BIOLOGY OF RIBBED MUSSELS
(Geukensia demissa) – With Focus on
Ecology and Life History
Ribbed Mussels are associated with Spartina alterniflora
tidal marshes of eastern
In New York and Southern New England,
mussels are found in dense aggregations of 2000-3000 per M-2 at the
Mussels are primarily attached to each other rather than embedded in sediment (Fell et al, 1982; Bertness & Grosholz, 1984; Franz & Tanacredi, 1993; Franz, 1993. Aggregations of mussels also occur at higher shore levels over the entire vertical gradient occupied by Spartina alterniflora, even into the Spartina patens high marsh zone, above MHW (Bertness & Grosholz, 1985; Franz, Unpubl.), although mussel abundance is sharply reduced at higher shore levels.
is a selective suspension feeder (Espinosa, et al, 2008). In
Ribbed mussels can be aged by back
counting annual growth lines on the shell (Lutz & Castagna,
1980; Brousseau, 1982.) In
Growth in Relation to Shore Level
Shell growth rates (Kuenzler, 1961;Jordan & Valiella, 1982; Bertness & Grosholz, 1985; Franz & Tanacredi, 1993) and shell length-specific body weights (Franz, 1993) decline significantly with increasing shore level, i.e. mussels of any specific shell length have smaller body weights at higher shore levels than at the marsh edge. (Generally, the marsh edge occurs at about half-tide level (half of the vertical distance between MLW and MHW.) However, when mussel clumps are moved down-shore (e.g. to 25% above MLW), shell and body growth rates are higher than at the marsh edge, as would be expected due to longer submersion times per tidal cycle. Although shell and body growth drops rapidly at shore levels above the marsh edge, fitness losses due to growth reduction may be counterbalanced by increased survivorship and longevity (Bertness, 1980; Bertness & Grosholz, 1985; Stiven & Gardner, 1992, Franz, 2001).
Recruitment and Survivorship
At the marsh edge in Jamaica Bay,
mortality rates of juveniles in the year following settlement averages about
55%, and is particularly sensitive to the severity of winter icing on the marsh
(Franz, 2001.) In Jamaica Bay, mussel
populations at the marsh edge are composed of 6 or 7 year classes, with
decreasing proportions with increasing age. Higher on the shore, the abundance
of mussels is much lower than at the edge but additional older age classes are
often present, with some mussels reaching 15 years or older. In
The general absence of mussels below
mid-shore levels in
Reproduction in Relation to Shore Level
Ribbed mussels have separate sexes, In spring and
early summer, gonad tubules migrate into the mantle, which becomes
thickened. Sex can be determined by
the color of the mantle (creamy yellowish-white in males; chocolate brown in
females.) Gametogenesis begin in early spring and, in
While almost all mussels from the edge population become reproductive in their second year, less than 15% of the higher shore level mussels do so, and even the following year, the frequency of maturation is less than 100%. For the reproductive period June through August, sexual maturation in Geukensia demissa primarily is determined by body weight. At the marsh edge, where submergence times and food abundance are highest, virtually all mussels mature during their second growing season, and some which settle early in the summer may become sexually mature late in their first season. At the higher site, where mussels are food-limited due to shorter feeding times and pre-filtration of tidal flow by mussels living lower on the shore, slower somatic growth rates result in a delay in maturation of one additional year.
Taxonomy and Distribution
Populations of Geukensia
demissa (Dillwyn) live predominantly intertidally in salt marshes from the Gulf of St. Lawrence
A subspecies, G. d. granosissima (Sowerby) is
distributed from both coasts of
Although not taxonomically significant, Fields et al
(2012) show that based on variation in protein expression, northern populations of G.
