Abstract
The marine environment contains suspended particulate matter which originates from natural and anthropogenic sources. Settlement of this material can leave benthic organisms susceptible to smothering, especially if burial is sudden i.e. following storms or activities such as dredging. Their survival will depend on their tolerance to, and their ability to escape from burial. Here we present data from a multi-factorial experiment measuring burial responses incorporating duration, sediment fraction and depth. Six macroinvertebrates commonly found in sediment rich environments were selected for their commercial and/or conservation importance. Assessments revealed that the brittle star (Ophiura ophiura), the queen scallop (Aequipecten opercularis) and the sea squirt (Ciona intestinalis) were all highly intolerant to burial whilst the green urchin (Psammichinus miliaris) and the anemone (Sagartiogeton laceratus), showed intermediate and low intolerance respectively, to burial. The least intolerant, with very high survival was the Ross worm (Sabellaria spinulosa). With the exception of C. intestinalis, increasing duration and depth of burial with finer sediment fractions resulted in increased mortality for all species assessed. For C. intestinalis depth of burial and sediment fraction were found to be inconsequential since there was complete mortality of all specimens buried for more than one day. When burial emergence was assessed O. ophiura emerged most frequently, followed by P. miliaris. The former emerged most frequently from the medium and fine sediments whereas P. miliaris emerged more frequently from coarse sediment. Both A. opercularis and S. laceratus showed similar emergence responses over time, with A. opercularis emerging more frequently under coarse sediments. The frequency of emergence of S. laceratus increased with progressively finer sediment and C. intestinalis did not emerge from burial irrespective of sediment fraction or depth. Finally, and perhaps unsurprisingly, the greatest ability to emerge from burial in all other species was from shallow (2 cm) burial. Although survival was consistently highly dependent on duration and depth of burial as expected, emergence behaviour was not as easily predictable thereby confounding predictions. We conclude that responses to burial are highly species specific and therefore tolerance generalisations are likely to be oversimplifications. These data may be used to inform environmental impact models that allow forecasting of the cumulative impacts of seabed disturbance and may provide mitigation measures for the sustainable use of the seabed.
Highlights
The marine environment contains particulate matter, both organic and inorganic in origin, some of which accumulates on the seabed whilst some is suspended in the water column and termed suspended particulate matter (SPM)
The results of the O. ophiura burial experiment demonstrate a high level of survivorship (9.9% overall mortality, n = 162). This is largely a reflection of the ability of the species to emerge from all depths of burial and all sediment fractions tested (69.8%), statistical analysis confirmed that the depth of burial and the sediment fraction were both significant factors influencing the ability of O. ophiura to emerge (Table B in S1 File)
To facilitate a between species comparison we categorise burial intolerance as the proportion of animals that survive burial for 32 days. This categorization is similar to the MARLIN sensitivity assessment [23] but noteworthy is that the MarLIN burial depth is defined as 5 cm from the seabed, not, as is the case here, from the top of the animal
Summary
The marine environment contains particulate matter, both organic and inorganic in origin, some of which accumulates on the seabed whilst some is suspended in the water column and termed suspended particulate matter (SPM). Near-seabed turbulence from waves, tides, currents and freshwater run-off typically results in sediment re-suspension, mobilisation and eventual deposition [1] leading to elevated SPM levels, in near shore habitats. For this reason, the sediment-water interface in shallow coastal water is often highly dynamic with erosion, transport, and deposition varying in magnitude over different time scales [2]. Whilst there is general consensus that large scale change in sediment dynamics are anticipated with increasing use of the coasts and seabed, it is hard to predict the environmental consequences of such activities. An increase in meteorological extremes including storm frequency that is predicted due to climate change [10, 11] is likely to affect sediment dynamics with associated increases in coastal SPM
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
