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We
have drawn on an extensive, multi-year database of
biota and physical characteristics of 64 sites in Puget
Sound to choose the appropriate study sites and generalize
our results. All experiments are conducted at 3 replicate
beaches with shared geophysical characteristics.
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Juvenile
Pacific oysters are settled on ceramic tiles in the laboratory
and outplanted to each of the 9 experimental beaches, where
the tiles are attached to stakes pounded into the sediment.
Plates are photographed every 1-2 months and the growth
rates of individual oysters are measured from these photographs.
The plates also serve as ways to measure natural colonization
of other organisms. After approximately 6 months, oysters
are sampled for stable isotope analyses (link back to Hypotheses). |
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Barnacle
larvae are allowed to settle on tiles placed in one location
(at the Friday Harbor Labs on San Juan Island), then tiles
are moved to the experimental beaches and attached to stakes
as for the oyster tiles. Barnacle growth is similarly measured
from photographs taken every month through the year. Other
organisms settling on the barnacle tiles are also quantified. |
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Chunks
of sandstone cobble approximately the size of large local
cobbles each had a uniform-size square of grey paint painted
onto one flat face, and these rocks (5 per beach) were
put out at the experimental beaches. Scouring of the paint
off the rock is quantified through time to compare the
degree of abrasion experienced by surface-dwelling organisms
at each of the 9 beaches.. |
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Small,
waterproof temperature dataloggers (TidbiTs, Onset Computer
Corporation) are placed at each of the 9 beaches and programmed
to log the temperature approximately once every hour. At
each beach, separate loggers record the temperature on
the surface of the beach (same tidal level as the experiments),
buried in the sediment of the beach, and just offshore
of the beach. These data will be used to seek correlations
between local processes (growth rates, distinct recruitment
or mortality events) and temperature, and also to quantify
how well nearshore temperatures track those recorded in
the middle of Puget Sound by other research groups (e.g.
the Washington Department of Ecology; link to their webpage). |
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Rocks
with small individuals of the common brown seaweed Fucus
gardneri (rockweed) were placed at each of the 9 sites
in June 2004, and all the individual plants were marked
and measured. Plants are remeasured monthly, and their
growth rates compared among sites. This provides a measure
of primary productivity. |
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To measure
the recruitment of organisms (especially juvenile clams
and worms) settling in beach sediments, cores of sterile
sediment enclosed in window-screening will be embedded
in each beach beginning in Feb. 2005. This cores will be
exchanged with new ones each month, so that we can examine
seasonal patterns in recruitment as well as patterns along
the north-south gradient. |
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To measure
the recruitment of organisms that live on surfaces (e.g.
on natural cobbles), we will put out ceramic settling tiles
at each beach beginning in Feb. 2005. These will be exchanged
with clean ones each month, as for the sediment |
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Basic
information on the abundance and diversity of
organisms on each beach are gathered each
year at each of the experimental sites. Sampling follows
the
protocol used by DNR’s
SCALE program. Briefly, a 50m line is laid along
the beach at 0' tide level. At 10 randomly placed intervals,
all the macroscopic organisms on the surface are counted
using a 50x50cm quadrat frame, and all the organisms
are sieved from a sediment core 15cm deep and 10cm diameter,
and identified later in the laboratory. |
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At
5 additional locations in June of each year, all organisms
are collected from the surface and from a sediment core
to measure biomasses. Species-specific
biomasses are measured by randomly collecting samples of epibiota
and large infauna (clams) and returning them to the lab to get
wet and dry masses; small infauna biomasses are measured
following laboratory identification. |
