Conclusion
Here, we implemented vegetation response functions to salinity and inundation to improve representation of coastal marsh ecosystems in a land surface model. In general, representing the responses of salt marsh photosynthesis to salinity and flooding via resistance to root water uptake worked well and is consistent with known plant physiological responses. Incorporating vegetation responses to salinity and inundation improved the accuracy of simulated GPP, but the updated model still overestimates productivity of freshwater wetlands. Vegetation responds to salinity and water level via several mechanisms beyond root water uptake, so our model improvements do not capture the complete vegetation response, but they provide a foundation to which additional mechanisms can be added. The stimulation of salt marsh productivity under moderate increases in inundation still needs to be addressed, as does the overestimation of productivity in freshwater marshes. Nevertheless, this work opens the door for modeling wetland C uptake along estuarine transects that include saline, brackish, and fresh marshes, or at different latitudes and tidal regimes. Additionally, salinity and flooding parameters could be applied to upland vegetation occurring at marsh edges that are much more sensitive to salinity and flooding to simulate carbon dynamics with saltwater intrusion or increasing hydroperiods.
References
Bradley, P.M., Morris, J.T., 1991. Relative Importance of Ion Exclusion, Secretion and Accumulation in Spartina alterniflora Loisel. J. Exp. Bot. 42, 1525–1532. https://doi.org/10.1093/jxb/42.12.1525
Colmer, T.D., Voesenek, L. a. C.J., 2009. Flooding tolerance: suites of plant traits in variable environments. Funct. Plant Biol. 36, 665–681. https://doi.org/10.1071/FP09144
Crain, C.M., Silliman, B.R., Bertness, S.L., Bertness, M.D., 2004. Physical and Biotic Drivers of Plant Distribution Across Estuarine Salinity Gradients. Ecology 85, 2539–2549. https://doi.org/10.1890/03-0745
Golaz, J.-C., Caldwell, P.M., Van Roekel, L.P., Petersen, M.R., Tang, Q., Wolfe, J.D., Abeshu, G., Anantharaj, V., Asay-Davis, X.S., Bader, D.C., Baldwin, S.A., Bisht, G., Bogenschutz, P.A., Branstetter, M., Brunke, M.A., Brus, S.R., Burrows, S.M., Cameron-Smith, P.J., Donahue, A.S., Deakin, M., Easter, R.C., Evans, K.J., Feng, Y., Flanner, M., Foucar, J.G., Fyke, J.G., Griffin, B.M., Hannay, C., Harrop, B.E., Hoffman, M.J., Hunke, E.C., Jacob, R.L., Jacobsen, D.W., Jeffery, N., Jones, P.W., Keen, N.D., Klein, S.A., Larson, V.E., Leung, L.R., Li, H.-Y., Lin, W., Lipscomb, W.H., Ma, P.-L., Mahajan, S., Maltrud, M.E., Mametjanov, A., McClean, J.L., McCoy, R.B., Neale, R.B., Price, S.F., Qian, Y., Rasch, P.J., Reeves Eyre, J.E.J., Riley, W.J., Ringler, T.D., Roberts, A.F., Roesler, E.L., Salinger, A.G., Shaheen, Z., Shi, X., Singh, B., Tang, J., Taylor, M.A., Thornton, P.E., Turner, A.K., Veneziani, M., Wan, H., Wang, H., Wang, S., Williams, D.N., Wolfram, P.J., Worley, P.H., Xie, S., Yang, Y., Yoon, J.-H., Zelinka, M.D., Zender, C.S., Zeng, X., Zhang, C., Zhang, K., Zhang, Y., Zheng, X., Zhou, T., Zhu, Q., 2019. The DOE E3SM Coupled Model Version 1: Overview and Evaluation at Standard Resolution. J. Adv. Model. Earth Syst. 11, 2089–2129. https://doi.org/10.1029/2018MS001603
Giblin, A. 2019. PIE LTER year 2018, meteorological data, 15 minute intervals, from the PIE LTER Marshview Farm weather station located in Newbury, MA ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/8bd014f569ac47efe4f8fcac49cf14f7 (Accessed 2022-08-31).
Giblin, A. 2020. PIE LTER year 2019, meteorological data, 15 minute intervals, from the PIE LTER Marshview Farm weather station located in Newbury, MA. ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/76db41052c9f8afce961fb105cc95693 (Accessed 2022-08-31).
