Key taxa in food web responses to stressors: the <i>Deepwater Horizon</i> oil spill

McCann, Michael J.; Able, Kenneth W.; Christian, Robert R.; Fodrie, F.J.; Jensen, Olaf P.; Johnson, Jessica J.; López‐Duarte, Paola C.; Martin, Charles W.; Olin, Jill A.; Polito, Michael J.; Roberts, Brian J.; Ziegler, Shelby L.

doi:10.1002/fee.1474

Cited by 59 publications

(51 citation statements)

References 37 publications

(46 reference statements)

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“…However, we also note that large portunid crabs may forage directly upon marsh‐platform fishes and fiddler crabs (McCann et al. ) or rely on marsh habitat structure primarily for refuge rather than food acquisition (sensu Boesch and Turner , Heck et al. ), emphasizing uncertainty in outwelling dynamics along marsh ecotones.…”

Section: Discussionmentioning

confidence: 76%

“…As coastal habitats continue to be degraded and impacted by a variety of anthropogenic activities (e.g., Deepwater Horizon Oil Spill; McCann et al. ), it is crucial that we develop a stronger understanding of food web dynamics and energy flows across regional scales to have increased predictive power regarding the vulnerability or resilience of coastal ecosystems to anticipated future perturbations.…”

Section: Discussionmentioning

confidence: 99%

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Dietary shifts across biogeographic scales alter spatial subsidy dynamics

2019

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Over heterogeneous landscapes, organisms and energy move across ecological boundaries and this can have profound effects on overall ecosystem functioning. Both abiotic and biotic factors along habitat boundaries may facilitate or impede key species interactions that drive these energy flows—especially along the land–sea interface. We synthesized the literature detailing estuarine fish diets and habitat characteristics of salt marshes from U.S. East and Gulf coasts to determine patterns and drivers of cross‐boundary trophic transfers at the land–sea interface. Notably, marsh‐platform species (i.e., killifishes, fiddler crabs) appear virtually absent in the diets of transient estuarine fishes in the Gulf of Mexico, while along the South Atlantic and Mid‐Atlantic Bights, marsh‐platform species appear regularly in the diets of many transient estuarine fishes. Tidal amplitude varied across these three biogeographic regions and likely regulates the availability of marsh‐platform species to transient estuarine fishes via both access to the marsh surface for marine predators and emergence of marsh‐resident prey into the adjacent estuary (i.e., higher tidal amplitude increases predator–prey encounter rates). Surprisingly, marsh shoot density was positively correlated with the presence of marsh‐platform species in the diet, but this pattern appears to be mediated by increased tidal amplitude, suggesting the mode and periodicity of abiotic cycles drive diet structure of transient estuarine fishes more so than local habitat structural complexity. Subsequently, these processes likely influence the degree to which “trophic relay” moves energy from the marsh toward the open estuary. Understanding the dynamics that determine energy flows, spatial subsidies, and ultimately, ecosystem‐level productivity, is essential for implementation of holistic ecosystem‐based approaches to conserve and manage complex landscape mosaics.

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Section: Discussionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Dietary shifts across biogeographic scales alter spatial subsidy dynamics

2019

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“…Biomarkers are measurable elemental and molecular signatures in consumer tissues that provide dietary information and can be used to trace the flow of matter and energy in food webs . Biomarkers can be especially useful in tracking carbon flow through complex food webs, such as in coastal systems like salt marshes, where trophic pathways are obscured by generalist consumers and a number of basal carbon sources …”

Section: Introductionmentioning

confidence: 99%

A multi‐biomarker approach supports the use of compound‐specific stable isotope analysis of amino acids to quantify basal carbon source use in a salt marsh consumer

