Respiration in the mesopelagic and bathypelagic zones of the oceans

Arı́stegui, Javier; Agustı́, Susana; Middelburg, Jack J.; Duarte, Carlos M.

doi:10.1093/acprof:oso/9780198527084.003.0010

Cited by 60 publications

(50 citation statements)

References 118 publications

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“…In fact, this delivery of large fluxes of POM to the WAP sea floor during the summer months supports a rich benthos throughout the year (Mincks et al 2005). Interestingly, these findings that microbial remineralization rates are higher at BATS than they are at WAP differs from the suggestions of previous authors that high latitude remineralization rates are higher due to more labile planktonic particles in these regions (Aristegui et al 2005;Francois et al 2002).…”

Section: (~0 13 D-')contrasting

confidence: 42%

Marine particle dynamics : sinking velocities, size distributions, fluxes, and microbial degradation rates

McDonnell¹

2011

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The sinking flux of particulate matter into the ocean interior is an oceanographic phenomenon that fuels much of the metabolic demand of the subsurface ocean and affects the distribution of carbon and other elements throughout the biosphere. In this thesis, I use a new suite of observations to study the dynamics of marine particulate matter at the contrasting sites of the subtropical Sargasso Sea near Bermuda and the waters above the continental shelf of the Western Antarctic Peninsula (WAP). An underwater digital camera system was employed to capture images of particles in the water column. The subsequent analysis of these images allowed for the determination of the particle concentration size distribution at high spatial, depth, and temporal resolutions. Drifting sediment traps were also deployed to assess both the bulk particle flux and determine the size distribution of the particle flux via image analysis of particles collected in polyacrylamide gel traps. The size distribution of the particle concentration and flux were then compared to calculate the average sinking velocity as a function of particle size. I found that the average sinking velocities of particles ranged from about 10-200 m d-and exhibited large variability with respect to location, depth, and date. Particles in the Sargasso Sea, which consisted primarily of small heterogeneous marine snow aggregates, sank more slowly than the rapidly sinking krill fecal pellets and diatom aggregates of the WAP. Moreover, the average sinking velocity did not follow a pattern of increasing velocities for the larger particles, a result contrary to what would be predicted from a simple formulation of Stokes' Law. At each location, I derived a best-fit fractal correlation between the flux size distribution and the total carbon flux. The use of this relationship and the computed average sinking velocities enabled the estimation of particle flux from measurements of the particle concentration size distribution. This approach offers greatly improved spatial and temporal resolution when compared to traditional sediment trap methods for measuring the downward flux of particulate matter. Finally, I deployed specialized in situ incubation chambers to assess the respiration rates of microbes attached to sinking particles. I found that at Bermuda, the carbon specific remineralization rate of sinking particulate matter ranged from 0.2 to 1.1 d', while along the WAP, these rates were very slow and below the detection limit of the instruments. The high microbial respiration rates and slow sinking velocities in the Sargasso Sea resulted in the strong attenuation of the flux with respect to depth, whereas the rapid sinking velocities and slow microbial degradation rates of the WAP resulted in nearly constant fluxes with respect to depth.

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Section: (~0 13 D-')contrasting

confidence: 42%

Marine particle dynamics : sinking velocities, size distributions, fluxes, and microbial degradation rates

McDonnell¹

2011

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“…These activities either act continuously (POC solubilization by microbes attached to sinking particles, Hoppe et al, 1993;Arístegui et al, 2005), or discretely (POC transformations by mesozooplankton grazing and residing within this stratum, Dagg, 1993) as reported by Steinberg et al (2008). A further pathway for sinking POC in the subsurface ocean is via zooplankton diurnal vertical FIGURE 1 | Schematic of the coupled surface-subsurface model.…”

Section: The Coupled Surface-subsurface Modelmentioning

confidence: 99%

Toward quantifying the response of the oceans' biological pump to climate change

Boyd

2015

Front. Mar. Sci.

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The biological pump makes a major global contribution to the sequestration of carbon-rich particles in the oceans' interior. This pump has many component parts from physics to ecology that together control its efficiency in exporting particles. Hence, the influence of climate change on the functioning and magnitude of the pump is likely to be complex and non-linear. Here, I employ a published 1-D coupled surface-subsurface Particulate Organic Carbon (POC) export flux model to systematically explore the potential influence of changing oceanic conditions on each of the pump's "moving parts," in both surface and subsurface waters. These simulations were run for typical high (High Nutrient Low Chlorophyll, HNLC) and low (Low Nutrient Low Chlorophyll, LNLC) latitude sites. Next, I couple pump components that have common drivers, such as temperature, to investigate more complex scenarios involving concurrent climate-change mediated alteration of multiple "moving parts" of the pump. Model simulations reveal that in the surface ocean, changes to algal community structure (i.e., a shift toward small cells) has the greatest individual influence (decreased flux) on downward POC flux in the coming decades. In subsurface waters, a shift in zooplankton community structure has the greatest single effect on POC flux (decreased) in a future ocean. More complex treatments, in which up to 10 individual factors (across both surface and subsurface processes) were concurrently altered, ∼ halved the POC flux at both high and low latitudes. In general climate-mediated changes to surface ocean processes had a greater effect on the magnitude of POC flux than alteration of subsurface processes, some of which negated one another. This relatively simple 1-D model provides initial insights into the most influential processes that may alter the future performance of this pump, and more importantly reveals many knowledge gaps that require urgent attention before we can accurately quantify future changes to the biological pump.

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“…In the global mesopelagic zone, ca. 15% of CR is associated with zooplankton and the rest is microbial (Bacteria, Archaea, and protists; Arístegui et al 2005a). Viral lysis of cells and the release of cell content and cell wall debris can also influence microbial respiration rates (Middelboe et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Seasonal variability of microbial respiration and bacterial and archaeal community composition in the upper twilight zone

Weinbauer¹,

Liu²,

Motegi³

et al. 2013

Aquat. Microb. Ecol.

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Respiration in the mesopelagic and bathypelagic zones of the oceans

Cited by 60 publications

References 118 publications

Marine particle dynamics : sinking velocities, size distributions, fluxes, and microbial degradation rates

Marine particle dynamics : sinking velocities, size distributions, fluxes, and microbial degradation rates

Toward quantifying the response of the oceans' biological pump to climate change

Seasonal variability of microbial respiration and bacterial and archaeal community composition in the upper twilight zone

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