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Menning DM, Gravley HA, Cady MN, Pepin D, Wyllie-Echeverria S, Ward DH, Talbot SL. Metabarcoding of environmental samples suggest wide distribution of eelgrass (Zostera marina) pathogens in the north Pacific. MBMG 2021. [DOI: 10.3897/mbmg.5.62823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Seagrass meadows provide important ecological services to the marine environment but are declining worldwide. Although eelgrass meadows in the north Pacific are thought to be relatively healthy, few studies have assessed the presence of known disease pathogens in these meadows. In a pilot study to test the efficacy of the methods and to provide foundational disease biodiversity data in the north Pacific, we leveraged metabarcoding of environmental DNA extracted from water, sediment, and eelgrass tissue samples collected from five widely distributed eelgrass meadows in Alaska and one in Japan and uncovered wide prevalence of two classes of pathogenic organisms – Labyrinthula zosterae and other associated strains of Labyrinthula, and the Phytophthora/Halophytophthora blight species complex – known to have caused decline in eelgrass (Zostera marina) elsewhere in the species’ global distribution. Although the distribution of these disease organisms is not well understood in the north Pacific, we uncovered the presence of at least one eelgrass pathogen at every locality sampled.
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Groner ML, Burge CA, Cox R, Rivlin ND, Turner M, Van Alstyne KL, Wyllie-Echeverria S, Bucci J, Staudigel P, Friedman CS. Oysters and eelgrass: potential partners in a high pCO 2 ocean. Ecology 2018; 99:1802-1814. [PMID: 29800484 DOI: 10.1002/ecy.2393] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/25/2018] [Accepted: 05/03/2018] [Indexed: 12/23/2022]
Abstract
Climate change is affecting the health and physiology of marine organisms and altering species interactions. Ocean acidification (OA) threatens calcifying organisms such as the Pacific oyster, Crassostrea gigas. In contrast, seagrasses, such as the eelgrass Zostera marina, can benefit from the increase in available carbon for photosynthesis found at a lower seawater pH. Seagrasses can remove dissolved inorganic carbon from OA environments, creating local daytime pH refugia. Pacific oysters may improve the health of eelgrass by filtering out pathogens such as Labyrinthula zosterae (LZ), which causes eelgrass wasting disease (EWD). We examined how co-culture of eelgrass ramets and juvenile oysters affected the health and growth of eelgrass and the mass of oysters under different pCO2 exposures. In Phase I, each species was cultured alone or in co-culture at 12°C across ambient, medium, and high pCO2 conditions, (656, 1,158 and 1,606 μatm pCO2 , respectively). Under high pCO2 , eelgrass grew faster and had less severe EWD (contracted in the field prior to the experiment). Co-culture with oysters also reduced the severity of EWD. While the presence of eelgrass decreased daytime pCO2 , this reduction was not substantial enough to ameliorate the negative impact of high pCO2 on oyster mass. In Phase II, eelgrass alone or oysters and eelgrass in co-culture were held at 15°C under ambient and high pCO2 conditions, (488 and 2,013 μatm pCO2 , respectively). Half of the replicates were challenged with cultured LZ. Concentrations of defensive compounds in eelgrass (total phenolics and tannins), were altered by LZ exposure and pCO2 treatments. Greater pathogen loads and increased EWD severity were detected in LZ exposed eelgrass ramets; EWD severity was reduced at high relative to low pCO2 . Oyster presence did not influence pathogen load or EWD severity; high LZ concentrations in experimental treatments may have masked the effect of this treatment. Collectively, these results indicate that, when exposed to natural concentrations of LZ under high pCO2 conditions, eelgrass can benefit from co-culture with oysters. Further experimentation is necessary to quantify how oysters may benefit from co-culture with eelgrass, examine these interactions in the field and quantify context-dependency.
