1,721,124 research outputs found
Functional effects of the hadal sea cucumber Elpidia atakama (Echinodermata: Holothuroidea, Elasipodida) reflect small-scale patterns of resource availability
Full text linkHolothuroidea represent the dominant benthic megafauna in hadal trenches (similar to 6,000-11,000 m), but little is known about their behaviour and functional role at such depths. Using a time-lapse camera at 8,074 m in the Peru-Chile Trench (SE Pacific Ocean), we provide the first in situ observations of locomotory activity for the elasipodid holothurian Elpidia atakama Belyaev in Shirshov Inst Oceanol 92: 326-367, (1971). Time-lapse sequences reveal 'run and mill' behaviour whereby bouts of feeding activity are interspersed by periods of locomotion. Over the total observation period (20 h 25 min), we observed a mean (+/- SD) locomotion speed of 7.0 +/- 5.7 BL h(-1), but this increased to 10.9 +/- 7.2 BL h(-1) during active relocation and reduced to 4.8 +/- 2.9 BL h(-1) during feeding. These observations show E. atakama translocates and processes sediment at rates comparable to shallower species despite extreme hydrostatic pressure and remoteness from surface-derived food
Observation and quantification of in situ animal-sediment relations using time-lapse sediment profile imagery (t-SPI)
No full textThe effect of flow and biodiversity on ecosystem functioning was investigated in an estuarine system using in situ benthic chambers. Macrofaunal communities were artificially assembled to manipulate both species richness and functional trait richness. In addition, naturally occurring communities were sampled in order to determine the effect of macrofaunal and sediment disruption. Ecosystem functioning was assessed by measurement of nutrient release (NH4–N) from the sediment, a process essential for primary production. Natural and assembled communities were found to differ significantly, demonstrating the effect of experimental manipulation on the system. Flow was found to have a highly significant effect on ecosystem functioning in both natural and assembled communities in treatments containing macrofauna. No significant difference between static and flow treatments was found in macrofaunal-free controls, indicating that flow generates an effect through promoting changes in bioturbatory activity of the infauna causing greater disruption to the sediment. In assembled communities, functional richness significantly increased ecosystem functioning. Species richness had no influence in assembled communities
Long term effects of warming and ocean acidification are modified by seasonal variation in species responses and environmental conditions
No full textWarming of sea surface temperatures and alteration of ocean chemistry associated with anthropogenic increases in atmospheric carbon dioxide will have profound consequences for a broad range of species, but the potential for seasonal variation to modify species and ecosystem responses to these stressors has received little attention. Here, using the longest experiment to date (542 days), we investigate how the interactive effects of warming and ocean acidification affect the growth, behaviour and associated levels of ecosystem functioning (nutrient release) for a functionally important non-calcifying intertidal polychaete (Alitta virens) under seasonally changing conditions. We find that the effects of warming, ocean acidification and their interactions are not detectable in the short term, but manifest over time through changes in growth, bioturbation and bioirrigation behaviour that, in turn, affect nutrient generation. These changes are intimately linked to species responses to seasonal variations in environmental conditions (temperature and photoperiod) that, depending upon timing, can either exacerbate or buffer the long-term directional effects of climatic forcing. Taken together, our observations caution against over emphasizing the conclusions from short-term experiments and highlight the necessity to consider the temporal expression of complex system dynamics established over appropriate timescales when forecasting the likely ecological consequences of climatic forcing
Does the ophiuroid Amphiura filiformis alert conspecifics to the danger of predation through the generation of an alarm signal?
