Aragonite dissolution kinetics and calcite/aragonite ratios in sinking and suspended particles in the North Pacific

Dong, Sijia; Berelson, William M.; Rollins, Nick; Subhas, Adam V.; Naviaux, John D.; Celestian, Aaron J.; Liu, Xuewu; Turaga, Nitya; Kemnitz, Nathaniel; Byrne, Robert H.; Adkins, Jess F.

doi:10.1016/j.epsl.2019.03.016

Cited by 47 publications

(118 citation statements)

References 49 publications

Supporting

Mentioning

106

Contrasting

Order By: Relevance

“…In addition, significant dissolution of pteropod aragonite has been observed in living and recently deceased pteropods (Bednaršek et al , b ; Peck et al ). It has also been demonstrated that a purely inorganic dissolution rate law for aragonite cannot explain the large alkalinity addition observed in the shallow North Pacific (Dong et al ). Instead, dissolution driven by the respiration of organic carbon, or by the production of acid in zooplankton guts, is more likely the driver of these shallow dissolution signals (Feely et al ; Dong et al ).…”

Section: Discussionmentioning

confidence: 99%

“…"n.d." indicates no activity was detected at that depth. POC data are presented for reference (see Dong et al 2019 for more analysis of these data). As mentioned in the Methods section, the conversion factor between [BCA] eff and k hyd is 1.41 × 10 8 s −1 M −1 .…”

Section: Suspended Particlesmentioning

confidence: 99%

“…In addition to its effects in vivo, CA has also been shown experimentally to catalyze the dissolution kinetics of calcium carbonate, in karst environments far from equilibrium (Liu et al ), and in seawater near equilibrium (Subhas et al ). Experimentally determined aragonite dissolution rate formulations, combined with measured saturation states in the North Pacific, can only explain a fraction of dissolution signals inferred from alkalinity addition to mid‐depth waters (Feely et al ; Berelson et al ; Dong et al ). This large, shallow dissolution signal in seawater supersaturated for aragonite therefore requires the production of metabolic CO 2 or other acids within microenvironments such as diffusively limited marine snow aggregates or the guts of zooplankton (Dong et al ).…”

mentioning

confidence: 99%

“…Experimentally determined aragonite dissolution rate formulations, combined with measured saturation states in the North Pacific, can only explain a fraction of dissolution signals inferred from alkalinity addition to mid‐depth waters (Feely et al ; Berelson et al ; Dong et al ). This large, shallow dissolution signal in seawater supersaturated for aragonite therefore requires the production of metabolic CO 2 or other acids within microenvironments such as diffusively limited marine snow aggregates or the guts of zooplankton (Dong et al ). These observations leave open the possibility that CA produced by marine organisms can catalyze the dissolution of calcium carbonate in these confined settings in situ.…”

mentioning

confidence: 99%

See 3 more Smart Citations

The carbonic anhydrase activity of sinking and suspended particles in the North Pacific Ocean

Subhas

Adkins

Dong

et al. 2019

Limnology & Oceanography

Self Cite

View full text Add to dashboard Cite

The enzyme carbonic anhydrase (CA) is crucial to many physiological processes involving CO2, from photosynthesis and respiration, to calcification and CaCO3 dissolution. We present new measurements of CA activity along a North Pacific transect, on samples from in situ pumps, sediment traps, discreet plankton samples from the ship's underway seawater line, plankton tows, and surface sediment samples from multicores. CA activity is highest in the surface ocean and decreases with depth, both in suspended and sinking particles. Subpolar gyre surface particles exhibit 10× higher CA activity per liter of seawater compared to subtropical gyre surface particles. Activity persists to 4700 m in the subpolar gyre, but only to 1000 m in the subtropics. All sinking CA activity normalized to particulate organic carbon (POC) follows a single relationship (CA/POC = 1.9 ± 0.2 × 10−7 mol mol−1). This relationship is consistent with CA/POC values in subpolar plankton tow material, suspended particles, and core top sediments. We hypothesize that most subpolar CA activity is associated with rapidly sinking diatom blooms, consistent with a large mat of diatomaceous material identified on the seafloor. Compared to the basin‐wide sinking CA/POC relationship, a lower subtropical CA/POC suggests that the inventory of subtropical biomass is different in composition from exported material. Pteropods also demonstrate substantial CA activity. Scaled to the volume within pteropod shells, first‐order CO2 hydration rate constants are elevated ≥ 1000× above background. This kinetic enhancement is large enough to catalyze carbonate dissolution within microenvironments, providing observational evidence for CA‐catalyzed, respiration‐driven CaCO3 dissolution in the shallow North Pacific.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Suspended Particlesmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