Importance of Mussels
Previous studies on the ecology of Geukensia demissa have emphasized their ecological roles in affecting nutrient dynamics of the marsh and estuary (Kuenzler, 1961a,b; Jordan and Valiela, 1982), their role in affecting structure of the water-column microbiota (Kemp, Newell & Krambeck, 1990), their interrelationships with the marsh grass Spartina alterniflora , their significance in affecting the physical structure of the marsh (Bertness, 1985), and the effects of shore level, mussel density, and mussel dispersion patterns on mussel growth (Bertness, 1980; Bertness and Grosholz, 1985; Borrero, 1987; Borero and Hilbish, 1988; Lin, 1989; Stiven and Gardner, 1992; Franz, 1993, 1997) or reproductive effort.
is clear that ribbed mussels are major – if not the dominant - suspension-feeders
the highly eutrophic and nitrogen-loaded
stored in organic
sediment in the marsh may be released into the Bay when marsh sediments erode,
a process which is occurring rapidly in
The implication of high and increasing mussel densities for marsh loss remains uncertain. Mussels armor and protect the marsh edge from erosion in the short term, (mussel aggregations are usually the last remnant of the marsh edge to disappear.) Biodeposition rates attributed to feeding processes of ribbed mussels are high, and in some locations may account for most if not all marsh accretion, particularly in summer (Smith & Frey, 1985.) However, it is possible that dense mussel concentrations may also contribute to destabilization of marsh sediments over the longer term. My own studies have shown that biodeposition by mussels is sufficient to produce elevations at the marsh edge (mussel berms) and that pools of standing water may form behind these elevations which do not drain on ebb tide. However, the importance of mussel berms and marsh pools for erosion in the longer term is uncertain. These studies do emphasize the important role of mussels in facilitating biodeposition at the marsh edge. Some of these biosediments wash off the marsh on the ebb tide and are exported back into the Bay, whereas some are retained on the marsh. Whether the marsh interior benefits from increased biodeposition, and whether these materials compensate for possible reduction in natural sediment trapping remain unknown.
Ribbed Mussel References Cited Above
Benotti, M.J., Abbene, Irene., and Terracciano, S.A., 2007, Nutrient Loading in Jamaica Bay, Long Island, New York: Predevelopment to 2005: U.S. Geological Survey Scientific Investigations Report 2007–5051, 17 p, online only.
Bertness, M.D., 1980. Growth and mortality of the ribbed mussel Geukensia demissa (Bivalvia: Dreissenacea). The Veliger 23: 62-69.
Bertness, M.D. and E. Grosholz, 1985. Population dynamics of the ribbed mussel, Geukensia demissa : The costs and benefits of an aggregated distribution. Oecologia 67:192-204.
Blackwell, J.F., L.F. Gainey, Jr. & M. J. Greenbert, 1977. Shell ultrastructure in two subspecies of the ribbed mussel, Geukensia demissa (Dillwyn, 1817) The Biological Bulletin 152: 1-11.
Borrero, F.J. & T.J. Hilbish, 1988. Temporal variation in shell and soft tissue growth of the mussel Geukensia demissa. Marine Ecology Progress Series 42: 9-15.
Brousseau, D.J., 1982. Gametogenesis and spawning in a population of Geukensia demissa (Pelecypoda: Mytilidae) from Westport, Connecticut. The Veliger 24: 247-251.
Castagna, M. and P. Chanley, 1973. Salinity tolerance of some marine bivalves from inshore and estuarine environments in Virginia waters of the western Mid- Atlantic coast. Malacologia 12: 47-96.
Chintala, M.M., C. Wigand & G. Thursby, 2006. Comparison of Geukensia demissa populations in Rhode Island fringe marshes with varying nitrogen loads. Marine Ecol. Prog. Ser. 320: 101-108.
Espinosa, E. P., B. Allam and S. E. Ford, 2008. Particle selection in the ribbed mussel Geukensia demissa and the Eastern oyster Crassostrea virginica: Effect of microalgae growth stage. Estuarine, Coastal and Shelf Science 79: 1–6.
Fields, P.A., M.C. Kelly & K.R. Karch, 2012. Latitudinal variation in protein expression after heat stress in the salt marsh mussel Geukensia demissa. Integr. Comp. Biol. 52: 636-647.
Franz, D.R. and J.T. Tanacredi, 1993. Variability in growth and age structure among populations of ribbed mussels Geukensia demissa (Dillwyn)(Bivalvia; Mytilidae), in Jamaica Bay, New York (Gatewaya NRA). The Veliger 36: 220- 227.
