Introduction Time-series photographs of the sea floor were obtained from an instrumented tripod deployed in western Massachusetts Bay at LT-A (42° 22.6' N, 70° 47.0' W, nominal water depth of 32 m, fig. 1) from December 1989 through September 2005. The photographs provide time-series observations of physical changes of the sea floor, near-bottom water turbidity, and life on the sea floor. Several reports present these photographs in digital form (table 1). This report, U.S. Geological Survey Data Series 265, Version 2.0, contains the photographs obtained from December 1989 to October 1996, adding to (and replacing) Version 1 of Data Series 265 (Butman, Dalyander, and others, 2007) that contained photographs from 1989 through 1993. Data Series 266 (Butman and others, 2008b) contains photographs obtained from October 1996 through September 2005. These reports present the photographs, originally collected on 35-mm film, in digital form to enable easy viewing and to provide a medium-resolution digital archive. The photographs, obtained every 4 or every 6 hours, are presented as individual photographs (in .png format) and as a movie (in .avi format). The time-series photographs taken at LT-A were collected as part of a U.S. Geological Survey (USGS) study to understand the transport and fate of sediments and associated contaminants in Massachusetts Bay and Cape Cod Bay (Bothner and Butman, 2007). This long-term study was carried out by the USGS in partnership with the Massachusetts Water Resources Authority (MWRA) (http://www.mwra.state.ma.us/) and with logistical support from the U.S. Coast Guard (USCG). Long-term oceanographic observations help to identify the processes causing bottom sediment resuspension and transport and provide data for developing and testing numerical models. The observations document seasonal and interannual changes in currents, hydrography, and suspended-matter concentration, and the importance of infrequent catastrophic events, such as major storms, in sediment resuspension and transport. LT-A is approximately 1 km south of the ocean outfall that began discharging treated sewage effluent from the Boston metropolitan area into Massachusetts Bay in September 2000. See Butman and others (2004) for a description of the oceanographic measurements at LT-A, and Butman, Warner, and others (2007) and Warner and others (2007) for discussion of sediment transport in Massachusetts Bay. Instrumentation The time-lapse bottom photographs were obtained by means of a Benthos 35-mm camera mounted on a tripod frame that rests on the sea floor (figs. 2 and 3). The camera (fig. 4) was mounted about 1.5 m above the sea floor and aimed downwards; a strobe (fig. 5) illuminated the sea floor from one side of the photograph. The field of view of the camera is 54 degrees, resulting in a photograph area on the sea floor measuring approximately 1.5 m x 1 m. A compass and vane (fig. 6) mounted in the field of view of the camera show the instantaneous direction of current flow and the scale and orientation of the photographs. The photographs were taken on Kodak 35-mm Ektachrome Professional Film (E200, a daylight-balanced 200-speed color transparency film, 100-ft roll, about 700 photographs/roll). The Benthos camera places the photographs in a nonstandard format along the long axis of the film. This allows a photograph of the sea floor larger than would be possible if the photograph were placed across the film in a standard 35-mm format. The film is advanced using an O-ring drive; the loose drive and drive-motor inertia cause the distance between frames to vary slightly with each photograph. The unevenly spaced photographs required alignment to view them as a time-series movie without jitter. The camera and strobe were controlled by a timer set to obtain a photograph every 4 or 6 hours, depending on the deployment. The time of each photograph differs from a uniform spacing by a few minutes because of drift in this analog controller. A digital light emitting diode (LED) clock, separate from the controller, places the hour, minute, second, and day on each photograph. The day counter on the LED clock counts to 31 and then resets to 1. The time on the LED typically differed from true time by only a few minutes at the end of the deployment and thus is assumed to provide a reasonably accurate time for each photograph. Instrumentation mounted on the same tripod frame measured current speed and direction, temperature, light transmission, conductivity, and pressure every 3.75 minutes (Butman and others, 2004d). Light transmission is a measure of water