Physical and Ecological Responses of Sandy Beaches to the 1997–98 El Niño

Marine Macrophyte Wrack Inputs and Dissolved Nutrients in Beach Sands

“…The interaction of tidal forcing/drainage, sediment dynamics, and erosive events will strongly affect release and transport of dissolved nutrients from beach aquifers, as will interactions with terrestrial groundwater sources when present. Given the large seasonal changes in beach widths and sand volumes characteristic of the study area (Revell et al 2011) and the regular occurrence of a seasonal minima in beach sand levels in the spring months , we expect high temporal variability in the detrital loading, nutrient processing, and subsequent availability of wrackderived dissolved nutrients to nearshore waters. To evaluate the relative importance of this source of nutrients to nearshore waters and primary producers, further study of biogeochemical processing, the dynamics of release, and the realized transport rates of dissolved nutrients from the shallow unconfined aquifers of sandy beaches to the nearshore ocean through porous beach sand is needed.…”

“…We suggest this value is likely a considerable underestimate as macrophyte wrack input rates were measured in summer when wave energy is low and seasonal peaks in wrack abundance on beaches generally occur in the fall in the study area (Revell et al 2011). A dry mass input of 50 kg m −1 year −1 was estimated using a 10:1 ratio for wet/dry weight for M. pyrifera (Reed et al 2008).…”

“…Although no information on groundwater was collected or available, the direct influence of terrestrial freshwater runoff and groundwater on intertidal pore water was generally expected to be reduced at this time of year in the study area. Beaches in the study region generally reach peak seasonal sand accumulation and volumes by late summer (Revell et al 2011). On each beach, we established three transects extending from the landward boundary of the beach (the lowest edge of terrestrial vegetation or the base of the sea bluff) to the swash level.…”

“…For example, estimated annual inputs of up to 1,800 kg wet wt m −1 of shoreline have been reported for kelps (Griffiths and Stenton-Dozey 1981;Koop et al 1982). Spatial and temporal variability of these inputs and standing stocks can also be high in response to both environmental and anthropogenic factors (e.g., Dugan et al 2003;Dugan et al 2008;Orr et al 2005;Revell et al 2011). Giant kelp, Macrocystis pyrifera, is a major component of the macrophyte subsidies that strand on sandy beaches in southern California Lastra et al 2008) where inputs have been estimated to exceed 450 kg wet wt m −1 year −1 (Hayes 1974).…”

Impacts of climate change on biodiversity in Israel: an expert assessment approach

“…New platforms will not be formed at higher shore levels due to the almost complete absence of the reefbuilding snail; thus, it is likely that much of the diversity in this unique ecosystem will be lost. In addition, increased severity and frequency of storms, anticipated as a result of climate change, may severely impact ecological communities by increasing disturbance (Revell et al 2011).…”