Organic matter contents and degradation in a highly trawled area during fresh particle inputs (Gulf of Castellammare, southwestern Mediterranean)
Organic matter contents and degradation in a highly trawled area during fresh particle inputs (Gulf of Castellammare, southwestern Mediterranean)
Bottom trawling in the deep sea is one of the main drivers of sediment resuspension, eroding the seafloor and altering the content and composition of sedimentary organic matter (OM). The physical and biogeochemical impacts of bottom trawling were studied on the continental slope of the Gulf of Castellammare, Sicily (southwestern Mediterranean), through the analysis of two triplicate sediment cores collected at trawled and untrawled sites (∼550 m water depth) during the summer of 2016. Geochemical and sedimentological parameters (excess 210Pb, excess 234Th, 137Cs, dry bulk density, and grain size), elemental (organic carbon and nitrogen) and biochemical composition of sedimentary OM (proteins, carbohydrates, lipids), as well as its freshness (phytopigments) and degradation rates were determined in both coring locations. The untrawled site had a sedimentation rate of 0.15 cm yr−1 and presented a 6 cm thick surface mixed layer that contained siltier sediment with low excess 210Pb concentrations, possibly resulting from the resuspension, posterior advection, and eventual deposition of coarser and older sediment from adjacent trawling grounds. In contrast, the trawled site was eroded and presented compacted century-old sediment highly depleted in OM components, which were between 20 % and 60 % lower than those in the untrawled site. However, the upper 2 cm of the trawled site consisted of recently accumulated sediments enriched in excess 234Th, excess 210Pb, and phytopigments, while OM contents were similar to those from the untrawled core. This fresh sediment supported protein turnover rates of 0.025 d−1, which doubled those quantified in surface sediments of the untrawled site. The enhancement of remineralization rates in surface sediment of the trawled site was associated with the arrival of fresh particles on a chronically trawled deep-sea region that is generally deprived of OM. We conclude that the detrimental effects of bottom trawling can be temporarily and partially abated by the arrival of fresh and nutritionally rich OM, which stimulate the response of benthic communities. However, these ephemeral deposits are likely to be swiftly eroded due to the high trawling frequency over fishing grounds, highlighting the importance of establishing science-based management strategies to mitigate the impacts of bottom trawling.
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Amoroso, R. O., Pitcher, C. R., Rijnsdorp, A. D., McConnaughey, R. A., Parma, A. M., Suuronen, P., Eigaard, O. R., Bastardie, F., Hintzen N. T., Althaus, F., Baird, S. J., Black, J., BuhlMortensen, L., Campbell, A. B., Catarino, R., Collie, J. S., Cowan, J. H., Durholtz, D., Engstrom, N., Fairweather, T. P., Fock, H. O., Ford, R., Gálvez, P. A., Gerritsen, H. D., Góngora, M. E., González, J., Hiddink, J. G., Hughes, K. M., Intelmann, S. S., Jenkins, C., Jonsson, P., Kainge, P., Kangas, M., Kathena, J. N., Kavadas, S., Leslie, R. W., Lewis, S. G., Lundy, M., Makin, D., Martin, J., Mazor, T., Mirelis, G. G., Newman, S. J., Papadopoulou, K. N., Posen, P. E., Rochester, W., Russo, T., Sala, A., Semmens, J. M., Silva, C., Tsolos, A., Vanelsander, B., Wakefield, C. B., Wood, B. A., Hilborn, R., Kaiser, M. J., and Jennings, S.: Bottom trawl-fishing footprints on the world's continental shelves, P. Natl. Acad. Sci. USA, 115, E10275-E10282, https://doi.org/10.1073/pnas.1802379115, 2018. [OpenAIRE]
Anderson, M. J.: A new method for non-parametric multivariate analysis of variance, Austral Ecol., 26, 32-46, https://doi.org/10.1111/j.1442-9993.2001.01070.pp.x, 2001.
Anderson, M. J. and Robinson, J.: Generalized discriminant analysis based on distances, Aust. N.Z. J. Stat., 45, 301-318, https://doi.org/10.1111/1467-842X.00285, 2003.
