Oceanographic transport along frontal zones forms carbon, nitrogen, and oxygen isoscapes on the east coast of New Zealand: Implications for ecological studies

Durante, Leonardo M.; Smith, Robert G.; Kolodzey, Stina; McMullin, Rebecca M.; Salmond, Nichola H.; Schlieman, Clara D.; O’Connell-Milne, Sorrel A.; Frew, Russell; Hale, Robert Van; Wing, Stephen R.

doi:10.1016/j.csr.2021.104368

Cited by 11 publications

(14 citation statements)

References 83 publications

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“…The above schematic description is a simplification of the rather complicated circulation over the New Zealand shelves (Chiswell et al, 2015;Durante et al, 2021;Stevens et al, 2021;de Souza et al, 2021). Most importantly, the coastal circulations east of the North and South Island are not isolated from one another.…”

Section: New Zealand Sectormentioning

confidence: 99%

“…Most importantly, the coastal circulations east of the North and South Island are not isolated from one another. Instead, the Southland Current branches into the Merno Saddle to connect to the East Auckland Current (Chiswell et al, 2015;Durante et al, 2021;Stevens et al, 2021). Since the Southland Current carries a substantial amount of subantarctic water (Sutton, 2003), the NSTF receives an influx of subantarctic water via the Merno Saddle.…”

Section: New Zealand Sectormentioning

confidence: 99%

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Subtropical Frontal Zone of the Southern Ocean

Im¹

2021

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This paper combines a literature survey and data analysis. The literature on the Subtropical Front (STF) in the Southern Ocean is reviewed with a two-pronged emphasis on the double-front structure of the STF, hence the existence of a subtropical frontal zone (STFZ), and the circumpolar continuity of the STFZ. The data analysis is based on the World Ocean Circulation Experiment (WOCE) sections. The STFZ is detected along each section independently from other sections, while moving circum-polarly downstream (eastward). The literature survey and data analysis confirm the circumpolar continuity of the STFZ extending from the Brazil Current across the South Atlantic, South Indian, and South Pacific up to Chile, being bound by the North and South STF. The circumpolar continuity of the STFZ is partly interrupted by South Africa and Tasmania, where the North STF ceases, while the South STF continues eastward. The South Atlantic STFZ is the southern boundary of the well-defined Subtropical Mode Water (STMW) thermostad, which cools eastward from 15°C to 11°C between the Brazil Current and Greenwich Meridian. In the southeast Pacific, the STFZ is the southern boundary of the 17-to-19°C thermostad (South Pacific Eastern STMW). The STFZ’s vertical extent is at maximum in the South Atlantic (>1000 m), decreasing eastward to 300 m in the southeast Pacific off Chile. A special attention is given to the South Pacific and the STFZ’s role in the ecology of Chilean jack mackerel Trachurus murphyi that spawn at the STFZ and migrate along the STFZ from Chile up to New Zealand.

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Section: New Zealand Sectormentioning

confidence: 99%

Section: New Zealand Sectormentioning

confidence: 99%

Subtropical Frontal Zone of the Southern Ocean

Im¹

2021

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“…Coastal (macroalgae), and pelagic (phytoplankton) primary producers were assumed to be the main contributors of organic matter to the fish communities within the study region and used as isotope baselines in the present study. 6.29‰) were used 35,44 . Both macroalgae and SPOM samples were collected concomitantly with the collection of specimens in the modern period.…”

Section: Estimates Of Trophic Level Based On Isotopic Analysis Rely On Knowledge Of Isotope Valuesmentioning

confidence: 99%

“…Because the variability of isotopic baselines can affect the bulk isotope values of fish muscle tissue, we used region-specific baselines from the two main primary producers, macroalgae and SPOM (corresponding mainly to phytoplankton 35 ), to estimate trophic level and percentage phytoplankton supporting the food webs for each fish. For the analysis, a two-step iterative procedure based on bulk isotope values was used to generate a mass balance model, following Phillips and Gregg (2001) 67 .…”

Section: Trophic Parameter Calculationsmentioning

confidence: 99%

“…Data analysis focused on two important themes: (1) comparing the trophic structure of modern and historical fish communities and (2) investigating the continuous effect of environmental and anthropogenic variables on the trophic structure of the fish community through time. Trophic level and resource use of historical fishes were compared to expected values from modern samples, while accounting for fish size and latitude of sampling (see Supplementary Materials), which are known to affect isotope values of consumers in the region 34,35 . While most species were widespread throughout the whole study region, species inhabiting the slope and mid shelf were primarily collected north of latitude 44˚ South.…”

Section: Introductionmentioning

confidence: 99%

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Changes in Trophic Structure of An Exploited Fish Community At The Centennial Scale Are Linked To Fisheries and Climate Forces

Durante

Wing

Ingram

et al. 2021

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Understanding how marine food webs are affected by anthropogenic stressors is an important steppingstone toward the improved management of natural resources. Stable isotope analysis of historical and modern samples spanning a century indicated that the niche breadth of an exploited fish community increased after the expansion of New Zealand fisheries. Since the 2000s most species increased their reliance on food webs supported by pelagic production and shifted to a higher trophic level. Overall changes were coincident with ocean warming, climate oscillations, prey abundance and fishing intensity, but their effects were specific to each fish assemblage analyzed. Data derived from historical samples revealed how anthropogenic stressors can drive long-term shifts in the trophic structure of an exploited fish community.

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