Nicholas Polunin | Newcastle University (original) (raw)
Papers by Nicholas Polunin
![Research paper thumbnail of Corrigendum to “Structure and dynamics of food webs in the water column on shelf and slope grounds of the western Mediterranean” [J. Mar. Syst. 138 (2014) 171–181]](https://attachments.academia-assets.com/115116430/thumbnails/1.jpg)
](Journal of Marine Systems, Nov 1, 2014
Journal of Marine Systems, Oct 1, 2014
Benthic-pelagic coupling is an important process connecting species throughout the water column, ... more Benthic-pelagic coupling is an important process connecting species throughout the water column, particularly, in deep-sea systems where faunal assemblages can be dense if indirectly sustained by production from the above. Through stable isotope analyses, this study explored the sources of production, trophic structure, and benthopelagic coupling in two locations with contrasting oceanographic conditions from the western Mediterranean, in the Balearic (BsB) and the Algerian (AsB) sub-basins. The samples of 89 dominant species (23 decapods, 19 cephalopods, 33 fishes, among the other taxa), inhabiting the hyperbenthic and pelagic domains, from the shelf break (250 m), upper slope (650 m), and middle slope (850 m) were analyzed. Results suggested long food webs of approximately four trophic levels (TrLs) that were sustained by planktonic source material in shallower waters and degraded particulate organic matter of planktonic origin in deeper waters. Most of the collected species (70%) occupied intermediate trophic positions between the 3rd and 4th TrLs. The species δ 15 N and δ 13 C values exhibited a broad range, consistent with the high diversity that might be attributed to the oligotrophic conditions. As the depth increased, stronger segregation occurred between the trophic groups, and spatial differences were found among consumers of the two locations. Species in the AsB always had consistently higher δ 15 N values than in the BsB, which could possibly be attributed to the basal δ 15 N that was present through the food web. Despite the contrasting basin characteristics, a similarly close bentho-pelagic coupling pattern was observed at both locations, except at the deepest ground, especially at the AsB, where the mean δ 13 C values from the hyperbenthic and pelagic compartments were more distant. This could be related to the higher degree of reworking of organic matter in the AsB. Overall, these findings suggested the need for a depth-stratified approach to analyze deep-sea food webs in the study site in future studies.
Marine Ecology Progress Series, Sep 29, 2015
It is widely accepted that habitat and movement are key determinants of animal distribution, and ... more It is widely accepted that habitat and movement are key determinants of animal distribution, and therefore local abundances (Kahler et al. 2001, Geraldi et al. 2009), particularly for animals closely associated with the benthos. Therefore, having an understanding of localised behaviour, habitat-inter
Philosophical Transactions of the Royal Society B, Nov 27, 2010
Global climate change has the potential to substantially alter the production and community struc... more Global climate change has the potential to substantially alter the production and community structure of marine fisheries and modify the ongoing impacts of fishing. Fish community composition is already changing in some tropical, temperate and polar ecosystems, where local combinations of warming trends and higher environmental variation anticipate the changes likely to occur more widely over coming decades. Using case studies from the Western Indian Ocean, the North Sea and the Bering Sea, we contextualize the direct and indirect effects of climate change on production and biodiversity and, in turn, on the social and economic aspects of marine fisheries. Climate warming is expected to lead to (i) yield and species losses in tropical reef fisheries, driven primarily by habitat loss; (ii) community turnover in temperate fisheries, owing to the arrival and increasing dominance of warm-water species as well as the reduced dominance and departure of cold-water species; and (iii) increased diversity and yield in Arctic fisheries, arising from invasions of southern species and increased primary production resulting from ice-free summer conditions. How societies deal with such changes will depend largely on their capacity to adapt-to plan and implement effective responses to change-a process heavily influenced by social, economic, political and cultural conditions.
