Eco-Research News
Eco-Research Program, Memorial University
of Newfoundland
Number 2, December 1996
The Natural Science Work
Introduction
The Eco-Research Project's natural scientists have been studying three watersheds - one
near the community of Bonavista, one on the Isthmus of the Avalon Peninsula and one in
the vicinity of Hickman's Harbour on Random Island. These watersheds were chosen to
represent the headland and bay focal points of the Project.
The Bonavista watershed is of particular interest because of the community's 400-year
history of fishery development. It is a north facing community, fully exposed to storms in
the Labrador Sea and the modern flora in the area has a distinctive sub-Arctic character.
Indigenous knowledge suggests that in the past a forest, now logged or burned,
completely covered the Bonavista Peninsula.
In contrast, the watershed on the isthmus has two industries situated within close
proximity - the Come-By-Chance oil refinery and the construction site for the Hibernia
Gravity Based Structure (GBS). The watershed near Hickman's Harbour is being studied
for comparative purposes since it is intermediate in character compared to the Bonavista
and Come-By-Chance watersheds.
Utilizing palynology and geochemistry the scientists are examining the degree to which
natural and anthropogenic changes have affected the region and their principal
watersheds (including materials entering the near shore marine environment).
The natural science group is divided into three sub-groups. Two of these are studying
terrestrial components in the watersheds and the other is studying marine aspects,
including the terrestrial-marine interface.
One of the terrestrial sub-groups is examining the physical aspects and is led by earth
scientist Moire Wadleigh. Other members include earth scientists Elliott Burden and
Peter Davenport, and chemist Niall Gogan, along with graduate students Alexei Smirnov
(Earth Science), Li Jin (Chemistry) and undergraduate student Nicholle Evans.
The other terrestrial sub-group is focusing on biological aspects and is led by biologist
Murray Colbo, along with fellow biologists Peter Scott, Bob Sheath and John Kingston.
Biology graduate students Tammy Lomond, José Perez, and undergraduate students
Kirsten Muller and Allison Sherwood are also members of this sub-group.
The Marine sub-group is led by oceanographer Chris Parrish along with earth scientist
Jun Abrajano, chemist Bob Helleur, and graduate students Sue Budge (Chemistry),
Yvette Favaro (Chemistry) and Jerry Pulchan (Earth Science).
Terrestrial Sub-Groups
Information on the past environment in Bonavista is accumulating. Geochemical analysis
of lake sediment suggests the ponds in the community area have been modified by
European settlement. Chemical indicators of erosion from forest clearing such as
aluminum (Al), titanium (Ti) and magnesium (Mg), increase by several orders of
magnitude at the top of the sedimentary column (Figure 1). The trace metals copper (Cu)
and lead (Pb) also increase, consistent with industrial and residential development.
According to pollen analyses, changes in vegetation associated with the increase in
metals are restricted to an increase in the percentage of herbs, interpreted as representing
the arrival of Europeans in the area and the beginning of forest clearance for agriculture
approximately 400 years ago.
Other changes in vegetation apparently indicated much older events in the history of the
area including the end of glaciation (approximately 10,000 years ago), a climatic
optimum (approximately 5,000 year ago), plus smaller climatic variation since, including
cooling and an increase in precipitation. Hinterland ponds show little change in chemistry
throughout their sediment profiles. This is not unexpected considering the absence of
population even today.
Water from ponds in each of the three watersheds were sampled in the spring and
summer of 1995. Total metal concentrations for zinc (Zn), cadmiium (Cd), copper (Cu)
and lead (Pb) were compared with the amount of "free" or bioavailable metal obtained
through speciation techniques. Measurable amounts of total Zn and Cu were found
throughout the study area. Cd was below detection limits in all samples while Pb was
detected in two ponds in the Bonavista watershed and one in the Come-By-Chance
watershed.
The highest concentrations of free Zn,
Cu and Pb were obtained in the
Bonavista watershed. Sites from the
Random Island watershed had the
lowest concentrations of all free metal
except Cu which was lowest at ComeBy-Chance. Some seasonal variation was observed with summer concentrations generally
higher than spring, but the overall pattern was similar with Zn greater than Cu, Pb and Cd
were below detecting limits in the summer samples except for a single sample with free
Cd from the site closest to the refinery in the Come-By-Chance watershed.