Giblin, A. 2021. PIE LTER year 2020, meteorological data, 15 minute intervals, from the PIE LTER Marshview Farm weather station located in Newbury, MA ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/f6985f2a9d4e9e381a08d2202caafa21 (Accessed 2022-08-31).
Giblin, A., I. Forbrich, and Plum Island Ecosystems LTER. 2022. Eddy flux measurements during 2018 from low marsh site (Spartina alterniflora) within Shad Creek catchment, Rowley, Massachusetts, PIE LTER. ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/409a028e57d8ddc08535316dc257d083 (Accessed 2022-08-31).
Giblin, A., I. Forbrich, and Plum Island Ecosystems LTER. 2022. Eddy flux measurements during 2019 from low marsh site (Spartina alterniflora) within Shad Creek catchment, Rowley, Massachusetts, PIE LTER. ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/1d2ec0bad48134f6924651c269ac1968 (Accessed 2022-08-31).
Giblin, A., I. Forbrich, and Plum Island Ecosystems LTER. 2022. Eddy flux measurements during 2020 from low marsh site (Spartina alterniflora) within Shad Creek catchment, Rowley, Massachusetts, PIE LTER. ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/14354b6ca10825d7e2b043429d8d4ba9 (Accessed 2022-08-31).
Giblin, A. 2019. Marsh water table height, logging data from the Shad Creek Spartina marsh site for April-November 2018, Rowley, MA, PIE LTER. ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/df7ab552dfdad512d91f5337e2327942 (Accessed 2022-08-31).
Giblin, A. 2021. Marsh water table height, logging data from the Shad Creek Spartina marsh site for April-November 2019, Rowley, MA, PIE LTER. ver 1. Environmental Data Initiative. https://doi.org/10.6073/pasta/605232aed464701c5b576c54f1ca7f62 (Accessed 2022-08-31).
Hwang, Y.-H., Morris, J.T., 1994. Whole-plant gas exchange responses of Spartina alterniflora (Poaceae) to a range of constant and transient salinities. Am. J. Bot. 81, 659–665. https://doi.org/10.1002/j.1537-2197.1994.tb15500.x
Kirwan, M.L., Guntenspergen, G.R., D’Alpaos, A., Morris, J.T., Mudd, S.M., Temmerman, S., 2010. Limits on the adaptability of coastal marshes to rising sea level. Geophys. Res. Lett. 37. https://doi.org/10.1029/2010GL045489
Kirwan, M.L., Temmerman, S., Skeehan, E.E., Guntenspergen, G.R., Fagherazzi, S., 2016. Overestimation of marsh vulnerability to sea level rise. Nat. Clim. Change 6, 253–260. https://doi.org/10.1038/nclimate2909
Koven, C. D., Riley, W. J., Subin, Z. M., Tang, J. Y., Torn, M. S., Collins, W. D., et al. (2013). The effect of vertically resolved soil biogeochemistry and alternate soil C and N models on C dynamics of CLM4. Biogeosciences , 10(11), 7109–7131. https://doi.org/10.5194/bg-10-7109-2013
LaFond‐Hudson, S. and Sulman, B., 2023. Modeling strategies and data needs for representing coastal wetland vegetation in land surface models. New Phytologist238 (3), pp.938-951.
