C.L. Szostek, A.J. Davies and H. Hinz

An individual specimen of Pecten affixed to Hall-effect sensor and magnet.

The effects of exposure to elevated levels of suspended particulate matter (SPM) and burial on juvenile king scallops Pecten maximus L. were assessed in 2 separate experiments. Shell gape activity was monitored during exposure to no SPM and ‘low’ (50 to 100 mg l−1) and ‘high’ (200 to 700 mg l−1) levels of SPM for 18 d. The frequency of shell ‘claps’ (a complete shell closure) and shell movements (of ≥ 10°) differed significantly among treatments. Shell ‘claps’ and movements were significantly greater under high SPM than under low or control conditions. Scallops under low and high levels of SPM showed significantly lower growth rates compared to scallops under control conditions. The response to burial was assessed under varying burial duration (1 to 8 d), depth (0 to 5 cm) and size-fraction of sediment (fine: 0.1 to 0.3 mm, medium fine: 0.4 to 0.8mm and coarse: 1.2 to 2.0 mm diameter). All 3 conditions had a significant influence on the ability of scallops to emerge from burial, as well as on mortality while buried. Emergence was higher at shallower depths and in coarse to medium grain sizes. Mortality rates while buried under coarse and medium grain sizes were low and appeared unrelated to depth, while within fine sediment, mortality increased with depth of burial. Survival decreased across all 3 sediment types with increasing burial duration. Comparison with earlier studies indicates that P. maximus appears more tolerant of burial and elevated levels of SPM than the queen scallop Aequipecten opercularis. Elevated SPM did not have any short-term effects on survival; however, the reduction in growth rate observed has implications for the management of scallop fishing grounds.

Request PDF

Full citation

Szostek CL, Davies AJ, Hinz H (2013) Effects of elevated levels of suspended particulate matter and burial on juvenile king scallops Pecten maximus. Marine Ecology Progress Series 474:155-165

DOI

doi:10.3354/meps10088

J.G. Hiddink, F. Ben Rais Lasram, J. Cantrill, A. J. Davies

Mediterranean Sea

Species need to move to keep pace with changing climates, but we do not know if species can move at the required speed. Spread rates of native species may underestimate how fast species can move, we therefore assessed how fast Lessepsian species (marine non-native species that invaded the Mediterranean from the Red Sea through the Suez Canal) can spread to give a ‘best-case’ assessment of the effects of climate change on marine biodiversity. We show that about 20% of Lessepsian species could not spread fast enough to keep pace with climate change in about 20% of the global seas and this suggests that climate change may lead to biodiversity loss. The velocity of climate change on the seabed is much lower than at the sea surface, and as a result of this the proportion of species that keep pace with climate change at the seabed was much larger than at the sea surface. This suggests that locations at depth could act as refuges for slow dispersing species. Our analysis compared different estimates of the spreading abilities of marine species and showed that the estimate of spread rates strongly affects the predicted effect of climate change on biodiversity. Providing more accurate estimates of the spreading ability of marine species should therefore have priority if we want to predict the effect of climate change on marine biodiversity. This study is a first approximation of the potential scale and distribution of global marine biodiversity loss and can provide benchmark estimates of the spread rates that species could achieve in colonizing suitable habitat. Assisted colonization may be required to maintain biodiversity in the most strongly affected areas.

Request PDF

Full citation

Hiddink JG, Ben Rais Lasram F, Cantrill J, Davies AJ (2012) Keeping pace with climate change: what can we learn from the spread of Lessepsian migrants? Global Change Biology 18:2161-2172

DOI

doi:10.1111/j.1365-2486.2012.02698.x

Chris Yesson, Michelle L. Taylor, Derek P. Tittensor, Andrew J. Davies, John Guinotte, Amy Baco, Julie Black, Jason M. Hall-Spencer and Alex D. Rogers

Paragorgia arborea from NOAA’s photolibrary

Three-quarters of Octocorallia species are found in deep waters. These cold-water octocoral colonies can form a major constituent of structurally complex habitats. The global distribution and the habitat requirements of deep-sea octocorals are poorly understood given the expense and difficulties of sampling at depth. Habitat suitability models are useful tools to extrapolate distributions and provide an understanding of ecological requirements. Here, we present global habitat suitability models and distribution maps for seven suborders of Octocorallia: Alcyoniina, Calcaxonia, Holaxonia, Scleraxonia, Sessiliflorae, Stolonifera and Subselliflorae.