Metals and major ions have been measured on rain
samples collected during the summer of 1995 in
Bonavista. The calculated marine component (i.e.
salts from the ocean) ranged from 7 to 60 percent.
The metals of interest in order of decreasing
concentration in the rain are Zn, Mn, Pb, Ni and Cd.
Values are intermediate between measurements
made in St. John's and Seal Cove and reflect average
urban to rural levels. Little seasonality has been documented previously so it is
reasonable to assume that these summer samples are representative of average
atmospheric input to the area.
Lichen samples were collected throughout the entire study area and have been analyzed
for their sulphur content and sulphur isotopic composition. Samples from the Bonavista
watershed average ð34S=15 per mil and S = 300 ppm consistent with proximity to the
ocean. Samples from Come By Chance average ð34S = 9 per mil and S = 600 ppm
consistent with proximity to the refinery while samples from the Random Island
watershed were intermediate averaging ð34S = 10 per mil and S = 400 ppm. Metal
analysis on the lichens will help to clarify the interpretation of this trend along the
peninsula but it seems to reflect a decreasing influence from the refinery and an
increasing marine influence moving away from Come-By- Chance toward Bonavista.
Marine Sub-Group
Five successful cruises to Trinity Bay were completed during 1994 and 1995 to
determine water, sediment and plankton chemistry. Net-tow, core and grab samples were
also collected at the land-margin in Random Sound and Trinity Harbour. Various
terrestrial plant samples were collected from the watershed surrounding Trinity Bay.
Analyses show significant inputs of terrestrial plant material in the Random Island area.
In the Trinity Bay eco-system there appear to be uniformly low inputs of labile organic
material throughout the year except during a brief period of a few weeks when there is a
massive input associated with the spring diatom increase. This is typical of this kind of
environment. The input of anthropogenic organic compounds in this area is apparently
low except in the vicinity of the Bonavista headland where it may be significant.
The results from the sediment trap
work show that for most of the year,
input rates of dry matter, organic
matter and total lipids in Trinity Bay
are only slightly higher than have
been found in the North Atlantic, but
in April the rates increase to a level
more typical of a highly productive
oceanic upwelling region. During
the spring bloom of 1995, several
net-tow samples were taken. They were characterized by having generally higher organic
contents by comparison with the sediment trap material and lower lipolysis indices. An
interesting sequence of net tows at four stations in a transect going into Trinity Harbour
indicates a very strong gradient in lipid content with the highest lipid values being
obtained right inside the harbour. Among the biomarkers, signatures for marine diatoms
and zooplankton were recognized, as well as small amounts of some terrestrial plants. In
the spring, diatoms were found to be the dominant source of fatty acids while terrestrial
plant material and zooplankton were more important sources in the summer and fall.
There seems to have been a higher softwood contribution to the shallower sediments
around Random Island in comparison with grass, suggesting a recent change in the nature
of terrestrial inputs. This could be a consequence of the natural evolution of the
surrounding terrestrial eco-system or of human activity such as logging and milling
causing an increased softwood input. Analysis of more cores will help to verify any
anthropogenic influence and to pinpoint where this activity has been the greatest.
Analyses of marine sediment cores show little indication of oil-based anthropogenic
hydrocarbons in the study area. The types of hydrocarbons found indicated combustion
product markers derived from wood-burning activity. Higher levels of these markers
from the Bonavista watershed versus that of Hickman's Harbour's indicate a higher
anthropogenic input from built-up areas. Analysis of the watershed near Come-ByChance shows unexpectedly low levels of refinery-based hydrocarbons and further
analysis may reveal that airborne hydrocarbons are not effectively deposited near this
source. Elevated levels of industrial plasticizers were also found in the Bonavista harbour
and it is anticipated that these markers will be found in marine sediments when cores are
taken in that area. Compound specific isotope analysis will further help determine the
source of some of the important polyaromatic hydrocarbons in sediment core sections.
Congratulations to Chemistry Masters Student, Yvette Favaro, who took first prize for
best overall poster at the EnviroAnalysis '96 Conference in Ottawa earlier this year.
Yvette also took first prize for the best student presentation at the Canadian Society for
Chemistry Conference and Exhibition held at Memorial in June of this year. Yvette is a
member of the Marine sub-group.
Previous Newsletter Back to List