Franz, D.R., 1993. Allometry of shell and body weight in relation to shore level in the intertidal bivalve Geukensia demissa (Bivalvia: Mytilidae). Journal Experimental Marine Biology Ecology 174: 193-207.
Franz, D.R., 1996. Size and age at first reproduction of the ribbed mussel Geukensia demissa (Dillwyn) in relation to shore level in a New York salt marsh. Journ. Experimental Marine Biology Ecology 205: 1-13.
Franz, D.R., 1997. Resource alloacation in the intertidal salt-marsh mussel Geukensia demissa in relation to shore level. Estuaries 20: 134-148.
Franz, D.R., 2001. Recruitment, survivorship, and age structure of a New York Ribbed Mussel population (Geukensia demissa) in relation to shore level - a nine year study. Estuaries 24: 319-327
Jordan, T.E. and I. Valiela, 1982. A nitrogen budget of the ribbed mussel, Geukensia demissa, and its significance in nitrogen flow in a New England salt marsh. Limnology and Oceanography 27: 75-90.
Jost, J. and B. Helmuth, 2007. Morphological and ecological determinants of body temperature of Geukensia demissa, the Atlantic ribbed mussel, and their effects on mussel mortality. Biological Bulletin 231(2): 141-151.
Kemp, P.F., S.Y Newall, and C. Krambeck, 1990. Effects of filter-feeding by the ribbed mussel Geukensia demissa on the water-column microbiota of Spartina alterniflora saltmarsh. Marine Ecology Progress Series 50: 119-131.
Kreeger, D.A., R.I.E. Newell and C. J. Langdon, 1990. Effects of tidal exposureon utilization of dietary lignocellulos by the ribbed mussel Geukensia demissa (Dillwyn) (Mollusca: Bivalvia) Journal Experimental Marine Biology Ecology 144: 85-100.
Kreeger, D.A. and R.I.E. Newell, 1996. Ingestion and assimilation of carbon from cellulolytic bacteria and heterotrophic flagellates by the mussels Geukensia demissa and Mytilus edulis (Bivalvia, Mollusca). Aquatic Microbial Ecology 11L 205-214.
Kuenzler, E.J., 1961. Structure and energy flow of a mussel population in a Georgia salt marsh. Limnology and Oceanography 6: 191-204.
Lutz, R.A. and M. Castagna, 1980. Age composition and growth rate of a mussel Geukensia demissa) population in a Virginia salt marsh. Journal Molluscan Studies 46: 106-11
McKinney, R.A., W.G. Nelson, M.A. Charpentier & C. Wigand, 2001. Ribbed Mussel nitrogen isotope signatures reflect nitrogen sources in coastal salt marshes. Ecological Applications 11(1): 203-214.
Nielsen, K.J. and D.R. Franz, 1995. The influence of adult conspecifics and shore level on recruitment of the ribbed mussel Geukensia demissa (Dillwyn) in Jamaica Bay, NY. Journal Experimental Marine Biology Ecology 188: 89-98.
Peterson, W.T. and H.,G. Dam, 1986. Hydrograpy and plankton of Jamaica Bay, New York. Gateway Institute for Natural Resource Science, US-NPS, Gate-N-021-III 21 pp.
Smith, J.M. and R.W. Frey, 1985. Biodeposition by the ribbed mussel Geukensia demissa in a salt marsh, Sapelo Island, Georgia. Journal Sedimentary Research 55: 817-828.
Stiven, A.E. and S.A. Gardner, 1992. Population processes in the ribbed mussel Geukensia demissa (Dillwyn) in a North Carolina salt marsh tidal gradient: spatial pattern, predation, growth and mortality. Journal Experimental Marine Biology Ecology 160: 81-102.
West, D.L. and A. H. Williams. 1986. Predation by Callinectes sapidus (Rathbun) within Spartina alterniflora (Loisel) marshes. Journal Experimental Marine Biology Ecology 100: 75-95.
Wright, R.T., R.B. Coffin, C.P. Ersing and D. Pearson, 1982. Field and laboratory measurements of bivalve filtration of natural marine bacterioplankton. Limnology and Oceanography 27 :91-98.