Document Type

Report

Department/Program

Virginia Institute of Marine Science

Publication Date

7-1-2008

Series

Special Reports in Applied Marine Science and Ocean Engineering (SRAMSOE) No. 401

Abstract

In 2007, wild celery (Vallisneria americana) and water stargrass (Heteranthera dubia) were planted at sites in the Hopewell region of the tidal James River. The SA V transplants from 2007 and previous years were monitoried by the Virginia Institute of Marine Science (VIMS) for survivorship and growth throughout the growing season. Nursery ponds were constructed at the VIMS campus for development of SA V transplant propagules. Water quality sampling was conducted at bi-weekly intervals throughout the year for water column nutrients, chlorophyll a, suspended solids, water transparency and other chemical and physical constituents important for SAV growth. Continuous water quality sampling was also conducted along the James River from the mouth of the Chickahominy River to the upstream limits of tidal water at Richmond. Objectives ofthis restoration and water quality study were to: 1) expand the SAV transplanted plots within the study sites previously transplanted; 2) conduct water quality sampling to determine the state of water quality in the tidal freshwater James relative to current water quality standards and SAV habitat requirements; 3) evaluate SAV 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 occurred at all James River field sites at depths of approximately 0.4 m below low water. Seeds obtained from wild stock and planted within the exclosures germinated and produced adult plants in 2006 and these demonstrated re-growth in 2007. Water stargrass stocks originally collected from non-tidal areas of the James and planted into grow out nursery ponds at VIMS in 2006, along with nursery grown wild celery were replanted into tidal sites in 2007. Both species transplanted in 2007 also were successful and grew throughout 2007. SAV growth throughout the tidal freshwater James continued to expand in 2007 reaching over 300 acres. Powell's Creek plantings continued to expand with coontail (Ceratophyllum demersum) plantings mixed with recruited Hydrilla (Hydrilla verticilata) reaching over 60 acres. Water quality monitoring in the tidal James River in 2007 indicated that turbidity levels were again suitable for SA V growth to depths of 0.5 m in most areas. Seasonal light levels were at or near water clarity criteria for most transplant sites. Turbidity levels were highest in the upper section of the JMSTF1 segment and lower section of the JMSTF2 segment. When integrated along each of the freshwater segments (JMSTF1 and JMSTF2) using continuous underway spatial sampling, turbidity goals were met for all eight SA V growing season cruises. Summertime levels of chlorophyll were the highest recorded over the past five years. When integrated across the entire segments, average concentrations were found to be well above spring and summer limits of 15-23 Jlg r 1 and 10-15 Jlg r 1 for JMSTF1 and JMSTF2 respectively. Similarly, average seasonal concentrations at the transplant sites were above SA V growing season goals of 15 Jlg r1 • Nutrient levels generally were comparable with earlier years' monitoring results, although dissolved ammonium concentrations were at or below detection for most of the year and a decreasing trend has been evident since 2002. Similarly dissolved inorganic phosphate (DIP) levels were very low throughout much of the year and all transplant sites met SAV growing season habitat requirements for DIP. Overall, the success of the SA V restoration in the tidal freshwater James River is encouraging, but the high levels of chlorophyll are of concern and warrant continued monitoring.

DOI

https://doi.org/10.21220/V51169

Keywords

Submerged Aquatic Vegetation, Ecology, Virginia

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