Erwin Reguindin's Senior Thesis - Glacier Bay National Park, AK

Erwin Reguindin's Contact Information UW Oceanography Senior Research Cruise

Cruise Videos

My incubation setup

Canadian Piolot Transfer

Andy's video of the Thompson breaking ice

Reflection off bow of Thompson

Cruise Photos

Margerie Glacier in Tarr Inlet	Grand Pacific Glacierin Tarr Inlet
Margerie Glacier	Grand Pacific Glacier
Margerie Glacier Calving	Two bald eagles hang out on a recently calved ice berg in Tarr Inlet
Margerie Calving	Bald Eagles
As we cruised by Port Renfrew (the last Canadian port heading north) we dropped off our Canadian pilots. This is an interesting process. The pilot boat (surrounded by a rubber bumper) came alongside the Thompson and matched its speed. As we cruised along in the swells the pilots simply jump from the ship to the boat.	I was the first student in 9 years to use radioactive isotopes (C14) in their senior thesis.
Canadian Pilot Transfer	Low Light Radioactive Working
This is a photo of my incubator running and me preparing my samples	The door to the radiation van
Incubator	Radiation Hazard

Glacier Bay Blog

R/V Thomas G. Thompson - Find out where it is!

R/V Thompson BlogFind out where the Tommy Thompspn is right now!

R/V Thomas G. Thompson (AGOR-23) is one of the newest, most modern vessels in the national oceanographic fleet. She entered service in 1991, and has greater endurance at higher speeds and with better sea-keeping ability than previous research vessels. These enhancements, together with modern navigation and communications capabilites and a state-of-the-art sea floor mapping system, enable the ship to perform a broad range of functions year round and world wide. The 274-foot-long ship carries a crew of 21 and up to 37 scientists. Thompson has over 4000 square feet of laboratory space, modern deep sea winches, bow and stern cranes, a stern A-frame, and spacious deck working areas. Her unique Z-drive main propulsion system and jet-type bow thruster provide the vessel with excellent station keeping ability, even in high seas.

The Effect of Suspended Glacier Sediments on Light Attenuation and Primary Productivity in Glacier Bay National Park, Alaska

Senior Thesis Paper

Research Cruise Completed!

Check out the cruise BLOG to catch up on how the cruise went and see some amazing VIDEOS and PHOTOS

Also check out my personal blogs I wrote while on the Glacier Bay cruise

What and Why

The objective of my project is to understand how suspended glacial sediments affect vertical light atteunation (light scattering, and absorption), with the hypothesis that an increase in light atteunation will cause a reduction in the attainable light which will limit phytoplankton production in areas more heavily impacted by glacial retreat. The amount of glacial flour in the photic layer is likely to decrease as a function of distance from the glacier toe, so my expectations would be to observe greater primary production -- and thus greater abundances of higher trophic levels from copepods up to whales, which the Glacier Bay is known to support a large population of -- in areas farther away from the glaciers, for example near the lower and central bay.

How

I measured 4 variables at 8 USGS Sations within Glacier Bay National Park.

Light Attenuation
Fluorescence
PAR
Primary Production .

Click to see data and log sheets from each of the 8 stations that I sampled.

Light Attenuation

The attenuation of light is caused by the scattering and absorption of light by optically interactive particulate matter and CDOM. For this particular variable, the main focus will be on the scattering of light due to the expected overwhelming contribution of suspended sediments, in this case glacial flour. Light attenuation is proportional to the concentration of glacial flour suspended in the water column and more light will be attenuated as concentrations of glacial flour increase (Sanchz 1985, Yentsch, 1962). The CTD mounted transmissometer was used to measure or infer the in situ optical properties of suspended material (sediment and algae). The instrument provided an in situ measure of the transmissivity of the water which will provide a proxy for the attenuation of light. One problem using the transmissometer is that it is sensitive to all suspended material that is affecting light attenuation including phytoplankton.

Glacial Flour

Glacial flour at the toe of Margerie Glacier.