Journal of Experimental Marine Biology and Ecology, Nov 1, 2007
δ 13 C data are often used in trophodynamic research where diet-tissue fractionation (Δδ 13 C) is... more δ 13 C data are often used in trophodynamic research where diet-tissue fractionation (Δδ 13 C) is assumed to be 0-1‰ per trophic level and unaffected by the size of animals or their environment. Variation in Δδ 13 C will influence conclusions about food sources, energy pathways and trophic level. To assess the effects of body size, age and environmental conditions on Δδ 13 C, European sea bass (Dicentrarchus labrax) were reared on constant diets of dab (Limanda limanda) or (Ammodytes marinus) for 2years under natural environmental regimes. Bass were sampled approximately monthly to determine Δδ 13 C for muscle, heart and liver tissue and were 1.66‰, − 0.18‰, −1.77‰ (sandeel diet) and 1.34‰, −1.18‰, −1.75‰ (dab diet) respectively. Arithmetic lipid correction increased Δδ 13 C to N 2‰ for muscle and liver. Δδ 13 C was dependent on body mass and experimental duration (age) and generally declined with weight or time even after correction for lipid content. For liver, increasing temperature increased Δδ 13 C. The Δδ 13 C estimates from this study were compared with all available published Δδ 13 C estimates for fish. Bass muscle Δδ 13 C was similar to previous estimates for fish white muscle Δδ 13 C (1.56 ± 1.10‰) and whole body Δδ 13 C (1.52 ± 1.13‰). Fractionations derived in this study, combined with those from the literature, support the use of diet-tissue fractionation values of between 1‰-2‰ for δ 13 C, rather than the commonly used 0‰ −1‰. For muscle Δδ 13 C, 1.5‰ is appropriate.
Scientific Reports
The Supplementary Information 1 and 2 files published with this Article contained errors, where t... more The Supplementary Information 1 and 2 files published with this Article contained errors, where the title was incorrectly given as "Multi-trophic marker analysis of a Marquesan food web highlights how reef ecosystems might respond to a warmer and nutrient-rich ocean future. " This error has now been corrected in the Supplementary Information 1 and 2 files that accompany the original Article.
Scientific Reports, 2021
We studied the food web structure and functioning of a coral reef ecosystem in the Marquesas Isla... more We studied the food web structure and functioning of a coral reef ecosystem in the Marquesas Islands, French Polynesia, characterized by low coral cover, high sea surface temperature and meso- to eutrophic waters. The Marquesas constitute a relevant ecosystem to understand the functioning of low diversity reefs that are also subject to global change. A multi-tracer assessment of organic matter pathways was run to delineate ecosystem functioning, using analysis of fatty acids, bulk and compound specific stable isotope analysis and stable isotopes mixing models. Macroalgae and phytoplankton were the two major food sources fueling this food web with, however, some marked seasonal variations. Specifically, zooplankton relied on phytoplankton-derived organic matter and herbivorous fishes on macroalgae-derived organic matter to a much higher extent in summer than in winter (~ 75%vs. ~ 15%, and ~ 70 to 75%vs. ~ 5 to 15%, respectively) . Despite remarkably high δ15N values for all trophic c...
Science Advances, 2021
Coral reef predators are overwhelmingly sustained by offshore pelagic plankton sources rather tha... more Coral reef predators are overwhelmingly sustained by offshore pelagic plankton sources rather than by reef-based sources.
Royal Society Open Science, 2019
Faunal assemblages at hydrothermal vents associated with island-arc volcanism are less well known... more Faunal assemblages at hydrothermal vents associated with island-arc volcanism are less well known than those at vents on mid-ocean ridges and back-arc spreading centres. This study characterizes chemosynthetic biotopes at active hydrothermal vents discovered at the Kemp Caldera in the South Sandwich Arc. The caldera hosts sulfur and anhydrite vent chimneys in 1375–1487 m depth, which emit sulfide-rich fluids with temperatures up to 212°C, and the microbial community of water samples in the buoyant plume rising from the vents was dominated by sulfur-oxidizing Gammaproteobacteria. A total of 12 macro- and megafaunal taxa depending on hydrothermal activity were collected in these biotopes, of which seven species were known from the East Scotia Ridge (ESR) vents and three species from vents outside the Southern Ocean. Faunal assemblages were dominated by large vesicomyid clams, actinostolid anemones, Sericosura sea spiders and lepetodrilid and cocculinid limpets, but several taxa abunda...
