117 (1) ◽

pp. 479-485 ◽

Cited By ~ 2

Author(s):

Tanya L. Rogers ◽

Stephan B. Munch

Keyword(s):

Atlantic Coast ◽

Marine Species ◽

Environmental Drivers ◽

Weight Of Evidence ◽

Dynamic Correlation ◽

Variable Environments ◽

The Us ◽

Unimodal Response ◽

Marine Metapopulation ◽

Noise Factors

Populations of many marine species are only weakly synchronous, despite coupling through larval dispersal and exposure to synchronous environmental drivers. Although this is often attributed to observation noise, factors including local environmental differences, spatially variable dynamics, and chaos might also reduce or eliminate metapopulation synchrony. To differentiate spatially variable dynamics from similar dynamics driven by spatially variable environments, we applied hierarchical delay embedding. A unique output of this approach, the “dynamic correlation,” quantifies similarity in intrinsic dynamics of populations, independently of whether their abundance is correlated through time. We applied these methods to 17 populations of blue crab (Callinectes sapidus) along the US Atlantic coast and found that their intrinsic dynamics were broadly similar despite largely independent fluctuations in abundance. The weight of evidence suggests that the latitudinal gradient in temperature, filtered through a unimodal response curve, is sufficient to decouple crab populations. As unimodal thermal performance is ubiquitous in ectotherms, we suggest that this may be a general explanation for the weak synchrony observed at large distances in many marine species, although additional studies are needed to test this hypothesis.

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