clarity and was converted to beam attenuation (attenuation = - 4ln(percent transmission over 0.25 m)). Current was measured, typically at 2 Hz, and vector-averaged to provide a mean current every 3.75 minutes. Pressure also was measured at 2 Hz; the standard deviation of pressure (called PSDEV) was computed every 3.75 minutes as a measure of wave-induced pressure fluctuations at the sea floor. Plots of these data are included in the .avi movies. Instrument Deployments During the USGS study, instrumented tripods were deployed and recovered at LT-A three times each year, typically in February, May or June, and September. This report presents photographs obtained during 18 deployments that took place during the period December 1989 to October 1996. The deployments are identified by a three-digit USGS mooring number that is assigned sequentially to all instrument deployments (table 2). Cameras on Tripod 396 (February to June 1992) and Tripod 465 (February to June 1996) failed to operate and left gaps in the time-series data. Each tripod was located near the USCG Boston Approach B Buoy (National Ocean Service, 1997) on the southern flank of a ridge in water about 32 m deep (fig. 7). This location was selected for long-term observations because the USCG buoy marked the site and provided some protection from other marine activities. Table 2. USGS mooring number, date, location, and water depth of time-series photographs contained in this Data Series report. Mooring Number Start/Stop Date Latitude (N) Longitude (W) Water Depth Depth (m) 338 December 5, 1989 to March 28, 1990 42° 23.65' 70° 47.27' 29 347 July 10, 1990 to October 23, 1990 42° 22.66' 70° 46.97' 34 358 October 24, 1990 to February 12, 1991 42° 22.62' 70° 47.10' 30 374 February 12, 1991 to June 11, 1991 42° 22.62' 70° 47.12' 30 383 June 11, 1991 to October 15, 1991 42° 22.63' 70° 47.07' 30 389 October 16, 1991 to October 30 1991 42° 22.63' 70° 47.11' 30 400 June 2, 1992 to October 20, 1992 42° 22.63' 70° 47.07' 30 407 October 20, 1992 to February 18, 1993 42° 22.62' 70° 47.07' 30 413 February 25, 1993 to June 15, 1993 42° 22.47' 70° 47.12' 32 420 June 15, 1993 to October 6, 1993 42° 22.55' 70° 47.23' 32 428 October 5, 1993 to February 13, 1994 42° 22.53' 70° 47.12' 32 430 February 15, 1994 to June 6, 1995 42° 22.54' 70° 47.22' 31 440 June 7, 1994 to October 4, 1994 42° 22.44' 70° 46.96' 33 445 October 4, 1994 to February 11, 1995 42° 22.43' 70° 46.98' 33 450 February 15, 1995 to June 13, 1995 42° 22.47' 70° 46.86' 33 460 June 13, 1995 to September 26, 1995 42° 22.62' 70° 47.07' 31 462 September 26, 1995 to February 3, 1996 42° 22.62' 70° 47.07' 32 470 June 11, 1996 to October 1, 1996 42° 22.63' 70° 47.07' 31 Digitizing the Films Each photograph on the 35-mm film was digitized as an image in .tif format at a resolution of 1920 by 1080 pixels at the Woods Hole Oceanographic Institution (WHOI) using a special film transport mechanism and aligned using Combustion 4.0 (http://dv411.com/combustion4.html) and Shake 5.0 (http://www.apple.com/shake/) software. The photographs were reduced to 600 by 337 pixels using PolyView (www.polybytes.com) and compressed to 256-color .png images using IrfanView (http://www.irfanview.com), reducing the photograph size by about a factor of 6. This photograph size and compression provide reasonable resolution and manageable size for publication. The full resolution digital photographs and the original 35-mm films are archived at the USGS Woods Hole Science Center. Creating the Time-Lapse Movies Time-lapse movies were created from the digitized photographs using MATLAB software (www.mathworks.com). The photographs collected at approximately 4-hour intervals (deployments 338 through 383) or 6-hour intervals (deployments 389 through 775) were distributed at an even interval between the start and stop time of the photographic record, as determined from the LED clock. The LED clock time was checked for consistency with camera start times and tripod deployment and recovery times, as recorded in field logs. During the deployment, the camera controller occasionally malfunctioned; in order to provide an equally spaced time series, missed photographs were filled with blanks and multiple photographs were deleted. The LED clock was sometimes set ahead of the true date to maximize the amount of time during a deployment that the clock would display the correct day (for example, the day counter of the LED clock was set three days ahead if the tripod was deployed in February to have the counter be correct during March and April). These offsets are corrected in the