Monitoring Regional Riparian Forest Cover Change Using Stratified Sampling and Multiresolution Imagery1

Claggett, Peter R., Judy A. Okay, and Stephen V. Stehman, 2010. Monitoring Regional Riparian Forest Cover Change Using Stratified Sampling and Multiresolution Imagery. Journal of the American Water Resources Association (JAWRA) 46(2):334-343. DOI: 10.1111/j.1752-1688.2010.00424.x Abstract: The Chesapeake Bay watershed encompasses 165,760 km² of land area with 464,098 km of rivers and streams. As part of the Chesapeake Bay restoration effort, state and federal partners have committed to restoring 26,000 miles (41,843 km) of riparian forest buffers. Monitoring trends in riparian forest buffers over large areas is necessary to evaluate the efficacy of these restoration efforts. A sampling approach for estimating change in riparian forest cover from 1993/1994 to 2005 was developed and implemented in Anne Arundel County, Maryland, to exemplify a method that could be applied throughout the Bay watershed. All stream reaches in the county were stratified using forest cover change derived from Landsat imagery. A stratified random sample of 219 reaches was selected and forest cover change within the riparian buffer of each sampled reach was interpreted from high-resolution aerial photography. The estimated footprint of gross change in riparian forest cover (i.e., the sum of gross gain and gross loss) for the county was 1.83% (SE = 0.22%). Stratified sampling taking advantage of a priori knowledge of locations of change proved to be a practical and efficient protocol for estimating riparian forest buffer change at the county scale and the protocol would readily extend to much broader scale monitoring.     

Effects of two herbicidal wastewaters on Chlorella sp. and Phaeodactylum tricornutum

The effects on Chlorella sp. and Phaeodactylum tricornutum of two industrial wastewaters known to contain the herbicide residues of Trifluralin and Propanil have been determined by monitoring the number of cells, the chlorophyll fluorescence and the carbon dioxide assimilation simultaneously for a period of 14 days. The growth of the diatom, Phaeodactylum tricornutum, was inhibited by concentrations of herbicidal waste of the order of 0.1-0.5%, apparently because the rate of reproduction was reduced. Chlorella sp. cells, on the other hand, whilst dramatically inhibited by 1% concentrations of herbicidal waste, were able to recover over a period of 14 days. If discharged at concentrations below 0.01%, the industrial wastes appeared not to affect phytoplankton.     

The role of algae (Isochrysis galbana) enrichment on the bioaccumulation of benzo[a]pyrene and its effects on the blue mussel Mytilus edulis

The role of algal concentration in the transfer of organic contaminants in a food chain has been studied using the ubiquitous model polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) as the contaminant, Isochrysis galbana as the phytoplankton food source, and the common mussel (Mytilus edulis) as the primary consumer. The effect of algal concentration on BaP uptake by M. edulis was determined by feeding M. edulis daily with I. galbana which had previously been kept in the presence of BaP for 24 h. Four combinations of concentrations of algae and BaP were used to give final exposure concentrations of 30,000 or 150,000 algal cells ml(-1) in combination with either 2 or 50 microg BaP l(-1). BaP concentrations were determined fluorometrically in rest tissues (excluding digestive glands) and digestive gland microsomal fractions of M. edulis after 1, 7 and 15 days exposure, and also in isolated algae. Potentially toxic effects of BaP on M. edulis were examined in terms of blood cell lysosomal membrane damage (neutral red dye retention assay) and induction of digestive gland microsomal mixed-function oxygenase (MFO) parameters [BaP hydroxylase (BPH) and NADPH-cytochrome c (P450) reductase activities]. BaP bioaccumulation in rest tissues (and to a lesser extent in digestive gland microsomes) of M. edulis increased with both increasing BaP and algal exposure concentrations, and over time, producing maximal bioconcentration factors in rest tissues after 15 days exposure to 150,000 algal cells ml(-1) and 50 microg BaP l(-1) of 250,000. The five-fold higher concentration of algae increased BaP bioaccumulation by a factor of approximately 2 for 50 microg BaP l(-1) at day 15. Blood cell neutral red dye retention time decreased linearly with increasing log(10) tissue BaP body burden, indicating an increased biological impact on M. edulis with increasing BaP exposure possibly due to a direct effect of BaP on blood cell lysosomal membrane integrity. An increase was seen in NADPH-cytochrome c reductase activity, and indicated in BPH activity, with 1 but not 7 or 15 days exposure to BaP, indicating a transient response of the digestive gland microsomal MFO system to BaP exposure.     

The pollution status and the toxicity of surface sediments in Izmit Bay (Marmara Sea), Turkey

Izmit Bay is one of the most polluted and populated enclosed sea in Turkey. It has been the centre of industrial activities for the last 30 years. Seven major sources enter the bay waters along the north coastline of the bay. This investigation forms part of continuing ecotoxicology studies in the Izmit Bay designed to constrain and minimise the pollution caused by flourishing industry and a growing population. Sediments sampled from the mouths of the major discharges of Izmit Bay were analysed for their organic carbon, total polycyclic aromatic hydrocarbon (t-PAH) and trace inorganic element (Cd, Al, As, Pb, Hg and Cu) contents and compared with those found in the sediments from the reference station in the outer bay (in the Marmara Sea). The toxicity of sediments was determined in the bulk and elutriate samples by using algal (Phaeodactylum tricornutum) batch bioassays. Chemical data showed that the sediments collected from the inner sites of the bay have been contaminated with Cd, Hg, As and PAHs. Organic carbon contents were also found higher. All the major industrial discharges into the bay are now biologically treated but bioassays performed with bulk sediments revealed that the recent sediments are toxic to the microalgae throughout the bay. The results are consistent with the previous toxicity studies performed with the industrial discharges.     

