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Zhang Q, Fisher TR, Trentacoste EM, Buchanan C, Gustafson AB, Karrh R, Murphy RR, Keisman J, Wu C, Tian R, Testa JM, Tango PJ. Nutrient limitation of phytoplankton in Chesapeake Bay: Development of an empirical approach for water-quality management. Water Res 2021; 188:116407. [PMID: 33065415 DOI: 10.1016/j.watres.2020.116407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 05/20/2020] [Revised: 09/04/2020] [Accepted: 09/06/2020] [Indexed: 06/11/2023]
Abstract
Understanding the temporal and spatial roles of nutrient limitation on phytoplankton growth is necessary for developing successful management strategies. Chesapeake Bay has well-documented seasonal and spatial variations in nutrient limitation, but it remains unknown whether these patterns of nutrient limitation have changed in response to nutrient management efforts. We analyzed historical data from nutrient bioassay experiments (1992-2002) and data from long-term, fixed-site water-quality monitoring program (1990-2017) to develop empirical approaches for predicting nutrient limitation in the surface waters of the mainstem Bay. Results from classification and regression trees (CART) matched the seasonal and spatial patterns of bioassay-based nutrient limitation in the 1992-2002 period much better than two simpler, non-statistical approaches. An ensemble approach of three selected CART models satisfactorily reproduced the bioassay-based results (classification rate = 99%). This empirical approach can be used to characterize nutrient limitation from long-term water-quality monitoring data on much broader geographic and temporal scales than would be feasible using bioassays, providing a new tool for informing water-quality management. Results from our application of the approach to 21 tidal monitoring stations for the period of 2007-2017 showed modest changes in nutrient limitation patterns, with expanded areas of nitrogen-limitation and contracted areas of nutrient saturation (i.e., not limited by nitrogen or phosphorus). These changes imply that long-term reductions in nitrogen load have led to expanded areas with nutrient-limited phytoplankton growth in the Bay, reflecting long-term water-quality improvements in the context of nutrient enrichment. However, nutrient limitation patterns remain unchanged in the majority of the mainstem, suggesting that nutrient loads should be further reduced to achieve a less nutrient-saturated ecosystem.
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Affiliation(s)
- Qian Zhang
- University of Maryland Center for Environmental Science / Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA.
| | - Thomas R Fisher
- University of Maryland Center for Environmental Science, Horn Point Laboratory, 2020 Horns Point Rd, Cambridge, MD 21613, USA
| | - Emily M Trentacoste
- U.S. Environmental Protection Agency, Chesapeake Bay Program Office, 410 Severn Avenue, Annapolis, MD 21403, USA
| | - Claire Buchanan
- Interstate Commission on the Potomac River Basin, 30 West Gude Drive, Suite 450, Rockville, MD 20850, USA
| | - Anne B Gustafson
- University of Maryland Center for Environmental Science, Horn Point Laboratory, 2020 Horns Point Rd, Cambridge, MD 21613, USA
| | - Renee Karrh
- Maryland Department of Natural Resources, 580 Taylor Ave, Annapolis, MD 21401, USA
| | - Rebecca R Murphy
- University of Maryland Center for Environmental Science / Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA
| | - Jennifer Keisman
- U.S. Geological Survey, MD-DE-DC Water Science Center, 5522 Research Park Drive, Catonsville, MD 21228, USA
| | - Cuiyin Wu
- Chesapeake Research Consortium / Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA
| | - Richard Tian
- University of Maryland Center for Environmental Science / Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA
| | - Jeremy M Testa
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 146 Williams Street, Solomons, MD 20688, USA
| | - Peter J Tango
- U.S. Geological Survey / Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA
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Zhang Q, Murphy RR, Tian R, Forsyth MK, Trentacoste EM, Keisman J, Tango PJ. Chesapeake Bay's water quality condition has been recovering: Insights from a multimetric indicator assessment of thirty years of tidal monitoring data. Sci Total Environ 2018; 637-638:1617-1625. [PMID: 29925196 PMCID: PMC6688177 DOI: 10.1016/j.scitotenv.2018.05.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/02/2018] [Accepted: 05/03/2018] [Indexed: 05/09/2023]
Abstract