time displayed below the data panel. The data plots shown with the photographs were made with MATLAB. The movies were compressed with the Microsoft Video 1 codec using VideoMach (http://www.gromada.com/). This reduced the .avi file size by a factor of about 6. Viewing Movies and Photographs The movies may be viewed using a movie player such as Imagen (available free at http://www.gromada.com/imagen.html), QuickTime (available free at http://www.apple.com/quicktime/download/), or Windows Media Player. Click on Movie in table 3 to open the movie, or navigate to the .avi file on the DVD (located in directories labeled TRIPODNNN, where NNN is the mooring number) and open with a movie player. See below for a description of the movie frames. Click on Photographs in table 3 to open a page of thumbnails of individual photographs; click on a thumbnail to view the photograph, in .png format, at a resolution of 600x337 pixels. An effective way to quickly scan a set of photographs is to download the movie file (.avi format) to your computer (right click on 'Movie' in table 3 and select 'Save Target As…'); downloading the movie allows a movie player to rapidily access the large data file and insures playing smoothly without interruption. Once on your computer, open the .avi file with Imagen or QuickTime movie player and drag the slider with your mouse, in either direction, to navigate through the movie frames. Table 3. Click on Movie to open the movie with a movie player such as Imagen, Quicktime or Windows Media Player. Or right click on Movie to download the .avi file to your hard drive. Some movie players allow adjustment of play speed, scanning of the movie by dragging a location slider with a mouse, and/or control of the movie one frame at a time forward or backward. Click on Photographs to open a page of thumbnails of the individual photographs; click on a thumbnail on the thumbnail page to view a larger-format photograph (in .png format). Click on Comments for a list of features and events of note for each set of time-series photographs. See table 4 for a list of frame date and times for each deployment. Mooring Number Start Date Stop Date Movie Photographs Comments 338 December 5, 1989 March 28, 1990 Movie Photographs Comments 347 July 10, 1990 October 23, 1990 Movie Photographs Comments 358 October 24, 1990 February 12, 1991 Movie Photographs Comments 374 February 12, 1991 June 11, 1991 Movie Photographs Comments 383 June 11, 1991 October 15, 1991 Movie Photographs Comments 389 October 16, 1991 October 30, 1991 Movie Photographs Comments 400 June 2, 1992 October 10, 1992 Movie Photographs Comments 407 October 20, 1992 February 18, 1993 Movie Photographs Comments 413 February 25, 1993 June 15, 1993 Movie Photographs Comments 420 June 15, 1993 October 6, 1993 Movie Photographs Comments 428 October 5, 1993 February 13, 1994 Movie Photographs Comments 430 February 15, 1994 June 6, 1994 Movie Photographs Comments 440 June 7, 1994 October 4, 1994 Movie Photographs Comments 445 October 4, 1994 February 11, 1995 Movie Photographs Comments 450 February 15, 1995 June 13, 1995 Movie Photographs Comments 460 June 13, 1995 September 26, 1995 Movie Photographs Comments 462 September 26, 1995 February 3, 1996 Movie Photographs Comments 470 June 11, 1996 October 1, 1996 Movie Photographs Comments Description of Movie Frames Each movie frame includes a photograph of the sea floor at the top of the frame and shows oceanographic data collected at the same time at the bottom of the frame. The movie plays at 3 frames/second (1.3 seconds/day for photographs obtained every 6 hours or 2 seconds/day for photographs obtained every 4 hours). The field of view of the photograph is approximately 1.5 m wide and 1 m high. The vane on the compass in the photographs swings with the current and points in the direction of current flow. The triangular black arrow on the compass points toward magnetic north (16 degrees west of true north at LT-A). The white arrow in the upper left of the frame points toward true north. The file name of the photograph is in the upper left corner of each frame. This number provides a key to the individual photograph; see 'Photographs' in table 3. The red digits in the lower left corner of the photograph show time (in Eastern Standard Time): HR.MM (hour and minute) on the upper line and SS.DD (second and day) on the second line. The day (DD) counter rolls over every 31 days and thus does not indicate true day of month for the entire deployment; the correct day of the month is below the data panel (see below). The third line of red digits is a