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Lowman HE, Shriver RK, Hall RO, Harvey JW, Savoy P, Yackulic CB, Blaszczak JR. Macroscale controls determine the recovery of river ecosystem productivity following flood disturbances. Proc Natl Acad Sci U S A 2024; 121:e2307065121. [PMID: 38266048 PMCID: PMC10835108 DOI: 10.1073/pnas.2307065121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024] Open
Abstract
River ecosystem function depends on flow regimes that are increasingly modified by changes in climate, land use, water extraction, and flow regulation. Given the wide range of variation in flow regime modifications and autotrophic communities in rivers, it has been challenging to predict which rivers will be more resilient to flow disturbances. To better understand how river productivity is disturbed by and recovers from high-flow disturbance events, we used a continental-scale dataset of daily gross primary production time series from 143 rivers to estimate growth of autotrophic biomass and ecologically relevant flow disturbance thresholds using a modified population model. We compared biomass recovery rates across hydroclimatic gradients and catchment characteristics to evaluate macroscale controls on ecosystem recovery. Estimated biomass accrual (i.e., recovery) was fastest in wider rivers with less regulated flow regimes and more frequent instances of biomass removal during high flows. Although disturbance flow thresholds routinely fell below the estimated bankfull flood (i.e., the 2-y flood), a direct comparison of disturbance flows estimated by our biomass model and a geomorphic model revealed that biomass disturbance thresholds were usually greater than bed disturbance thresholds. We suggest that primary producers in rivers vary widely in their capacity to recover following flow disturbances, and multiple, interacting macroscale factors control productivity recovery rates, although river width had the strongest overall effect. Biomass disturbance flow thresholds varied as a function of geomorphology, highlighting the need for data such as bed slope and grain size to predict how river ecosystems will respond to changing flow regimes.
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Affiliation(s)
- Heili E. Lowman
- Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, NV89557
| | - Robert K. Shriver
- Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, NV89557
| | - Robert O. Hall
- Division of Biological Sciences, Flathead Lake Biological Station, University of Montana, Polson, MT59860
| | - Judson W. Harvey
- U.S. Geological Survey, Earth System Processes Division, Reston, VA20192
| | - Philip Savoy
- U.S. Geological Survey, Earth System Processes Division, Reston, VA20192
| | - Charles B. Yackulic
- U.S. Geological Survey, Southwest Biological Science Center, Flagstaff, AZ86001
| | - Joanna R. Blaszczak
- Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, NV89557
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Ardón M, Zeglin LH, Utz RM, Cooper SD, Dodds WK, Bixby RJ, Burdett AS, Follstad Shah J, Griffiths NA, Harms TK, Johnson SL, Jones JB, Kominoski JS, McDowell WH, Rosemond AD, Trentman MT, Van Horn D, Ward A. Experimental nitrogen and phosphorus enrichment stimulates multiple trophic levels of algal and detrital-based food webs: a global meta-analysis from streams and rivers. Biol Rev Camb Philos Soc 2020; 96:692-715. [PMID: 33350055 DOI: 10.1111/brv.12673] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 02/24/2024]
Abstract
Anthropogenic increases in nitrogen (N) and phosphorus (P) concentrations can strongly influence the structure and function of ecosystems. Even though lotic ecosystems receive cumulative inputs of nutrients applied to and deposited on land, no comprehensive assessment has quantified nutrient-enrichment effects within streams and rivers. We conducted a meta-analysis of published studies that experimentally increased concentrations of N and/or P in streams and rivers to examine how enrichment alters ecosystem structure (state: primary producer and consumer biomass and abundance) and function (rate: primary production, leaf breakdown rates, metabolism) at multiple trophic levels (primary producer, microbial heterotroph, primary and secondary consumers, and integrated ecosystem). Our synthesis included 184 studies, 885 experiments, and 3497 biotic responses to nutrient enrichment. We documented widespread increases in organismal biomass and abundance (mean response = +48%) and rates of ecosystem processes (+54%) to enrichment across multiple trophic levels, with no large differences in responses among trophic levels or between autotrophic or heterotrophic food-web pathways. Responses to nutrient enrichment varied with the nutrient added (N, P, or both) depending on rate versus state variable and experiment type, and were greater in flume and whole-stream experiments than in experiments using nutrient-diffusing substrata. Generally, nutrient-enrichment effects also increased with water temperature and light, and decreased under elevated ambient concentrations of inorganic N and/or P. Overall, increased concentrations of N and/or P altered multiple food-web pathways and trophic levels in lotic ecosystems. Our results indicate that preservation or restoration of biodiversity and ecosystem functions of streams and rivers requires management of nutrient inputs and consideration of multiple trophic pathways.
