Location: Bowdoin / Earth and Oceanographic Science / Research / new folder / Poster Abstracts

Earth and Oceanographic Science

Poster Abstracts

MEASURING NUTRIENT DYNAMICS OPTICALLY: TOWARDS AN UNDERSTANDING OF THE IN SITU RELATIONSHIP OF NITRATE TO PHYTOPLANKTON
Anderson, Amy, Bowdoin College, Brunswick, ME, aanderso@bowdoin.edu
Roesler, Collin, Bowdoin College, Brunswick, ME, croesler@bowdoin.edu

Currently, there is a need to measure phytoplankton and nutrients in situ on the same time and space scales to resolve dynamics. Using recent advances in underwater UV spectroscopy, detection of nitrate and other UV absorbing components is possible in open ocean conditions, where CDOM is negligible and salinity is relatively invariant. In coastal waters the latter two components vary tremendously due to influences from river systems. A model for estimating nitrate in the presence of varying salinity and CDOM is developed here. The absorption in the UV range of 210-250 nm is decomposed into absorption by these components. Each component is represented by the product of the concentration (unknown) and the mass-specific absorption coefficient (measured in the lab). A linear regression of the linear model against measured absorption yields the concentration of the three components. The model was tested with laboratory-constructed media representing a range of aquatic environments and a time series of samples coming from the natural environment. Overall, the method shows that nitrate and seasalt concentrations can be determined by using the UV absorption spectrum.

LOCAL AUTHORITY IN THE CONTEXT OF COASTAL MARINE SPATIAL PLANNING IN THE NORTHEAST REGION OF THE U.S.

Dean, Hannah, University of Massachusetts Boston, Department of Environmental, Earth and Ocean Sciences (EEOS), University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125-3393, USA, hdean83@gmail.com

State-local authority sharing relationships vary in the Northeastern states (Maine, New Hampshire, Massachusetts, Rhode Island,
Connecticut, and New York) in terms of history, regulation of marine resources, and roles in state coastal management. As regional Coastal Marine Spatial Planning (CMSP) develops from the data gathering and planning stage towards the action stage, it will be important to acknowledge these differences and provide a suitably flexible framework for funding mechanisms, local partnerships, and local incentives for the CMSP process. In large part, these are built into the current coastal and ocean law framework, but this is layered over a landscape of local practices and administrative structures. Using statutory, policy, and case law research, this paper provides an initial region-wide assessment of the role of local authority in the CMSP process. By doing so, the paper also points to further avenues of research on the role of local authority in the context of ocean andcoastal planning.

CHARLES OTIS WHITMAN, 1868: BOWDOIN’S FORGOTTEN ZOOLOGIST
Edwards, Jennifer, Bowdoin College, Brunswick, ME, jedwards@bowdoin.edu, Greenberg, Joel, Research Associate at both Peggy Notebaert Nature Museum, Chicago, Academy of Sciences, and Field Museum, Chicago, IL, joelgreenberg@earthlink.net, Wegner, Susan, Bowdoin College, Brunswick, ME, swegner@bowdoin.edu

Charles Otis Whitman (1842, Woodstock, Maine -1910, Chicago) was a pioneer in establishing the discipline of biology in the United States.  Graduating from Bowdoin College in 1868, Whitman went on to earn hisPh.D. in Zoology at the University of Leipzig in 1878.  Like his colleague, Edward Sylvester Morse (1838-1925) (Chair of comparative anatomy and zoology at Bowdoin College, 1871-1874; lecturer at Harvard from 1876 on), Whitman worked with Louis Agassiz of the Museum of Comparative Zoology at Harvard.  After holding research and teaching positions in Tokyo and Naples, Italy, in the study of marine organisms, Whitman returned to the United States to become founding Director of Woods Hole Marine Biological Laboratory (1888-1908).  He also organized the Biology programs at Clark University (1889-1892) and at the University of Chicago (1892-1910).  In his 50s, Whitman undertook the study of evolutionary bases for the behavior of pigeons, including one of the last flocks of passenger pigeons (Ectopistes migratorius) shortly before their extinction in 1914.

For more on Charles Otis Whitman, see Project Passenger Pigeon, an international interdisciplinary initiative for 2014, at http://pasengerpigeon.org/

EXAMINING AND INTERPOLATING FLOOR SEDIMENTS IN HARPSWELL SOUND BASED ON GRAB SAMPLES ALONG FIVE TRANSECTS
Handy, Connor, Bowdoin College chandy@bowdoin.edu  Adviser: Eileen S. Johnson

In this study, I collected grab samples of sediments from the floor of Harpswell Sound along five separate transects spanning the width of the sound. Each transect consisted of five grabs spaced roughly evenly across the sound. This data was collected in the afternoon of October 21, 2011 with the help of David Mercier and Conor O’Toole. The information collected during the study (depth, latitude, longitude, time, grain size) was then added to an Excel spreadsheet which was in turn imported to ArcGIS. After some latitude-longitude conversion, I plotted the points, which are seen here in every map. In order to predict which grain sizes would be found in which areas of the sound, I decided to conduct an Inverse Depth-Weighted interpolation based on the twenty-five grab samples I collected. To do this, I ranked the grain sized I found from 1 to 5—one being the finest clay and five being hard rock bottom. The IDW interpolation was conducted using these values, and is shown in Figure 1.