record identifier (N.N., the last two digits of the USGS mooring number). Below the photograph to the right is a data panel that shows: (1) a plot of current speed (in cm/s) at 1 m above bottom (in red); (2) beam attenuation (in m-1), a measure of water clarity, at about 2 mab (in blue); (3) standard deviation of bottom pressure (PSDEV) (in mb), a measure of wave intensity, at about 2 mab (in black); and (4) water temperature (in degrees C), at about 2 mab obtained every 3.75 minutes (in green). The data scales are the same for all movies and have been selected to show the data under most conditions. However, sometimes during large storms PSDEV and beam attenuation are offscale. The values of current speed, beam attenuation, standard deviation of pressure, and bottom temperature at the approximated time of the photograph (by evenly spacing the photographs over the deployment period) are also listed in the data panel. The vertical black line in the center of the data panel is the time of the photograph. The plot shows 4 days of data, 2 days before and 2 days after the photograph displayed was obtained. Below the photograph to the left is a vector plot showing current speed (length of line) and direction toward which the current flows (true north is up in this display). The time below the data panel is the time for each photograph (in Greenwich Mean Time), computed by evenly spacing the photographs over the deployment. This evenly-spaced time and frame number are tabulated in an Excel file to facilitate finding a specific photograph (table 4). A link to the table of photograph times is also on each page of thumbnails. The best estimate of the time of the photograph is obtained from the hour and minute recorded by the digital clock on the photograph (in EST), and the day from the data panel (or from the framelist.xls). Table 4. Link to tables in Excel format that lists frame number and frame date and time for each deployment. [GMT, Greenwich Mean Time]. Mooring Number Table of frame date and time (GMT) 338 framelist338.xls 347 framelist347.xls 358 framelist358.xls 374 framelist374.xls 383 framelist383.xls 389 framelist389.xls 400 framelist400.xls 407 framelist407.xls 413 framelist413.xls 420 framelist420.xls 428 framelist428.xls 430 framelist430.xls 440 framelist440.xls 445 framelist445.xls 450 framelist450.xls 460 framelist460.xls 462 framelist462.xls 470 framelist470.xls Highlights of Time-Series Photographs The sea floor in the area of tripod deployments in western Massachusetts Bay is typically covered by gravel. Although tripod locations were within about 200 m of each other (fig. 7), the sea floor under each tripod is unique. The placement of the camera, strobe, and compass on the tripod frame differs slightly from deployment to deployment, and thus each set of time-series photographs has different lighting and field of view. Each set of time-series photographs presents a unique view of approximately a 1 square meter area of the sea floor that shows changes in the sea floor, near-bottom water turbidity, and plants and animals. Some features and events for each set of time-series photographs are described in the Comments Section. Some of the deployments have unique characteristics that are a result of the unattended operation of the equipment on the ocean bottom. In some deployments, the lighting decreases with time due to failure of the strobe battery, biological fouling on the strobe bulb or reflector that decreases the light reaching the sea floor, or failure caused by corrosion. The oceanographic sensors or recording electronic equipment do not always function properly for the entire 4-month deployment, resulting in lack of data. In some deployments, the tripod frame was tipped on its side ending the photograph sequence, or continuing the sequence with the camera no longer focused on the sea floor. Sometimes the tripod was tipped by currents associated with storms (record 389) and sometimes apparently by entanglement with fishing gear (records 407 and 428). In almost all of the time-series sequences, movement of the surficial material (pebbles, cobbles, and shells) are observed during the deployment. This movement is best seen by playing the movie, or by scrolling through the movie using the slidebar in the movie player; this viewing shows constant rearrangement of shells and pebble to cobble-sized material on the sea floor. In some deployments, cobbles are rolled or overturned during periods with weak currents (for example in record 400 (see frames 417-418) and in record 462 (see frames 399-400)). The relative role of