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Spatial Patterns and Temperature Predictions of Tuna Fatty Acids: Tracing Essential Nutrients and Changes in Primary Producers.

Pethybridge HR, Parrish CC, Morrongiello J, Young JW, Farley JH, Gunasekera RM, Nichols PD - PLoS ONE (2015)

Bottom Line: Model projections show that the supply and availability of EFA are likely to be negatively affected by increases in SST especially in temperate waters where a 12% reduction in both total fatty acid content and EFA proportions are predicted.Such changes will have large implications for the availability of energy and associated health benefits to high-order consumers.Results convey new concerns on impacts of projected climate change on fish-derived EFA in marine systems.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Oceans and Atmosphere Flagship, Hobart, Tasmania, Australia.

ABSTRACT
Fatty acids are among the least understood nutrients in marine environments, despite their profile as key energy components of food webs and that they are essential to all life forms. Presented here is a novel approach to predict the spatial-temporal distributions of fatty acids in marine resources using generalized additive mixed models. Fatty acid tracers (FAT) of key primary producers, nutritional condition indices and concentrations of two essential long-chain (≥C20) omega-3 fatty acids (EFA) measured in muscle of albacore tuna, Thunnus alalunga, sampled in the south-west Pacific Ocean were response variables. Predictive variables were: location, time, sea surface temperature (SST) and chlorophyll-a (Chla), and phytoplankton biomass at time of catch and curved fork length. The best model fit for all fatty acid parameters included fish length and SST. The first oceanographic contour maps of EFA and FAT (FATscapes) were produced and demonstrated clear geographical gradients in the study region. Predicted changes in all fatty acid parameters reflected shifts in the size-structure of dominant primary producers. Model projections show that the supply and availability of EFA are likely to be negatively affected by increases in SST especially in temperate waters where a 12% reduction in both total fatty acid content and EFA proportions are predicted. Such changes will have large implications for the availability of energy and associated health benefits to high-order consumers. Results convey new concerns on impacts of projected climate change on fish-derived EFA in marine systems.

No MeSH data available.


Related in: MedlinePlus

Smoother plots of GAMM predicted albacore fatty acid tracers of large primary producers: (A) diatoms (EPA +14:0), (B) C18 algae, (C) dinoflagellates (DHA), and (D) ɷ6 protists.The dashed horizontal black lines represent the intercept in each plot. The dashed vertical lines approximately delineate the range of the explanatory variable above the zero line used as thresholds. The solid grey area bracketing the response curves show the confidence limits of the model and are twice the standard error. A star represents the model fit for that particular response variable with the highest % deviance explained (S3 Table).
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pone.0131598.g002: Smoother plots of GAMM predicted albacore fatty acid tracers of large primary producers: (A) diatoms (EPA +14:0), (B) C18 algae, (C) dinoflagellates (DHA), and (D) ɷ6 protists.The dashed horizontal black lines represent the intercept in each plot. The dashed vertical lines approximately delineate the range of the explanatory variable above the zero line used as thresholds. The solid grey area bracketing the response curves show the confidence limits of the model and are twice the standard error. A star represents the model fit for that particular response variable with the highest % deviance explained (S3 Table).

Mentions: Sea surface temperature 3-day composite (SST3), as a single explanatory variable, was more important than fork length for the FAT of larger primary producers (diatoms and C18 algae) accounting for 61 and 73% of the variability respectively, compared to 60 and 71% for fork length (data in S3 Table). In contrast, for FAT of smaller dinoflagellates, albacore fork length was shown to be more important than SST3, particularly for ɷ6 protists. For all SST3—FAT models, there was a clear transition at 18–19°C with steepest inclines observed at <18°C (Fig 2). FAT of larger primary producers were more prevalent at lower temperatures than smaller producers. For SST3 models of NCI, predicted proportions of TFA and ratios of ɷ3/ɷ6 were highest in cooler waters <19°C and <21°C, respectively (Fig 3A and 3B). Concentrations of EFA also showed similar trends with EPA and DHA decreasing linearly with SST3 and the intercept crossing at 22°C (Fig 3C and 3D).