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Affiliation(s)
- Marcelo Ardón
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, U.S.A
| | - Lydia H Zeglin
- Division of Biology, Kansas State University, Manhattan, KS, 66506, U.S.A
| | - Ryan M Utz
- Falk School of Sustainability, Chatham University, Pittsburgh, PA, 15232, U.S.A
| | - Scott D Cooper
- Department of Ecology, Evolution, and Marine Biology and Marine Science Institute, University of California - Santa Barbara, Santa Barbara, CA, 93106, U.S.A
| | - Walter K Dodds
- Division of Biology, Kansas State University, Manhattan, KS, 66506, U.S.A
| | - Rebecca J Bixby
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, U.S.A
| | | | - Jennifer Follstad Shah
- Environmental and Sustainability Studies Program/Department of Geography, University of Utah, Salt Lake City, UT, 84112, U.S.A
| | - Natalie A Griffiths
- Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A
| | - Tamara K Harms
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775, U.S.A
| | - Sherri L Johnson
- Pacific Northwest Research Station, U. S. Forest Service, Corvallis, OR, 97731, U.S.A
| | - Jeremy B Jones
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775, U.S.A
| | - John S Kominoski
- Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, FL, 33199, U.S.A
| | - William H McDowell
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, 03824, U.S.A
| | - Amy D Rosemond
- Odum School of Ecology, University of Georgia, Athens, GA, 30602, U.S.A
| | - Matt T Trentman
- Division of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, U.S.A
| | - David Van Horn
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, U.S.A
| | - Amelia Ward
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487, U.S.A
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Abstract
Submarine groundwater discharge (SGD) influences near-shore coral reef ecosystems worldwide. SGD biogeochemistry is distinct, typically with higher nutrients, lower pH, cooler temperature and lower salinity than receiving waters. SGD can also be a conduit for anthropogenic nutrients and other pollutants. Using Bayesian structural equation modelling, we investigate pathways and feedbacks by which SGD influences coral reef ecosystem metabolism at two Hawai'i sites with distinct aquifer chemistry. The thermal and biogeochemical environment created by SGD changed net ecosystem production (NEP) and net ecosystem calcification (NEC). NEP showed a nonlinear relationship with SGD-enhanced nutrients: high fluxes of moderately enriched SGD (Wailupe low tide) and low fluxes of highly enriched SGD (Kūpikipiki'ō high tide) increased NEP, but high fluxes of highly enriched SGD (Kūpikipiki'ō low tide) decreased NEP, indicating a shift toward microbial respiration. pH fluctuated with NEP, driving changes in the net growth of calcifiers (NEC). SGD enhances biological feedbacks: changes in SGD from land use and climate change will have consequences for calcification of coral reef communities, and thereby shoreline protection.
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Affiliation(s)
- Nyssa J Silbiger
- Biology Department, California State University, Northridge, CA 91330, USA
| | - Megan J Donahue
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI 96744, USA
| | - Katie Lubarsky
- Scripps Institution of Oceanography, University of California, San Diego, CA, 92037, USA
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Masese FO, Kiplagat MJ, González-Quijano CR, Subalusky AL, Dutton CL, Post DM, Singer GA. Hippopotamus are distinct from domestic livestock in their resource subsidies to and effects on aquatic ecosystems. Proc Biol Sci 2020; 287:20193000. [PMID: 32345142 PMCID: PMC7282896 DOI: 10.1098/rspb.2019.3000] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/31/2020] [Indexed: 12/31/2022] Open
Abstract
In many regions of the world, populations of large wildlife have been displaced by livestock, and this may change the functioning of aquatic ecosystems owing to significant differences in the quantity and quality of their dung. We developed a model for estimating loading rates of organic matter (dung) by cattle for comparison with estimated rates for hippopotamus in the Mara River, Kenya. We then conducted a replicated mesocosm experiment to measure ecosystem effects of nutrient and carbon inputs associated with dung from livestock (cattle) versus large wildlife (hippopotamus). Our loading model shows that per capita dung input by cattle is lower than for hippos, but total dung inputs by cattle constitute a significant portion of loading from large herbivores owing to the large numbers of cattle on the landscape. Cattle dung transfers higher amounts of limiting nutrients, major ions and dissolved organic carbon to aquatic ecosystems relative to hippo dung, and gross primary production and microbial biomass were higher in cattle dung treatments than in hippo dung treatments. Our results demonstrate that different forms of animal dung may influence aquatic ecosystems in fundamentally different ways when introduced into aquatic ecosystems as a terrestrially derived resource subsidy.
