Pelagic and benthic ecology of the lower interface of the Eastern Tropical Pacific oxygen minimum zone

Wishner, Karen F.; Ashjian, Carin J.; Gelfman, Celia; Gowing, Marcia M.; Kann, Lisa; Levin, Lisa A.; Mullineaux, Lauren S.; Saltzman, Jennifer

doi:10.1016/0967-0637(94)00021-j

Cited by 129 publications

(79 citation statements)

References 43 publications

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“…A notable feature of these patterns is that abundance peaks are located at progressively greater depths with increasing organism size; ~750 m for foraminiferans, 850-950 m for macrofauna, and ~1000 m for megafauna (ophiuroids). Previous studies have reported that abundance peaks coincide with lower oxygen concentrations for macrofauna than for megafauna (Thomsen et al, 1985;Wishner et al, 1995;Levin 2002). Such patterns are consistent with the generally greater tolerance to hypoxia of foraminiferans than metazoan macrofauna, which in turn are more tolerant than megafauna (Josefson & Widbom, 1988;Moodley et al, 1997;Levin 2003) The rapid changes in megafaunal community composition across the lower transition zone, noted above, are probably another expression of an edge effect.…”

Section: Edge Effectssupporting

confidence: 65%

“…The distribution of organisms was strongly patterned by depth with narrow bands of galatheid crabs, natant decapods, ophiuroids and anemones succeeding each other between 750 and 800 m (Wishner et al, 1995;Levin, 2002). On the Pakistan margin, trawl samples indicate that the megafauna changed rapidly with depth across the lower transition zone of the OMZ.…”

Section: This Volume)mentioning

confidence: 95%

“…Therefore, we focus our comparison on data from this area, particularly the studies of Wishner et al (1990Wishner et al ( , 1995 and Levin et al (1991) across the summit and flanks of the Volcano 7 seamount which penetrates the OMZ to the west of Mexico (see also Levin 2002), and of Levin et al (2002) across the OMZ off Peru during the 1997-98 El Niño.…”

Section: Comparison With Other Deep-water Hypoxic Systemsmentioning

confidence: 99%

“…Dense concentrations of two polychaete species occur at the border between the oxygenated and anoxic/sulphidic parts of the Black Sea (Zaika et al, 1999). These narrow, densely populated bands reflect an abundant food supply combined with a release from oxygen limitation (Levin 2003) and appear to be associated with enhanced biological and biogeochemical activity (Wishner et al, 1995). Woulds et al (2007) documented enhanced rates of carbon processing at the upper and lower transition zones of the Pakistan margin.…”

Section: Foraminiferan-metazoan Interactionsmentioning

confidence: 99%

“…Woulds et al (2007) documented enhanced rates of carbon processing at the upper and lower transition zones of the Pakistan margin. These benthic edge effects have parallels in the water column, where zooplankton aggregate and microbial activity is elevated in narrow zones (Wishner et al 1995(Wishner et al , 2000.…”

Section: Foraminiferan-metazoan Interactionsmentioning

confidence: 99%

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Faunal responses to oxygen gradients on the Pakistan margin: A comparison of foraminiferans, macrofauna and megafauna

Gooday

Levin

Silva

et al. 2009

Deep Sea Research Part II: Topical Studies in Oceanography

142

103

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The Pakistan margin is characterized by a strong midwater oxygen minimum zone (OMZ) that intercepts the seabed at bathyal depths (150 to 1300 m). We investigated whether faunal abundance and diversity trends were similar among protists (foraminiferans and gromiids), metazoan macrofauna and megafauna along a transect (140-1850 m water depth) across the OMZ during the 2003 intermonsoon (March-May) and late/post monsoon (August-October) seasons. All groups exhibited some drop in abundance in the OMZ core (250-500 m water depth; O 2 : 0.10-0.13 ml l -1 = 4.46-5.80 μM l -1 ) but to differing degrees. Densities of foraminiferans >63 µm were slightly depressed at 300 m, peaked at 738 m, and were much lower at deeper stations. Foraminiferans >300 µm were the overwhelmingly dominant macrofaunal organisms in the OMZ core.Macrofaunal metazoans reached maximum densities at 140 m depth, with additional peaks at 850, 940 and 1850 m where foraminiferans were less abundant. The polychaete Linopherus sp. was responsible for a macrofaunal biomass peak at 950 m. Apart from large swimming animals (fish and natant decapods), metazoan megafauna were absent between 300 and 900 m (O 2 <0.14-0.15 ml l -1 = 6.25-6.69 μM l -1 ) but were represented by a huge, ophiuroid-dominated abundance peak at 1000 m (O 2 ~0.15-0.18 ml l -1 = 6.69-8.03μM l -1 ). Gromiid protists were confined largely to depths below 1150 m (O 2 >0.2 ml l -1 = 8.92 μM l -1 ). The progressively deeper abundance peaks for foraminiferans (>63 µm), Linopherus sp. and ophiuroids probably represent lower OMZ boundary edge effects and suggest a link between body size and tolerance of hypoxia. Macro-and megafaunal organisms collected between 800 and 1100 m were dominated by a succession of different taxa, indicating that the lower part of the OMZ is also a region of rapid faunal change. Species diversity was depressed in all groups in the OMZ core, but this was much more pronounced for macrofauna and megafauna than for foraminiferans. Oxygen levels strongly influenced the taxonomic composition of all faunal groups. Calcareous foraminiferans dominated the seasonally and permanently hypoxic sites (136-300 m); agglutinated foraminiferans were relatively more abundant at deeper stations where oxygen concentrations were >0.13 ml l -1 (= 5.80 μM l -1 ). Polychaetes were the main macrofaunal taxon within the OMZ; calcareous macrofauna and megafauna (decapods, 3 echinoderms) were rare or absent where oxygen levels were lowest. The rarity of larger animals between 300 and 700 m on the Pakistan margin, compared with the abundant macrofauna in the OMZ core off Oman, is the most notable contrast between the two sides of the Arabian Sea. This difference probably reflects the slightly higher oxygen levels and better food quality on the western side.

