An early warning sign: trophic structure changes in the oceanic Gulf of Mexico from 2011—2018

Woodstock, Matthew S.; Sutton, Tracey; Frank, Tamara M.; Zhang, Yuying

doi:10.1016/j.ecolmodel.2021.109509

Cited by 10 publications

(5 citation statements)

References 54 publications

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“…Despite being less reactive on average than upper-ocean POC, meso-and bathypelagic organic particles are microbial hotspots that host key biogeochemical functions, from enzymatic decomposition of macromolecules (Arnosti et al, 2012;Baltar et al, 2010a, b) to aerobic and anaerobic respiration (Bianchi et al, 2018;Karthäuser et al, 2021) and chemosynthesis Herndl and Reinthaler, 2014;Pachiadaki et al, 2017). Moreover, mesopelagic particles are consumed by upper trophic levels that sustain fisheries (Bode et al, 2021;Woodstock et al, 2021).…”

Section: Towards a Globally Consistent Picture Of Poc Fields In Obser...mentioning

confidence: 99%

Bridging the gaps between particulate backscattering measurements and modeled particulate organic carbon in the ocean

Galí¹,

Falls

Claustre

et al. 2022

Biogeosciences

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Abstract. Oceanic particulate organic carbon (POC) is a small but dynamic component of the global carbon cycle. Biogeochemical models historically focused on reproducing the sinking flux of POC driven by large fast-sinking particles (LPOC). However, suspended and slow-sinking particles (SPOC, here < 100 µm) dominate the total POC (TPOC) stock, support a large fraction of microbial respiration, and can make sizable contributions to vertical fluxes. Recent developments in the parameterization of POC reactivity in PISCES (Pelagic Interactions Scheme for Carbon and Ecosystem Studies model; PISCESv2_RC) have improved its ability to capture POC dynamics. Here we evaluated this model by matching a global 3D simulation and 1D simulations at 50 different locations with observations made from biogeochemical (BGC-) Argo floats and satellites. Our evaluation covers globally representative biomes between 0 and 1000 m depth and relies on (1) a refined scheme for converting particulate backscattering at 700 nm (bbp700) to POC, based on biome-dependent POC / bbp700 ratios in the surface layer that decrease to an asymptotic value at depth; (2) a novel approach for matching annual time series of BGC-Argo vertical profiles to PISCES 1D simulations forced by pre-computed vertical mixing fields; and (3) a critical evaluation of the correspondence between in situ measurements of POC fractions, PISCES model tracers, and SPOC and LPOC estimated from high vertical resolution bbp700 profiles through a separation of the baseline and spike signals. We show that PISCES captures the major features of SPOC and LPOC across a range of spatiotemporal scales, from highly resolved profile time series to biome-aggregated climatological profiles. Model–observation agreement is usually better in the epipelagic (0–200 m) than in the mesopelagic (200–1000 m), with SPOC showing overall higher spatiotemporal correlation and smaller deviation (typically within a factor of 1.5). Still, annual mean LPOC stocks estimated from PISCES and BGC-Argo are highly correlated across biomes, especially in the epipelagic (r=0.78; n=50). Estimates of the SPOC / TPOC fraction converge around a median of 85 % (range 66 %–92 %) globally. Distinct patterns of model–observations misfits are found in subpolar and subtropical gyres, pointing to the need to better resolve the interplay between sinking, remineralization, and SPOC–LPOC interconversion in PISCES. Our analysis also indicates that a widely used satellite algorithm overestimates POC severalfold at high latitudes during the winter. The approaches proposed here can help constrain the stocks, and ultimately budgets, of oceanic POC.

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Section: Towards a Globally Consistent Picture Of Poc Fields In Obser...mentioning

confidence: 99%

Bridging the gaps between particulate backscattering measurements and modeled particulate organic carbon in the ocean

Galí¹,

Falls

Claustre

et al. 2022

Biogeosciences

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“…Growth was calculated as the product of the ingestion rate and 0.16 (Davison et al 2013). Fish mortality ( M ) was a stochastic procedure where the daily probability of M occurring was estimated as the proportion of total mortality not derived from epipelagic predators in an ecosystem model for the region (derived from Woodstock et al 2021). The values for M were 0.143, 0.227, 0.378, 0.0925, 0.15, and 0.427 for gonostomatids, myctophids, sternoptychids, stomiids, other mesopelagic micronektonivores (cephalopod and fish feeding guilds), and other mesopelagic zooplanktivores, respectively.…”

