Bellingham Bay hypoxia and water quality study

Transcription

1 Bellingham Bay hypoxia and water quality study Jude Apple Shannon Point Marine Center Western Washington University Dan Burns, Charlotte Clausing, L. Jessica Urbanec, Jason Seber and Eleno Alaniz Northwest Indian College, Bellingham, WA SHANNON POINT MARINE CENTER

2 NWIC Science Internship and Hypoxia Study Objectives Educational Use an investigation of hypoxia and WQ in the Bellingham Bay/Nooksack River system as a teaching platform for the Northwest Indian College (NWIC) Native Environmental Science (NES) program Research Baseline of temporal and spatial extent of bottom water hypoxia Nooksack watershed WQ (nutrients, sources of fecal coliform) Benthic infaunal diversity and abundance Phytoplankton community (composition and succession) Historical/cultural Bring together current, historic and traditional knowledge to form a longterm picture of water quality in Bellingham Bay. Frame research within the context of cultural, ecological and public health priorities for the Lummi reservation and people.

3 Bellingham Bay Hypoxia Study Northwest Indian College Nooksack River Shannon Point Marine Center Bellingham Lummi Indian Reservation Seattle Bellingham Bay

4 Sampling in Bellingham Bay - Eight routine monitoring stations - Water column profiles - Surface and bottom water Chl-a DOC/CDOM dissolved nutrients phytoplankton community - Spatially intensive transects

5 Water column profiles Bellingham Bay - Frequently stratified - Concurrent oxy/thermocline - Nooksack influence on surface salinity - Depth of <4mgL -1 used to evaluate extent of hypoxia Depth (m) DO (mg/l) Temperature ( C) Depth (m) Eleno Alaniz Salinity DO (mg/l) Temperature ( C)

6 Mapping hypoxia in Bellingham Bay Spatial Patterns DO mg L -1 Temporal Patterns

7 Bottom Water Residence time in Bellingham Bay Limited flushing of bottom waters in central region of Bellingham Bay. Flushing time of days Coincides with areas of low DO we have identified historically and during sampling Jason Seber From Rubash and Kilanowski 2007

8 Mapping Hypoxia in Bellingham Bay Hypoxic waters do not necessarily occur in deepest regions, rather where residence time is longer and organic matter deposition may be higher.

9 Historical sources for water quality data Survey of Bellingham-Samish Bay system (Calias & Barnes 1962)

10 Historical sources for water quality data Washington Dept. of Ecology and USGS 1. Long-term evidence of increase in the intensity and frequency of hypoxia (anthropogenic or climatic?). 2. Potential relationship between the timing and structure of Nooksack River flow and severity of hypoxia Bottom water dissolved oxygen (mg L -1 ) hypoxic conditions Average monthly cfs Year Bellingham Bay bottom water dissolved oxygen Jan Feb Mar Apr May Jun Jul Aug Sep Nooksack River flow (cfs)

11 Benthic community surveys Sediment grabs (R/V Centennial) Grain size analysis Benthic infaunal community analysis Shannon Weiner Diversity indices H - BB1 (well flushed, southern bay) BB3 (low DO, periodic hypoxia) 0.6

12 Phytoplankton abundance and succession - Tracking abundance and composition - Bloom events - Shifts in community composition as indices of nutrient regime Thalassiosira sp. Chaetoceros Phytoplankton abundance in Bellingham Bay Mean abundance from eight stations Chaetoceros Rhizosolenia Thalassiosira Coscinodiscus Rhizosolenia Coscinodiscus 7/1/2008 7/8/2008 7/15/2008 7/22/2008 7/29/2008 8/5/2008 Images and figures courtesy of Eleno Alaniz and Jessica Urbanec Charlotte Clausing

13 Fecal coliform in Nooksack River - Monitoring Nooksack and tributaries - Identifying potential point sources - Reduce clam bed closures Nooksack River

14 Outcomes and Future Work Hypoxia Seasonal bottom-water hypoxia is a natural feature of Bellingham Bay Duration and severity of hypoxic events may be increasing (need to increase temporal and spatial resolution of sampling; establish baseline) Increase coverage of benthic surveys Fecal Coliform Map sources of fecal coliform within Nooksack watershed (GIS at NWIC; explore ribotyping) Phytoplankton communities Evaluate composition in Bellingham Bay and as part of Tribal Journeys USGS program Investigate community succession and incidence of HABs through direct counts, HPLC Continue to build field guide to phytoplankton

15 Outcomes and Future Work Historical data/cultural resources Continue pursuing sources (DOE, archives) for building a historical baseline of water quality and hypoxia in Bellingham Bay. Explore traditional knowledge: crabbers, fishermen, tribal Elders (NSF Geosciences Funding) Keeping eyes on the prize Conduct all research within the context of addressing cultural, public health, and environmental priorities of the Lummi reservation and people.