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Section: Edge Effectssupporting

confidence: 65%

Section: This Volume)mentioning

confidence: 95%

Section: Comparison With Other Deep-water Hypoxic Systemsmentioning

confidence: 99%

Section: Foraminiferan-metazoan Interactionsmentioning

confidence: 99%

Section: Foraminiferan-metazoan Interactionsmentioning

confidence: 99%

See 3 more Smart Citations

Faunal responses to oxygen gradients on the Pakistan margin: A comparison of foraminiferans, macrofauna and megafauna

Gooday

Levin

Silva

et al. 2009

Deep Sea Research Part II: Topical Studies in Oceanography

142

103

View full text Add to dashboard Cite

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Quantifying manganese and nitrogen cycle coupling in manganese‐rich, organic carbon‐starved marine sediments: Examples from the Clarion‐Clipperton fracture zone

Mogollón

Mewes

Kasten

2016

Geophysical Research Letters

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Extensive deep‐sea sedimentary areas are characterized by low organic carbon contents and thus harbor suboxic sedimentary environments where secondary (autotrophic) redox cycling becomes important for microbial metabolic processes. Simulation results for three stations in the Eastern Equatorial Pacific with low organic carbon content (<0.5 dry wt %) and low sedimentation rates (10−1–100 mm ky−1) show that ammonium generated during organic matter degradation may act as a reducing agent for manganese oxides below the oxic zone. Likewise, at these sedimentary depths, dissolved reduced manganese may act as a reducing agent for oxidized nitrogen species. These manganese‐coupled transformations provide a suboxic conversion pathway of ammonium and nitrate to dinitrogen. These manganese‐nitrogen interactions further explain the presence and production of dissolved reduced manganese (up to tens of μM concentration) in sediments with high nitrate (>20 μM) concentrations.

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Understanding the impact of climate change on the oceanic circulation in the Chilean island ecoregions

Dewitte

Conejero

Ramos

et al. 2021

Aquatic Conservation

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1. The largest changes in the circulation of the Southeastern Pacific resulting from global warming are associated with the southward shift and intensification of the anticyclone and with coastal surface warming. Coastal upwelling is projected to be increase off central Chile, due to an increase in equatorward winds, although increased oceanic stratification and associated enhanced nearshore turbulence will yield an onshore deepening/flattening of the thermocline. 2. The overall increase in south-easterly trade winds of the Southeastern Pacific in a warmer climate are likely to increase the connectivity pattern between Juan Fernandez and Desventuradas islands, and along the Sala y Gomez ridge, through increasing wind-driven mean ocean currents. 3. Deoxygenation associated with the warmer temperatures and changes in ventilation are likely to modify marine habitat and the respiratory barriers of species in the seamounts located in the vicinity of the limits of the minimum oxygen zone. 4. In the Southeastern Pacific, the prevailing 2D understanding of the responses of marine life to climate change needs to be expanded to 3D approaches, integrating the vertical habitat compression of marine organisms as a result of ocean warming and deoxygenation, as climate velocities for temperature and oxygen have contrasting vertical and horizontal patterns. 5. There is a need for regional biogeochemical-coupled modelling studies dedicated to the Chilean islands in order to provide an integrated view of the impact of anthropogenic stressors (e.g. deoxygenation, increased stratification, and climate shift) at the scale required for addressing socio-ecological interactions. 6. A refined understanding of the large-scale biogeography and spatial dynamics of marine populations through experimentation with high-resolution regional ocean models is a prerequisite for scaling-up regional management planning and optimizing the conservation of interconnected marine ecosystems across large scales.

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Pelagic and benthic ecology of the lower interface of the Eastern Tropical Pacific oxygen minimum zone

Cited by 129 publications

References 43 publications

Faunal responses to oxygen gradients on the Pakistan margin: A comparison of foraminiferans, macrofauna and megafauna

Faunal responses to oxygen gradients on the Pakistan margin: A comparison of foraminiferans, macrofauna and megafauna

Quantifying manganese and nitrogen cycle coupling in manganese‐rich, organic carbon‐starved marine sediments: Examples from the Clarion‐Clipperton fracture zone

Understanding the impact of climate change on the oceanic circulation in the Chilean island ecoregions

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