ISSN:
1432-1793
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Several field experiments have shown that bottom sediment type affects growth of the hard clam, Mercenaria mercenaria. A previous manipulative field experiment carried out within a moderate range of tidal current speed/seston concentration regimes in Great Sound, a coastal lagoon in southern New Jersey, USA, indicated that growth of M. mercenaria was more influenced by horizontal seston fluxes than sediment type. The present descriptive/correlative study was also conducted at Great Sound, during 1985 and 1986, and was designed to quantify the relationships between shell growth of M. mercenaria and a wide range of levels of tidal currents, seston, and bottom sediments. It showed: (1) near-bottom tidal currents and seston were best correlated with growth when combined as a horizontal seston flux rate, [i.e., current speed (cm s-1) x seston concentration dry wt cm-3=dry wt seston cm-2 s-1]; (2) the correlation between seston fluxes and growth was positive to some point, then became negative with further increases in seston fluxes; (3) sediment characteristics were correlated with growth; and (4) there may be an interaction between sediment characteristics and seston fluxes as they affect growth. These findings suggested a statistical model of the general form: $$\eqalign{ & SG = B_0 + B_1 (X_1 ) + B_2 (X_1 )^2 \cr & {\rm{ }} + B_3 (X_2 ) + B_4 (X_1 )(X_2 ) + E, \cr}$$ where SG=shell growth; B o=y-intercept; B i =coefficient of the ith term; X 1=mean horizontal seston flux; X 2=sediment characteristic; E=error term. Multiple regression techniques were used to determine values for the coefficients in the model, and associated R 2 values. R 2 values for models using various shell growth measurements, seston fluxes, and bottom sediment characteristics ranged from 0.69 (P=0.35) to 0.90 (P=0.07). Maximum growth occurred at moderate seston flux rates (e.g. 90 to 130 mg particulate organic matter cm-2 s-1) combined with sand sediments. Increased or decreased (relative to moderate rates) seston fluxes, and/or decreased grain size of the bottom sediments, resulted in reduced growth.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00391327
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