Biological vs. physical mixing effects on benthic food web dynamics.
Biological particle mixing (bioturbation) and solute transfer (bio-irrigation) contribute extensively to ecosystem functioning in sediments where physical mixing is low. Macrobenthos transports oxygen and organic matter deeper into the sediment, thereby likely providing favourable niches to lower tr...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2011-03-01
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| Series: | PLoS ONE |
| Online Access: | https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21455308/?tool=EBI |
| _version_ | 1818838005139374080 |
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| author | Ulrike Braeckman Pieter Provoost Tom Moens Karline Soetaert Jack J Middelburg Magda Vincx Jan Vanaverbeke |
| author_facet | Ulrike Braeckman Pieter Provoost Tom Moens Karline Soetaert Jack J Middelburg Magda Vincx Jan Vanaverbeke |
| author_sort | Ulrike Braeckman |
| collection | DOAJ |
| description | Biological particle mixing (bioturbation) and solute transfer (bio-irrigation) contribute extensively to ecosystem functioning in sediments where physical mixing is low. Macrobenthos transports oxygen and organic matter deeper into the sediment, thereby likely providing favourable niches to lower trophic levels (i.e., smaller benthic animals such as meiofauna and bacteria) and thus stimulating mineralisation. Whether this biological transport facilitates fresh organic matter assimilation by the metazoan lower part of the food web through niche establishment (i.e., ecosystem engineering) or rather deprives them from food sources, is so far unclear. We investigated the effects of the ecosystem engineers Lanice conchilega (bio-irrigator) and Abra alba (bioturbator) compared to abiotic physical mixing events on survival and food uptake of nematodes after a simulated phytoplankton bloom. The (13)C labelled diatom Skeletonema costatum was added to 4 treatments: (1) microcosms containing the bioturbator, (2) microcosms containing the bio-irrigator, (3) control microcosms and (4) microcosms with abiotic manual surface mixing. Nematode survival and subsurface peaks in nematode density profiles were most pronounced in the bio-irrigator treatment. However, nematode specific uptake (Δδ(13)C) of the added diatoms was highest in the physical mixing treatment, where macrobenthos was absent and the diatom (13)C was homogenised. Overall, nematodes fed preferentially on bulk sedimentary organic material rather than the added diatoms. The total C budget (µg C m(-2)), which included TO(13)C remaining in the sediment, respiration, nematode and macrobenthic uptake, highlighted the limited assimilation by the metazoan benthos and the major role of bacterial respiration. In summary, bioturbation and especially bio-irrigation facilitated the lower trophic levels mainly over the long-term through niche establishment. Since the freshly added diatoms represented only a limited food source for nematodes, the macrobenthic effect was more pronounced in niche establishment than the negative structuring effects such as competition. |
| first_indexed | 2024-12-19T03:31:31Z |
| format | Article |
| id | doaj.art-451dd4956cfb4b958c8d4c85764506d4 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-19T03:31:31Z |
| publishDate | 2011-03-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-451dd4956cfb4b958c8d4c85764506d42022-12-21T20:37:30ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-03-0163e1807810.1371/journal.pone.0018078Biological vs. physical mixing effects on benthic food web dynamics.Ulrike BraeckmanPieter ProvoostTom MoensKarline SoetaertJack J MiddelburgMagda VincxJan VanaverbekeBiological particle mixing (bioturbation) and solute transfer (bio-irrigation) contribute extensively to ecosystem functioning in sediments where physical mixing is low. Macrobenthos transports oxygen and organic matter deeper into the sediment, thereby likely providing favourable niches to lower trophic levels (i.e., smaller benthic animals such as meiofauna and bacteria) and thus stimulating mineralisation. Whether this biological transport facilitates fresh organic matter assimilation by the metazoan lower part of the food web through niche establishment (i.e., ecosystem engineering) or rather deprives them from food sources, is so far unclear. We investigated the effects of the ecosystem engineers Lanice conchilega (bio-irrigator) and Abra alba (bioturbator) compared to abiotic physical mixing events on survival and food uptake of nematodes after a simulated phytoplankton bloom. The (13)C labelled diatom Skeletonema costatum was added to 4 treatments: (1) microcosms containing the bioturbator, (2) microcosms containing the bio-irrigator, (3) control microcosms and (4) microcosms with abiotic manual surface mixing. Nematode survival and subsurface peaks in nematode density profiles were most pronounced in the bio-irrigator treatment. However, nematode specific uptake (Δδ(13)C) of the added diatoms was highest in the physical mixing treatment, where macrobenthos was absent and the diatom (13)C was homogenised. Overall, nematodes fed preferentially on bulk sedimentary organic material rather than the added diatoms. The total C budget (µg C m(-2)), which included TO(13)C remaining in the sediment, respiration, nematode and macrobenthic uptake, highlighted the limited assimilation by the metazoan benthos and the major role of bacterial respiration. In summary, bioturbation and especially bio-irrigation facilitated the lower trophic levels mainly over the long-term through niche establishment. Since the freshly added diatoms represented only a limited food source for nematodes, the macrobenthic effect was more pronounced in niche establishment than the negative structuring effects such as competition.https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21455308/?tool=EBI |
| spellingShingle | Ulrike Braeckman Pieter Provoost Tom Moens Karline Soetaert Jack J Middelburg Magda Vincx Jan Vanaverbeke Biological vs. physical mixing effects on benthic food web dynamics. PLoS ONE |
| title | Biological vs. physical mixing effects on benthic food web dynamics. |
| title_full | Biological vs. physical mixing effects on benthic food web dynamics. |
| title_fullStr | Biological vs. physical mixing effects on benthic food web dynamics. |
| title_full_unstemmed | Biological vs. physical mixing effects on benthic food web dynamics. |
| title_short | Biological vs. physical mixing effects on benthic food web dynamics. |
| title_sort | biological vs physical mixing effects on benthic food web dynamics |
| url | https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21455308/?tool=EBI |
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