Journal of Animal Ecology, 2018
Pelagic and benthic systems usually interact, but their dynamics and production rates differ. Suc... more Pelagic and benthic systems usually interact, but their dynamics and production rates differ. Such differences influence the distribution, reproductive cycles, growth rates, stability and productivity of the consumers they support. Consumer preferences for, and dependence on, pelagic or benthic production are governed by the availability of these sources of production and consumer life history, distribution, habitat, behavioural ecology, ontogenetic stage and morphology. Diet studies may demonstrate the extent to which consumers feed on prey in pelagic or benthic environments. But they do not discriminate benthic production directly supported by phytoplankton from benthic production recycled through detrital pathways. The former will track the dynamics of phytoplankton production more closely than the latter. We develop and apply a new analytical method that uses carbon (C) and sulphur (S) natural abundance stable isotope data to assess the relative contribution of pelagic and benth...
Food Webs, 2017
Deep-sea communities are subject to a growing number of extrinsic pressures, which threaten their... more Deep-sea communities are subject to a growing number of extrinsic pressures, which threaten their structure and function. Here we use carbon and nitrogen stable isotopes to provide new insights into the community structure of a data-poor deep-sea island slope system, the Exuma Sound, the Bahamas. A total of 78 individuals from 16 species were captured between 462 m and 923 m depth, and exhibited a broad range of δ 13 C (9.45‰) and δ 15 N (6.94‰). At the individual-level, δ 13 C decreased strongly with depth, indicative of shifting production sources, as well as potential shifts in community composition, and species-specific feeding strategies. δ 15 N did not follow strong depth relationships, suggesting trophic level and depth are not tightly coupled across individuals. We observed ontogenetic enrichment in δ 13 C and δ 15 N for Squalus cubensis (Cuban dogfish) highlighting a shift to larger, higher trophic level prey through ontogeny. These data provide the first assessment of food-web structure in the Exuma Sound, and suggest inherent complexity associated with deep-sea island slope ecosystems. Such observations are needed to further our understanding and develop contemporary management plans for these systems.
Journal of Experimental Marine Biology and Ecology, 2017
Polar compounds preclude mathematical lipid correction of carbon stable isotopes in deep-water sh... more Polar compounds preclude mathematical lipid correction of carbon stable isotopes in deep-water sharks.
Marine Ecology Progress Series, 2016
Marine Ecology Progress Series, 1997
6I5N and 6°C were determlned for plants invertebrdtes and f~s h e s collected from 3 s~t e s on t... more 6I5N and 6°C were determlned for plants invertebrdtes and f~s h e s collected from 3 s~t e s on the southern coast of the Mediterranean Island of Mallorca Spdln The sites were separated by distances of 1250 to 3750 m The mean Si5N of plants was 1 1 to 4 1 " W , , benthic Invertebrates 5 9 to 6 g':%) planktonic Invertebrates 5 5 to 5 8% and fishes 8 4 to 13 8%" 6"N became ennched with increasing trophic level The mean 6I3C of plants was-11 4 to-16 3'Xo benthlc invertebrates-14 8 to-16 8'X, planktonlc Invertebrates-19 3 to-19 8 O W b and fishes-16 1 to-19 2"y) There were s~g n~f i c a n t d~f f e iences in the lsotopic c o m p o s~t~o n of ~ndividual specles w~t h i n the plant invertebrate 01 flsh groupings at each slte and there were s~g n~f i c a n t d~fferences in the ~s o t o p~c composit~on of the same specles at dlfferent sites Depleted ' < C was assoc~ated w~t h b e n t h~c food chalns and enrlched ''C w~t h planktonlc chalns The data suggest that b e n t h~c food chalns are Important to the rocky reef assoclated f~s h e s studled as might be expected In a nutrlent poor system where planktonlc product~on IS relatively low Hoivever, the vanance In 6I1C composltlon between sltes was such that the r e l a t~v e s~g n~f l c a n c e of the 2 pdthways could not be determlned I5N measurements indicated that some of the flsh species studled had adopted d~fferent feedlng strategies at d~fferent sites and, as a result ~n d l v~d u a l s of the same species could sometimes be a s s~g n e d to different t r o p h~c groups at different sltes The data suggest that these f~s h e s e x h i b~t plast~clty in t h e~r feedlng strateg~es and this may p r o v~d e them wlth greater adaptlve flexibll~ty to respond to s~t e-s p e c~f~c changes In food avallabllity Moreover the data p r o v~d e emplrlcal support for current theones of food web dynamlcs w h~c h suggest that trophlc levels a r e dynamlc rather than flxed and that multlchannel omnivory IS an Important feature of food webs KEY WORDS Stable lsotopes T r o p h~c interact~ons Variablllty Mediterranean Reefs Feeding strategy O Inter-Research 1997 Resale of full artlcle not permitted