Anderson, M. J. and Willis, T. J.: Canonical analysis of principal coordinates: A useful method of constrained ordination for ecology, Ecology, 84, 511-525, https://doi.org/10.1890/0012- 9658(2003)084[0511:CAOPCA]2.0.CO;2, 2003.
Arculeo, M., Lo Brutto, S., Cannizzaro, L., and Vitale, S.: Growth and reproduction of the deep-water rose shrimp, Parapenaeus longirostris (Lucas, 1846) (Decapoda, Penaeidae), in the Southern Tyrrhenian Sea, Crust., 87, 1168-1184, https://doi.org/10.1163/15685403-00003334, 2014.
Arias-Ortiz, A., Masqué, P., Garcia-Orellana, J., Serrano, O., Mazarrasa, I., Marbà, N., Lovelock, C. E., Lavery, P. S., and Duarte, C. M.: Reviews and syntheses: 210Pb-derived sediment and carbon accumulation rates in vegetated coastal ecosystems - setting the record straight, Biogeosciences, 15, 6791-6818, https://doi.org/10.5194/bg-15-6791-2018, 2018. [OpenAIRE]
Arjona-Camas, M., Puig, P., Palanques, A., Emelianov, M., and Durán, R.: Evidence of trawling-induced resuspension events in the generation of nepheloid layers in the Foix submarine canyon (NW Mediterranean), J. Marine Syst., 196, 86-96, https://doi.org/10.1016/j.jmarsys.2019.05.003, 2019.
Bett, B. J., Malzone, M. G., Narayanaswamy, B., and Wigham, B. D.: Temporal variability in phytodetritus and megabenthic activity at the seabed in the deep Northeast Atlantic, Prog. Oceanogr., 50, 349-368, https://doi.org/10.1016/S0079-6611(01)00066-0, 2001.
Bligh, E. G. and Dyer, W. J.: A rapid method of total lipid extraction and purification, Can. J. Biochem Phys., 37, 911-917, https://doi.org/10.1139/o59-099, 1959.
Buscail, R., Pocklington, R., Daumas, R., and Guidi, L.: Fluxes and budget of organic matter in the benthic boundary layer over the northwestern Mediterranean margin, Cont. Shelf Res., 10, 1089- 1122, https://doi.org/10.1016/0278-4343(90)90076-X, 1990. [OpenAIRE]
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Bottom trawling in the deep sea is one of the main drivers of sediment resuspension, eroding the seafloor and altering the content and composition of sedimentary organic matter (OM). The physical and biogeochemical impacts of bottom trawling were studied on the continental slope of the Gulf of Castellammare, Sicily (southwestern Mediterranean), through the analysis of two triplicate sediment cores collected at trawled and untrawled sites (∼550 m water depth) during the summer of 2016. Geochemical and sedimentological parameters (excess 210Pb, excess 234Th, 137Cs, dry bulk density, and grain size), elemental (organic carbon and nitrogen) and biochemical composition of sedimentary OM (proteins, carbohydrates, lipids), as well as its freshness (phytopigments) and degradation rates were determined in both coring locations. The untrawled site had a sedimentation rate of 0.15 cm yr−1 and presented a 6 cm thick surface mixed layer that contained siltier sediment with low excess 210Pb concentrations, possibly resulting from the resuspension, posterior advection, and eventual deposition of coarser and older sediment from adjacent trawling grounds. In contrast, the trawled site was eroded and presented compacted century-old sediment highly depleted in OM components, which were between 20 % and 60 % lower than those in the untrawled site. However, the upper 2 cm of the trawled site consisted of recently accumulated sediments enriched in excess 234Th, excess 210Pb, and phytopigments, while OM contents were similar to those from the untrawled core. This fresh sediment supported protein turnover rates of 0.025 d−1, which doubled those quantified in surface sediments of the untrawled site. The enhancement of remineralization rates in surface sediment of the trawled site was associated with the arrival of fresh particles on a chronically trawled deep-sea region that is generally deprived of OM. We conclude that the detrimental effects of bottom trawling can be temporarily and partially abated by the arrival of fresh and nutritionally rich OM, which stimulate the response of benthic communities. However, these ephemeral deposits are likely to be swiftly eroded due to the high trawling frequency over fishing grounds, highlighting the importance of establishing science-based management strategies to mitigate the impacts of bottom trawling.