No full textBiogenic particle reworking and bacterial-invertebrate interactions in marine sediments
No full textSoft-sediment systems are subject to both biotic and abiotic processes that actively and passively redistribute particles. Changes in hydrodynamic regime, such as tides and storms, have the ability to turn over large volumes of sediment even in the deepest oceans. However, it is the role of benthic animals in the reworking of sediment particles (= biotur-bation) that may have the greatest impact on microbial communities and the biogeochem-istry of the system. While the effects of bioturbating fauna on the structure and function of sediment communities has received considerable attention, the relative contribution of the microbial community to organism-sediment relations is still not fully understood. It is known that sediment bacteria play a key role in the biogeochemical cycling of nutrients, provide a nutrient source for infaunal organisms, and are also important in the binding of particles through the production of mucus. Aggregation or dissociation of particles through invertebrate faunal activity, such as feeding or burrow construction, may impact the diver-sity, structure, and function of sediment bacteria and, in turn, have a significant effect on many ecosystem processes. Here we summarise the available literature on faunal-mediated particle transport and explore the mechanistic processes by which invertebrate activity may influence bacterial assemblages
Effects of copper and the sea lice treatment Slice® on nutrient release from marine sediments
No full textCopper-based antifoulant paints and the sea lice treatment Slice® are widely used, and often detectable in the sediments beneath farms where they are administered. Ten-day, whole sediment mesocosm experiments were conducted to examine how increasing sediment concentrations of copper or Slice® influenced final water column concentrations of ammonium–nitrogen (NH4–N), nitrate + nitrite–nitrogen (NOX–N) and phosphate–phosphorus (PO4–P) in the presence of the non-target, benthic organisms Corophium volutator and Hediste diversicolor. Nominal sediment concentrations of copper and Slice® had significant effects on the resulting concentrations of almost all nutrients examined. The overall trends in nutrient concentrations at the end of the 10-day incubations were highly similar between the trials with either copper or Slice®, irrespective of the invertebrate species present. This suggests that nutrient exchange from the experimental sediments was primarily influenced by the direct effect of copper/Slice® dose on the sediment microbial community, rather than the indirect effect of reduced bioturbation/irrigation due to increased macrofaunal mortality
Coastal Biodiversity and Ecosystem Service Sustainability (CBESS) sediment particle size in mudflat and saltmarsh habitats
No full textThe dataset details particle size of sediments across 6 intertidal sites in the winter and summer of 2013. The data provide a quantitative measure of the sediment particle size fractions present within surface sediments (up to a depth of 2 cm). Three sites were located in Essex, South East England and the other 3 in Morecambe Bay, North West England. Each site consisted of a saltmarsh habitat and adjacent mudflat habitat. 22 sampling quadrats were placed in each habitat covering 4 spatial scales. 3 replicate samples of surface sediment were collected at each quadrat. They were then processed using laser particle size analysis (detailed below) Values are expressed as different metrics of particle size and as specified size fractions as percentages of the total. This data was collected as part of Coastal Biodiversity and Ecosystem Service Sustainability (CBESS): NE/J015644/1. The project was funded with support from the Biodiversity and Ecosystem Service Sustainability (BESS) programme. BESS is a six-year programme (2011-2017) funded by the UK Natural Environment Research Council (NERC) and the Biotechnology and Biological Sciences Research Council (BBSRC) as part of the UK's Living with Environmental Change (LWEC) programme.,The location of the sample sites was determined by randomly allocated quadrats. Twenty two 1 x 1 m quadrats were randomly allocated to each mudflat and saltmarsh site using R (R Development Core Team, 2014) to specify four different spatial scales (A = 1 quadrat only, B = 3 quadrats at 1 m to 10 m apart, C = 6 quadrats at 10 m to 100 m apart, D = 12 quadrats at 100 m to 1000 m or site maximum). Mudflats: surface scrapes of sediment were taken. Saltmarsh: sediment was cut from 2cm below the surface. All samples were frozen at minus 20 degrees and then analysed using the Malvern Mastersizer protocol for particle size analysis, full details of which can be found here: http://www.geog.cam.ac.uk/facilities/laboratories/techniques/loi.html</span
Coastal Biodiversity and Ecosystem Service Sustainability (CBESS) macrofaunal abundance in mudflat and saltmarsh habitats