Methods: We use maximum entropy modelling to predict octocoral distribution using a database of 12,508 geolocated octocoral specimens and 32 environmental grids resampled to 30 arc-second (approximately 1 km2) resolution. Additionally, a meta-analysis determined habitat preferences and niche overlap between the different suborders of octocorals.

Results: Suborder Sessiliflorae had the widest potential habitat range, but all records for all suborders implied a habitat preference for continental shelves and margins, particularly the North and West Atlantic and Western Pacific Rim. Temperature, salinity, broad scale slope, productivity, oxygen and calcite saturation state were identified as important factors for determining habitat suitability. Less than 3% of octocoral records were found in waters undersaturated for calcite, but this result is affected by a shallow-water sampling bias.

Main conclusions: The logistical difficulties, expense and vast areas associated with deep-sea sampling leads to a gap in the knowledge of faunal distributions that is difficult to fill without predictive modelling. Global distribution estimates are presented, highlighting many suitable areas which have yet to be studied. We suggest that approximately 17% of oceans are suitable for at least one suborder but 3.5% may be suitable for all seven. This is the first global habitat suitability modelling study on the distribution of octocorals and forms a useful resource for researchers, managers and conservationists.

Request PDF

Full citation

Yesson C, Taylor ML, Tittensor DP, Davies AJ, Guinotte J, Baco A, Black J, Hall-Spencer JM, Rogers AD (2012) Global habitat suitability of cold-water octocorals. J Biogeogr 39:1278-1292

DOI

5th ISDSC, Amsterdam

Well, Amsterdam is certainly a unique city and was the recent host of the International Deep-sea Coral Symposium 2012. This was the 5th conference and the 3rd that I’ve been to since I started working on cold-water corals. Whilst not as distant as Florida (3rd ISDSC) or New Zealand (4th ISDSC), there was an enthusiasm to the conference which was organised by our friends Furu Mienis and Tjeerd van Weering. We were located slap-bang in central Amsterdam at the Artis Zoo conference centre, which has a magnificent butterfly house, on par with Anglesey’s Pilli Pallas but without the meerkats!

Myself and our newest PhD student Craig went along, luckily I had been asked to present a keynote on our recent predictive modelling work which saved me from having to think of something to present! We stayed at a hotel on Prinze Hendricks, which I do not recommend but will not name… Those of you who heard me complain about it will understand, over priced and horrid… But, was a place to bed down after a long day of networking and conferencing.

All in all, an absolutely fantastic conference, in great surroundings with great friends. For those of you who are interested, you can download a PDF copy of my presentation

Download

Davies Presentation 5th ISDSC Amsterdam 2012

Citation

Davies, A.J. (2012) “Locating vulnerable marine ecosystems in the greatest wilderness on earth” Keynote presentation at the 5th International Symposium for Deep-sea Corals, Amsterdam, 1st-6th April.

