Review of BPOP-v1 model: exploring the impact of changes in the biological pump on the shelf sea and ocean nutrient and redox state (Lovecchio & Lenton)

Abstract. The ocean’s biological pump has changed over Earth history from one dominated by prokaryotes, to one involving a mixture of prokaryotes and eukaryotes with trophic structure. Changes in the biological pump are in turn hypothesised to have caused important changes in the ocean’s nutrient and redox properties. To explore these hypotheses, we present here a new box model including oxygen (O), phosphorus (P) and a dynamical biological pump. Our Biological Pump, Oxygen and Phosphorus (BPOP) model accounts for two – small and large – organic matter species generated by production and coagulation, respectively. Export and burial of these particles are regulated by a remineralization length (zrem) scheme. We independently vary zrem of small and large particles in order to study how changes in sinking speeds and remineralization rates affect the major biogeochemical fluxes, and O and P ocean concentrations. Modelled O and P budgets and fluxes lay close to present estimates for zrem in the range of currently measured values. Our results highlight that relatively small changes in zrem of the large particles can have important impacts on the O and P ocean availability and support the idea that an early ocean dominated by small particles was nutrient rich due to inefficient removal to sediments. The results also highlight that shelf ocean anoxia can coexist with an oxygenated deep open ocean for realistic values of zrem, especially for large values of the small particle zrem. This could challenge conventional interpretations that the Proterozoic deep ocean was anoxic, which are derived from shelf and slope sediment redox data. This simple and computationally inexpensive model is a promising tool to investigate the impact of changes in the organic matter sinking and remineralization rates as well as changes in physical processes coupled to the biological pump in a variety of case studies.

Download Full-text

BPOP-v1 model: exploring the impact of changes in the biological pump on the shelf sea and ocean nutrient and redox state

Geoscientific Model Development ◽

10.5194/gmd-13-1865-2020 ◽

2020 ◽

Vol 13 (4) ◽

pp. 1865-1883 ◽

Cited By ~ 1

Author(s):

Elisa Lovecchio ◽

Timothy M. Lenton

Keyword(s):

Organic Matter ◽

Deep Ocean ◽

Biological Pump ◽

Low Oxygen ◽

Promising Tool ◽

Structure Changes ◽

Large Particles ◽

Shelf Sea ◽

Slope Sediment ◽

The Impact

Abstract. The biological pump of the ocean has changed over Earth's history, from one dominated by prokaryotes to one involving a mixture of prokaryotes and eukaryotes with trophic structure. Changes in the biological pump are in turn hypothesized to have caused important changes in the nutrient and redox properties of the ocean. To explore these hypotheses, we present here a new box model including oxygen (O), phosphorus (P) and a dynamical biological pump. Our Biological Pump, Oxygen and Phosphorus (BPOP) model accounts for two – small and large – organic matter species generated by production and coagulation, respectively. Export and burial of these particles are regulated by a remineralization length (zrem) scheme. We independently vary zrem of small and large particles in order to study how changes in sinking speeds and remineralization rates affect the major biogeochemical fluxes and O and P ocean concentrations. Modeled O and P budgets and fluxes lie reasonably close to present estimates for zrem in the range of currently measured values. Our results highlight that relatively small changes in zrem of the large particles can have important impacts on the O and P ocean availability and support the idea that an early ocean dominated by small particles was nutrient rich due to the inefficient removal of P to sediments. The results also suggest that extremely low oxygen concentrations in the shelf can coexist with an oxygenated deep open ocean for realistic values of zrem, especially for large values of the small-particle zrem. This could challenge conventional interpretations that the Proterozoic deep ocean was anoxic, which are derived from shelf and slope sediment redox data. This simple and computationally inexpensive model is a promising tool to investigate the impact of changes in the organic matter sinking and remineralization rates as well as changes in physical processes coupled with the biological pump in a variety of case studies.