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Affiliation(s)
- Frank O. Masese
- Department of Fisheries and Aquatic Sciences, University of Eldoret, P.O. Box 1125-30100, Eldoret, Kenya
- Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Mary J. Kiplagat
- Department of Fisheries and Aquatic Sciences, University of Eldoret, P.O. Box 1125-30100, Eldoret, Kenya
| | | | - Amanda L. Subalusky
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - Christopher L. Dutton
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - David M. Post
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - Gabriel A. Singer
- Department of Ecohydrology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
- Department of Ecology, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
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Collins SE, Matter SF, Buffam I, Flotemersch JE. A patchy continuum? Stream processes show varied responses to patch- and continuum-based analyses. Ecosphere 2018; 9. [PMID: 31297300 DOI: 10.1002/ecs2.2481] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many conceptual syntheses in ecology and evolution are undergirded by either a patch- or continuum-based model. Examples include gradualism and punctuated equilibrium in evolution, and edge effects and the theory of island biogeography in ecology. In this study, we sought to determine how patch- or continuum-based analyses could explain variation in concentrations of stream macronutrients and system metabolism, represented by measures of productivity and respiration rates, at the watershed scale across the Kanawha River Basin, USA. Using Strahler stream order (SSO; continuum) and functional process zone (FPZ; patch) as factors, we produced statistical models for each variable and compared model performance using likelihood ratio tests. Only one nutrient (i.e., PO 4 3 - ) responded better to patch-based analysis. Both models were significantly better than a null model for ecosystem respiration; however, neither outperformed the other. Importantly, in most cases, a combination model, including both SSO and FPZ, best described observed variation in the system. Our findings suggest that several patch- and continuum-based processes may simultaneously influence the concentration of macronutrients and system metabolism. Nutrient spiral- ing along a continuum and the patch mosaic of land cover may both alter macronutrients, for example. Similarly, increases in temperature and discharge associated with increasing SSO, as well as the differences in light availability and channel morphology associated with different FPZs, may influence system metabolism. For these reasons, we recommend a combination of patch- and continuum-based analyses when modeling, analyzing, and interpreting patterns in stream ecosystem parameters.
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Affiliation(s)
- Sean E Collins
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221 USA.,National Exposure Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio 45220 USA
| | - Stephen F Matter
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221 USA
| | - Ishi Buffam
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221 USA
| | - Joseph E Flotemersch
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio 45220 USA
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Abstract
There are still significant uncertainties in the magnitude and direction of carbon fluxes through coastal ecosystems. An important component of these biogeochemical budgets is ecosystem metabolism, the net result of organismal metabolic processes within an ecosystem. In this paper, I present a synthesis of published ecosystem metabolism studies from coastal ecosystems and describe an empirical observation that size-dependent patterns in aquatic gross primary production and community respiration exist across a wide range of coastal geomorphologies. Ecosystem metabolism scales to the 3/4 power with volume in deeper estuaries dominated by pelagic primary production and nearly linearly with area in shallow estuaries dominated by benthic primary production. These results can be explained by applying scaling arguments for efficient, directed transport networks developed to explain similar size-dependent patterns in organismal metabolism. The main conclusion from this synthesis is that the residence time of new, nutrient-rich water is a fundamental organizing principle for the observed patterns. Residence time changes allometrically with size in pelagic ecosystems because velocities change by only an order of magnitude across systems that span more than ten orders of magnitude in size. This nonisometric change in velocity with size requires lower specific metabolic rates at larger ecosystem sizes. This change in transport may also explain a shift from predominantly net heterotrophy to net autotrophy with increasing size. The scaling results are applied to the total estuarine area in the continental United States to estimate the contribution of estuarine systems to the overall coastal budget of organic carbon.
