Seattle, Washington 98195 USA. The Ogeechee River is a 6th-order river in the coastal plain of Georgia, USA. Most of our stud- ies of this blackwater river were ...
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N. B. 1987. Nitrogen dynamics during sucGRIMM, cession in a desert stream.Ecology68:1157-1170. N. B. 1993. Disturbance,succession,and ecoGRIMM, system processes in streams:a case study from the desert. Pages 93-112 in P S. Giller,A. G. Hildrew, and D. G. Raffaeli(editors).Aquaticecology: scale,patternand process.BlackwellScientific Publications,Oxford,UK. GRIMM,N. B., AND S. G. FISHER.1984. Exchange be-
tween interstitialand surfacewater:implications for stream metabolismand nutrientcycling. Hydrobiologia111:219-228. JACKSON, J. K., ANDS. G. FISHER.1986. Secondary pro-
duction,emergence,and export of aquaticinsects of a SonoranDesert stream.Ecology 67:629-638. ANDN. B. GRIMM.1995. VerJONES,J. B., S. G. FISHER,
tical hydrologicexchangeand ecosystem metabolism in a Sonoran Desert stream. Ecology 76: 942-952.
[Volume 16
Organic matter dynamics in the Ogeechee River, a blackwater river in Georgia, USA JUDY L. MEYER1, ARTHUR C. BENKE2,
RICK T. EDWARDS3, AND J. BRUCE WALLACE1 1 Institute of Ecology, University of Georgia, Athens, Georgia30602 USA 2 Departmentof BiologicalSciences, University of Alabama, Tuscaloosa,Alabama 35487 USA 3 Centerfor StreamsideStudies, University of Washington, Seattle, Washington98195 USA
JONES,J. B., S. G. FISHER,AND N. B. GRIMM.1996. A
long-term perspective of dissolved organic carbon transportin SycamoreCreek,Arizona,USA. Hydrobiologia317:183-188. SCHADE,J. D. 1995. The influenceof leaf litterinputs on a SonoranDesert streamecosystem. MS Thesis. Arizona StateUniversity,Tempe. E. H. 1993. Drying disturbanceand stabilSTANLEY, ity in a desert stream ecosystem. PhD Dissertation. Arizona StateUniversity,Tempe.
The Ogeechee River is a 6th-order river in the coastal plain of Georgia, USA. Most of our studies of this blackwater river were done at a site in Effingham County (32?08'N, 81?25'W), 331 km from the river's source and 63 km from its mouth near Savannah (Benke and Meyer 1988). The river at the study site drains a watershed of 6860 km2: 5 % in the Piedmont, 95 % in the B. W, AND H. H. SCHUMANN.1968. Water THOMSEN, Coastal Plain (Edwards and Meyer 1987a, Benke resourcesof the SycamoreCreekwatershed,Marand Meyer 1988). Human population in the waicopa County,Arizona, USA. GeologicalSurvey tershed is primarily rural (12 persons/km2) 1861. Water-SupplyPaper with permitted point source discharges that toSURVEY.1989-1993. Water resources US GEOLOGICAL data for Arizona.UnitedStatesGeologicalSurvey tal 0.6 % of mean annual river discharge (Meyer WaterData Report,Arizona. 1992). The watershed is primarily in agriculture ANDE. H. STANLEY.1990. with forested areas of hardwood and VALETT,H. M., S. G. FISHER, pine, Physical and chemical characteristicsof the hy- which is extensively harvested. Watershed geporheiczone of a SonoranDesert stream.Joural consists of sandy sediments of marine orof the North American BenthologicalSociety 9: ology igin deposited on igneous and metamorphic 201-215. rock (Meyer 1992). The Ogeechee is one of relatively few rivers of its length in North America with no major dams (Benke 1990). There are a few mill ponds in the headwaters, but the main stem escaped damming because of its extremely low gradient (0.0002 m/m at the study site). The climate is subtropical with annual average water temperature of 18.5?C. Minimum water temperatures usually occur during January (7?C daily mean) and maximum during JulyAugust (28?C) with daily maximum temperatures over 30?C common during summer (Benke and Meyer 1988). Total annual degree days vary around 7000. Mean annual precipitation in the basin ranges from 100 to 130 cm (Meyer 1992) with extremes of 70 cm during a dry year and
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STREAMORGANICMATTERBUDGETS
1997]
TABLE1. Physical characteristics and organic matter parameters for the Ogeechee River. All masses of inputs, storage, and outputs are as AFDM and expressed per m2 of channel area.
Value
Reference
Latitude Order Watershedarea (ha)
32?N 6 6.86 x 106
Edwardsand Meyer(1987a)
Streambed area (m2)
1.33 x 107
Gradient(m/m) Mean annual water temperature(?C) Mean annual discharge(L/s) Mean annual precipitation(cm)
0.0002 18.5 66,800 117
Variable Physical characteristics
Benkeand Meyer(1988) Benkeand Meyer(1988) Benkeand Meyer(1988) Benkeand Meyer(1988)
Inputs (g m-2 y-')
Gross primaryproduction Litterfall Lateralmovement GroundwaterDOM Standingcrops (g/m2) CBOM> 1 mm FBOM< 1 mm Wood > 1 mm Outputs Autotrophicrespiration(g m-2 y- ) Heterotrophicrespiration(g m-2 y-') Particulatetransport(kg/y) Dissolved transport(kg/y)
509 843 3520 632
Edwardsand Meyer(1987a) Cuffney(1988) Cuffney(1988)
869 1903 6460
Benkeand Meyer(1988) Benkeand Meyer(1988) Benkeand Meyer(1988)
254.5 2664 2.4 x 106 60.2 x 106
170 cm during a wet year (Pulliam and Meyer 1992). Mean annual precipitation is 117 cm at the study site (Benke and Meyer 1988). Mean discharge at the study site is 66.8 m3/s (57-year mean), which is 58% of its discharge at the mouth (Benke and Meyer 1988, Meyer 1992). Discharge extremes range from 3.7 to 850 m3/ s, and mean annual discharge has varied from 24 m3/s in 1985 to 152 m3/s in 1948 (USGS 1994). Surface water withdrawals in the entire basin total 0.8% of discharge at the mouth (Meyer 1992). Average monthly discharge varies 4-fold over the year with February, March, and April as the months with highest mean flow (110-150 m3/s), and September, October, and November with the lowest (27-30 m3/s) (Cuffney 1984). The river meanders across a broad, forested floodplain that floods regularly. In an average year, the entire floodplain is inundated for 3 mo (February-April), and there are only 4 mo of the year (August-November) when