To protect the aquatic living resources of Chesapeake Bay, the Chesapeake Bay Program partnership has developed guidance for state water quality standards, which include ambient water quality criteria to protect designated uses (DUs), and associated assessment procedures for dissolved oxygen (DO), water clarity/underwater bay grasses, and chlorophyll-a. For measuring progress toward meeting the respective states' water quality standards, a multimetric attainment indicator approach was developed to estimate combined standards attainment. We applied this approach to three decades of monitoring data of DO, water clarity/underwater bay grasses, and chlorophyll-a data on annually updated moving 3-year periods to track the progress in all 92 management segments of tidal waters in Chesapeake Bay. In 2014-2016, 40% of tidal water segment-DU-criterion combinations in the Bay (n = 291) are estimated to meet thresholds for attainment of their water quality criteria. This index score marks the best 3-year status in the entire record. Since 1985-1987, the indicator has followed a nonlinear trajectory, consistent with impacts from extreme weather events and subsequent recoveries. Over the period of record (1985-2016), the indicator exhibited a positive and statistically significant trend (p < 0.05), indicating that the Bay has been recovering since 1985. Patterns of attainment of individual DUs are variable, but improvements in open water DO, deep channel DO, and water clarity/submerged aquatic vegetation have combined to drive the improvement in the Baywide indicator in 2014-2016 relative to its long-term median. Finally, the improvement in estimated Baywide attainment was statistically linked to the decline of total nitrogen, indicating responsiveness of attainment status to the reduction of nutrient load through various management actions since at least the 1980s.
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Affiliation(s)
- Qian Zhang
- University of Maryland Center for Environmental Science/U.S. Environmental Protection Agency Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA.
| | - Rebecca R Murphy
- University of Maryland Center for Environmental Science/U.S. Environmental Protection Agency Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA
| | - Richard Tian
- University of Maryland Center for Environmental Science/U.S. Environmental Protection Agency Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA
| | - Melinda K Forsyth
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 146 Williams Street, Solomons, MD 20688, USA
| | - Emily M Trentacoste
- U.S. Environmental Protection Agency, Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA
| | - Jennifer Keisman
- U.S. Geological Survey, MD-DE-DC Water Science Center, Catonsville, MD 21228, USA
| | - Peter J Tango
- U.S. Geological Survey/U.S. Environmental Protection Agency Chesapeake Bay Program, 410 Severn Avenue, Annapolis, MD 21403, USA
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Zhang Q, Tango PJ, Murphy RR, Forsyth MK, Tian R, Keisman J, Trentacoste EM. Chesapeake Bay Dissolved Oxygen Criterion Attainment Deficit: Three Decades of Temporal and Spatial Patterns. Front Mar Sci 2018; 5:10.3389/fmars.2018.00422. [PMID: 31534947 PMCID: PMC6750769 DOI: 10.3389/fmars.2018.00422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Low dissolved oxygen (DO) conditions are a recurring issue in waters of Chesapeake Bay, with detrimental effects on aquatic living resources. The Chesapeake Bay Program partnership has developed criteria guidance supporting the definition of state water quality standards and associated assessment procedures for DO and other parameters, which provides a binary classification of attainment or impairment. Evaluating time series of these two outcomes alone, however, provides limited information on water quality change over time or space. Here we introduce an extension of the existing Chesapeake Bay water quality criterion assessment framework to quantify the amount of impairment shown by space-time exceedance of DO criterion ("attainment deficit") for a specific tidal management unit (i.e., segment). We demonstrate the usefulness of this extended framework by applying it to Bay segments for each 3-year assessment period between 1985 and 2016. In general, the attainment deficit for the most recent period assessed (i.e., 2014-2016) is considerably worse for deep channel (DC; n = 10) segments than open water (OW; n = 92) and deep water (DW; n = 18) segments. Most subgroups - classified by designated uses, salinity zones, or tidal systems - show better (or similar) attainment status in 2014-2016 than their initial status (1985-1987). Some significant temporal trends (p < 0.1) were detected, presenting evidence on the recovery for portions of Chesapeake Bay with respect to DO criterion attainment. Significant, improving trends were observed in seven OW segments, four DW segments, and one DC segment over the 30 3-year assessment periods (1985-2016). Likewise, significant, improving trends were observed in 15 OW, five DW, and four DC segments over the recent 15 assessment periods (2000-2016). Subgroups showed mixed trends, with the Patuxent, Nanticoke, and Choptank Rivers experiencing significant, improving short-term (2000-2016) trends while Elizabeth experiencing a significant, degrading short-term trend. The general lack of significantly improving trends across the Bay suggests that further actions will be necessary to achieve full attainment of DO criterion. Insights revealed in this work are critical for understanding the dynamics of the Bay ecosystem and for further assessing the effectiveness of management initiatives aimed toward Bay restoration.
