runoff and anti-fouling paint (tributyltin) from marinas? What is the extent of heavy metal contami¬ 
nation in nursery areas by discharge of oil production water? What are the effects of production water 
on larval stages of crabs, shrimps, oysters and fishes? What are the impacts of production water 
discharged on wintering waterfowl food items? What is the composition of non-point runoff from 
agricultural areas? How are contaminants partitioned in the nursery areas? What is the extent of 
contamination from maintenance dredged material put in confined disposal areas that drain into the 
bay? What are the dynamics of contaminants in dredged spoil disposal areas as they dry out and then 
receive precipitation? What is the extent of contaminant remobilization caused by dredging and 
other bottom disturbances? What are the transfer coefficients for the uptake of sediment contami¬ 
nants by the biota? How are toxic contaminants degraded in sediment and water? What are the effects 
of toxicants on endocrinology and reproduction? What are past, current and projected petroleum and 
chemical spill rates? What were the environmental consequences of past spills? What are the 
biological effects of eutrophic and hypoxic events? Wha t are current nutrient levels in the bay, at what 
point would nutrients become excessive, and is this likely to occur in the near future? Do anoxic 
conditions reach the bay itself? Are there any temporary circumstances that extend the anoxic zone? 
What is the near-future prognosis regarding bacterial contamination —improvement, deterioration, 
no change? Would the proposed increase in dredging activity produce a real threat to human health? 
Do any thermal effluent outfalls constitute a public hazard regarding thermophilic pathogens? Are 
toxicant levels in human food species a threat to human health? 
How important are nutrients in freshwater inflow to the maintenance of our estuaries as we know 
them today? If nutrients in the freshwater were reduced by a factor of 10, would the resultant effect 
be linear or non-linear? Would plant growth be reduced enough to affect the feeding of animal 
populations?? What is the relative importance of in-situ regeneration of nutrients compared to inputs 
to such shallow estuaries? How do the roles of point and non-point sources compare? Do non-point 
sources provide different chemical species than point sources? Does a smaller yet highly impacted 
region around a point source produce a mini-environment of eutrophication with more lethal effects 
on plant or animal life than non-point sources? What is the short-term temporal behavior of nutrient 
species that influence primary production processes? Do nutrients display diurnal behavior related 
to other biological processes, like denitrification, nitrification or decomposition? Are microalgae and 
phytoplankton species nutrient-limited in Galveston Bay, or do other factors control their growth? 
Freshwater Inflow 
Galveston Bay is connected to the Gulf of Mexico through two natural entrances, Bolivar Roads 
and San Luis Pass, and man-made Rollover Pass. Without freshwater input, tidal action would 
produce equal salinities in both bay and gulf, 35 parts per thousand (ppt, or 3.5 percent) salt. The 
amount of precipitation that falls on the bay exceeds the volume of water that evaporates from the 
bay surface by 6 inches, and precipitation accounts for 14 percent of all freshwater that reaches the 
bay. Thus, precipitation alone would lower bay salinity but an equal amount of water enters from the 
San Jacinto River, 25 percent of the input drains from the surrounding shoreline, and 48 percent of 
all freshwater inflow enters from the Trinity River alone (see Appendix I). The average amount of 
freshwater that enters the bay each year is sufficient to totally replace the volume of water in the bay 
more than four times. 
The salinity gradient in Galveston Bay is highly dynamic, responding to brief environmental 
changes, such as heavy precipitation events and frontal passages, or extended changes, such as 
droughts. Passage of a cold front, accompanied by strong northerly winds, has dropped surface 
salinity at Bolivar Roads from 18 ppt to 0.5 ppt as water was pushed out of the bay, and rebounded 
to 25 ppt as gulf waters flooded back in, all within 29 hours (7). Although the bay system is shallow 
throughout, vertical salinity gradients are common, particularly in the navigation channels. Differ¬ 
ences as great as 5 ppt can occur in water only 3 feet deep, or 15 ppt in the 40-foot deep channel (8). 
The efficacy of two-dimensional salinity modeling is questioned when the model fails to predict 
salinities as high as historical records. Other calculations have predicted that salinities could reach 
28 ppt in Trinity Bay when authorized water rights are fully exploited during periods of low Trinity 
River flow. Salinity increases of this magnitude could seriously affect oyster productivity. 
Information Needs 
How will changes in salinity affect the distribution of living organisms in the secondary bays 
(Trinity, East, West)? Will increased salinities permit the persistence of oyster pathogens and 
predators, thus reducing oyster productivity? How will full utilization of authorized water yields for 
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