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Affiliation(s)
- Maya L Groner
- Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave., Charlottetown, Prince Edward Island, C1A 4P3, Canada
| | - Colleen A Burge
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt St., Baltimore, Maryland, 21202, USA
| | - Ruth Cox
- Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave., Charlottetown, Prince Edward Island, C1A 4P3, Canada
| | - Natalie D Rivlin
- Institute of Marine and Environmental Technology, University of Maryland Baltimore County, 701 E Pratt St., Baltimore, Maryland, 21202, USA
| | - Mo Turner
- Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, Washington, 98105, USA
| | - Kathryn L Van Alstyne
- Shannon Point Marine Center, Western Washington University, 1900 Shannon Point Rd., Anacortes, Washington, 98221, USA
| | - Sandy Wyllie-Echeverria
- Friday Harbor Laboratories, University of Washington, 620 University Rd., Friday Harbor, Washington, 98250, USA.,Center for Marine and Environmental Studies, University of the Virgin Islands, 2 John Brewers Bay, St. Thomas, Virgin Islands, 00802, USA
| | - John Bucci
- School of Marine Science and Ocean Engineering, University of New Hampshire, 8 College Rd., Durham, New Hampshire, 03824, USA
| | - Philip Staudigel
- Rosenstiel School for Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, Florida, 33149, USA
| | - Carolyn S Friedman
- Friday Harbor Laboratories, University of Washington, 620 University Rd., Friday Harbor, Washington, 98250, USA.,School of Aquatic & Fishery Sciences, University of Washington, 1122 NE Boat St., Seattle, Washington, 98105, USA
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Inaba N, Trainer VL, Onishi Y, Ishii KI, Wyllie-Echeverria S, Imai I. Algicidal and growth-inhibiting bacteria associated with seagrass and macroalgae beds in Puget Sound, WA, USA. Harmful Algae 2017; 62:136-147. [PMID: 28118888 DOI: 10.1016/j.hal.2016.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [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: 06/22/2015] [Revised: 04/07/2016] [Accepted: 04/07/2016] [Indexed: 06/06/2023]
Abstract
The algicidal and growth-inhibiting bacteria associated with seagrasses and macroalgae were characterized during the summer of 2012 and 2013 throughout Puget Sound, WA, USA. In 2012, Heterosigma akashiwo-killing bacteria were observed in concentrations of 2.8×106CFUg-1 wet in the outer organic layer (biofilm) on the common eelgrass (Zostera marina) in north Padilla Bay. Bacteria that inhibited the growth of Alexandrium tamarense were detected within the biofilm formed on the eelgrass canopy at Dumas Bay and North Bay at densities of ∼108CFUg-1 wet weight. Additionally, up to 4100CFUmL-1 of algicidal and growth-inhibiting bacteria affecting both A. tamarense and H. akashiwo were detected in seawater adjacent to seven different eelgrass beds. In 2013, H. akashiwo-killing bacteria were found on Z. marina and Ulva lactuca with the highest densities of ∼108CFUg-1 wet weight at Shallow Bay, Sucia Island. Bacteria that inhibited the growth of H. akashiwo and A. tamarense were also detected on Z. marina and Z. japonica at central Padilla Bay. Heterosigma akashiwo cysts were detected at a concentration of 3400cystsg-1 wet weight in the sediment from Westcott Bay (northern San Juan Island), a location where eelgrass disappeared in 2002. These findings provide new insights on the ecology of algicidal and growth-inhibiting bacteria, and suggest that seagrass and macroalgae provide an environment that may influence the abundance of harmful algae in this region. This work highlights the importance of protection and restoration of native seagrasses and macroalgae in nearshore environments, in particular those regions where shellfish restoration initiatives are in place to satisfy a growing demand for seafood.
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Affiliation(s)
- Nobuharu Inaba
- Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido, 041-8611, Japan.
| | - Vera L Trainer
- Marine Biotoxins Program, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd. E., Seattle, WA, 98112, United States.
| | - Yuka Onishi
- Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido, 041-8611, Japan
| | - Ken-Ichiro Ishii
- Division of Environmental Biotechnology, Graduate School of Global Environmental Study, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Sandy Wyllie-Echeverria
- Friday Harbor Laboratories, College of the Environment, University of Washington, 620 University Road, Friday Harbor, WA, 98250, United States
| | - Ichiro Imai
- Plankton Laboratory, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido, 041-8611, Japan.
