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3 results on '"McNeill, C.L."'

1. Comparing benthic biogeochemistry at a sandy and a muddy site in the Celtic Sea using a model and observations

Author

Aldridge, J.N., Lessin, G., Amoudry, L.O., Hicks, N., Hull, T., Klar, J.K., Kitidis, V., McNeill, C.L., Ingels, J., Parker, E.R., Silburn, B., Silva, T., Sivyer, D.B., Smith, H.E.K., Widdicombe, S., and Woodward, E.M.S.

Subjects
Biogeochemistry, Modelling
Abstract

Results from a 1D setup of the European Regional Seas Ecosystem Model (ERSEM) biogeochemical model were compared with new observations collected under the UK Shelf Seas Biogeochemistry (SSB) programme to assess model performance and clarify elements of shelf-sea benthic biogeochemistry and carbon cycling. Observations from two contrasting sites (muddy and sandy) in the Celtic Sea in otherwise comparable hydrographic conditions were considered, with the focus on the benthic system. A standard model parameterisation with site-specific light and nutrient adjustments was used, along with modifications to the within-seabed diffusivity to accommodate the modelling of permeable (sandy) sediments. Differences between modelled and observed quantities of organic carbon in the bed were interpreted to suggest that a large part (>90%) of the observed benthic organic carbon is biologically relatively inactive. Evidence on the rate at which this inactive fraction is produced will constitute important information to quantify offshore carbon sequestration. Total oxygen uptake and oxic layer depths were within the range of the measured values. Modelled depth average pore water concentrations of ammonium, phosphate and silicate were typically 5–20% of observed values at the muddy site due to an underestimate of concentrations associated with the deeper sediment layers. Model agreement for these nutrients was better at the sandy site, which had lower pore water concentrations, especially deeper in the sediment. Comparison of pore water nitrate with observations had added uncertainty, as the results from process studies at the sites indicated the dominance of the anammox pathway for nitrogen removal; a pathway that is not included in the model. Macrofaunal biomasses were overestimated, although a model run with increased macrofaunal background mortality rates decreased macrofaunal biomass and improved agreement with observations. The decrease in macrofaunal biomass was compensated by an increase in meiofaunal biomass such that total oxygen demand remained within the observed range. The permeable sediment modification reproduced some of the observed behaviour of oxygen penetration depth at the sandy site. It is suggested that future development in ERSEM benthic modelling should focus on: (1) mixing and degradation rates of benthic organic matter, (2) validation of benthic faunal biomass against large scale spatial datasets, (3) incorporation of anammox in the benthic nitrogen cycle, and (4) further developments to represent permeable sediment processes.

Published
2017

2. Geographic patterns of biodiversity in European coastal marine benthos

Author

Hummel, H., van Avesaath, P., Wijnhoven, S., Kleine-Schaars, L., Degraer, S., Kerckhof, F., Bojanic, N., Skejic, S., Vidjak, O., Rousou, M., Orav-Kotta, H., Kotta, J., Jourde, J., Pedrotti, M.L., Leclerc, J.-C., Simon, N., Rigaut-Jalabert, F., Bachelet, G., Lavesque, N., Arvanitidis, C., Pavloudi, C., Faulwetter, S., Crowe, T., Coughlan, J., Benedetti-Cecchi, L., dal Bello, M., Magni, P., Como, S., Coppa, S., Ikauniece, A., Ruginis, T., Jankowska, E., Weslawski, J.M., Warzocha, J., Gromisz, S., Witalis, B., Silva, T., Ribeiro, P., De Matos, V.K.F., Sousa-Pinto, I., Veiga, P., Troncoso, J., Guinda, X., De La Pena, J.A.J., Puente, A., Espinosa, F., Pérez-Ruzafa, A., Frost, M., Mcneill, C.L., Peleg, O., Rilov, G., Hummel, H., van Avesaath, P., Wijnhoven, S., Kleine-Schaars, L., Degraer, S., Kerckhof, F., Bojanic, N., Skejic, S., Vidjak, O., Rousou, M., Orav-Kotta, H., Kotta, J., Jourde, J., Pedrotti, M.L., Leclerc, J.-C., Simon, N., Rigaut-Jalabert, F., Bachelet, G., Lavesque, N., Arvanitidis, C., Pavloudi, C., Faulwetter, S., Crowe, T., Coughlan, J., Benedetti-Cecchi, L., dal Bello, M., Magni, P., Como, S., Coppa, S., Ikauniece, A., Ruginis, T., Jankowska, E., Weslawski, J.M., Warzocha, J., Gromisz, S., Witalis, B., Silva, T., Ribeiro, P., De Matos, V.K.F., Sousa-Pinto, I., Veiga, P., Troncoso, J., Guinda, X., De La Pena, J.A.J., Puente, A., Espinosa, F., Pérez-Ruzafa, A., Frost, M., Mcneill, C.L., Peleg, O., and Rilov, G.