currents, waves and currents during storms, and biological activity in causing movement of the surficial material remains to be determined. However, the near-bottom currents at LT-A are typically less than 0.2 m/s during non-storm periods, so much of the movement is hypothesized to be caused by biological activity. Although the results are observed in the time-series photographs, the role of particular animals cannot be documented with pictures only every 4-6 hours. Animals and some plants appear in the photographs (see table 5 for identifications). Note that objects, such as fish, close to the camera lens, appear larger than they are in relation to features on the bottom. In most cases, individual animals are observed in only one frame but some are observed in several frames spaced 4-6 hours apart. In some sequences, animals remain in nearly the same location for extended periods of time, or sometimes return to the same location at a later time. For example, in record 338, a skate is observed in the same location (frames 116-125) for at least 48 hours. In record 383, a spiny sunstar is visible for 48 hours (frames 383-390). In record 420, a crab excavates a depression and remains in the depression for at least 12 hours (frames 011- 014). In record 445, a flounder occupies a depression for at least 12 hours (frames 155-157), then a nearby depression is occupied for at least 12 hours (frames 161-163), and finally the first depression is reoccupied for another 12 hours in frames 167-169 and again in frames 221-223. In record 450, two apparently different ocean pout, are observed in nearly the same location, both for at least 8 hours (frames 493-494, and 495-496); later in the same deployment, a similar ocean pout is observed in nearly the same location (frames 657-658). These observations suggest that there may be preferred locations on the sea floor that are occupied for a period of time by the same animals, in the case of these observations typically 12 hours. The animals may also find some shelter beneath the tripod frame which encourages them to stay in the same location. A major process illustrated in the photographs is the resuspension of sediments caused by oscillatory currents associated with surface waves. Increases in beam attenuation (indicating decreased water clarity) usually coincide with periods of increased wave intensity (caused by storms) and visible turbidity in the photographs. The sea floor in this region of Massachusetts Bay is mostly covered by cobbles, pebbles, and coarse sand; however, there are patches of fine-grained sediment to the west of this site (fig. 7), and a thin veneer of fine sediments is likely to accumulate at the tripod site during periods of low waves. These fine sediments are resuspended by the oscillatory currents associated with surface waves. Other observations and modeling suggest that fine sediment resuspended during storms with winds from the northeast in this part of western Massachusetts Bay is transported to the southeast toward the long-term depositional sites of Cape Cod Bay and Stellwagen Basin (fig. 1; Butman, Warner, and others, 2007, Warner and others, 2007). Oceanographic Data The time-series data of current, temperature, light transmission, beam attenuation, and pressure shown in the time-lapse movie of the photographs obtained at LT-A are available in Butman and others (2004). The data may also be obtained from the U.S. Geological Survey oceanographic time-series database at http://stellwagen.er.usgs.gov/mbay_lt.html. The data are archived by mooring number. MATLAB Routines MATLAB software (www.mathworks.com) was used to make the data plots and the .avi movie, the Excel table of frame date and time, and the thumbnail Web pages. M-files may either be opened within a text viewer or within the MATLAB editor. To download the m-files, right click on the links below.       create_movie (makes .avi movie)       create_table (makes the .xls table of frame date and time)       create_thumbnail_page (makes the thumbnail pages) Acknowledgments W. Strahle, M. Martini, and J. Boden prepared the cameras and instruments for deployment and deployed and . F. Lightsom processed the time-series data. We thank the officers and crew of the USCG Cutter White Heath for deployment and recovery of instruments at sea. Maryann Morin digitized and aligned the photographs. We thank Barbara Hecker and Ken Keay for assistance with the animal identifications. This work was supported by the U.S. Geological Survey Coastal and Marine Geology Program and by the Massachusetts Water Resources Authority. Donna Newman