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Wang L, Tomas F, Mueller RS. Nutrient enrichment increases size of Zostera marina shoots and enriches for sulfur and nitrogen cycling bacteria in root-associated microbiomes. FEMS Microbiol Ecol 2021; 96:5861935. [PMID: 32578844 DOI: 10.1093/femsec/fiaa129] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/22/2020] [Indexed: 01/09/2023] Open
Abstract
Seagrasses are vital coastal ecosystem engineers, which are mutualistically associated with microbial communities that contribute to the ecosystem services provided by meadows. The seagrass microbiome and sediment microbiota play vital roles in belowground biogeochemical and carbon cycling. These activities are influenced by nutrient, carbon and oxygen availability, all of which are modulated by environmental factors and plant physiology. Seagrass meadows are increasingly threatened by nutrient pollution, and it is unknown how the seagrass microbiome will respond to this stressor. We investigated the effects of fertilization on the physiology, morphology and microbiome of eelgrass (Zostera marina) cultivated over 4 weeks in mesocosms. We analyzed the community structure associated with eelgrass leaf, root and rhizosphere microbiomes, and of communities from water column and bulk sediment using 16S rRNA amplicon sequencing. Fertilization led to a higher number of leaves compared with that of eelgrass kept under ambient conditions. Additionally, fertilization led to enrichment of sulfur and nitrogen bacteria in belowground communities. These results suggest nutrient enrichment can stimulate belowground biogeochemical cycling, potentially exacerbating sulfide toxicity in sediments and decreasing future carbon sequestration stocks.
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Affiliation(s)
- Lu Wang
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
| | - Fiona Tomas
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, USA.,Instituto Mediterráneo de Estudios Avanzados (CSIC-UIB), C/ Miquel Marquès, 21 07190 Esporles Illes Balears, Spain
| | - Ryan S Mueller
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
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Wang X, Yan J, Bai J, Shao D, Cui B. Effects of interactions between macroalgae and seagrass on the distribution of macrobenthic invertebrate communities at the Yellow River Estuary, China. MARINE POLLUTION BULLETIN 2021; 164:112057. [PMID: 33515816 DOI: 10.1016/j.marpolbul.2021.112057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 08/20/2020] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
Algae-dominance in seagrass beds has been well recognized, however, the competitive relationship between seagrass and macroalgae along land-sea gradients and their ecological effects has received little attention. In this study, a field survey was conducted at the Yellow River Estuary to investigate the effects of macroalgal proliferation on seagrass and macrobenthic invertebrate communities. Our results suggested that strong competitive interaction existed between the two primary producers, and the positive or negative effects of macroalgae on seagrass growth varied along land-sea gradient. Furthermore, the dominant controlling factors on the biomass, density and diversity of macrobenthic invertebrate communities were found to vary accordingly, i.e., from features of the primary producers in the nearshore where macroalgae suppressed seagrass growth to hydrodynamic disturbance in the offshore where macroalgae facilitated seagrass growth. Our study emphasizes the importance to integrate interspecific competition into ecosystem-based management of seagrass ecosystem, and provides references for additional ecological indicators.
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Affiliation(s)
- Xinyan Wang
- State Key Laboratory of Water Environment Simulation & School of Environment, Beijing Normal University, Beijing 100875, China; Yellow River Estuary Wetland Ecosystem Observation and Research Station, Ministry of Education, Shandong, China
| | - Jiaguo Yan
- State Key Laboratory of Water Environment Simulation & School of Environment, Beijing Normal University, Beijing 100875, China; Yellow River Estuary Wetland Ecosystem Observation and Research Station, Ministry of Education, Shandong, China
| | - Junhong Bai
- State Key Laboratory of Water Environment Simulation & School of Environment, Beijing Normal University, Beijing 100875, China; Yellow River Estuary Wetland Ecosystem Observation and Research Station, Ministry of Education, Shandong, China
| | - Dongdong Shao
- State Key Laboratory of Water Environment Simulation & School of Environment, Beijing Normal University, Beijing 100875, China; Yellow River Estuary Wetland Ecosystem Observation and Research Station, Ministry of Education, Shandong, China; Tang Scholar, Beijing Normal University, Beijing, China.