No full textThe location of the sample sites was determined by randomly allocated quadrats. Twenty two 1 x 1 m quadrats were randomly allocated to each mudflat and saltmarsh site using R (R Development Core Team, 2014) to specify four different spatial scales (A = 1 quadrat only, B = 3 quadrats at 1 m to 10 m apart, C = 6 quadrats at 10 m to 100 m apart, D = 12 quadrats at 100 m to 1000 m or site maximum). 3 cylindrical cores of sediment (10cm depth and diameter) were taken at each quadrat and fixed in 4 percent buffered formalin in seawater. The cores were then sieved on a 0.5mm mesh and the residue retained and preserved in 70 percent Industrial Methylated Spirit (IMS). Using a stereo microscope, all the animals were picked out of the residue, identified to species level (or appropriate taxon) and stored in vials containing 70 percent IMS. The individual numbers of each taxa were counted to give abundance data. This was determined by the presence of a head in cases where specimens had been damaged (any badly damaged specimens or parts of specimens where no head was present were separated into major group debris (annelid, mollusc and crustacea) pots and their presence noted as YES/NO for abundance). The data were then multiplied by 127.323955 and rounded to the nearest whole individual to give results in metre squared.,The dataset details macrofaunal abundance across 6 intertidal sites in the winter and summer of 2013. The data provide a quantitative measure of the invertebrate species present within the top 10cm of sediment. Three sites were located in Essex, South East England and the other 3 in Morecambe Bay, North West England. Each site consisted of a saltmarsh habitat and adjacent mudflat habitat. 22 sampling quadrats were placed in each habitat covering 4 spatial scales. 3 replicate cores of sediment were collected at each quadrat. They were sieved on a 0.5mm mesh and the macrofauna was removed, identified to species (or appropriate taxon) and individuals counted. Values for macrofaunal abundance are expressed as number of individuals per square metre of sediment. Abundance data for mudflat habitats across Essex and Morecambe are complete, however, saltmarsh data is only available for one full Essex site (Tillingham Marsh), in one season (winter) and across all sites, but only at the 1m scale. This data was collected as part of Coastal Biodiversity and Ecosystem Service Sustainability (CBESS): NE/J015644/1. The project was funded with support from the Biodiversity and Ecosystem Service Sustainability (BESS) programme. BESS is a six-year programme (2011-2017) funded by the UK Natural Environment Research Council (NERC) and the Biotechnology and Biological Sciences Research Council (BBSRC) as part of the UK's Living with Environmental Change (LWEC) programme.</span
Coastal Biodiversity and Ecosystem Service Sustainability (CBESS) population bioturbation potential in mudflat and saltmarsh habitats
No full textThe location of the sample sites was determined by randomly allocated quadrats. Twenty two 1 x 1 m quadrats were randomly allocated to each mudflat and saltmarsh site using R (R Development Core Team, 2014) to specify four different spatial scales (A = 1 quadrat only, B = 3 quadrats at 1 m to 10 m apart, C = 6 quadrats at 10 m to 100 m apart, D = 12 quadrats at 100 m to 1000 m or site maximum). 3 cylindrical cores of sediment (10cm depth and diameter) were taken at each quadrat and fixed in 4 percent buffered formalin in seawater. The cores were then sieved on a 0.5mm mesh and the residue retained and preserved in 70 percent Industrial Methylated Spirit (IMS). Using a stereo microscope, all the animals were picked out of the residue, identified to species level (or appropriate taxon). To obtain the abundance data, each individual of each species was counted and stored in vials containing 70 percent IMS. In cases where specimens had been damaged (any badly damaged specimens or parts of specimens where no head was present were separated into major group debris (annelid, mollusc and crustacea) pots and a YES/NO presence noted. To obtain the biomass data, the individuals of each taxon (from one replicate) were blotted on tissue paper to remove any excess IMS. They were then weighed on a balance and the weight was recorded to 0.0001g. In situations where the animals were too light to register on the balance, a weight of 0.0001g was recorded. (The same method was used to obtain biomass values for major group debris.) The data were then multiplied by 127.323955 to give results in m squared (rounded to the nearest whole individual for abundance and nearest 0.0001g for biomass). The abundance and biomass data was then used to calculate BPp as follows: BPp = BPi x Ai Where Ai = Individual species abundance per m squared and BPi = (square root Bi) x Mi x Ri Where Bi = individual biomass per m squared. Mi = individual species mobility. Ri = individual species reworking.,The dataset details population bioturbation potential (BPp) across 6 intertidal sites in the winter and summer of 2013. The data provide an index of bioturbation potential of invertebrate species populations present within the top 10cm of sediment. Three sites were located in Essex, South East England and the other 3 in Morecambe Bay, North West England. Each site consisted of a saltmarsh habitat and adjacent mudflat habitat. 22 sampling quadrats were placed in each habitat covering 4 spatial scales. 3 replicate cores of sediment were collected at each quadrat. They were sieved on a 0.5mm mesh and the macrofauna was removed, identified to species (or appropriate taxon) and individuals were identified to species (or most appropriate taxon), counted and weighed. The resulting abundance and biomass data were then used to calculate BPp of each individual species present within a sample. BPp data for mudflat habitats across Essex and Morecambe are complete, however, saltmarsh data is only available for one full Essex site (Tillingham Marsh), in one season (winter) and across all sites, at the 1m scale. This data was collected as part of Coastal Biodiversity and Ecosystem Service Sustainability (CBESS): NE/J015644/1. The project was funded with support from the Biodiversity and Ecosystem Service Sustainability (BESS) programme. BESS is a six-year programme (2011-2017) funded by the UK Natural Environment Research Council (NERC) and the Biotechnology and Biological Sciences Research Council (BBSRC) as part of the UK's Living with Environmental Change (LWEC) programme.</span
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