1 / 16

Update on Submerged Aquatic Vegetation (SAV) in Chesapeake Bay: Status and Trends (2007)

This workshop update by Peter Bergstrom from NOAA highlights the state of Submerged Aquatic Vegetation (SAV) in the Chesapeake Bay, including survey results for 2006-2007. Emphasizing data from river transects and interactive maps, the workshop discusses observed declines in SAV across Maryland and Virginia zones. It also addresses the influence of water temperature, clarity, and the impact on eelgrass populations. Plans for future SAV enhancement and species introduction are explored, with a call to improve water clarity and implement successful SAV planting strategies.

salaam
Télécharger la présentation

Update on Submerged Aquatic Vegetation (SAV) in Chesapeake Bay: Status and Trends (2007)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Submerged Aquatic Vegetation (SAV) update Peter Bergstrom, NOAA Chesapeake Bay Office MASC Workshop, 10/18/07 10/18/2007

  2. SAV survey status & results • 2007 areas will not be ready at least until February • Flight lines completed only recently—see map, next slide • SAV transects in several rivers; better ground survey data • Done for years by Nancy Rybicki’s group in the Potomac; can show patterns by species (see examples below) • 2007 transects started in MD by riverkeepers and volunteers in Bush, Patuxent, Chester, West/Rhode, Severn, South and Magothy rivers • VA transects done by VIMS in 2006-07 in York (6 sites) and Mobjack Bay (3 sites); also about 100 sites on both VA shores surveyed 2006-07 for eelgrass abundance • 2006 report incorporates new interactive map • This now contains the ground truth data; these are no longer shown on the quad maps • 2006 results show declines from 2004 & 2005 in all zones, including MD & VA coastal bays—why? 10/18/2007

  3. 2007 Flight Lines (all are done now) 10/18/2007

  4. Collecting SAV transect data Tools: oyster tongs, graduated cylinders, GPS, buoys 10/18/2007

  5. SAV patterns by species from Potomac transect data Peak in Hydrilla moved downriver Source: Nancy Rybicki, USGS More TN means less species diversity 10/18/2007

  6. Sample transect data: abundance by species by distance from shore 10/18/2007

  7. New interactive map in 2006 shows ground truth data Upper Magothy 10/18/2007

  8. Recent SAV patterns • Baywide area and some zones increased during 2001-2002 drought • Increased in higher salinity zones only (mid and lower Bay) • SAV area declined baywide and in all zones, including coastal bays, in 2006 • In lower Bay, this was delayed response to 2005 hot summer (photos taken in spring) • May be some increases in 2007 10/18/2007

  9. Baywide area peaked in 2002, declined in 2006 Drought Not including Coastal bays 10/18/2007

  10. SAV area declined in all zones in 2006 Coastal bays not surveyed in 2005; similar declines 05-06 in other zones 10/18/2007

  11. SAV Area by zone through 2006 (upper Bay) May be up in 2007 (Flats, Bush, Gun- powder very healthy) Drought Probably down in 2007 (very little in Chester, Eastern Bay, Choptank, or lower Potomac) 10/18/2007

  12. Area by zone through 2006 (lower & coastal bays) Drought Up slightly in 2007 (2006 drop caused by 2005 summer heat) May be down in 2007 (only healthy beds near inlets) 10/18/2007

  13. Why is SAV declining baywide? • Declining water clarity • Are water temperatures increasing? • either on average, or the summer peaks are getting higher & longer? • Extra-high peak preceded 2005 eelgrass dieback, lower Bay (see next slide) 10/18/2007

  14. Warmer water in 2005 preceded eelgrass dieback Source: Bob Orth, VIMS 10/18/2007

  15. The future of SAV in the Bay • If summer water temperatures keep climbing, eelgrass (Zostera marina) will continue to have trouble • If water clarity keeps declining, all species will have trouble • So, what can we do to increase SAV area? • SAV planting -139 acres planted to date in Bay, but success is low. Some of planted beds are present & expanding, though (6-7 sites) • Improve water clarity - how?? • Introduce other SAV species that can tolerate higher temperatures and/or lower water clarity? • Shoal grass, Halodule wrightii, grows from NC south at present, BUT its minimum salinity is 18 ppt vs. 10 ppt for eelgrass, so it could not really replace eelgrass • Japanese eelgrass, Zostera japonica, is naturalized in Pacific NW, tolerates salinity lower than Z. marina, and may hold promise for the Chesapeake (need to know its ecology better) 10/18/2007

  16. Zostera japonica images Zostera at Padilla Bay, WA Intertidal Z. japonica Z. marina Z. japonica Intertidal Z. japonica in Japan Z. japonica 10/18/2007

More Related