| | - Baoshan Cui
- State Key Laboratory of Water Environment Simulation & School of Environment, Beijing Normal University, Beijing 100875, China; Yellow River Estuary Wetland Ecosystem Observation and Research Station, Ministry of Education, Shandong, China
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Developing an Introductory UAV/Drone Mapping Training Program for Seagrass Monitoring and Research. DRONES 2020. [DOI: 10.3390/drones4040070] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Unoccupied Aerial Vehicles (UAVs), or drone technologies, with their high spatial resolution, temporal flexibility, and ability to repeat photogrammetry, afford a significant advancement in other remote sensing approaches for coastal mapping, habitat monitoring, and environmental management. However, geographical drone mapping and in situ fieldwork often come with a steep learning curve requiring a background in drone operations, Geographic Information Systems (GIS), remote sensing and related analytical techniques. Such a learning curve can be an obstacle for field implementation for researchers, community organizations and citizen scientists wishing to include introductory drone operations into their work. In this study, we develop a comprehensive drone training program for research partners and community members to use cost-effective, consumer-quality drones to engage in introductory drone mapping of coastal seagrass monitoring sites along the west coast of North America. As a first step toward a longer-term Public Participation GIS process in the study area, the training program includes lessons for beginner drone users related to flying drones, autonomous route planning and mapping, field safety, GIS analysis, image correction and processing, and Federal Aviation Administration (FAA) certification and regulations. Training our research partners and students, who are in most cases novice users, is the first step in a larger process to increase participation in a broader project for seagrass monitoring in our case study. While our training program originated in the United States, we discuss our experiences for research partners and communities around the globe to become more confident in introductory drone operations for basic science. In particular, our work targets novice users without a strong background in geographic research or remote sensing. Such training provides technical guidance on the implementation of a drone mapping program for coastal research, and synthesizes our approaches to provide broad guidance for using drones in support of a developing Public Participation GIS process.
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Biogeography of Macrophyte Elemental Composition: Spatiotemporal Modification of Species-Level Traits. Ecosystems 2020. [DOI: 10.1007/s10021-020-00484-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Lanari M, S Copertino M, Colling LA, C Bom F. The impact of short-term depositions of macroalgal blooms on widgeon-grass meadows in a river-dominated estuary. HARMFUL ALGAE 2018; 78:36-46. [PMID: 30196923 DOI: 10.1016/j.hal.2018.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 07/13/2018] [Accepted: 07/17/2018] [Indexed: 06/08/2023]
Abstract
Macroalgal blooms can trigger adverse biogeochemical conditions at the sediment-water interface of shallow coastal areas, hence threatening critical habitats such as seagrasses meadows. The direction and magnitude of macroalgal blooms impacts on the aquatic ecosystem can be context-dependent, varying according to the local hydrodynamic conditions. Thus, studies investigating the impacts of stagnant algal depositions on the benthos may fail to address realistic situations and interactions which are common in well-flushed systems. This is especially true for the South America coast, where no study has investigated the effects of macroalgal blooms on seagrasses meadows. To fully understand the impacts of macroalgal blooms on sediment biogeochemistry and seagrass habitats across distinct environmental conditions and biogeographical regions, two independent, complementary field experiments replicated the natural temporal patterns of drift macroalgal mats depositions on unvegetated and vegetated (Ruppia maritima meadows) shoals of the Patos Lagoon estuary (PLE), a subtropical, high hydrodynamic system in southern Brazil. Transitory depositions of algal mats alleviated deleterious biogeochemical conditions in the sediment-water interface of unvegetated bottoms. Nevertheless, these unstable algal depositions promoted significant reductions in R. maritima biomass, by reducing their shoot height and density, and rhizome length. That plant biomass reductions were followed by a decrease in the abundance of the dominant infaunal tanaidacean Monokalliapseudes schubarti, indicating that algal impacts on seagrasses were transferred to higher trophic levels. Our results suggest that, although unstable deposition of drift algal mats can attenuate potential adverse impacts at the sediment-water interface, the physical stress during mats advection can still trigger small seagrass losses. This process may diminish the resilience of R. maritima meadows in the PLE, with impacts on estuarine nutrient cycling and secondary production. We conclude that, although harmful drift macroalgal blooms area global phenomenon, the mechanisms through which macroalgae impair seagrass habitats may vary according to the environmental context. Therefore, further studies are necessary to identify the underlying mechanisms of drift macroalgae-seagrass-macrofauna interactions in high hydrodynamic systems and their generality across distinct biogeographical areas.
