RaNae, Ryan, Mike, Mark, and Adam 5/22/97
Pacific Marine Research Field Trip
Mail us your comments for clams!
During the course of this trip we saw and learned about many new
animals we had never been introduced to before. Many of these
new animals were so small, they required a microscope or some
type of special electronic equipment. The animals we found are
summarized in the following table.
| Animal | Phylum | Class | Feeding Guild | Habitat |
| Larvacean | filter feeder | Zooplankton, middle water | ||
| Gammarid | sometimes preditory or scavenger of rotting algae | Zooplankton, middle water | ||
| Calanoid Copepod | active filter feeder, eats diatoms | Zooplankton, middle water | ||
| Euphausid, (krill) | Mollusca | Gastropoda | filter feeder, a popular food for the baleen whale | Zooplankton, middle water |
| Zoea (early crab) | Anthropoda | Crustaceans | filter feeder and scavenger | Zooplankton, middle water |
| Chaetognath (arrowworm) | Annelida | active predator, impales prey with its spears | Zooplankton, middle water | |
| Hyperid (amphipod) | active predator, has a spear on frontlegs | Zooplankton, middle water |
Zooplankton, middle water Diatoms photosynthesis Phytoplankton,
surface water (photozoic zone) Sea Slug (nudibranchs) The smallest
animal seen in this above table is a phytoplankton.
***Something garbled here in the email.***
The food web liot bay is very ant. Without one of se animal it
makes it very difficult to survive. The phytoplankton are at the
very bottom of the food chain. They are food to everything. They
are most commonly eaten by the zooplankton thought because many
larger animals can eat the phytoplankton because they are too
small. The zooplankton help make a barrier by eating the phytoplankton,
and then the larger animals are able to eat the larger zooplankton.
An example of a larger animal would be the baleen whale which
enjoys feeding off of the euphausids. The larger animals take
in the zooplankton for food or other larger animals. Such as the
sea star feeding on sea squirts and muscles. This processed is
then recycled by the larger animals dying or their fecal pellets
giving of nutrients back to the phytoplankton.
Weather and Wind Climate
On this particular day the wind was out of the north at under 10 knots. The waves corresponded to the wind to make wind waves except for the boat waves. The marine forecast for the area seemed fairly close to this above observation. Three factors determine wave height. They are the wind speed, wind duration, and the fetch. The fetch is the distance over water in which the wind blows in only one direction. All of these factors contributed to the observed conditions. The waves in which we experienced were relatively consistently calm, expect for a few interruptions of stronger wave activity. This would make since because the wind speed was not incredibly strong. The intervals where we had stronger wave activity could have resulted from a boat passing by or a strong gust of wind.
The observed atmospheric pressure pattern was that we were experiencing
a high pressure system off of the coast. This would account for
a northerly wind, which would appear as a clock wise flow around
the highs in a weather picture:
The geostrophic winds, are formed in relation to the geostrophic flow. The geostrophic flow occurs when the balance between the gravitational forces and the Coriolis effect are being accounted for. This creates a horizontal flow of water, which in turn effects the pattern of thds.
The shoreline of Elliot Bay has been highly altered. This has been caused by human intervention. The original shoreline of the Bay would have been free of all manmade structures such as buildings, docks and other beach structures. This area probably used to look a lot like Padilla Bay, with its shallow waters and muddy environment. The kingdom and much of the industrial area of south Seattle are located on a reclaimed portion of Puget Sound. The land that holds these buildings were diked and drained which damaged the intertital region. The type of organisms that would have lived in this area is similar to the animals found at Padilla Bay. Some of these animals would include a variety of worms, eelgrass, and kelps. Some larger organisms would include oysters, clams, and crabs. This area also probably supported a breading ground for the larger animals in Elliot Bay.
Tidal and Current Environment of Elliott Bay
The tidal height predictions for the day of the field trip are as follows:
H 2:13 AM 10.7
L 9:01 AM 2.8
H 3:12 PM 8.2
L 8:30 PM 4.3
Although there is definitely a tidal change occurring here, the low never goes beyond mean low low water, explaining why the tide at Alki appeared average, although it was coming in. As we were cruising in the bay for much of the trip it was difficult to properly analyze the tides.
The tidal ranges increase in magnitude with the new and full moons. On average, mid-month tides tend to be regular, with near equal highs on both highs. This is due to the tendency to have a full moon in mid-month. Summer tides have the lowest lows in the daytime, while winter tides have the lowest lows in the night. This demonstrates the superior pull of the sun in summer months and the moon in the winter months.
A hydrometer was used to measure the salinity. The two type of bottles used to take the water samples were the Nansen bottle and the Niskin bottle. The Nansen bottle is older and the Niskin bottle is much more modern. These bottles work by opening the hatch, then sending them down to a desired depth, then using a messenger are closed up. A messenger is simply a brass weight that slide along the cord the bottles are attached to. The depths of the two water samples we ook were 15m andhe surface Our measur water temperature as 12 C. The salinity would be greater as the depth increases because saltwater is more dense then freshwater. There would be more fresh water in puget sound at low tide (which was around the time we left the dock) than at high tide (when we returned) due to the fact that fresh seawater is flowing into Puget sound during high tide. Puget sound has fresh water because it is an estuary, where the rivers drain into the sea.
Predominant surface currents near the river mouths (Suamish) are almost always outwards from the river, but because fresh water floats on salt water, deeper currents could be going in the opposite direction during a flood tide.