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Groner ML, Maynard J, Breyta R, Carnegie RB, Dobson A, Friedman CS, Froelich B, Garren M, Gulland FMD, Heron SF, Noble RT, Revie CW, Shields JD, Vanderstichel R, Weil E, Wyllie-Echeverria S, Harvell CD. Managing marine disease emergencies in an era of rapid change. Philos Trans R Soc Lond B Biol Sci 2016; 371:rstb.2015.0364. [PMID: 26880835 DOI: 10.1098/rstb.2015.0364] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [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: 01/01/2023] Open
Abstract
Infectious marine diseases can decimate populations and are increasing among some taxa due to global change and our increasing reliance on marine environments. Marine diseases become emergencies when significant ecological, economic or social impacts occur. We can prepare for and manage these emergencies through improved surveillance, and the development and iterative refinement of approaches to mitigate disease and its impacts. Improving surveillance requires fast, accurate diagnoses, forecasting disease risk and real-time monitoring of disease-promoting environmental conditions. Diversifying impact mitigation involves increasing host resilience to disease, reducing pathogen abundance and managing environmental factors that facilitate disease. Disease surveillance and mitigation can be adaptive if informed by research advances and catalysed by communication among observers, researchers and decision-makers using information-sharing platforms. Recent increases in the awareness of the threats posed by marine diseases may lead to policy frameworks that facilitate the responses and management that marine disease emergencies require.
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Affiliation(s)
- Maya L Groner
- Centre for Veterinary Epidemiological Research, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Jeffrey Maynard
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA Laboratoire d'Excellence 'CORAIL' USR 3278 CNRS-EPHE, CRIOBE, Papetoai, Moorea, French Polynesia
| | - Rachel Breyta
- School of Aquatic and Fisheries Sciences, University of Washington, Seattle, WA 98195, USA
| | - Ryan B Carnegie
- Department of Aquatic Health Sciences, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062, USA
| | - Andy Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Carolyn S Friedman
- School of Aquatic and Fisheries Sciences, University of Washington, Seattle, WA 98195, USA
| | - Brett Froelich
- Institute of Marine Sciences, University of North Carolina-Chapel Hill, Morehead City, NC 28557, USA
| | - Melissa Garren
- Division of Science and Environmental Policy, California State University Monterey Bay, 100 Campus Center, Seaside, CA 93955, USA
| | | | - Scott F Heron
- NOAA Coral Reef Watch, NESDIS Center for Satellite Applications and Research, 5830 University Research Ct., E/RA3, College Park, MD 20740, USA Marine Geophysical Laboratory, Physics Department, College of Science, Technology and Engineering, James Cook University, Townsville, Queensland 4814, Australia
| | - Rachel T Noble
- Institute of Marine Sciences, University of North Carolina-Chapel Hill, Morehead City, NC 28557, USA
| | - Crawford W Revie
- Centre for Veterinary Epidemiological Research, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Jeffrey D Shields
- Department of Aquatic Health Sciences, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062, USA
| | - Raphaël Vanderstichel
- Centre for Veterinary Epidemiological Research, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Ernesto Weil
- Department of Marine Sciences, University of Puerto Rico, Mayaguez, PR 00680, USA
| | - Sandy Wyllie-Echeverria
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA Center for Marine and Environmental Studies, University of the Virgin Islands, St Thomas, VI 00802, USA
| | - C Drew Harvell
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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Talbot SL, Sage GK, Rearick JR, Fowler MC, Muñiz-Salazar R, Baibak B, Wyllie-Echeverria S, Cabello-Pasini A, Ward DH. The Structure of Genetic Diversity in Eelgrass (Zostera marina L.) along the North Pacific and Bering Sea Coasts of Alaska. PLoS One 2016; 11:e0152701. [PMID: 27104836 PMCID: PMC4841600 DOI: 10.1371/journal.pone.0152701] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/17/2016] [Indexed: 11/25/2022] Open
Abstract
Eelgrass (Zostera marina) populations occupying coastal waters of Alaska are separated by a peninsula and island archipelago into two Large Marine Ecosystems (LMEs). From populations in both LMEs, we characterize genetic diversity, population structure, and polarity in gene flow using nuclear microsatellite fragment and chloroplast and nuclear sequence data. An inverse relationship between genetic diversity and latitude was observed (heterozygosity: R2 = 0.738, P < 0.001; allelic richness: R2 = 0.327, P = 0.047), as was significant genetic partitioning across most sampling sites (θ = 0.302, P < 0.0001). Variance in allele frequency was significantly partitioned by region only in cases when a population geographically in the Gulf of Alaska LME (Kinzarof Lagoon) was instead included with populations in the Eastern Bering Sea LME (θp = 0.128-0.172; P < 0.003), suggesting gene flow between the two LMEs in this region. Gene flow among locales was rarely symmetrical, with notable exceptions generally following net coastal ocean current direction. Genetic data failed to support recent proposals that multiple Zostera species (i.e. Z. japonica and Z. angustifolia) are codistributed with Z. marina in Alaska. Comparative analyses also failed to support the hypothesis that eelgrass populations in the North Atlantic derived from eelgrass retained in northeastern Pacific Last Glacial Maximum refugia. These data suggest northeastern Pacific populations are derived from populations expanding northward from temperate populations following climate amelioration at the terminus of the last Pleistocene glaciation.