Journal of Marine Systems, Nov 1, 2014
Journal of Marine Systems, Oct 1, 2014
Benthic-pelagic coupling is an important process connecting species throughout the water column, ... more Benthic-pelagic coupling is an important process connecting species throughout the water column, particularly, in deep-sea systems where faunal assemblages can be dense if indirectly sustained by production from the above. Through stable isotope analyses, this study explored the sources of production, trophic structure, and benthopelagic coupling in two locations with contrasting oceanographic conditions from the western Mediterranean, in the Balearic (BsB) and the Algerian (AsB) sub-basins. The samples of 89 dominant species (23 decapods, 19 cephalopods, 33 fishes, among the other taxa), inhabiting the hyperbenthic and pelagic domains, from the shelf break (250 m), upper slope (650 m), and middle slope (850 m) were analyzed. Results suggested long food webs of approximately four trophic levels (TrLs) that were sustained by planktonic source material in shallower waters and degraded particulate organic matter of planktonic origin in deeper waters. Most of the collected species (70%) occupied intermediate trophic positions between the 3rd and 4th TrLs. The species δ 15 N and δ 13 C values exhibited a broad range, consistent with the high diversity that might be attributed to the oligotrophic conditions. As the depth increased, stronger segregation occurred between the trophic groups, and spatial differences were found among consumers of the two locations. Species in the AsB always had consistently higher δ 15 N values than in the BsB, which could possibly be attributed to the basal δ 15 N that was present through the food web. Despite the contrasting basin characteristics, a similarly close bentho-pelagic coupling pattern was observed at both locations, except at the deepest ground, especially at the AsB, where the mean δ 13 C values from the hyperbenthic and pelagic compartments were more distant. This could be related to the higher degree of reworking of organic matter in the AsB. Overall, these findings suggested the need for a depth-stratified approach to analyze deep-sea food webs in the study site in future studies.
Marine Ecology Progress Series, Sep 29, 2015
It is widely accepted that habitat and movement are key determinants of animal distribution, and ... more It is widely accepted that habitat and movement are key determinants of animal distribution, and therefore local abundances (Kahler et al. 2001, Geraldi et al. 2009), particularly for animals closely associated with the benthos. Therefore, having an understanding of localised behaviour, habitat-inter
Philosophical Transactions of the Royal Society B, Nov 27, 2010
Global climate change has the potential to substantially alter the production and community struc... more Global climate change has the potential to substantially alter the production and community structure of marine fisheries and modify the ongoing impacts of fishing. Fish community composition is already changing in some tropical, temperate and polar ecosystems, where local combinations of warming trends and higher environmental variation anticipate the changes likely to occur more widely over coming decades. Using case studies from the Western Indian Ocean, the North Sea and the Bering Sea, we contextualize the direct and indirect effects of climate change on production and biodiversity and, in turn, on the social and economic aspects of marine fisheries. Climate warming is expected to lead to (i) yield and species losses in tropical reef fisheries, driven primarily by habitat loss; (ii) community turnover in temperate fisheries, owing to the arrival and increasing dominance of warm-water species as well as the reduced dominance and departure of cold-water species; and (iii) increased diversity and yield in Arctic fisheries, arising from invasions of southern species and increased primary production resulting from ice-free summer conditions. How societies deal with such changes will depend largely on their capacity to adapt-to plan and implement effective responses to change-a process heavily influenced by social, economic, political and cultural conditions.
