. The ecology of Tijuana Estuary, California : a national estuarine research reserve . 1977 1978 O ) Mix â Import ⢠â CO CO Q CO Q .X S D â o Z Export O z o z. â JUN ' â ⢠AUG â OCT -j 1â DEC FEB i 1 APR i 1 MAY JUL SEP NOV JAN MAR 1977 1978 1977 1978 Figure Net flux of particulate (left) and dissolved (right) organic carbon in tidal waters of a) the succulent-dominated and b) mixed cordgrass-succulent study sites of Winfield (1980). Reprinted from Winfield (1980) with permission. because of enormous difficulties in sampling. Since temporal variability in all of these processes is high,
. The ecology of Tijuana Estuary, California : a national estuarine research reserve . 1977 1978 O ) Mix â Import ⢠â CO CO Q CO Q .X S D â o Z Export O z o z. â JUN ' â ⢠AUG â OCT -j 1â DEC FEB i 1 APR i 1 MAY JUL SEP NOV JAN MAR 1977 1978 1977 1978 Figure Net flux of particulate (left) and dissolved (right) organic carbon in tidal waters of a) the succulent-dominated and b) mixed cordgrass-succulent study sites of Winfield (1980). Reprinted from Winfield (1980) with permission. because of enormous difficulties in sampling. Since temporal variability in all of these processes is high, it is unwise to set a percentage for materials lost from the marsh to adjacent tidal creeks. Suffice it to say that, from these data, most of the marsh plant production appears to be used within the marsh. Temporal Variability in Filtering Functions There is little information on year-to- year differences in nutrient uptake rates, sediment accretion, and peat formation. Limited studies of peat accumulation (Scott 1976; Mudie and Byrne 1980) show that marsh elevations have increased through geologic time, and comparisons of elevations before and after flooding (Zedler 1983b) document short-term accretion. Not much can be said about the processes that reverse these "filtering" functions either. No measure- ments have been made of erosion, other than what is obvious from aerial photos (Chapter 2). Overall, Tijuana Estuary is accumulating sediments within the channels and losing area due to shoreline retreat. The importance of catastrophic sedimentation events makes prediction difficult. A conceptual model was developed by Zedler and Onuf (1984) to describe estuarine filtering during the wet and dry seasons of nonflood years and during flood years (Figure ). Nonflood years are the most commonly occurring condition. During these times, the estuary is believed to be a sink for nutrients and sediments coming from both the watershed and the ocean. It is
Size: 3099px × 1613px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiversity, bookleafnumber105