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Affiliation(s)
- Sandra L. Talbot
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
| | - George K Sage
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
| | - Jolene R. Rearick
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Meg C. Fowler
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
| | - Raquel Muñiz-Salazar
- Escuela de Ciencias de la Salud, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico
| | - Bethany Baibak
- Biological Sciences, Humboldt State University, Arcata, California, United States of America
| | - Sandy Wyllie-Echeverria
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, United States of America
- Center for Marine and Environmental Studies, University of Virgin Islands, St. Thomas, Virgin Islands, United States of America
| | - Alejandro Cabello-Pasini
- Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, California, Mexico
| | - David H. Ward
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, United States of America
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Groner ML, Burge CA, Kim CJS, Rees E, Van Alstyne KL, Yang S, Wyllie-Echeverria S, Harvell CD. Plant characteristics associated with widespread variation in eelgrass wasting disease. Dis Aquat Organ 2016; 118:159-168. [PMID: 26912046 DOI: 10.3354/dao02962] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Seagrasses are ecosystem engineers of essential marine habitat. Their populations are rapidly declining worldwide. One potential cause of seagrass population declines is wasting disease, which is caused by opportunistic pathogens in the genus Labyrinthula. While infection with these pathogens is common in seagrasses, theory suggests that disease only occurs when environmental stressors cause immunosuppression of the host. Recent evidence suggests that host factors may also contribute to disease caused by opportunistic pathogens. In order to quantify patterns of disease, identify risk factors, and investigate responses to infection, we surveyed shoot density, shoot length, epiphyte load, production of plant defenses (phenols), and wasting disease prevalence in eelgrass Zostera marina across 11 sites in the central Salish Sea (Washington state, USA), a region where both wasting disease and eelgrass declines have been documented. Wasting disease was diagnosed by the presence of necrotic lesions, and Labyrinthula cells were identified with histology. Disease prevalence among sites varied from 6 to 79%. The probability of a shoot being diseased was higher in longer shoots, in patches of higher shoot density, and in shoots with higher levels of biofouling from epiphytes. Phenolic concentration was higher in diseased leaves. We hypothesize that this results from the induction of phenols during infection. Additional research is needed to evaluate whether phenols are an adaptive defense against Labyrinthula infection. The high site-level variation in disease prevalence emphasizes the potential for wasting disease to be causing some of the observed decline in eelgrass beds.