Journal of Experimental Marine Biology and Ecology, Nov 1, 2007
δ 13 C data are often used in trophodynamic research where diet-tissue fractionation (Δδ 13 C) is... more δ 13 C data are often used in trophodynamic research where diet-tissue fractionation (Δδ 13 C) is assumed to be 0-1‰ per trophic level and unaffected by the size of animals or their environment. Variation in Δδ 13 C will influence conclusions about food sources, energy pathways and trophic level. To assess the effects of body size, age and environmental conditions on Δδ 13 C, European sea bass (Dicentrarchus labrax) were reared on constant diets of dab (Limanda limanda) or (Ammodytes marinus) for 2years under natural environmental regimes. Bass were sampled approximately monthly to determine Δδ 13 C for muscle, heart and liver tissue and were 1.66‰, − 0.18‰, −1.77‰ (sandeel diet) and 1.34‰, −1.18‰, −1.75‰ (dab diet) respectively. Arithmetic lipid correction increased Δδ 13 C to N 2‰ for muscle and liver. Δδ 13 C was dependent on body mass and experimental duration (age) and generally declined with weight or time even after correction for lipid content. For liver, increasing temperature increased Δδ 13 C. The Δδ 13 C estimates from this study were compared with all available published Δδ 13 C estimates for fish. Bass muscle Δδ 13 C was similar to previous estimates for fish white muscle Δδ 13 C (1.56 ± 1.10‰) and whole body Δδ 13 C (1.52 ± 1.13‰). Fractionations derived in this study, combined with those from the literature, support the use of diet-tissue fractionation values of between 1‰-2‰ for δ 13 C, rather than the commonly used 0‰ −1‰. For muscle Δδ 13 C, 1.5‰ is appropriate.
Scientific Reports
The Supplementary Information 1 and 2 files published with this Article contained errors, where t... more The Supplementary Information 1 and 2 files published with this Article contained errors, where the title was incorrectly given as "Multi-trophic marker analysis of a Marquesan food web highlights how reef ecosystems might respond to a warmer and nutrient-rich ocean future. " This error has now been corrected in the Supplementary Information 1 and 2 files that accompany the original Article.
Scientific Reports, 2021
We studied the food web structure and functioning of a coral reef ecosystem in the Marquesas Isla... more We studied the food web structure and functioning of a coral reef ecosystem in the Marquesas Islands, French Polynesia, characterized by low coral cover, high sea surface temperature and meso- to eutrophic waters. The Marquesas constitute a relevant ecosystem to understand the functioning of low diversity reefs that are also subject to global change. A multi-tracer assessment of organic matter pathways was run to delineate ecosystem functioning, using analysis of fatty acids, bulk and compound specific stable isotope analysis and stable isotopes mixing models. Macroalgae and phytoplankton were the two major food sources fueling this food web with, however, some marked seasonal variations. Specifically, zooplankton relied on phytoplankton-derived organic matter and herbivorous fishes on macroalgae-derived organic matter to a much higher extent in summer than in winter (~ 75%vs. ~ 15%, and ~ 70 to 75%vs. ~ 5 to 15%, respectively) . Despite remarkably high δ15N values for all trophic c...
Science Advances, 2021
Coral reef predators are overwhelmingly sustained by offshore pelagic plankton sources rather tha... more Coral reef predators are overwhelmingly sustained by offshore pelagic plankton sources rather than by reef-based sources.
Royal Society Open Science, 2019
Faunal assemblages at hydrothermal vents associated with island-arc volcanism are less well known... more Faunal assemblages at hydrothermal vents associated with island-arc volcanism are less well known than those at vents on mid-ocean ridges and back-arc spreading centres. This study characterizes chemosynthetic biotopes at active hydrothermal vents discovered at the Kemp Caldera in the South Sandwich Arc. The caldera hosts sulfur and anhydrite vent chimneys in 1375–1487 m depth, which emit sulfide-rich fluids with temperatures up to 212°C, and the microbial community of water samples in the buoyant plume rising from the vents was dominated by sulfur-oxidizing Gammaproteobacteria. A total of 12 macro- and megafaunal taxa depending on hydrothermal activity were collected in these biotopes, of which seven species were known from the East Scotia Ridge (ESR) vents and three species from vents outside the Southern Ocean. Faunal assemblages were dominated by large vesicomyid clams, actinostolid anemones, Sericosura sea spiders and lepetodrilid and cocculinid limpets, but several taxa abunda...
Journal of Animal Ecology, 2018
Pelagic and benthic systems usually interact, but their dynamics and production rates differ. Suc... more Pelagic and benthic systems usually interact, but their dynamics and production rates differ. Such differences influence the distribution, reproductive cycles, growth rates, stability and productivity of the consumers they support. Consumer preferences for, and dependence on, pelagic or benthic production are governed by the availability of these sources of production and consumer life history, distribution, habitat, behavioural ecology, ontogenetic stage and morphology. Diet studies may demonstrate the extent to which consumers feed on prey in pelagic or benthic environments. But they do not discriminate benthic production directly supported by phytoplankton from benthic production recycled through detrital pathways. The former will track the dynamics of phytoplankton production more closely than the latter. We develop and apply a new analytical method that uses carbon (C) and sulphur (S) natural abundance stable isotope data to assess the relative contribution of pelagic and benth...