Much of the data in the other maps was collected by Stuart MacNeil and Thomas Duffy in an effort to accurately map the physical characteristics of Harpswell Sound. The Bowdoin College Earth and Oceanographic Science department employed these two to help decide the best placement for the data collection buoy now located in the sound. Figure 2 shows bathymetry data of the northern end of the sound they collected, overlayed with the points I collected grab samples at. Figure 3 shows a depth TIN constructed from data they collected in the study, again overlayed with the points I collected grab samples at.

Figure 4 shows backscatter data collected by MacNeil and Duffy in their study of Harpswell sound. Backscatter imaging shows the grain sizes of floor sediments using a reflecting technique. Circled images in this figure highlight areas where the backscatter image correlates with the interpolation of grain sizes that I conducted using grab sample data.

ANNUAL REPORTS OF MAINE FISH INSPECTORS 1804-1820
Leavenworth, William, University of New Hampshire
WilliamLeavenworth@gmail.com

Annual reports of the Maine Fish Inspectors for the years 1804-1820 show three sharp declines in anadromous fish catch. Two declines are attributable to political events (Embargo and War of 1812) but the third is contemporaneous with the "Winter of 1800 and Froze to Death," a result of the Tambora eruption in 1815, which destroyed crops around the world in the latitude of Northern New England. I argue that Tambora's sulfate aerosol precipitation and accompanying colder temperatures depressed alewife and shad reproduction in Maine's major rivers for several years following the eruption, while local consumption in lieu of other normally accessible protein sources further depressed the spawning population. These circumstances are not noticeable to such a degree in Massachusetts Rivers, which also contributed a large percentage of locally-consumed protein.

A NEW TOOL TO TRACK THE ENVIRONMENTAL EVOLUTION OF THE GULF OF MAINE: THE UK’37 SEA SURFACE TEMPERATURE PROXY
Salacup, Jeffrey, Brown University, 324 Brook St., Providence, RI, 02912, Jeffrey_Salacup@brown.edu
Herbert, Timothy, Brown University, 324 Brook St., Providence, RI, 02912, Timothy_Herbert@brown.edu
Prell, Warren, Brown University, 324 Brook St., Providence, RI, 02912, Warren_Prell@brown.edu

Decadal-scale reconstructions of Holocene sea surface temperature (SST) are rare but essential to understanding recent climate trends. This is largely due to low sedimentation rates encountered in the open ocean. Hence, our understanding of climate system variability over the Holocene is largely dependent on terrestrial data. Given the importance of the ocean to local and global heat budgets, the acquisition of more high-resolution marine records should be of primary concern. Recent advances in the application of the Uk’37 SST proxy, based on organic compounds called alkenones, allow for the first time the application of this well-established proxy to high sedimentation-rate shelf sediments. Here we present results on a core from Jordan Basin of a feasibility test to determine the suitability of Gulf of Maine sediments for further Uk’37 investigation by comparing a Uk’37-inferred SST reconstruction with that based on oxygen isotope ratios of planktonic foraminifera.

SSTs based on Uk’37 and oxygen isotopes suggest a cooling in the Gulf of Maine of ~4.5 and ~2.4°C, respectively, over the past ~8000 years. The core top estimate of Uk’37 SST (~10.0°C) is in good agreement with instrumental annual average SST (9.8°C; 2004-2010; http://gyre.umeoce.maine.edu) supporting the use Uk’37 at this location. To test the hypothesis that cooling was due to an increased contribution of Labrador Sea Water, we reconstructed the oxygen isotope composition of the water by correcting for temperature effects using Uk’37. The results imply a slight freshening of the Gulf of Maine over the Holocene consistent with increased Labrador Sea Water export.

ALEWIFE RESTORATION IN THE KENNEBEC WATERSHED: A SPATIAL ANALYSIS OF LAKE SPAWNING HABITAT AND DAM REMOVAL
Sneed, Anne I.  asneed@bowdoin.edu, Adviser: Eileen Johnson, ejohnson@bowdoin.edu

My research question looks at the potential for alewife restoration in the Kennebec watershed. As a migratory fish, alewives are born in freshwater lakes, migrate to the ocean where they spend most of their adult lives, and return to their freshwater birthplace to reproduce. However, dams without fishways prevent alewives from reaching freshwater spawning habitat. Dams, along with other factors, have decimated alewives so that in certain Maine rivers, alewife runs have decreased by 99.9%.

My spatial analysis evaluates how much littoral zone and overall lake habitat become accessible to alewives after the removal of a dam in the Kennebec watershed. Alewives tend to lay their eggs in littoral (shallower) areas of lakes. Therefore, understanding accessibility to littoral zone and lake area is an important part of alewife restoration. I analyzed lakes in the Kennebec watershed, calculating how much littoral zone each one contained. I analyzed lakes in the Kennebec watershed, calculating how much littoral zone each one contained. I then performed a connectivity analysis, evaluating how much littoral zone and overall lake habitat was upstream of a dam.

The littoral zone and overall lake habitat accessible to alewives after dam removal accounts only for areas between the ‘removed’ dam and the next dam(s) upstream that blocks connectivity, not the cumulative effect of removing a dam and all the dams above it. Also, the removal of a dam will not open any habitat to alewives if dams downstream block access to the ocean.

Note: Natural and undocumented human-made barriers were not included in this analysis.