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Affiliation(s)
- Maya L Groner
- Centre for Veterinary and Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
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Groner M, Breyta R, Dobson A, Friedman CS, Froelich B, Garren M, Gulland F, Maynard J, Weil E, Wyllie-Echeverria S, Harvell D. Emergency response for marine diseases. Science 2015; 347:1210. [DOI: 10.1126/science.347.6227.1210-a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Maya Groner
- Centre for Veterinary and Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada
| | - Rachel Breyta
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA
| | - Andy Dobson
- Department of Ecology and Evolutionary Biology, Princeton, NJ 08544, USA
| | - Carolyn S. Friedman
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA
| | - Brett Froelich
- Department of Marine Science, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Melissa Garren
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Jeffrey Maynard
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Ernesto Weil
- Department of Marine Sciences, University of Puerto Rico, Mayaguez, Mayaguez, PR 00680, USA
| | | | - Drew Harvell
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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Ort BS, Cohen CS, Boyer KE, Reynolds LK, Tam SM, Wyllie-Echeverria S. Conservation of eelgrass (Zostera marina) genetic diversity in a mesocosm-based restoration experiment. PLoS One 2014; 9:e89316. [PMID: 24586683 PMCID: PMC3931754 DOI: 10.1371/journal.pone.0089316] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 01/21/2014] [Indexed: 11/18/2022] Open
Abstract
Eelgrass (Zostera marina) forms the foundation of an important shallow coastal community in protected estuaries and bays. Widespread population declines have stimulated restoration efforts, but these have often overlooked the importance of maintaining the evolutionary potential of restored populations by minimizing the reduction in genetic diversity that typically accompanies restoration. In an experiment simulating a small-scale restoration, we tested the effectiveness of a buoy-deployed seeding technique to maintain genetic diversity comparable to the seed source populations. Seeds from three extant source populations in San Francisco Bay were introduced into eighteen flow-through baywater mesocosms. Following seedling establishment, we used seven polymorphic microsatellite loci to compare genetic diversity indices from 128 shoots to those found in the source populations. Importantly, allelic richness and expected heterozygosity were not significantly reduced in the mesocosms, which also preserved the strong population differentiation present among source populations. However, the inbreeding coefficient FIS was elevated in two of the three sets of mesocosms when they were grouped according to their source population. This is probably a Wahlund effect from confining all half-siblings within each spathe to a single mesocosm, elevating FIS when the mesocosms were considered together. The conservation of most alleles and preservation of expected heterozygosity suggests that this seeding technique is an improvement over whole-shoot transplantation in the conservation of genetic diversity in eelgrass restoration efforts.
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Affiliation(s)
- Brian S. Ort
- Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America
- * E-mail:
| | - C. Sarah Cohen
- Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America
| | - Katharyn E. Boyer
- Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America
| | - Laura K. Reynolds
- Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America
| | - Sheh May Tam
- Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, California, United States of America
| | - Sandy Wyllie-Echeverria
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, United States of America
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Groner ML, Burge CA, Couch CS, Kim CJS, Siegmund GF, Singhal S, Smoot SC, Jarrell A, Gaydos JK, Harvell CD, Wyllie-Echeverria S. Host demography influences the prevalence and severity of eelgrass wasting disease. Dis Aquat Organ 2014; 108:165-175. [PMID: 24553421 DOI: 10.3354/dao02709] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Many marine pathogens are opportunists, present in the environment, but causing disease only under certain conditions such as immunosuppression due to environmental stress or host factors such as age. In the temperate eelgrass Zostera marina, the opportunistic labyrinthulomycete pathogen Labyrinthula zosterae is present in many populations and occasionally causes severe epidemics of wasting disease; however, risk factors associated with these epidemics are unknown. We conducted both field surveys and experimental manipulations to examine the effect of leaf age (inferred from leaf size) on wasting disease prevalence and severity in Z. marina across sites in the San Juan Archipelago, Washington, USA. We confirmed that lesions observed in the field were caused by active Labyrinthula infections both by identifying the etiologic agent through histology and by performing inoculations with cultures of Labyrinthula spp. isolated from observed lesions. We found that disease prevalence increased at shallower depths and with greater leaf size at all sites, and this effect was more pronounced at declining sites. Experimental inoculations with 2 strains of L. zosterae confirmed an increased susceptibility of older leaves to infection. Overall, this pattern suggests that mature beds and shallow beds of eelgrass may be especially susceptible to outbreaks of wasting disease. The study highlights the importance of considering host and environmental factors when evaluating risk of disease from opportunistic pathogens.
