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Calcium carbonate alters the functional response of coastal sediments to eutrophication-induced acidification. Sci Rep 2019; 9:12012. [PMID: 31427639 PMCID: PMC6700140 DOI: 10.1038/s41598-019-48549-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 08/05/2019] [Indexed: 11/08/2022] Open
Abstract
Coastal ocean acidification research is dominated by laboratory-based studies that cannot necessarily predict real-world ecosystem response given its complexity. We enriched coastal sediments with increasing quantities of organic matter in the field to identify the effects of eutrophication-induced acidification on benthic structure and function, and assess whether biogenic calcium carbonate (CaCO3) would alter the response. Along the eutrophication gradient we observed declines in macrofauna biodiversity and impaired benthic net primary productivity and sediment nutrient cycling. CaCO3 addition did not alter the macrofauna community response, but significantly dampened negative effects on function (e.g. net autotrophy occurred at higher levels of organic matter enrichment in +CaCO3 treatments than −CaCO3 (1400 vs 950 g dw m−2)). By identifying the links between eutrophication, sediment biogeochemistry and benthic ecosystem structure and function in situ, our study represents a crucial step forward in understanding the ecological effects of coastal acidification and the role of biogenic CaCO3 in moderating responses.
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Gladstone-Gallagher RV, Lohrer AM, Lundquist CJ, Pilditch CA. Effects of Detrital Subsidies on Soft-Sediment Ecosystem Function Are Transient and Source-Dependent. PLoS One 2016; 11:e0154790. [PMID: 27138563 PMCID: PMC4854381 DOI: 10.1371/journal.pone.0154790] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 04/19/2016] [Indexed: 11/18/2022] Open
Abstract
Detrital subsidies from marine macrophytes are prevalent in temperate estuaries, and their role in structuring benthic macrofaunal communities is well documented, but the resulting impact on ecosystem function is not understood. We conducted a field experiment to test the effects of detrital decay on soft-sediment primary production, community metabolism and nutrient regeneration (measures of ecosystem function). Twenty four (2 m2) plots were established on an intertidal sandflat, to which we added 0 or 220 g DW m-2 of detritus from either mangroves (Avicennia marina), seagrass (Zostera muelleri), or kelp (Ecklonia radiata) (n = 6 plots per treatment). Then, after 4, 17 and 46 d we measured ecosystem function, macrofaunal community structure and sediment properties. We hypothesized that (1) detrital decay would stimulate benthic primary production either by supplying nutrients to the benthic macrophytes, or by altering the macrofaunal community; and (2) ecosystem responses would depend on the stage and rate of macrophyte decay (a function of source). Avicennia detritus decayed the slowest with a half-life (t50) of 46 d, while Zostera and Ecklonia had t50 values of 28 and 2.6 d, respectively. However, ecosystem responses were not related to these differences. Instead, we found transient effects (up to 17 d) of Avicennia and Ecklonia detritus on benthic primary production, where initially (4 d) these detrital sources suppressed primary production, but after 17 d, primary production was stimulated in Avicennia plots relative to controls. Other ecosystem function response variables and the macrofaunal community composition were not altered by the addition of detritus, but did vary with time. By sampling ecosystem function temporally, we were able to capture the in situ transient effects of detrital subsidies on important benthic ecosystem functions.
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Affiliation(s)
| | - Andrew M. Lohrer
- National Institute of Water and Atmospheric Research Ltd. (NIWA), Hamilton, New Zealand
| | - Carolyn J. Lundquist
- National Institute of Water and Atmospheric Research Ltd. (NIWA), Hamilton, New Zealand
- Institute of Marine Science, University of Auckland, Auckland, New Zealand
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Pratt DR, Lohrer AM, Thrush SF, Hewitt JE, Townsend M, Cartner K, Pilditch CA, Harris RJ, van Colen C, Rodil IF. Detecting Subtle Shifts in Ecosystem Functioning in a Dynamic Estuarine Environment. PLoS One 2015. [PMID: 26214854 PMCID: PMC4516327 DOI: 10.1371/journal.pone.0133914] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Identifying the effects of stressors before they impact ecosystem functioning can be challenging in dynamic, heterogeneous 'real-world' ecosystems. In aquatic systems, for example, reductions in water clarity can limit the light available for photosynthesis, with knock-on consequences for secondary consumers, though in naturally turbid wave-swept estuaries, detecting the effects of elevated turbidity can be difficult. The objective of this study was to investigate the effects of shading on ecosystem functions mediated by sandflat primary producers (microphytobenthos) and deep-dwelling surface-feeding macrofauna (Macomona liliana; Bivalvia, Veneroida, Tellinidae). Shade cloths (which reduced incident light intensity by ~80%) were deployed on an exposed, intertidal sandflat to experimentally stress the microphytobenthic community associated with the sediment surface. After 13 weeks, sediment properties, macrofauna and fluxes of oxygen and inorganic nutrients across the sediment-water interface were measured. A multivariate metric of ecosystem function (MF) was generated by combining flux-based response variables, and distance-based linear models were used to determine shifts in the drivers of ecosystem function between non-shaded and shaded plots. No significant differences in MF or in the constituent ecosystem function variables were detected between the shaded and non-shaded plots. However, shading reduced the total explained variation in MF (from 64% in non-shaded plots to 15% in shaded plots) and affected the relative influence of M. liliana and other explanatory variables on MF. This suggests that although shade stress may shift the drivers of ecosystem functioning (consistent with earlier investigations of shading effects on sandflat interaction networks), ecosystem functions appear to have a degree of resilience to those changes.
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Affiliation(s)
- Daniel R. Pratt
- National Institute of Water and Atmospheric Research, P.O. Box 11–115, Hillcrest, Hamilton, New Zealand
- * E-mail:
| | - Andrew M. Lohrer
- National Institute of Water and Atmospheric Research, P.O. Box 11–115, Hillcrest, Hamilton, New Zealand
| | - Simon F. Thrush
- National Institute of Water and Atmospheric Research, P.O. Box 11–115, Hillcrest, Hamilton, New Zealand
- Institute of Marine Science, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Judi E. Hewitt
- National Institute of Water and Atmospheric Research, P.O. Box 11–115, Hillcrest, Hamilton, New Zealand
| | - Michael Townsend
- National Institute of Water and Atmospheric Research, P.O. Box 11–115, Hillcrest, Hamilton, New Zealand
| | - Katie Cartner
- National Institute of Water and Atmospheric Research, P.O. Box 11–115, Hillcrest, Hamilton, New Zealand
| | - Conrad A. Pilditch
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
| | - Rachel J. Harris
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
| | - Carl van Colen
- Marine Biology Group, Biology Department, Ghent University, Krijgslaan 281-S8, Ghent, Belgium
| | - Iván F. Rodil
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, Porto, Portugal
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