Performance of butyl rubber–based macroporous sorbents as passive samplers

Environmental Science and Pollution Research - In this study, two macroporous butyl rubber (BR)–based sorbents prepared in benzene (H-BR) and in cyclohexane (L-BR) with different porosities...     

Monitoring of organic pollutants in marine environment by semipermeable membrane devices and mussels: accumulation and biochemical responses

This study involves the monitoring of organic pollutants using transplanted mussels (Mytilus galloprovincialis) as bioindicator organisms and semipermeable membrane devices (SPMDs) as passive samplers. Mussels and SPMDs were deployed to marinas, shipyards and shipbreaking yards on the coastal area of Turkey and retrieved after 60 days. Polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB) and organochlorine pesticide (OCP) compounds were analysed with high-resolution GC-MS. Total PAH concentrations in SPMDs and mussels ranged from 200 to 4740 ng g sampler^?1 and from 7.0 to 1130 ng g^?1 in wet weight (ww). PCB and OCP concentrations in SPMDs changed between 0.04–200 and 4.0–26 ng g sampler^?1, respectively. The highest PCB (190 ng g^?1 ww) and OCP (200 ng g^?1 ww) concentrations in mussels were measured at shipyard stations. A strong correlation was observed between the PAH and PCB concentrations in SPMDs and mussels. Enzyme assays (acetylcholinesterase, ethoxyresorufin-O-deethylase, glutathione S-transferase, glutathion reductase and carboxylesterase activities) were performed as biomarkers to reveal the effects of pollution on the mussels. There was no clear relationship found between the enzyme levels and the pollutant concentrations in mussels. Integrated biomarker responses were calculated to interpret the overall effect of pollutants.

     

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in the Bay of Marmara sea: Izmit Bay

In 1999, the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), the total PAH and polychlorinated biphenyls (PCBs) were measured in sea water, sediment and mussels collected along the coast of Izmit Bay, the most important bay of the Marmara Sea. The total-PAH concentrations, measured by Spectrofluorometry were in the range of 1.16-13.68 microg/l in sea water, in the range of 30.0 1670.0 microg/g dry weight in sediments and in the range from 5.67 to 14.81 microg/g wet weight in edible part of mussel. HPLC revealed Phenanthrene (three rings), chrysene (four rings) and benz[a]antracene (five rings) to be the dominant PAHs in sea water, while 16 different PAHs compounds were observed and measured in mussel samples. The most pollution occured at Dogu Kanali and Dil Deresi where were the main rivers containing wastes fall into the the Izmit Bay. Although the maximum mono-ortho PCB concentrations in sea water were measured in the Dil Deresi River (26.33 ng/l) and the Solventa? (22.19 ng/l) stations, maximum PCB concentrations in mussels were measured in the SEKA (28.11 microg/kg) and the Dil Deresi River (25.68 microg/kg). The dominant congeners of PCBs were from tetra to hexachlorobiphenyls. The toxicity equivalent values were very low in sea water and mussels.     

Polycyclic aromatic hydrocarbon contamination in coastal sediments of the Izmit Bay (Marmara Sea): case studies before and after the Izmit Earthquake

Izmit Bay and its coastal environment was strongly affected by the August 17th, 1999 Izmit Earthquake. The changes in the Bay ecosystem and its chemical oceanography have been studied in detail previously [Okay, O.S., Tolun, L, Telli-Karako?, F., Tüfek?i, V., Tüfek?i, H. And Morko?, E. 2001. Yzmit Bay ecosystem after Marmara earthquake and subsequent fire: The long-term data. Marine Pollution Bulletin 42, 361-369; Balkys, N. 2003. The effect of Marmara (Izmit ) Earthquake on the chemical oceanography of Izmit Bay, Turkey. Marine Pollution Bulletin 46, 865-878.]. In this study surface sediments collected from the Izmit Bay before and after the earthquake have been analysed for total and individual (14 compounds) polycyclic aromatic hydrocarbons (PAH). Analyses have been performed by high performance liquid chromatography with fluorescence detection (HPLC/FD). Before the earthquake, total PAH concentrations in the Bay sediments ranged from 120 to 8900 ng/g while after the earthquake PAH concentrations varied between 240 and 11,400 ng/g. Molecular indices based on isomeric PAH ratios used to differentiate the pollution sources, clearly indicate the differences in molecular distribution of PAHs before and after the earthquake. Sediment data obtained before the earthquake shows that most of the contamination originated from high temperature pyrolytic inputs while after the earthquake it originated from petrogenic sources. This difference emphasises the environmental impact of uncontrolled discharges from petroleum industries after the earthquake. The LMW/HMW ratio (sum of the low molecular weight PAHs / the sum of higher molecular weight PAHs) predominance also changed after the earthquake as a result of the strong water movements. According to the characteristics of aromatic rings distributed in the bay sediments, the soluble parts of the total PAH were probably transferred to the water column after the earthquake as a result of resuspension process. The TEL/PEL (Threshold Effect Level / Probable Effect Level) analysis suggests that the Izmit Bay sediments were likely contaminated by acutely toxic PAH compounds.