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Affiliation(s)
- Qian Zhang
- Chesapeake Bay Program Office, University of Maryland Center for Environmental Science, Annapolis, MD, United States
| | - Peter J. Tango
- Chesapeake Bay Program Office, U.S. Geological Survey, Annapolis, MD, United States
| | - Rebecca R. Murphy
- Chesapeake Bay Program Office, University of Maryland Center for Environmental Science, Annapolis, MD, United States
| | - Melinda K. Forsyth
- Chesapeake Biologicai Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, United States
| | - Richard Tian
- Chesapeake Bay Program Office, University of Maryland Center for Environmental Science, Annapolis, MD, United States
| | - Jennifer Keisman
- Maryland-Delaware-District of Columbia Water Science Center, U.S. Geological Survey, Catonsville, MD, United States
| | - Emily M. Trentacoste
- Chesapeake Bay Program Office, U.S. Environmental Protection Agency, Annapolis, MD, United States
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Trentacoste EM, Martinez AM, Zenk T. The place of algae in agriculture: policies for algal biomass production. Photosynth Res 2015; 123:305-15. [PMID: 24599393 PMCID: PMC4331613 DOI: 10.1007/s11120-014-9985-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 02/12/2014] [Indexed: 05/08/2023]
Abstract
Algae have been used for food and nutraceuticals for thousands of years, and the large-scale cultivation of algae, or algaculture, has existed for over half a century. More recently algae have been identified and developed as renewable fuel sources, and the cultivation of algal biomass for various products is transitioning to commercial-scale systems. It is crucial during this period that institutional frameworks (i.e., policies) support and promote development and commercialization and anticipate and stimulate the evolution of the algal biomass industry as a source of renewable fuels, high value protein and carbohydrates and low-cost drugs. Large-scale cultivation of algae merges the fundamental aspects of traditional agricultural farming and aquaculture. Despite this overlap, algaculture has not yet been afforded a position within agriculture or the benefits associated with it. Various federal and state agricultural support and assistance programs are currently appropriated for crops, but their extension to algal biomass is uncertain. These programs are essential for nascent industries to encourage investment, build infrastructure, disseminate technical experience and information, and create markets. This review describes the potential agricultural policies and programs that could support algal biomass cultivation, and the barriers to the expansion of these programs to algae.
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Affiliation(s)
- Emily M Trentacoste
- Scripps Institution of Oceanography, University of California-San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, USA,
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Hildebrand M, Abbriano RM, Polle JEW, Traller JC, Trentacoste EM, Smith SR, Davis AK. Metabolic and cellular organization in evolutionarily diverse microalgae as related to biofuels production. Curr Opin Chem Biol 2013; 17:506-14. [PMID: 23538202 DOI: 10.1016/j.cbpa.2013.02.027] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 02/18/2013] [Accepted: 02/26/2013] [Indexed: 12/18/2022]
Abstract
Microalgae are among the most diverse organisms on the planet, and as a result of symbioses and evolutionary selection, the configuration of core metabolic networks is highly varied across distinct algal classes. The differences in photosynthesis, carbon fixation and processing, carbon storage, and the compartmentation of cellular and metabolic processes are substantial and likely to transcend into the efficiency of various steps involved in biofuel molecule production. By highlighting these differences, we hope to provide a framework for comparative analyses to determine the efficiency of the different arrangements or processes. This sets the stage for optimization on the based on information derived from evolutionary selection to diverse algal classes and to synthetic systems.
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Affiliation(s)
- Mark Hildebrand
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0202, USA.
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