 Abstract

Predictive habitat models are increasingly being used by conservationists, researchers and governmental bodies to identify vulnerable ecosystems (VMEs) and species’ distributions in areas that have not been sampled. Despite improvements in model algorithms, environmental data and species presences, there are still significant limitations in the reliability of this technique, especially in the deep sea. Recent studies have begun to address a key limitation, the quality of data, by using multibeam echosounder surveys and species data from video surveys to acquire high resolution data. Whilst these data are often amongst the very best that can be acquired in the deep ocean, the surveys are highly localised, often targeted towards known VME-containing areas, are very expensive and time consuming. Whilst these local surveys are useful for site-specific management, they are less useful for identifying areas not yet sampled or for influencing regional or basin-scale management. It is impossible to survey whole regions (although Ireland has mapped their entire EEZ) or ocean basins using these techniques, so alternative approaches are required. Predictive modelling in data poor areas is difficult, limited heavily by the quality of data. There is no doubt that the adoption of predictive modelling is increasing amongst researchers who work in areas that are poorly studied. But, there are still significant improvements that need to be made to increase the reliability and thus adoption of this technique.

Classifying rasters in ArcMap 8-10

Gerard Duineveld, Rachel Jeffreys, Marc Lavaleye, Andrew Davies, Magda Bergman, Thalia Watmough, Rob Witbaard

The finding of a previously undescribed cold-water coral reef (Banana Reef) in the Scottish Mingulay reef complex, with denser coverage of living Lophelia pertusa than the principal Mingulay 1 Reef, was the incentive for a comparative study of the food supply to the 2 reefs. Suspended particulate matter (SPM) samples from the surface and bottom water covering a tidal cycle were compared with respect to lipids, pigments, and δ13C and δ15N. Lipid profiles and stable isotope signatures of SPM were compared with those of coral tissue samples. Concurrently, hydrographic measurements were conducted to track the movement of the water masses across both reefs. Between-reef differences in SPM lipid concentrations were small compared to those in coral tissue. Corals at Banana Reef had lower lipid concentrations, pointing to less favourable food conditions than at Mingulay 1. Stable isotopes signatures and lipid profiles showed that corals on both reefs feed primarily on surface algal matter, within the timeframe of our study. At Mingulay 1, fresh microalgae are supplied to the coral reef by local downwelling. This downwelling pulse is tidally advected to Banana Reef. Food conditions observed during this study at both reefs do not explain the between-reef difference in coral coverage. A speculative explanation for the denser coral coverage at the deeper Banana Reef encompasses the slightly lower temperature that exhibits lower metabolic stress on corals, in combination with a higher current speed and particle encounter rate.

Request PDF

Full citation

Duineveld GCA, Jeffreys RM, Lavaleye MSS, Davies AJ, Bergman MJN, Watmough T & Witbaard R (2012) Spatial and tidal variation in food supply to shallow cold-water coral reefs of the Mingulay Reef complex (Outer Hebrides, Scotland). Marine Ecology Progress Series 444: 97-115.

 DOI

doi:10.3354/meps09430

The functioning of canyons on the US East Coast.

3 year PhD studentship at the School of Ocean Sciences, Bangor University with Dr Andrew J Davies.

Project description:

This is an exciting opportunity to join an international team of researchers investigating the functioning of deep-sea canyons on the US East Coast. This studentship is part of a larger project funded by BOEMRE (now the Bureau of Energy Management), incorporating elements of archaeology, physics, geology and biology. The successful candidate will be based in Menai Bridge, but will be expected to conduct fieldwork on NOAA vessels off the coast of the USA in collaboration with Dr Steve Ross of the University of North Carolina at Wilmington and Dr Sandra Brooke of the Marine Conservation Institute. The candidate will also be expected to travel to the Netherlands Institute for Sea Research (NIOZ) on the Island of Texel to conduct data analysis and project preparation with Drs Furu Mienis and Gerard Duineveld.

Overall, the study will conduct a full ecosystem evaluation of deep-water hard bottom, coral and soft substrata communities, and shipwreck sites off Virginia and Maryland within and adjacent to submarine canyons. The project essentially has three main components, 1) initially the student will be expected to develop habitat suitability models of the canyons based on archived and current data, but will develop these further as we collate more information of the canyons. 2) Investigate the physical setting and transport of sediment and organic material through the canyons using deep-sea lander technology developed by the NIOZ. 3) Devise observations and experiments to determine distributional drivers of sessile fauna within the physical context of the canyon.

