Publication Date:
2022-10-26
Description:
Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 125(10), (2020): e2020JG005664, doi:10.1029/2020JG005664.
Description:
Shallow ponds are expanding in many salt marshes with potential impacts on ecosystem functioning. Determining how pond characteristics change over time and scale with physical dimensions and other spatial predictors could facilitate incorporation of ponds into projections of ecosystem change. We evaluated scaling relationships across six differently sized ponds in three regions of the high marshes within the Plum Island Ecosystems‐Long Term Ecological Research site (MA, USA). We further characterized diel fluctuations in surface water chemistry in two ponds to understand short‐term processes that affect emergent properties (e.g., habitat suitability). Primary producers drove oxygen levels to supersaturation during the day, while nighttime respiration resulted in hypoxic to anoxic conditions. Diel swings in oxygen were mirrored by pH and resulted in successive shifts in redox‐sensitive metabolisms, as indicated by nitrate consumption at dusk followed by peaks in ammonium and then sulfide overnight. Abundances of macroalgae and Ruppia maritima correlated with whole‐pond oxygen metabolism rates, but not with surface area (SA), volume (V), or SA:V. Moreover, there were no clear patterns in primary producer abundances, surface water chemistry, or pond metabolism rates across marsh regions supplied by different tidal creeks or that differed in distance to upland borders or creekbanks. Comparisons with data from 2 years prior demonstrate that plant communities and biogeochemical processes are not in steady state. Factors contributing to variability between ponds and years are unclear but likely include infrequent tidal exchange. Temporal and spatial variability and the absence of scaling relationships complicate the integration of high marsh ponds into ecosystem biogeochemical models.
Description:
Thanks to S. McNichol, S. Jayne, E. Neel, and PIE‐LTER (NSF‐OCE1238212) for field assistance; I. Forbrich for meteorological data (Giblin & Forbrich, 2018); J. Jennings for dissolved nutrient analyses; J. Seewald for ion chromatograph access; and G. Mariotti for elevation data. C. Wilson and an anonymous reviewer provided comments that greatly improved our manuscript. A. C. S. was supported by NSF (OCE1233678), NOAA (NA14NOS4190145), and Sea Grant (NA14OAR4170104) awards, and A. D. by the MIT Undergraduate Research Opportunities Program.
Description:
2021-03-15
Keywords:
Salt marsh
;
Global change
;
Biogeochemistry
;
Metabolism
;
Scaling
;
Ecosystem function
Repository Name:
Woods Hole Open Access Server
Type:
Article
Permalink