Fluorescence

Phytoplankton fluorescence is the excitation of the pigment system from the photo pigment chlorophyll a. The measurement of chlorophyll a will provide a proxy for biomass and photopigments available for primary production. To measure fluorescence, an in situ fluorometer attached to the CTD provided a profile of the fluorescence which can be converted to chlorophyll a, when appropriately calibrated. With the assistance of oceanography scientists, Jasper Boas and Christine Sislak also aboard the R/V Thompson, chlorophyll a was measured by filtration, extraction of photopigments and the use of a Turner design fluorometer. The information from the transmissometer and the fluorometer will be used to approximate the fraction of phytoplankton fluorescence responsible for the observed attenuation of light. The combined data from irradiance and fluorescence will be used to create a chlorophyll a specific photosynthesis vs. irradiance curve (Forget, 2007; Furuya, 2007).

An example of a P vs. I curve

Photosynthetically Active Radiation (PAR)

Photosynthetically active radiation is the range of wavelengths of light from 400 to 700 nanometers that contribute most to photosynthesis. The PAR sensor attached to the CTD provided a continuous profile with depth in the water column. This instrument provides a total flux of light penetrating into the water column and the light extinction coefficient "a" with depth. Deviations from an exponential decrease with depth can be inferred from in situ data using the transmissometer. The light extinction coefficient is the measure of how well PAR is attenuated with depth through the water column. Low values indicate that light is passing through un-attenuated and a high value is the opposite. This information will be used to determine the depth to which light penetrates into the water and will allow for estimations of primary productivity based on empirically determined P. vs. I. relationships of the algae.

Primary Production

Primary production is the incorporation of new organic matter into living tissue through the process of photosynthesis and fixation of dissolved inorganic carbon through photosynthesis. As this is the primary focus of the project, primary production was measured via the carbon-14 (¹⁴C) method as first proposed by Steemann and Nielson (1952) with modifications by Strickland and Parsons (1968). The method is based off the fact that the biological uptake of ¹⁴CO₂ is proportional to the biological uptake of ¹²C (Galloway, 1969). There are still uncertainties in this method as demonstrated and evaluated by Lean (1979), Peterson (1980), and Miller (2004). These uncertainties will be discussed in the final thesis.

The CTD rosette was cast at 8 USGS stations (21,12, 11, 08, 06, 05, 02, and 01) to collect water samples from 4 depths (surface, 10 m, 20 m, Chlorophyll max). Each 1 liter sample will be divided into 6 – 15ml sub-samples in 20ml glass bottles. One incubation was run for each depth at each of the midpoint stations (12, 11, 08, 06) and mouth stations (02, 01). Sub-samples from USGS stations 21 and 5 were incubated in triplicate for all depths totaling 288 sub-samples (Table 1). Each sub-sample was labeled with USGS station number, depth, and replicate number. Each su sample was then inoculated with 40 ml of 53mCi mmol^-1 Na¹⁴CO₂ sodium bicarbonate (Research Products Inc.), capped and inverted several times to mix. Each inoculated bottle was kept in the dark inside a light tight box until time for incubation. Each of the 20ml vials was placed into the incubator and the incubation start time was recorded and bottles were incubated for 1 hour. The incubating apparatus holds 25 sub-samples which can be incubated at different irradiances ranging from 0.1 mE m^-2 sec^-1(quantums) to 440 mE m^-2 sec^-1(quantums). There will be 24 sub samples per station. For stations requiring triplicates, 24 sub-samples were incubated at a time 3 times. After the incubation the vials were removed and placed back into a light tight box. Then the contents of the vials were filtered through 0.2mm GF/F filters to concentrate phytoplankton. Each filter was then placed into a 7ml vial containing about 5ml of biofluor scintillation cocktail. A period of several days was used to allow the cocktail to rest before the sample is put into the scintillation counter to measure the amount of ¹⁴C assimilated by the phytoplankton. All wastes were contained and kept inside the radiation van for disposal after the cruise.