Download Full-text

Imaging NAD(H) Redox Alterations in Cryopreserved Alveolar Macrophages from Ozone-Exposed Mice and the Impact of Nutrient Starvation during Long Lag Times

Antioxidants ◽

10.3390/antiox10050767 ◽

2021 ◽

Vol 10 (5) ◽

pp. 767

Author(s):

He N. Xu ◽

Joanna Floros ◽

Lin Z. Li ◽

Shaili Amatya

Keyword(s):

Oxidative Stress ◽

Alveolar Macrophages ◽

Redox State ◽

Redox Status ◽

Nutrient Starvation ◽

Ozone Exposure ◽

Reduced Form ◽

Time Period ◽

Lag Times ◽

The Impact

Employing the optical redox imaging technique, we previously identified a significant redox shift of nicotinamide adenine dinucleotide (NAD and the reduced form NADH) in freshly isolated alveolar macrophages (AM) from ozone-exposed mice. The goal here was twofold: (a) to determine the NAD(H) redox shift in cryopreserved AM isolated from ozone-exposed mice and (b) to investigate whether there is a difference in the redox status between cryopreserved and freshly isolated AM. We found: (i) AM from ozone-exposed mice were in a more oxidized redox state compared to that from filtered air (FA)-exposed mice, consistent with the results obtained from freshly isolated mouse AM; (ii) under FA exposure, there was no significant NAD(H) redox difference between fresh AM that had been placed on ice for 2.5 h and cryopreserved AM; however, under ozone exposure, fresh AM were more oxidized than cryopreserved AM; (iii) via the use of nutrient starvation and replenishment and H2O2-induced oxidative stress of an AM cell line, we showed that this redox difference between cryopreserved and freshly isolated AM is likely the result of the double “hit”, i.e., the ozone-induced oxidative stress plus nutrient starvation that prevented freshly isolated AM from a full recovery after being on ice for a prolonged time period. The cryopreservation technique we developed eliminates/minimizes the effects of oxidative stress and nutrient starvation on cells. This method can be adopted to preserve lung macrophages from animal models or clinical patients for further investigations.

Download Full-text

The impact of childhood maltreatment on redox state: Relationship with oxidative damage and antioxidant defenses in adolescents with no psychiatric disorder

Neuroscience Letters ◽

10.1016/j.neulet.2016.01.062 ◽

2016 ◽

Vol 617 ◽

pp. 173-177 ◽

Cited By ~ 11

Author(s):

Carine Hartmann do Prado ◽

Rodrigo Grassi-Oliveira ◽

Andréa Wieck ◽

Aline Zaparte ◽

Ledo Daruy Filho ◽

...

Keyword(s):

Psychiatric Disorder ◽

Oxidative Damage ◽

Childhood Maltreatment ◽

Redox State ◽

Antioxidant Defenses ◽

The Impact

Download Full-text

Resolving ecological feedbacks on the ocean carbon sink in Earth system models

10.5194/esd-2020-41 ◽

2020 ◽

Author(s):

David I. Armstrong McKay ◽

Sarah E. Cornell ◽

Katherine Richardson ◽

Johan Rockström

Keyword(s):

Climate Change ◽

Carbon Sink ◽

Biological Pump ◽

Earth System ◽

Temperature Dependent ◽

System Models ◽

Plankton Ecology ◽

Ocean Carbon ◽

The Impact ◽

Earth System Models

Abstract. The Earth’s oceans are one of the largest sinks in the Earth system for anthropogenic CO2 emissions, acting as a negative feedback on climate change. Earth system models predict, though, that climate change will lead to a weakening ocean carbon uptake rate as warm water holds less dissolved CO2 and biological productivity declines. However, most Earth system models do not incorporate the impact of warming on bacterial remineralisation and rely on simplified representations of plankton ecology that do not resolve the potential impact of climate change on ecosystem structure or elemental stoichiometry. Here we use a recently-developed extension of the cGEnIE Earth system model (ecoGEnIE) featuring a trait-based scheme for plankton ecology (ECOGEM), and also incorporate cGEnIE's temperature-dependent remineralisation (TDR) scheme. This enables evaluation of the impact of both ecological dynamics and temperature-dependent remineralisation on the soft-tissue biological pump in response to climate change. We find that including TDR strengthens the biological pump relative to default runs due to increased nutrient recycling, while ECOGEM weakens the biological pump by enabling a shift to smaller plankton classes. However, interactions with concurrent ocean acidification cause opposite sign responses for the carbon sink in both cases: TDR leads to a smaller sink relative to default runs whereas ECOGEM leads to a larger sink. Combining TDR and ECOGEM results in a net strengthening of the biological pump and a small net reduction in carbon sink relative to default. These results clearly illustrate the substantial degree to which ecological dynamics and biodiversity modulate the strength of climate-biosphere feedbacks, and demonstrate that Earth system models need to incorporate more ecological complexity in order to resolve carbon sink weakening.