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Affiliation(s)
- Marianna Lanari
- Institute of Oceanography, Federal University of Rio Grande, Rio Grande, RS, 93203-900, Brazil.
| | - Margareth S Copertino
- Institute of Oceanography, Federal University of Rio Grande, Rio Grande, RS, 93203-900, Brazil
| | - Leonir A Colling
- Institute of Oceanography, Federal University of Rio Grande, Rio Grande, RS, 93203-900, Brazil
| | - Fábio C Bom
- Institute of Oceanography, Federal University of Rio Grande, Rio Grande, RS, 93203-900, Brazil
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Bittick SJ, Sutula M, Fong P. A tale of two algal blooms: Negative and predictable effects of two common bloom-forming macroalgae on seagrass and epiphytes. MARINE ENVIRONMENTAL RESEARCH 2018; 140:1-9. [PMID: 29807625 DOI: 10.1016/j.marenvres.2018.05.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 04/14/2018] [Accepted: 05/20/2018] [Indexed: 05/20/2023]
Abstract
Recent evidence suggests macroalgal blooms may play a role in the worldwide decline in seagrass, but the shape of the functional relationship between seagrass health and dominant bloom-forming macroalgae is poorly characterized. We tested whether the impact of varying abundances of two cosmopolitan bloom-forming macroalgal genera caused linear/quasi-linear or sudden threshold changes in measures of eelgrass, Zostera marina, meadow health. We conducted two caging experiments in a shallow Z. marina bed (∼1 m depth) in Bodega Harbor, California, USA where we maintained six densities within the range of natural abundances of macroalgae, Ulva (0-4.0 kg m-2) and Gracilariopsis (0-2.0 kg m-2), as well as uncaged controls over a 10-week period. Shoot density, blade growth, and epiphyte load were measured every two weeks and algal treatments reset. We did not find support for threshold transitions between algal abundance and measures of seagrass bed health using sigmoidal and broken-stick regression analyses for each data set; these models are commonly used to identify threshold patterns in ecological shifts. Instead, final measurements of shoot density and epiphyte load were best modelled as linear or slightly non-linear declines with increasing Ulva abundance. A negative linear relationship also existed between shoot density and Gracilariopsis abundance and a trend towards linear negative effects on epiphyte load. The similar shape of these functional relationships across different types of algae suggests the relationship may be generalizable. At algal abundances that are commonly observed, we found smooth and predictable negative impacts to Z. marina by decline in shoot density and potential impacts to food webs by loss of epiphytes rather than sudden threshold shifts or "ecological surprises". Our work contrasts with the growing body of literature suggesting highly non-linear shifts in response to human impact; thus, it is important to broaden understanding of shifts to more than just pattern but to the processes that drive different patterns of shifts.
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Affiliation(s)
- Sarah Joy Bittick
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA.
| | - M Sutula
- Southern California Coastal Water Research Project, 3535 Harbor Boulevard, Costa Mesa, CA 92626, USA
| | - P Fong
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
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Nelson WG. An evaluation of factors controlling the abundance of epiphytes on Zostera marina along an estuarine gradient in Yaquina Bay, Oregon, USA. AQUATIC BOTANY 2018; 148:53-63. [PMID: 29910529 PMCID: PMC5998682 DOI: 10.1016/j.aquabot.2018.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Epiphytes on seagrass (Zostera marina) growing in the lower intertidal were examined along an estuarine gradient within Yaquina Bay, Oregon over a period of 4 years. The Yaquina Estuary receives high levels of nutrients from the watershed during the wet season and from the ocean during the dry season. Mean epiphyte biomass per unit seagrass leaf surface area (epiphyte load) peaked during the summer, and thus epiphyte load was higher during dry season than wet season in both marine and riverine dominated regions. Epiphyte load was greater in marine than in riverine dominated areas in both wet and dry seasons, although only dry season differences were significant. There was no evidence that grazers controlled epiphyte load differences. Annual DIN concentration was inversely related to epiphyte load, principally because of elevated wet season dissolved inorganic nitrogen from river inputs. While there was a positive annual relation of epiphyte load to PO4 concentration, it is not clear that phosphorus becomes a limiting nutrient for epiphyte growth. Water column light attenuation tends to increase linearly with distance from the estuary mouth, while both epiphyte load and Z. marina biomass tend to decrease. Both seagrass and seagrass epiphytes may be increasingly light limited in the upper estuary, and thus, epiphyte loads may have proportionally more impact on seagrass occurrence in this estuarine region.