The successful candidate:

This is a 3 year funded position, the successful candidate will be expected to hold an upper second class honours degree and a master’s degree in relevant science, preferentially with training in marine ecology. The project is available as soon as possible, so preference will be given to candidates who can start in January or February 2012. The successful candidate will be expected to travel to the US to conduct research, and as such must hold a valid passport and a full clean driving license. To apply please send a CV and a comprehensive covering letter, outlining your plans and your reasons for wanting to complete this project. The application deadline is the 13^th January 2012.

Informal enquiries and submission of an application should be made to:

Dr Andrew Davies at andrew.j.davies @ bangor.ac.uk.

The Nancy Foster was our base in the GoM

Near-bed hydrodynamic conditions were recorded for almost one year in the Viosca Knoll area (lease block 826), one of the most well-developed cold-water coral habitats in the Gulf of Mexico. Here, a reef-like cold-water coral ecosystem, dominated by the coral Lophelia pertusa, resembles coral habitats found off the southeastern US coast and the North East Atlantic. Two landers were deployed in the vicinity and outside of the coral habitat and measured multiple near-bed parameters, including temperature, salinity, current speed and direction and optical and acoustic backscatter. Additionally, the lander deployed closest to the coral area was equipped with a sediment trap that collected settling particles over the period of deployment at 27 day intervals. Long-term monitoring showed, that in general, environmental parameters, such as temperature (6.5–11.6 °C), salinity (34.95–35.4) and current speed (average 8 cm s⁻¹, peak current speed up to 38 cm s⁻¹) largely resembled conditions previously recorded within North East Atlantic coral habitats. Major differences between site VK 826 and coral areas in the NE Atlantic were the much higher particle load, and the origin of the particulate matter. Several significant events occurred during the deployment period beginning with an increase in current speed followed by a gradual increase in temperature and salinity, followed by a rapid decrease in temperature and salinity. Simultaneously with the decrease in temperature and salinity, the direction of the current changed from west to east and cold and less turbid water was transported upslope. The most prominent event occurred in July, when a westward flow lasted over 21 days. These events are consistent with bottom boundary layer dynamics influenced by friction (bottom Ekman layer). The Mississippi River discharges large quantities of sediment and dominates sedimentation regimes in the area. Furthermore, the Mississippi River disperses large amounts of terrestrial organic matter and nutrients, resulting in increased primary productivity, whereby marine organic matter is produced that will sink to the seafloor and can serve as food for the cold-water corals and associated species. As a result mass fluxes from the sediment trap were higher (1120–4479 mg m⁻² day⁻¹) than those observed in the North East Atlantic and were highest during periods of westward-flow, which corresponded to warm turbid water. During eastward-flow, colder and less turbid water was pushed upslope, resulting in lower mass fluxes. Trap samples had a low CaCO₃, high organic carbon content and high C/N ratios, suggesting a fluvial origin. The high sediment load in the water column can be a limiting factor for coral growth, especially since the corals can be smothered with sediment. However, eastward-flows provided periods of relatively clearer water that can remove sediment from the coral area and allow corals to expel sediment from their polyps. Around Viosca Knoll food supply comes from two possible sources. During April and June several fluorescence peaks were observed near the seabed, showing the arrival of phytodetritus in the area. Furthermore, a consistent diel vertical migration of zooplankton was observed that might provide an additional food source.

Request PDF

Full citation

F. Mienis, G.C.A. Duineveld, A.J. Davies, S.W. Ross, H. Seim, J. Bane & T.C.E. van Weering (2012) “The influence of near-bed hydrodynamic conditions on cold-water corals in the Viosca Knoll area, Gulf of Mexico” Deep-sea Research vol 1 60(1): 32-45.

 DOI

doi:10.1016/j.dsr.2011.10.007

What a machine!

http://www.youtube.com/watch?v=wbgkMHDGCMI