The carbonic anhydrase activity of sinking and suspended particles in the North Pacific Ocean

Subhas

Adkins

Dong

et al. 2019

Limnology & Oceanography

Self Cite

View full text Add to dashboard Cite

show abstract

“…Percent CaCO 3 and δ 13 C were measured on a separate aliquot using a modified Picarro CRDS‐Liaison system (Dong et al, ; Subhas et al, ). Between 0.8 and 3 mg of sediment sample was weighed into 12 ml Labco Exetainer vials with screw‐top septum caps.…”

Section: Methodsmentioning

confidence: 99%

Selective Preservation of Coccolith Calcite in Ontong‐Java Plateau Sediments

Subhas¹,

McCorkle

Quizon

et al. 2019

Paleoceanog and Paleoclimatol

Self Cite

View full text Add to dashboard Cite

Dissolution of calcite in deep ocean sediments, which is required to balance global marine CaCO 3 production and burial fluxes, is still a poorly understood process. In order to assess the mechanisms of dissolution in sediments, we analyzed four multicore tops taken along a depth transect on the Ontong-Java Plateau. These cores were taken directly on the equator, and span water column calcite saturation states from ∼0.93 to ∼0.74, allowing us to assess the effect of dissolution on carbonate sediment composition. The top 2 cm of each multicore was sectioned and sieved to separate coccolith from foraminiferal calcite, and the %CaCO 3 , 13 C, Δ 14 C, and Mg/Ca were evaluated. The mass ratio of coccoliths to foraminifera increases by a factor of 3 as a function of water depth, reflecting the preferential dissolution of foraminifera. Carbon isotope ( 13 C and Δ 14 C) data suggest that most dissolution takes place at the sediment-water interface and primarily affects foraminifera. Mg/Ca analyses indicate that the Mg content of the entire foraminiferal assemblage decreases as a function of dissolution. In contrast, coccolith dissolution takes place within the sediments, rather than at the interface. Together these two processes cause coccoliths to be up to 1,000 radiocarbon years younger than foraminifera from the same depth horizon. Despite this within-sediment coccolith dissolution flux, sediments below the calcite saturation horizon remain enriched in coccolith calcite. Combined with global seafloor hypsometry and calcium carbonate content, this enrichment suggests that globally, coccoliths may outweigh foraminifera in deep ocean sediments by a factor of 1.8.

show abstract

Depth profiles of suspended carbon and nitrogen along a North Pacific transect: Concentrations, isotopes, and ratios

Dong

Wang

Subhas

et al. 2021

Limnology & Oceanography

Self Cite

View full text Add to dashboard Cite

We present concentrations of total particulate carbon (PC), carbonate (PIC), total particulate nitrogen (PN), δ 13 C and δ 15 N of suspended particles along a North Pacific transect. In the upper 400 m, suspended PIC to particulate organic carbon (POC) ratios generally follow published sinking PIC/POC ratios. Below 600 m, suspended PIC/POC become significantly lower than sinking PIC/POC, likely indicating PIC dissolution within the suspended load. In three out of the five stations, suspended PN δ 15 N increase with depth from the euphotic zone to the thermocline, consistent with previous observations in many ocean regions (e.g.,BATS and HOT). However, in the other two stations where phytoplankton blooms were encountered, high suspended PN δ 15 N (up to 12‰) were observed in the euphotic zone, which was likely caused by the export of low-δ 15 N PN during the phytoplankton blooms. Average C org : N ratio of suspended particles along the transect is 5.1 AE 0.2, with the value in the subtropical gyre (5.8 AE 0.3) slightly higher than the subarctic gyre (4.6 AE 0.2).

show abstract

Aragonite dissolution kinetics and calcite/aragonite ratios in sinking and suspended particles in the North Pacific

Cited by 47 publications

References 49 publications

The carbonic anhydrase activity of sinking and suspended particles in the North Pacific Ocean

The carbonic anhydrase activity of sinking and suspended particles in the North Pacific Ocean

Selective Preservation of Coccolith Calcite in Ontong‐Java Plateau Sediments

Depth profiles of suspended carbon and nitrogen along a North Pacific transect: Concentrations, isotopes, and ratios

Contact Info

Product

Resources

About