Lawrence, D.M., Fisher, R.A., Koven, C.D., Oleson, K.W., Swenson, S.C., Bonan, G., Collier, N., Ghimire, B., van Kampenhout, L., Kennedy, D., Kluzek, E., Lawrence, P.J., Li, F., Li, H., Lombardozzi, D., Riley, W.J., Sacks, W.J., Shi, M., Vertenstein, M., Wieder, W.R., Xu, C., Ali, A.A., Badger, A.M., Bisht, G., van den Broeke, M., Brunke, M.A., Burns, S.P., Buzan, J., Clark, M., Craig, A., Dahlin, K., Drewniak, B., Fisher, J.B., Flanner, M., Fox, A.M., Gentine, P., Hoffman, F., Keppel-Aleks, G., Knox, R., Kumar, S., Lenaerts, J., Leung, L.R., Lipscomb, W.H., Lu, Y., Pandey, A., Pelletier, J.D., Perket, J., Randerson, J.T., Ricciuto, D.M., Sanderson, B.M., Slater, A., Subin, Z.M., Tang, J., Thomas, R.Q., Val Martin, M., Zeng, X., 2019. The Community Land Model Version 5: Description of New Features, Benchmarking, and Impact of Forcing Uncertainty. J. Adv. Model. Earth Syst. 11, 4245–4287. https://doi.org/10.1029/2018MS001583
Li, Y., Yuan, L., Cao, H.-B., Tang, C.-D., Wang, X.-Y., Tian, B., Dou, S.-T., Zhang, L.-Q., Shen, J., 2021. A dynamic biomass model of emergent aquatic vegetation under different water levels and salinity. Ecol. Model. 440, 109398. https://doi.org/10.1016/j.ecolmodel.2020.109398
Mcleod, E., Chmura, G.L., Bouillon, S., Salm, R., Björk, M., Duarte, C.M., Lovelock, C.E., Schlesinger, W.H., Silliman, B.R., 2011. A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2. Front. Ecol. Environ. 9, 552–560. https://doi.org/10.1890/110004
Morris, J.T., Sundareshwar, P.V., Nietch, C.T., Kjerfve, B., Cahoon, D.R., 2002. Responses of Coastal Wetlands to Rising Sea Level. Ecology 83, 2869–2877. https://doi.org/10.1890/0012-9658(2002)083[2869:ROCWTR]2.0.CO;2
Morris, J.T., Sundberg, K., Hopkinson, C.S., 2013. Salt Marsh Primary Production and Its Responses to Relative Sea Level and Nutrients in Estuaries at Plum Island, Massachusetts, and North Inlet, South Carolina, USA. Oceanography 26, 78–84.
Munns, R., Tester, M., 2008. Mechanisms of Salinity Tolerance. Annu. Rev. Plant Biol. 59, 651–681. https://doi.org/10.1146/annurev.arplant.59.032607.092911
Naidoo, G., McKee, K.L., Mendelssohn, I.A., 1992. Anatomical and Metabolic Responses to Waterlogging and Salinity in Spartina alterniflora and S. patens (Poaceae). Am. J. Bot. 79, 765–770. https://doi.org/10.2307/2444942
O’Meara, T.A., Thornton, P.E., Ricciuto, D.M., Noyce, G.L., Rich, R.L., Megonigal, J.P., 2021. Considering coasts: Adapting terrestrial models to characterize coastal wetland ecosystems. Ecol. Model. 450, 109561. https://doi.org/10.1016/j.ecolmodel.2021.109561
Thornton, P. E., & Rosenbloom, N. A. (2005). Ecosystem model spin-up: Estimating steady state conditions in a coupled terrestrial carbon and nitrogen cycle model. Ecological Modelling, 189(1-2), 25–48. https://doi.org/10.1016/j.ecolmodel.2005.04.008
Vasquez, E.A., Glenn, E.P., Guntenspergen, G.R., Brown, J.J., Nelson, S.G., 2006. Salt tolerance and osmotic adjustment of Spartina alterniflora (Poaceae) and the invasive M haplotype of Phragmites australis (Poaceae) along a salinity gradient. Am. J. Bot. 93, 1784–1790. https://doi.org/10.3732/ajb.93.12.1784
Ward, N.D., Megonigal, J.P., Bond-Lamberty, B., Bailey, V.L., Butman, D., Canuel, E.A., Diefenderfer, H., Ganju, N.K., Goñi, M.A., Graham, E.B., Hopkinson, C.S., Khangaonkar, T., Langley, J.A., McDowell, N.G., Myers-Pigg, A.N., Neumann, R.B., Osburn, C.L., Price, R.M., Rowland, J., Sengupta, A., Simard, M., Thornton, P.E., Tzortziou, M., Vargas, R., Weisenhorn, P.B., Windham-Myers, L., 2020. Representing the function and sensitivity of coastal interfaces in Earth system models. Nat. Commun. 11, 2458. https://doi.org/10.1038/s41467-020-16236-2
Wasson, K., Ganju, N.K., Defne, Z., Endris, C., Elsey-Quirk, T., Thorne, K.M., Freeman, C.M., Guntenspergen, G., Nowacki, D.J., Raposa, K.B., 2019. Understanding tidal marsh trajectories: evaluation of multiple indicators of marsh persistence. Environ. Res. Lett. 14, 124073. https://doi.org/10.1088/1748-9326/ab5a94