Virginia Institute of Marine Science
Special Reports in Applied Marine Science and Ocean Engineering (SRAMSOE) No. 426
In 2009, wild celery (Vallisneria americana) and water stargrass (Heteranthera dubia) shoots were transplanted into shallow water sites in the Hopewell region of the tidal James River and sampled for survivorship and growth throughout the SAV growing season. Water quality sampling was conducted at bi-weekly to monthly intervals throughout the year for water column nutrients, chlorophyll a, suspended solids, water transparency and other chemical and physical constituents important for SA V growth. Objectives of this restoration and water quality study were to: 1) expand the SA V transplanted plots within the study areas previously transplanted; 2) conduct water quality sampling to determine the state of water quality for 2009 in the tidal freshwater James relative to current water quality standards and SAV habitat requirements; 3) evaluate SA V transplant performance and compare to water quality conditions; 4) monitor SA V re-growth in the upper tidal James River. SA V transplant growth and survival again occurred at all James River field sites at depths of approximately 0.4-0.5 m below low water. Water stargrass and wild celery stocks originally collected from non-tidal areas of the James and planted into grow out nursery ponds at VIMS, were transplanted into the enclosed tidal restoration sites in 2008. SA V growth throughout the tidal freshwater James continued to expand in 2009 reaching over 350 acres. All three species grew to form beds with canopies of60-90 em and maximum bottom covers of60 to 100%. Powell's Creek plantings continued to expand with coon tail ( Ceratophyllum demersum) plantings mixed with recruited hydrilla reaching over 68 acres in 2008. Water quality monitoring in the tidal James River in 2009 indicated that turbidity levels were again suitable for SA V growth to depths of 0.5 m in most areas, but did not meet levels suitable for SA V growth to 1m depths. Seasonal light levels were at or near water clarity criteria for growth to 0.5m depths at most transplant sites. Turbidity levels were lowest in the upper section of the JMSTF2 near Richmond. When integrated along each of the freshwater segments (JMSTFI and JMSTF2) using continuous underway spatial sampling, turbidity levels for growth to 0.5m were met for all eight SAV growing season cruises. Summertime levels of chlorophyll were generally lower than 2007. When integrated across the entire segments, average concentrations were found to be well above spring and summer limits of 15-23 ).lg r 1 and 10-15 ).lg r 1 for JMSTF1 and JMSTF2 respectively. Similarly, average seasonal concentrations at the transplant sites were above SA V growing season goals of 15 ).lg r 1 and ranged from 30 to 72 ).lg r during the spring and 72-82 11g r during the summer. No noxious blooms or other symptoms of excess algae were observed, however. Nutrient levels generally were comparable with earlier years' monitoring results, although increases in analytical detection limits precluded trend analysis. Total kjeldahl nitrogen, dissolved ammonium and dissolved inorganic phosphorus concentrations were at or below detection for most of the year. Dissolved nitrate plus nitrite also were below detection during the summer, while total phosphorus showed higher concentrations than in previous years. Overall, the success of the SAV restoration and growth in the tidal freshwater James River is encouraging Most water quality parameters remain consistent from earlier years, but continued high levels of chlorophyll are still prevalent during the summer.
Submerged Aquatic Vegetation, Ecology, Virginia
Moore, K., Neikirk, B., Shields, E. C., & Parrish, D. (2010) Water Quality Conditions and Restoration of Submerged Aquatic Vegetation (SAV) in the Tidal Freshwater James River 2009. Special Reports in Applied Marine Science and Ocean Engineering (SRAMSOE) No. 426. Virginia Institute of Marine Science, William & Mary. https://doi.org/10.21220/V56J14