oxygen and carbon metabolism of zostera muelleri across a depth gradient implications for resilience and blue carbon

Oxygen and carbon metabolism of Zostera muelleri across a depth gradient –Implications for resilience and blue carbon Angus J.P.. Figure 1 Map of Lake Macquarie showing the location of t

Oxygen and carbon metabolism of Zostera muelleri across a depth gradient –

Implications for resilience and blue carbon

Angus J.P Ferguson, Renee Gruber, Jaimie Potts, Aaron Wright, David T Welsh,

Peter Scanes

PII: S0272-7714(17)30011-2

DOI: 10.1016/j.ecss.2017.01.005

Reference: YECSS 5363

To appear in: Estuarine, Coastal and Shelf Science

Received Date: 13 July 2016

Revised Date: 8 December 2016

Accepted Date: 4 January 2017

Please cite this article as: Ferguson, A.J.P., Gruber, R., Potts, J., Wright, A., Welsh, D.T., Scanes, P.,

Oxygen and carbon metabolism of Zostera muelleri across a depth gradient – Implications for resilience and blue carbon, Estuarine, Coastal and Shelf Science (2017), doi: 10.1016/j.ecss.2017.01.005.

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AGB gross gain

leaf extension

∆ AGB

measured (8)

∆ BGB

measured (8)

∆ BGB

predicted (11)

measured

Carbon inputs /

CR

Carbon imports / exports

Figure 1 Map of Lake Macquarie showing the location of the Swansea

Shoals study area

depth (m) 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Figure 2 A) Sediment organic matter (OM) content, B) particulate

trapping rates; C) Sediment oxygen demand (SOD); D) seagrass above

ground biomass (AGB); E) below ground biomass (BGB); and F) the AGB:

BGB ratio All plots show means ±SE

early spring late summer

B.

C.

Ferguson et al Figure 3

Figure 3 A) Incident solar radiation at the study site, including the running

120 mean B) Pearson correlation coefficients for the predictive power of

different light integration windows for seagrass above ground biomass at the

study site C) The 120 day light integration window was the best predictor of

above ground biomass

depth (m)

0.5 1.0 1.5 2.0 2.5 3.0 3.5

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Figure 4 A) Gross primary productivity (GPP); B) Community

respiration (CR); C) Net community metabolism (NCM); D) and above

ground biomass-specific GPP; E) Below ground biomass-specific CR;

F) Community P:R All plots show means ±SE.

late summer 0.75m

1.5m 3.0m

Ferguson et al Figure 5

Figure 5 The relationship between sediment oxygen demand

and community P:R (means ±SE)

pre zenith post zenith

dawn to zenith zenith to dusk

A.

B.

C.

Ferguson et al Figure 6

Figure 6 A) Example of hysteresis in oxygen fluxes during the light, showing the

effects of increased respiration during the post zenith period (fluxes are

calculated for each ten minute period during the light); B) Oxygen fluxes during the morning and afternoon across the depth gradient during summer; C)

Fluxes of dissolved organic nitrogen during the morning and afternoon across the depth gradient during summer Plots B and C show means ±SE

Ferguson et al Figure 7

Figure 7 The relationships between GPP, CR, p/r

and total seagrass biomass (A-C), and the above

ground: below ground biomass ratio (D-F) All

plots show means ±SE

Figure 8 Annual carbon and oxygen budget for the Zostera muelleri meadow Black

arrows indicate the pathways estimated in this study while grey arrows indicate likely

Carbon inputs (GPP – DOC– wrack + seston) / CR = 1

Carbon imports (seston) / exports (DOC+wrack) = 0.99

Figure 9 Comparison of A) community respiration; B) gross primary

production; and C) net community metabolism for Zostera

marina(Duarte 2010) and Zostera muelleri (this study) Data from

Duarte (2010) are from a range of studies, incorporating

measurements from various depths within systems at a wide range of

latitudes and trophic status

Community respiration (mmol O2 m-2 d-1)