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Affiliation(s)
- Maya L Groner
- Centre for Veterinary and Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave., Charlottetown, Prince Edward Island, Canada
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Ort BS, Cohen CS, Boyer KE, Wyllie-Echeverria S. Population structure and genetic diversity among eelgrass (Zostera marina) beds and depths in San Francisco Bay. J Hered 2012; 103:533-46. [PMID: 22577191 DOI: 10.1093/jhered/ess022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The seagrass Zostera marina is widely distributed in coastal regions throughout much of the northern hemisphere, forms the foundation of an important ecological habitat, and is suffering population declines. Studies in the Atlantic and Pacific oceans indicate that the degree of population genetic differentiation is location dependent. San Francisco Bay, California, USA, is a high-current, high-wind environment where rafting of seed-bearing shoots has the potential to enhance genetic connectivity among Z. marina populations. We tested Z. marina from six locations, including one annual population, within the bay to assess population differentiation and to compare levels of within-population genetic diversity. Using 7 microsatellite loci, we found significant differentiation among all populations. The annual population had significantly higher clonal diversity than the others but showed no detectible differences in heterozygosity or allelic richness. There appears to be sufficient input of genetic variation through sexual reproduction or immigration into the perennial populations to prevent significant declines in the number and frequency of alleles. In additional depth comparisons, we found differentiation among deep and shallow portions in 1 of 3 beds evaluated. Genetic drift, sweepstakes recruitment, dispersal limitation, and possibly natural selection may have combined to produce genetic differentiation over a spatial scale of 3-30 km in Z. marina. This implies that the scale of genetic differentiation may be smaller than expected for seagrasses in other locations too. We suggest that populations in close proximity may not be interchangeable for use as restoration material.
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Affiliation(s)
- Brian S Ort
- Romberg Tiburon Center for Environmental Studies, Department of Biology, San Francisco State University, Tiburon, CA 94920, USA.
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Lacy JR, Wyllie-Echeverria S. The influence of current speed and vegetation density on flow structure in two macrotidal eelgrass canopies. ACTA ACUST UNITED AC 2011. [DOI: 10.1215/21573698-1152489] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Pergent G, Boudouresque CF, Dumay O, Pergent-Martini C, Wyllie-Echeverria S. Competition between the invasive macrophyte Caulerpa taxifolia and the seagrass Posidonia oceanica: contrasting strategies. BMC Ecol 2008; 8:20. [PMID: 19077242 PMCID: PMC2621152 DOI: 10.1186/1472-6785-8-20] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 12/11/2008] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Plant defense strategy is usually a result of trade-offs between growth and differentiation (i.e. Optimal Defense Theory--ODT, Growth Differentiation Balance hypothesis--GDB, Plant Apparency Theory--PAT). Interaction between the introduced green alga Caulerpa taxifolia and the endemic seagrass Posidonia oceanica in the Mediterranean Sea offers the opportunity to investigate the plausibility of these theories. We have accordingly investigated defense metabolite content and growth year-round, on the basis of an interaction gradient. RESULTS When in competition with P. oceanica, C. taxifolia exhibits increased frond length and decreased Caulerpenyne--CYN content (major terpene compound). In contrast, the length of P. oceanica leaves decreases when in competition with C. taxifolia. However, the turnover is faster, resulting in a reduction of leaf longevity and an increase on the number of leaves produced per year. The primary production is therefore enhanced by the presence of C. taxifolia. While the overall concentration of phenolic compounds does not decline, there is an increase in some phenolic compounds (including ferulic acid and a methyl 12-acetoxyricinoleate) and the density of tannin cells. CONCLUSION Interference between these two species determines the reaction of both, confirming that they compete for space and/or resources. C. taxifolia invests in growth rather than in chemical defense, more or less matching the assumptions of the ODT and/or PAT theories. In contrast, P. oceanica apparently invests in defense rather than growth, as predicted by the GDB hypothesis. However, on the basis of closer scrutiny of our results, the possibility that P. oceanica is successful in finding a compromise between more growth and more defense cannot be ruled out.