prepared this document in HTML. References Cited Bothner, M.A and Butman, Bradford, eds., 2007, Processes influencing the transport and fate of contaminated sediments in the coastal ocean - Boston Harbor and Massachusetts Bay: U.S. Geological Survey Circular 1302, 87 p. Also available at http://pubs.usgs.gov/circ/2007/1302/ Butman, Bradford, Alexander, P.S., Bothner, M.H., 2004a, Time-series photographs of the sea floor in western Massachusetts Bay - June 1997 to June 1998: U.S. Geological Survey Data Series 87, DVD-ROM. Also online at http://pubs.usgs.gov/ds/2004/87/ Butman, Bradford, Alexander, P.S., Bothner, M.H., 2004b, Time-series photographs of the sea floor in western Massachusetts Bay - June 1998 to May 1999: U.S. Geological Survey Data Series 96, DVD-ROM. Also online at http://pubs.usgs.gov/ds/2004/96/ Butman, Bradford, Alexander, P.S., Bothner, M.H., 2004c, Time-series photographs of the sea floor in western Massachusetts Bay - May 1999 to September 1999; May 2000 to September 2000; and October 2001 to February 2002: U.S. Geological Survey Data Series 97, DVD-ROM. Also online at http://pubs.usgs.gov/ds/2004/97/ Butman, Bradford, Bothner, M.H., Alexander, P.S., Lightsom, F.L., Martini, M.A., Gutierrez, B.T., and Strahle, W.S., 2004, Long-term observations in western Massachusetts Bay offshore of Boston, Massachusetts; Data report for 1989 - 2000: U.S. Geological Survey Digital Data Series DDS-74, Version 2.0, DVD-ROM. Also online at http://pubs.usgs.gov/dds/dds74/ Butman, Bradford, Dalyander, P.S., Bothner, M.H., Lange, W.H., 2007, Time-series photographs of the sea floor in western Massachusetts Bay, Version 1, 1989 - 1993: U.S. Geological Survey Data Series 265, Version 1.0, DVD-ROM. Also online at http://pubs.usgs.gov/ds/265/ Butman, Bradford, Dalyander, P.S., Bothner, M.H., Lange, W.H., 2008a, Time-series photographs of the sea floor in western Massachusetts Bay, Version 2, 1989 - 1996: U.S. Geological Survey Data Series DS 265, Version 2.0, DVD-ROM. Also online at http://pubs.usgs.gov/ds/265/ Butman, Bradford, Dalyander, P.S., Bothner, M.H., Lange, W.H., 2008b, Time-series photographs of the sea floor in western Massachusetts Bay, 1996 - 2005: U.S. Geological Survey Data Series DS 266, Version 1.0, DVD-ROM. Also online at http://pubs.usgs.gov/ds/266/. Butman, Bradford, Hayes, Laura, Danforth, W.W., and Valentine, P.C., 2003, Backscatter intensity, shaded relief, and sea floor topography of Quadrangle 2 in western Massachusetts Bay offshore of Boston, Massachusetts: U.S. Geological Survey Geologic Investigations Series Map I-2732-C, scale 1:25,000. Also online at http://pubs.usgs.gov/imap/i-2732c/ Butman, Bradford, Valentine, P.C., Middleton, T.J., and Danforth, W.W., 2007, A GIS library of multibeam data for Massachusetts Bay and the Stellwagen Bank National Marine Sanctuary, offshore of Boston, Massachusetts. U.S. Geological Survey Data Series 99, Version 1.0, 1 DVD-ROM. Also online at http://pubs.usgs.gov/ds/99/ Butman, Bradford, Warner, J.C., Bothner, M.H., and Dalyander, P.S., 2007, Predicting the transport and fate of sediments caused by northeast storms, Section 6 in Bothner, M.A and Butman, Bradford, eds., 2007, Processes influencing the transport and fate of contaminated sediments in the coastal ocean-Boston Harbor and Massachusetts Bay: U.S. Geological Survey Circular 1302. National Ocean Service, 1997, Massachusetts Bay: National Oceanic and Atmospheric Administration, National Ocean Service, Chart 13267, scale 1:80,000. Warner, J.C., Butman, B. and Dalyander, P.S., 2007, Storm-driven sediment transport in Massachusetts Bay: Continental Shelf Research, doi:10.1016/j.csr.2007.08.008.

Click on thumbnail below for figure in PDF format. Figure 1. Location of long-term mooring at LT-A in western Massachusetts Bay. Figure 2. Instrumented tripod on deck of USCG Cutter Marcus Hanna. Figure 3. Instrumented tripod being deployed from USCG Cutter Marcus Hanna. Figure 4. Benthos 35-mm underwater camera mounted on tripod frame. Figure 5. Benthos strobe mounted on tripod frame. The reflector is painted with white antifouling paint to discourage biological growth. Figure 6. Compass and vane assembly mounted in the field of view of the camera. Figure 7. Location of tripod moorings (over-lapping red triangles) at LT-A in western Massachusetts Bay deployed from 1989-2005. Table 1. Chronological list of moorings deployed at LT-A in western Massachusetts Bay between 1989 and 2006, and citation for publications. (HTML format; PDF format) Table 5. Selected images of animals and plants observed in the time-series bottom photographs.