Food Webs, 2017
Deep-sea communities are subject to a growing number of extrinsic pressures, which threaten their... more Deep-sea communities are subject to a growing number of extrinsic pressures, which threaten their structure and function. Here we use carbon and nitrogen stable isotopes to provide new insights into the community structure of a data-poor deep-sea island slope system, the Exuma Sound, the Bahamas. A total of 78 individuals from 16 species were captured between 462 m and 923 m depth, and exhibited a broad range of δ 13 C (9.45‰) and δ 15 N (6.94‰). At the individual-level, δ 13 C decreased strongly with depth, indicative of shifting production sources, as well as potential shifts in community composition, and species-specific feeding strategies. δ 15 N did not follow strong depth relationships, suggesting trophic level and depth are not tightly coupled across individuals. We observed ontogenetic enrichment in δ 13 C and δ 15 N for Squalus cubensis (Cuban dogfish) highlighting a shift to larger, higher trophic level prey through ontogeny. These data provide the first assessment of food-web structure in the Exuma Sound, and suggest inherent complexity associated with deep-sea island slope ecosystems. Such observations are needed to further our understanding and develop contemporary management plans for these systems.
Journal of Experimental Marine Biology and Ecology, 2017
Polar compounds preclude mathematical lipid correction of carbon stable isotopes in deep-water sh... more Polar compounds preclude mathematical lipid correction of carbon stable isotopes in deep-water sharks.
Marine Ecology Progress Series, 2016
Marine Ecology Progress Series, 1997
6I5N and 6°C were determlned for plants invertebrdtes and f~s h e s collected from 3 s~t e s on t... more 6I5N and 6°C were determlned for plants invertebrdtes and f~s h e s collected from 3 s~t e s on the southern coast of the Mediterranean Island of Mallorca Spdln The sites were separated by distances of 1250 to 3750 m The mean Si5N of plants was 1 1 to 4 1 " W , , benthic Invertebrates 5 9 to 6 g':%) planktonic Invertebrates 5 5 to 5 8% and fishes 8 4 to 13 8%" 6"N became ennched with increasing trophic level The mean 6I3C of plants was-11 4 to-16 3'Xo benthlc invertebrates-14 8 to-16 8'X, planktonlc Invertebrates-19 3 to-19 8 O W b and fishes-16 1 to-19 2"y) There were s~g n~f i c a n t d~f f e iences in the lsotopic c o m p o s~t~o n of ~ndividual specles w~t h i n the plant invertebrate 01 flsh groupings at each slte and there were s~g n~f i c a n t d~fferences in the ~s o t o p~c composit~on of the same specles at dlfferent sites Depleted ' < C was assoc~ated w~t h b e n t h~c food chalns and enrlched ''C w~t h planktonlc chalns The data suggest that b e n t h~c food chalns are Important to the rocky reef assoclated f~s h e s studled as might be expected In a nutrlent poor system where planktonlc product~on IS relatively low Hoivever, the vanance In 6I1C composltlon between sltes was such that the r e l a t~v e s~g n~f l c a n c e of the 2 pdthways could not be determlned I5N measurements indicated that some of the flsh species studled had adopted d~fferent feedlng strategies at d~fferent sites and, as a result ~n d l v~d u a l s of the same species could sometimes be a s s~g n e d to different t r o p h~c groups at different sltes The data suggest that these f~s h e s e x h i b~t plast~clty in t h e~r feedlng strateg~es and this may p r o v~d e them wlth greater adaptlve flexibll~ty to respond to s~t e-s p e c~f~c changes In food avallabllity Moreover the data p r o v~d e emplrlcal support for current theones of food web dynamlcs w h~c h suggest that trophlc levels a r e dynamlc rather than flxed and that multlchannel omnivory IS an Important feature of food webs KEY WORDS Stable lsotopes T r o p h~c interact~ons Variablllty Mediterranean Reefs Feeding strategy O Inter-Research 1997 Resale of full artlcle not permitted