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Affiliation(s)
- Gérard Pergent
- UMR CNRS SPE 6134, University of Corsica, Faculty of Sciences, BP 52, 20250 Corte, France
| | | | - Olivier Dumay
- UMR CNRS SPE 6134, University of Corsica, Faculty of Sciences, BP 52, 20250 Corte, France
| | | | - Sandy Wyllie-Echeverria
- University of Washington, UW Botanic Gardens, Center for Urban Horticulture, Box 354115, Seattle, WA 98195, USA
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14
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Olsen JL, Stam WT, Coyer JA, Reusch TBH, Billingham M, Boström C, Calvert E, Christie H, Granger S, la Lumière R, Milchakova N, Oudot-Le Secq MP, Procaccini G, Sanjabi B, Serrao E, Veldsink J, Widdicombe S, Wyllie-Echeverria S. North Atlantic phylogeography and large-scale population differentiation of the seagrass Zostera marina L. Mol Ecol 2005; 13:1923-41. [PMID: 15189214 DOI: 10.1111/j.1365-294x.2004.02205.x] [Citation(s) in RCA: 226] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
As the most widespread seagrass in temperate waters of the Northern Hemisphere, Zostera marina provides a unique opportunity to investigate the extent to which the historical legacy of the last glacial maximum (LGM18 000-10 000 years bp) is detectable in modern population genetic structure. We used sequences from the nuclear rDNA-internal transcribed spacer (ITS) and chloroplast matK-intron, and nine microsatellite loci to survey 49 populations (> 2000 individuals) from throughout the species' range. Minimal sequence variation between Pacific and Atlantic populations combined with biogeographical groupings derived from the microsatellite data, suggest that the trans-Arctic connection is currently open. The east Pacific and west Atlantic are more connected than either is to the east Atlantic. Allelic richness was almost two-fold higher in the Pacific. Populations from putative Atlantic refugia now represent the southern edges of the distribution and are not genetically diverse. Unexpectedly, the highest allelic diversity was observed in the North Sea-Wadden Sea-southwest Baltic region. Except for the Mediterranean and Black Seas, significant isolation-by-distance was found from ~150 to 5000 km. A transition from weak to strong isolation-by-distance occurred at ~150 km among northern European populations suggesting this scale as the natural limit for dispersal within the metapopulation. Links between historical and contemporary processes are discussed in terms of the projected effects of climate change on coastal marine plants. The identification of a high genetic diversity hotspot in Northern Europe provides a basis for restoration decisions.
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Affiliation(s)
- Jeanine L Olsen
- Department of Marine Biology, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
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15
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Abstract
SummaryMany natural and human-induced events create disturbances in seagrasses throughout the world, but quantifying losses of habitat is only beginning. Over the last decade, 90000 ha of seagrass loss have been documented although the actual area lost is certainly greater. Seagrasses, an assemblage of marine flowering plant species, are valuable structural and functional components of coastal ecosystems and are currently experiencing worldwide decline. This group of plants is known to support a complex trophic food web and a detritus-based food chain, as well as to provide sediment and nutrient filtration, sediment stabilization, and breeding and nursery areas for finfish and shellfish.We define disturbance, natural or human-induced, as any event that measurably alters resources available to seagrasses so that a plant response is induced that results in degradation or loss. Applying this definition, we find a common thread in many seemingly unrelated seagrass investigations. We review reports of seagrass loss from both published and ‘grey’ literature and evaluate the types of disturbances that have caused seagrass decline and disappearance. Almost certainly more seagrass has been lost globally than has been documented or even observed, but the lack of comprehensive monitoring and seagrass. mapping makes an assessment of true loss of this resource impossible to determine.Natural disturbances that are most commonly responsible for seagrass loss include hurricanes, earthquakes, disease, and grazing by herbivores. Human activities most affecting seagrasses are those which alter water quality or clarity: nutrient and sediment loading from runoff and sewage disposal, dredging and filling, pollution, upland development, and certain fishing practices. Seagrasses depend on an adequate degree of water clarity to sustain productivity in their submerged environment. Although natural events have been responsible for both large-scale and local losses of seagrass habitat, our evaluation suggests that human population expansion is now the most serious cause of seagrass habitat loss, and specifically that increasing anthropogenic inputs to the coastal oceans are primarily responsible for the world-wide decline in seagrasses.
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