Abstract

Within the COST action EMBOS (European Marine Biodiversity Observatory System) the degree and variation of the diversity and densities of soft-bottom communities from the lower intertidal or the shallow subtidal was measured at 28 marine sites along the European coastline (Baltic, Atlantic, Mediterranean) using jointly agreed and harmonized protocols, tools and indicators. The hypothesis tested was that the diversity for all taxonomic groups would decrease with increasing latitude. The EMBOS system delivered accurate and comparable data on the diversity and densities of the soft sediment macrozoobenthic community over a large-scale gradient along the European coastline. In contrast to general biogeographic theory, species diversity showed no linear relationship with latitude, yet a bell-shaped relation was found. The diversity and densities of benthos were mostly positively correlated with environmental factors such as temperature, salinity, mud and organic matter content in sediment, or wave height, and related with location characteristics such as system type (lagoons, estuaries, open coast) or stratum (intertidal, subtidal). For some relationships, a maximum (e.g. temperature from 15–20°C; mud content of sediment around 40%) or bimodal curve (e.g. salinity) was found. In lagoons the densities were twice higher than in other locations, and at open coasts the diversity was much lower than in other locations. We conclude that latitudinal trends and regional differences in diversity and densities are strongly influenced by, i.e. merely the result of, particular sets and ranges of environmental factors and location characteristics specific to certain areas, such as the Baltic, with typical salinity clines (favouring insects) and the Mediterranean, with higher temperatures (favouring crustaceans). Therefore, eventual trends with latitude are primarily indirect and so can be overcome by local variation of environmental factors.

Published
2017

3. An approach for the identification of exemplar sites for scaling up targeted field observations of benthic biogeochemistry in heterogeneous environments

Author

Thompson, C.E.L., Silburn, B., Williams, M.E., Hull, T., Sivyer, D., Amoudry, L.O., Widdicombe, S., Ingels, J., Carnovale, G., McNeill, C.L., Hale, R., Laguionie Marchais, C., Hicks, N., Smith, H.E.K., Klar, J.K., Hiddink, J.G., Kowalik, J., Kitidis, V., Reynolds, S., Woodward, E.M.S., Tait, K., Homoky, W.B., Kröger, S., Bolam, S., Godbold, J.A., Aldridge, J., Mayor, D.J., Benoist, N.M.A., Bett, B.J., Morris, K.J., Parker, E.R., Ruhl, H.A., Statham, P.J., Solan, M., Thompson, C.E.L., Silburn, B., Williams, M.E., Hull, T., Sivyer, D., Amoudry, L.O., Widdicombe, S., Ingels, J., Carnovale, G., McNeill, C.L., Hale, R., Laguionie Marchais, C., Hicks, N., Smith, H.E.K., Klar, J.K., Hiddink, J.G., Kowalik, J., Kitidis, V., Reynolds, S., Woodward, E.M.S., Tait, K., Homoky, W.B., Kröger, S., Bolam, S., Godbold, J.A., Aldridge, J., Mayor, D.J., Benoist, N.M.A., Bett, B.J., Morris, K.J., Parker, E.R., Ruhl, H.A., Statham, P.J., and Solan, M.

Abstract

Continental shelf sediments are globally important for biogeochemical activity. Quantification of shelf-scale stocks and fluxes of carbon and nutrients requires the extrapolation of observations made at limited points in space and time. The procedure for selecting exemplar sites to form the basis of this up-scaling is discussed in relation to a UK-funded research programme investigating biogeochemistry in shelf seas. A three-step selection process is proposed in which (1) a target area representative of UK shelf sediment heterogeneity is selected, (2) the target area is assessed for spatial heterogeneity in sediment and habitat type, bed and water column structure and hydrodynamic forcing, and (3) study sites are selected within this target area encompassing the range of spatial heterogeneity required to address key scientific questions regarding shelf scale biogeochemistry, and minimise confounding variables. This led to the selection of four sites within the Celtic Sea that are significantly different in terms of their sediment, bed structure, and macrofaunal, meiofaunal and microbial community structures and diversity, but have minimal variations in water depth, tidal and wave magnitudes and directions, temperature and salinity. They form the basis of a research cruise programme of observation, sampling and experimentation encompassing the spring bloom cycle. Typical variation in key biogeochemical, sediment, biological and hydrodynamic parameters over a pre to post bloom period are presented, with a discussion of anthropogenic influences in the region. This methodology ensures the best likelihood of site-specific work being useful for up-scaling activities, increasing our understanding of benthic biogeochemistry at the UK-shelf scale.

Published
2017

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