Download Full-text

A novel flavin derivative reveals the impact of glucose on oxidative stress in adipocytes

Chemical Communications ◽

10.1039/c4cc03464c ◽

2014 ◽

Vol 50 (60) ◽

pp. 8181-8184 ◽

Cited By ~ 20

Author(s):

Jonathan Yeow ◽

Amandeep Kaur ◽

Matthew D. Anscomb ◽

Elizabeth J. New

Keyword(s):

Oxidative Stress ◽

Redox State ◽

Fluorescent Sensor ◽

Oxidative Capacity ◽

Biologically Relevant ◽

Oxidation Reduction ◽

The Impact

A fluorescent sensor for redox state shows reversible oxidation/reduction at biologically-relevant potentials, and is used to visualise cellular oxidative capacity.

Download Full-text

The impact of aging, hearing loss, and body weight on mouse hippocampal redox state, measured in brain slices using fluorescence imaging

Neurobiology of Aging ◽

10.1016/j.neurobiolaging.2016.03.006 ◽

2016 ◽

Vol 42 ◽

pp. 101-109 ◽

Cited By ~ 10

Author(s):

Kevin A. Stebbings ◽

Hyun W. Choi ◽

Aditya Ravindra ◽

Daniel Adolfo Llano

Keyword(s):

Hearing Loss ◽

Body Weight ◽

Fluorescence Imaging ◽

Redox State ◽

Brain Slices ◽

The Impact

Download Full-text

Impact of a warm anomaly in the Pacific Arctic region derived from time-series export fluxes

PLoS ONE ◽

10.1371/journal.pone.0255837 ◽

2021 ◽

Vol 16 (8) ◽

pp. e0255837

Author(s):

Catherine Lalande ◽

Jacqueline M. Grebmeier ◽

Andrew M. P. McDonnell ◽

Russell R. Hopcroft ◽

Stephanie O’Daly ◽

...

Keyword(s):

Sea Ice ◽

Bering Sea ◽

Chukchi Sea ◽

Arctic Region ◽

Ice Cover ◽

Biological Pump ◽

Northern Bering Sea ◽

Pacific Waters ◽

The Pacific ◽

The Impact

Unusually warm conditions recently observed in the Pacific Arctic region included a dramatic loss of sea ice cover and an enhanced inflow of warmer Pacific-derived waters. Moored sediment traps deployed at three biological hotspots of the Distributed Biological Observatory (DBO) during this anomalously warm period collected sinking particles nearly continuously from June 2017 to July 2019 in the northern Bering Sea (DBO2) and in the southern Chukchi Sea (DBO3), and from August 2018 to July 2019 in the northern Chukchi Sea (DBO4). Fluxes of living algal cells, chlorophyll a (chl a), total particulate matter (TPM), particulate organic carbon (POC), and zooplankton fecal pellets, along with zooplankton and meroplankton collected in the traps, were used to evaluate spatial and temporal variations in the development and composition of the phytoplankton and zooplankton communities in relation to sea ice cover and water temperature. The unprecedented sea ice loss of 2018 in the northern Bering Sea led to the export of a large bloom dominated by the exclusively pelagic diatoms Chaetoceros spp. at DBO2. Despite this intense bloom, early sea ice breakup resulted in shorter periods of enhanced chl a and diatom fluxes at all DBO sites, suggesting a weaker biological pump under reduced ice cover in the Pacific Arctic region, while the coincident increase or decrease in TPM and POC fluxes likely reflected variations in resuspension events. Meanwhile, the highest transport of warm Pacific waters during 2017–2018 led to a dominance of the small copepods Pseudocalanus at all sites. Whereas the export of ice-associated diatoms during 2019 suggested a return to more typical conditions in the northern Bering Sea, the impact on copepods persisted under the continuously enhanced transport of warm Pacific waters. Regardless, the biological pump remained strong on the shallow Pacific Arctic shelves.

Download Full-text