Persistence of Zostera marina L. (eelgrass) seeds in the sediment seed bank Jessie C. Jarvis a, ⁎, Kenneth A. Moore a , W. Judson Kenworthy b,1 a Virginia Institute of Marine Science, College of William & Mary, P.O. Box 1346, Gloucester Point, VA 23062, USA b Center for Coastal Fisheries and Habitat Research, NCCOS, NOS, NOAA, Beaufort NC 28516, USA abstract article info Article history: Received 30 January 2014 Received in revised form 20 May 2014 Accepted 25 May 2014 Available online xxxx Keywords: Seagrass Zostera marina Mixed-annual Seed bank Viability Persistence Two separate field experiments in the Newport River/Back Sound, North Carolina (NC) and the lower Chesapeake Bay (CB), Virginia were conducted in 2007 and 2008 to quantify the effects of time (6, 12, 15 months), seed source (mixed-annual, perennial NC; perennial CB), site (local environmental factors), and sediment type (fine, coarse) on the persistence of Zostera marina seeds in the sediment seed bank. It is here, at the southern limit of the species distribution along the western Atlantic, that the probability of population loss may be high and the importance of a seed bank in the resilience and recovery of these populations great. Experimental results indicate that viability of both NC and CB seeds decreased significantly after just 6 months in the sediment follow- ing the seasonal period of maximum germination and continued to decline over time with no seeds viable remaining in CB cores and b 5% of seeds remaining viable after 15 months in NC treatments. In these experiments time was the overriding factor affecting the persistence Z. marina seed banks for all treatments in both NC and CB and viability was not significantly affected by seed source, site, or sediment type. Based on the results of the in situ experiments, mixed-annual and perennial Zostera marina populations in North Carolina and perennial popula- tions in Virginia produce transient seed banks (seeds viable b 12 months). The lack of a persistent seed bank may reduce the resilience of Z. marina at the limits of the species distribution to repeated stress events. As a result these populations may be particularly susceptible to disturbance with only a limited capacity for recovery if sexual reproduction is impaired. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Zostera marina (eelgrass) is a dominant and ecologically important seagrass species distributed circumglobally in temperate coastal envi- ronments in the Northern Hemisphere (den Hartog, 1970; Green and Short, 2003; Short and Moore, 2006). Eelgrass meadows provide essen- tial habitat for both economically and ecologically important faunal spe- cies (Heck et al., 2008; Thayer et al., 1984), improve local water quality conditions (Dennison et al., 1993), and can be an important carbon sink in coastal environments (Fourqurean et al., 2012). Many seagrass popu- lations, including those containing Z. marina, are rapidly declining in re- sponse to anthropogenic disturbances (Costello and Kenworthy, 2011; Orth et al., 2006; Short and Wyllie-Echeverria, 1996; Waycott et al., 2009). During the past several decades it has become increasingly im- portant to understand what factors are influencing seagrass population fluctuations and their resilience to stressors, as well as their recovery from chronic and short term disturbances. Across their broad geographic distribution, Z. marina populations ex- press a range of different life history strategies from perennial to annual growth forms (den Hartog, 1970; Jarvis et al., 2012; Setchell, 1929; van Lent and Verschuure, 1994). While asexual reproduction is impor- tant for sustaining persistent beds on local scales (den Hartog, 1970; Setchell, 1929; Thayer et al., 1984; Tomlinson, 1974), sexual reproduc- tion via seed production is critical for maintaining genetic diversity (Reynolds et al., 2013), dispersing populations over short (m) and long (km) distances (Harwell and Orth, 2002; Kendrick et al., 2012; Orth et al., 1994), and as a source of propagules for the sediment seed bank that can replenish populations following acute disturbances or long term declines (Jarvis and Moore, 2010; Lee et al., 2007; Plus et al., 2003; Riddin and Adamns, 2009). Of these three features of sexual re- production, the least understood for eelgrass is the sediment seed bank (Orth et al., 2000). Sediment seed banks are formed when seeds are deposited on or in the sediment (Fenner and Thompson, 2005). Negatively buoyant Z. marina seeds that are not removed from the parent bed via dispersal (Harwell and Orth, 2002; Kendrick et al., 2012) are deposited on the sediment surface and generally do not move more than a few meters Journal of Experimental Marine Biology and Ecology 459 (2014) 126–136 ⁎ Corresponding author at: Centre for Tropical Water & Aquatic Ecosystem Research, James Cook University, Cairns Queensland 4870, Australia. Tel.: +61 7 4232 2028; fax: + 61 7 4781 5589. E-mail addresses: jessie.jarvis@jcu.edu.au (J.C. Jarvis), moore@vims.edu (K.A. Moore), Jud.Kenworthy@gmail.com (W. Judson Kenworthy). 1 Present address; 109 Holly Ln, Beaufort, NC 28516. http://dx.doi.org/10.1016/j.jembe.2014.05.024 0022-0981/© 2014 Elsevier B.V. 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