Johnson

Olin

Polito

2019

Rapid Comm Mass Spectrometry

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Rationale Determining the flow of energy from primary producers to higher trophic levels in complex systems remains an important task for ecologists. Biomarkers can be used to trace carbon or energy sources contributing to an organism's tissues. However, different biomarkers vary in their ability to trace carbon sources based on how faithfully they transfer between trophic levels. Comparing emerging biomarker techniques with more commonly used techniques can demonstrate the relative efficacy of each in specific systems. Methods Two common biomarker techniques, fatty acid analysis (FAA) and bulk stable isotope analysis (SIA), and one emerging biomarker technique, compound‐specific stable isotope analysis of amino acids (CSIA‐AA), were compared to assess their ability to characterize and quantify basal carbon sources supporting the seaside sparrow (Ammodramus maritimus), a common salt marsh species. Herbivorous insect and deposit‐feeding fiddler crab biomarker values were analyzed as proxies of major terrestrial and aquatic basal carbon sources, respectively. Results All three biomarker techniques indicated that both terrestrial and aquatic carbon sources were important to seaside sparrows. However, FAA could only be evaluated qualitatively, due to a currently limited understanding of trophic modification of fatty acids between primary producer and this consumer's tissues. Quantitative stable isotope (SIA or CSIA‐AA) mixing models predicted nearly equal contributions of terrestrial and aquatic carbon sources supporting seaside sparrows, yet estimates based on CSIA‐AA had greater precision. Conclusions These findings support the use of CSIA‐AA as an emerging tool to quantify the relative importance of basal carbon sources in salt marsh consumers. Integrating multiple biomarker techniques, with their differing benefits and limitations, will help to constrain models of carbon and energy flow in future ecosystem studies.

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“…Such noted responses of the foundational and lower trophic‐level invertebrate taxa to the DWH spill have a capacity to destabilize or re‐organize saltmarsh food webs by altering the amount and pathways of energy flow, with direct consequences for higher trophic‐level consumers exploiting the affected habitats (McCann et al. ).…”

Section: Introductionmentioning

confidence: 99%

Seaside Sparrows reveal contrasting food web responses to large‐scale stressors in coastal Louisiana saltmarshes

et al. 2017

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Turner. 2017. Seaside Sparrows reveal contrasting food web responses to large-scale stressors in coastal Louisiana saltmarshes. Ecosphere 8(7):e01878. 10.1002/ecs2.1878Abstract. Large-scale ecosystem disturbances can alter the flow of energy through food webs, but such processes are not well defined for Gulf of Mexico saltmarsh ecosystems vulnerable to multiple interacting stressors. The 2010 Deepwater Horizon (DWH) oil spill significantly affected the composition of terrestrial saltmarsh communities in Louisiana, and thus had the potential to alter energy pathways through terrestrial and aquatic food webs, with direct consequences for higher trophic-level species restricted to these habitats. The Seaside Sparrow (Ammodramus maritimus) is endemic to saltmarshes and relies completely on the habitat and resources they provide; thus, the sparrows can serve as indicators of ecological change in response to disturbances. We analyzed food web pathways for birds residing in oiled and unoiled saltmarshes for the four years following the oil spill by quantifying the bulk carbon and nitrogen stable isotopes and fatty acid profiles of liver tissues, in addition to primary producers (e.g., marsh grasses) and invertebrate consumers representing the major energy resources in these systems. The stable isotope values of primary producers and most invertebrate consumers did not differ between oiled and unoiled sites, suggesting that the energy pathways within the food web were stable in spite of observed declines in these populations following the spill. The tracer profiles of the Seaside Sparrows confirmed that there was a nominal effect of oil on resource use or trophic position (TP). However, we detected significant interannual variation in resource use by these birds; the sparrows occupied a lower TP and exhibited greater assimilation of resources derived from benthic-aquatic relative to terrestrial pathways in 2013 compared to other years. This distinction is likely attributable to the effects of Hurricane Isaac in 2012, whose significant storm surge extensively inundated the saltmarsh landscape. Despite widespread concern for the saltmarsh ecosystem after the DWH event, the significant effects noted at the population level translated into only subtle differences to the flow of energy through this food web. These results demonstrate varying responses to different degrees of landscape-level disturbance, such as oil and hurricanes, and establish the need to better understand food web dynamics in these saltmarsh ecosystems.

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Key taxa in food web responses to stressors: the Deepwater Horizon oil spill

Cited by 59 publications

References 37 publications

Dietary shifts across biogeographic scales alter spatial subsidy dynamics

Dietary shifts across biogeographic scales alter spatial subsidy dynamics

A multi‐biomarker approach supports the use of compound‐specific stable isotope analysis of amino acids to quantify basal carbon source use in a salt marsh consumer

Seaside Sparrows reveal contrasting food web responses to large‐scale stressors in coastal Louisiana saltmarshes

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