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Val J, Chinarro D, Pino MR, Navarro E. Global change impacts on river ecosystems: A high-resolution watershed study of Ebro river metabolism. Sci Total Environ 2016; 569-570:774-783. [PMID: 27392332 DOI: 10.1016/j.scitotenv.2016.06.098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/14/2016] [Accepted: 06/14/2016] [Indexed: 06/06/2023]
Abstract
Global change is transforming freshwater ecosystems, mainly through changes in basin flow dynamics. This study assessed how the combination of climate change and human management of river flow impacts metabolism of the Ebro River (the largest river basin in Spain, 86,100km(2)), assessed as gross primary production-GPP-and ecosystem respiration-ER. In order to investigate the influence of global change on freshwater ecosystems, an analysis of trends and frequencies from 25 sampling sites of the Ebro river basin was conducted. For this purpose, we examined the effect of anthropogenic flow control on river metabolism with a Granger causality study; simultaneously, took into account the effects of climate change, a period of extraordinary drought (largest in past 140years). We identified periods of sudden flow changes resulting from both human management and global climate effects. From 1998 to 2012, the Ebro River basin was trending toward a more autotrophic condition indicated by P/R ratio. Particularly, the results show that floods that occurred after long periods of low flows had a dramatic impact on the respiration (i.e., mineralization) capacity of the river. This approach allowed for a detailed characterization of the relationships between river metabolism and drought impacts at the watershed level. These findings may allow for a better understanding of the ecological impacts provoked by flow management, thus contributing to maintain the health of freshwater communities and ecosystem services that rely on their integrity.
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Affiliation(s)
- Jonatan Val
- FACOPS Foundation, Calle Pineta 17, 50410 Cuarte de Huerva, Zaragoza, Spain; Research Institute for Environment and Sustainability of San Jorge University, Villanueva de Gállego, 50830, Zaragoza, Spain; Pyrenean Institute of Ecology (CSIC), Av. Montañana 1005, 50059 Zaragoza, Spain.
| | - David Chinarro
- Research Institute for Environment and Sustainability of San Jorge University, Villanueva de Gállego, 50830, Zaragoza, Spain.
| | - María Rosa Pino
- Research Institute for Environment and Sustainability of San Jorge University, Villanueva de Gállego, 50830, Zaragoza, Spain.
| | - Enrique Navarro
- Pyrenean Institute of Ecology (CSIC), Av. Montañana 1005, 50059 Zaragoza, Spain.
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Richter DD, Billings SA. 'One physical system': Tansley's ecosystem as Earth's critical zone. New Phytol 2015; 206:900-912. [PMID: 25731586 DOI: 10.1111/nph.13338] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/08/2015] [Indexed: 06/04/2023]
Abstract
Integrative concepts of the biosphere, ecosystem, biogeocenosis and, recently, Earth's critical zone embrace scientific disciplines that link matter, energy and organisms in a systems-level understanding of our remarkable planet. Here, we assert the congruence of Tansley's (1935) venerable ecosystem concept of 'one physical system' with Earth science's critical zone. Ecosystems and critical zones are congruent across spatial-temporal scales from vegetation-clad weathering profiles and hillslopes, small catchments, landscapes, river basins, continents, to Earth's whole terrestrial surface. What may be less obvious is congruence in the vertical dimension. We use ecosystem metabolism to argue that full accounting of photosynthetically fixed carbon includes respiratory CO₂ and carbonic acid that propagate to the base of the critical zone itself. Although a small fraction of respiration, the downward diffusion of CO₂ helps determine rates of soil formation and, ultimately, ecosystem evolution and resilience. Because life in the upper portions of terrestrial ecosystems significantly affects biogeochemistry throughout weathering profiles, the lower boundaries of most terrestrial ecosystems have been demarcated at depths too shallow to permit a complete understanding of ecosystem structure and function. Opportunities abound to explore connections between upper and lower components of critical-zone ecosystems, between soils and streams in watersheds, and between plant-derived CO₂ and deep microbial communities and mineral weathering.
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Affiliation(s)
- Daniel deB Richter
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Sharon A Billings
- Department of Ecology and Evolutionary Biology and Kansas Biological Survey, University of Kansas, Lawrence, KS, 66047, USA
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