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Affiliation(s)
- Walter G Nelson
- United States Environmental Protection Agency, Western Ecology Division, Pacific Coastal Ecology Branch, 2111 SE Marine Science Drive, Newport, OR, 97365, USA
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Nelson W, Sullivan G. Effects of microtopographic variation and macroalgal cover on morphometrics and survival of the annual form of eelgrass ( Zostera marina). AQUATIC BOTANY 2018; 145:37-44. [PMID: 29290642 PMCID: PMC5746198 DOI: 10.1016/j.aquabot.2017.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A disjunct population of the annual form of the seagrass Zostera marina that occurred in the upper intertidal zone of Yaquina Bay, Oregon was sampled to determine whether there were differences in recruitment, growth, survivorship and morphology associated with microtopographic location on the sand flat. Population responses of seagrass found in areas differing by only a few cm in vertical elevation were compared. There was higher plant abundance and higher number of shoots per plant in microtopographic low areas. Plants in lower areas also had significantly longer shoots, greater total above ground biomass, greater biomass per shoot, and greater biomass of reproductive spathes than plants growing in immediately adjacent, microtopographic high areas. Cover of green macroalgae was higher and accumulated more rapidly in microtopographic high areas as compared to low areas, and both spatially and temporally was correlated with decreased recruitment and increased plant loss in these slightly elevated areas. While impacts of desiccation may have played some role in determining the influence of microtopographic variation on the annual Z. marina population, macroalgal effects appear to be predominant.
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Affiliation(s)
- W.G. Nelson
- Corresponding Author: Pacific Coastal Ecology Branch, U.S. EPA,
2111 S.E. Marine Science Dr., Newport OR 97366,
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Kaldy JE, Brown CA, Nelson WG, Frazier M. Macrophyte Community Response to Nitrogen Loading and Thermal Stressors in Rapidly Flushed Mesocosm Systems. JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY 2017; 497:107-119. [PMID: 29225370 PMCID: PMC5716360 DOI: 10.1016/j.jembe.2017.09.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A mesocosm system was developed to simulate estuarine conditions characteristic of short water-residence time ecosystems of the Pacific Coast of North America, and used to evaluate the response of multiple macrophyte metrics to gradients of NO3 loading and temperature. Replicated experiments found that few responses could be directly attributed to NO3 loading up to 6 x ambient. Some response metrics exhibited weak relationships with nutrient loading but could not be resolved with available statistical power. While direct nutrient responses were found for some species-specific metrics (e.g. green macroalgal growth and biomass, tissue N%, etc.), many patterns were confounded with temperature. Temperature generally had a larger effect on response metrics than did nutrient load. Experimental macrophyte communities exhibited community shifts consistent with the predicted effects of nutrient loading at 20 °C, but there was no evidence of other eutrophication symptoms (phytoplankton blooms or hypoxia) due to the short system-residence time. The Z. marina Nutrient Pollution Index (NPI) tracked the NO3 gradient at 10 °C, but exhibited no response at 20 °C, which may limit the utility of this metric in areas with marked thermal seasonality. Results suggest that teasing apart the influence of temperature and nutrients on the expression of eutrophication symptoms will require complex multi-stressor experiments and the use of indicators that are sensitive across a broad range of conditions.
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Affiliation(s)
- James E. Kaldy
- Western Ecology Division, US – EPA, 2111 SE Marine Science Dr., Newport, OR, USA
- Corresponding author: , Phone: 541-867-4026
| | - Cheryl A. Brown
- Western Ecology Division, US – EPA, 2111 SE Marine Science Dr., Newport, OR, USA
| | - Walter G. Nelson
- Western Ecology Division, US – EPA, 2111 SE Marine Science Dr., Newport, OR, USA
| | - Melanie Frazier
- National Center for Ecological Analysis and Synthesis, 735 State St., Santa Barbara, CA, USA
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Green L, Fong P. The good, the bad and theUlva: the density dependent role of macroalgal subsidies in influencing diversity and trophic structure of an estuarine community. OIKOS 2015. [DOI: 10.1111/oik.02860] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lauri Green
- Dept of Ecology and Evolutionary Biology; UCLA; 621 Charles E. Young Dr. South Los Angeles CA 90095 USA
| | - Peggy Fong
- Dept of Ecology and Evolutionary Biology; UCLA; 621 Charles E. Young Dr. South Los Angeles CA 90095 USA
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