Section: Methodsmentioning

confidence: 99%

A trait‐based carbon export model for mesopelagic fishes in the Gulf of Mexico with consideration of asynchronous vertical migration, flux boundaries, and feeding guilds

Woodstock

Sutton

Zhang

2022

Limnology & Oceanography

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Fish-mediated carbon export provides a significant proportion of the biological carbon pump in oligotrophic regions. Bioenergetic models estimate this carbon transport, but many lack species-specific traits and no carbon export model has been developed in the mesopelagic Gulf of Mexico. Intensive mesopelagic sampling efforts in the northern and eastern Gulf of Mexico have provided high-resolution information regarding community composition, species' vertical migratory characteristics, diel depth occupancies, and diets. A stochastic, individualbased model was developed for deep-pelagic fishes in the northern Gulf of Mexico to estimate bioenergetic rates and carbon export fluxes. Fishes that ate gelatinous zooplankton consumed more mass per body weight per day than predators of cephalopods and fishes, ostensibly to increase the throughput of prey with less carbon (gelata) or more refractory materials (Crustacea). A dynamic energy budget submodel indicated that during 81% of occurrences, asynchronous vertically migrating fishes rested for 1 d before migrating again, but migrations on successive days were possible. In terms of carbon export, myctophids and stomiids contributed greater than 53% and 12% of the active carbon flux for the entire assemblage in all scenarios. The assemblage-wide carbon export rate driven by vertically migrating fishes was 0.14-0.72 mg C m À2 d À1 , 61% of the ingested carbon by the assemblage. Incorporating species-specific traits and individual variability in bioenergetic models allows for more complex research questions (e.g., the effect of feeding guilds and asynchronous migration on carbon export) compared to the carbon export models that otherwise assume all fishes within a functional group are equivalent.

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“…Evidence exists that there may have been significant changes in the trophic structure in the GoMx as a consequence of the oil spill (e.g. Woodstock et al 2021). More complex models are required to deal explicitly with such indirect effects and with environmental stochasticity.…”

Section: Discussionmentioning

confidence: 99%

Population consequences of the Deepwater Horizon oil spill on pelagic cetaceans

Marques

Thomas

Booth

et al. 2023

Mar. Ecol. Prog. Ser.

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The Deepwater Horizon disaster resulted in the release of 490000 m3 of oil into the northern Gulf of Mexico. We quantified population consequences for pelagic cetaceans, including sperm whales, beaked whales and 11 species of delphinids. We used existing spatial density models to establish pre-spill population size and distribution, and overlaid an oil footprint to estimate the proportion exposed to oil. This proportion ranged from 0.058 (Atlantic spotted dolphin, 95% CI = 0.041-0.078) to 0.377 (spinner dolphin, 95% CI = 0.217-0.555). We adapted a population dynamics model, developed for an estuarine population of bottlenose dolphins, to each pelagic species by scaling demographic parameters using literature-derived estimates of gestation duration. We used expert elicitation to translate knowledge from dedicated studies of oil effects on bottlenose dolphins to pelagic species and address how density dependence may affect reproduction. We quantified impact by comparing population trajectories under baseline and oil-impacted scenarios. The number of lost cetacean years (difference between trajectories, summed over years) ranged from 964 (short-finned pilot whale, 95% CI = 385-2291) to 32584 (oceanic bottlenose dolphin, 95% = CI 13377-71967). Maximum proportional population decrease ranged from 1.3% (Atlantic spotted dolphin 95% CI = 0.5-2.3) to 8.4% (spinner dolphin 95% CI = 3.2-17.7). Estimated time to recover to 95% of baseline was >10 yr for spinner dolphin (12 yr, 95% CI = 0-21) and sperm whale (11 yr, 95% CI = 0-21), while 7 taxonomic units remained within 95% of the baseline population size (time to recover, therefore, as per its definition, was 0). We investigated the sensitivity of results to alternative plausible inputs. Our methods are widely applicable for estimating population effects of stressors in the absence of direct measurements.

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An early warning sign: trophic structure changes in the oceanic Gulf of Mexico from 2011—2018

Cited by 10 publications

References 54 publications

Bridging the gaps between particulate backscattering measurements and modeled particulate organic carbon in the ocean

Bridging the gaps between particulate backscattering measurements and modeled particulate organic carbon in the ocean

A trait‐based carbon export model for mesopelagic fishes in the Gulf of Mexico with consideration of asynchronous vertical migration, flux boundaries, and feeding guilds

Population consequences of the Deepwater Horizon oil spill on pelagic cetaceans

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