Spatial Patterns and Temperature Predictions of Tuna Fatty Acids: Tracing Essential Nutrients and Changes in Primary Producers.

Pethybridge HR, Parrish CC, Morrongiello J, Young JW, Farley JH, Gunasekera RM, Nichols PD - PLoS ONE (2015)

Smoother plots of GAMM predicted albacore fatty acid tracers of large primary producers: (A) diatoms (EPA +14:0), (B) C18 algae, (C) dinoflagellates (DHA), and (D) ɷ6 protists.The dashed horizontal black lines represent the intercept in each plot. The dashed vertical lines approximately delineate the range of the explanatory variable above the zero line used as thresholds. The solid grey area bracketing the response curves show the confidence limits of the model and are twice the standard error. A star represents the model fit for that particular response variable with the highest % deviance explained (S3 Table).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4489677&req=5

pone.0131598.g002: Smoother plots of GAMM predicted albacore fatty acid tracers of large primary producers: (A) diatoms (EPA +14:0), (B) C18 algae, (C) dinoflagellates (DHA), and (D) ɷ6 protists.The dashed horizontal black lines represent the intercept in each plot. The dashed vertical lines approximately delineate the range of the explanatory variable above the zero line used as thresholds. The solid grey area bracketing the response curves show the confidence limits of the model and are twice the standard error. A star represents the model fit for that particular response variable with the highest % deviance explained (S3 Table).
Mentions: Sea surface temperature 3-day composite (SST3), as a single explanatory variable, was more important than fork length for the FAT of larger primary producers (diatoms and C18 algae) accounting for 61 and 73% of the variability respectively, compared to 60 and 71% for fork length (data in S3 Table). In contrast, for FAT of smaller dinoflagellates, albacore fork length was shown to be more important than SST3, particularly for ɷ6 protists. For all SST3—FAT models, there was a clear transition at 18–19°C with steepest inclines observed at <18°C (Fig 2). FAT of larger primary producers were more prevalent at lower temperatures than smaller producers. For SST3 models of NCI, predicted proportions of TFA and ratios of ɷ3/ɷ6 were highest in cooler waters <19°C and <21°C, respectively (Fig 3A and 3B). Concentrations of EFA also showed similar trends with EPA and DHA decreasing linearly with SST3 and the intercept crossing at 22°C (Fig 3C and 3D).

Bottom Line: Model projections show that the supply and availability of EFA are likely to be negatively affected by increases in SST especially in temperate waters where a 12% reduction in both total fatty acid content and EFA proportions are predicted.Such changes will have large implications for the availability of energy and associated health benefits to high-order consumers.Results convey new concerns on impacts of projected climate change on fish-derived EFA in marine systems.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Oceans and Atmosphere Flagship, Hobart, Tasmania, Australia.

ABSTRACT
Fatty acids are among the least understood nutrients in marine environments, despite their profile as key energy components of food webs and that they are essential to all life forms. Presented here is a novel approach to predict the spatial-temporal distributions of fatty acids in marine resources using generalized additive mixed models. Fatty acid tracers (FAT) of key primary producers, nutritional condition indices and concentrations of two essential long-chain (≥C20) omega-3 fatty acids (EFA) measured in muscle of albacore tuna, Thunnus alalunga, sampled in the south-west Pacific Ocean were response variables. Predictive variables were: location, time, sea surface temperature (SST) and chlorophyll-a (Chla), and phytoplankton biomass at time of catch and curved fork length. The best model fit for all fatty acid parameters included fish length and SST. The first oceanographic contour maps of EFA and FAT (FATscapes) were produced and demonstrated clear geographical gradients in the study region. Predicted changes in all fatty acid parameters reflected shifts in the size-structure of dominant primary producers. Model projections show that the supply and availability of EFA are likely to be negatively affected by increases in SST especially in temperate waters where a 12% reduction in both total fatty acid content and EFA proportions are predicted. Such changes will have large implications for the availability of energy and associated health benefits to high-order consumers. Results convey new concerns on impacts of projected climate change on fish-derived EFA in marine systems.

No MeSH data available.


Related in: MedlinePlus