Ecological Condition of Coastal Ocean Waters within Stellwagen Bank National Marine Sanctuary: 2008


Autoria(s): Balthis, W. Leonard; Hyland, Jeffrey L.; Cooksey, Cynthia; Fulton, Michael H.; Wirth, Edward F.; Cobb, Donald; Wiley, David N.
Data(s)

2011

Resumo

In June 2008, the NOAA National Ocean Service (NOS), in conjunction with the EPA National Health and Environmental Effects Laboratory (NHEERL), conducted an assessment of the status of ecological condition of soft-bottom habitat and overlying waters within the boundaries of Stellwagen Bank National Marine Sanctuary (SBNMS). The sanctuary lies approximately 20 nautical miles east of Boston, MA in the southwest Gulf of Maine between Cape Ann and Cape Cod and encompassing 638 square nautical miles (2,181 km2). A total of 30 stations were targeted for sampling using standard methods and indicators applied in prior NOAA coastal studies and EPA’s Environmental Monitoring and Assessment Program (EMAP) and National Coastal Assessment (NCA). A key feature adopted from these studies was the incorporation of a random probabilistic sampling design. Such a design provides a basis for making unbiased statistical estimates of the spatial extent of ecological condition relative to various measured indicators and corresponding thresholds of concern. Indicators included multiple measures of water quality, sediment quality, and biological condition (benthic fauna, fish tissue contaminant levels). Depths ranged from 31 – 137 m throughout the study area. About 76 % of the area had sediments composed of sands (< 20 % silt-clay), 17 % of the area was composed of intermediate muddy sands (20 – 80 % silt-clay), and 7 % of the sampled area consisted of mud (> 80 % siltclay). About 70 % of the area (represented by 21 sites) had sediment total organic carbon (TOC) concentrations < 5 mg/g and all but one site (located in Stellwagen Basin) had levels of TOC < 20 mg/g, which is well below the range potentially harmful to benthic fauna (> 50 mg/g). Surface salinities ranged from 30.6 – 31.5 psu, with the majority of the study region (approximately 80 % of the area) having surface salinities between 30.8 and 31.4 psu. Bottom salinities varied between 32.1 and 32.5 psu, with bottom salinities at all sites having values above the range of surface salinities. Surface-water temperatures varied between 12.1 and 16.8 ºC, while near-bottom waters ranged in temperature from 4.4 – 6.2 ºC. An index of density stratification (Δσt) indicated that the waters of SBNMS were stratified at the time of sampling. Values of Δσt at 29 of the 30 sites sampled in this study (96.7 % of the study area) varied from 2.1 – 3.2, which is within the range considered to be indicative of strong vertical stratification (Δσt > 2) and typical of the western Gulf of Maine in summer. Levels of dissolved oxygen (DO) were confined to a fairly narrow range in surface (8.8 – 10.4 mg/L) and bottom (8.5 – 9.6 mg/L) waters throughout the survey area. These levels are within the range considered indicative of good water quality (> 5 mg/L) with respect to DO. None of these waters had DO at low levels (< 2 mg/L) potentially harmful to benthic fauna and fish.

Formato

application/pdf

Identificador

http://aquaticcommons.org/14762/1/nos-nccos-129.pdf

Balthis, W. Leonard and Hyland, Jeffrey L. and Cooksey, Cynthia and Fulton, Michael H. and Wirth, Edward F. and Cobb, Donald and Wiley, David N. (2011) Ecological Condition of Coastal Ocean Waters within Stellwagen Bank National Marine Sanctuary: 2008. Charleston, SC, NOAA/National Centers for Coastal Ocean Science, 59pp. (NOAA Technical Memorandum NOS NCCOS , 129)

Idioma(s)

en

Publicador

NOAA/National Centers for Coastal Ocean Science

Relação

http://aquaticcommons.org/14762/

http://purl.fdlp.gov/GPO/gpo18173

Palavras-Chave #Conservation #Ecology #Fisheries #Management
Tipo

Monograph or Serial Issue

NonPeerReviewed