title: Dr
first_name: Evelyn
middle_name: B
last_name: Sherr
organization: COAS-Oregon State University
email: sherre@coas.oregonstate.edu
mailing_address: 104 Ocean Admin Bldg
city: Corvallis
state_province: OR
postal_code: 97331-5503
country: USA
phone: 541-737-4369
fax: 541-737-2064
additional_investigators: 1
project_or_program: SBI
grant_number: 0124892-OPP
grant_title: COLLABORATIVE RESEARCH: Mesozooplankton-Microbial 
Food Web
Interactions in Western Arctic Shelf and Basin Regions
prop_summary: A central goal of the Shelf-Basin Interactions (SBI) 
program is to understand the processes affecting carbon 
transformations and fluxes within and between Arctic shelf and 
basin ecosystems, and how climate change might impact these 
processes. The cycling of carbon in Arctic shelf and basin habitats 
depends on the structure and functioning of the food webs of these 
regions. In the pelagial, both micro- and meso- zooplankton are 
significant consumers of primary production. The partitioning of 
primary production between the fractions remaining in the water 
column or sedimenting to the benthos (where organic matter is less 
available for export from the shelf) can be greatly affected by the 
relative grazing rates of microzooplankton versus mesozooplankton 
herbivores. Microzooplankton grazing dampens export flux, while 
mesozooplankton grazing enhances it. The primary focus of our 
proposed collaborative project is an analysis of the impact of 
microzooplankton and mesoz
 ooplankton grazers on the fluxes and exchanges of carbon within 
the oceanic waters of the Canada Basin and the shelf waters of the 
Chukchi/Beaufort Seas. We will use standard methods and 
experimental protocols to determine the standing stocks and size 
structures of microzooplankton, phytoplankton, and 
mesozooplankton assemblages, to measure growth 
(microzooplankton) and reproduction (mesozooplankton) rates, to 
measure grazing
rates of heterotrophic protists and dominant mesozooplankton in 
the two regions, and to identify mesozooplankton that are sentinel 
species of Arctic change. Our collaborative study will explicitly 
address trophic linkages previously unexplored in this region of the 
Arctic. We hypothesize that changing ecosystem structure, such as 
might occur during climate change, will alter the role of these 
trophic interactions in the utilization and cycling of carbon in arctic 
shelves and basin systems. We propose participation in the four 
process cruises of the SBI Phase II program. The plannedcruise 
schedules of May-June and July-August will permit us to work in 
contrasting scenarios of ice cover, and importance of ice algae 
versus phytoplankton in primary production, during early summer 
compared to late summer. Since we plan a comparison of the 
phytoplankton - microzooplankton - mesozooplankton trophic 
coupling in shelf versus basin systems, we will carry out a full set of 
analyses (sta
 nding stock determinations and rate measurements) at a number 
of stations in both basin and shelf regions of the SBI-II study area. 
Abundances and rate measures will be combined to determine 
relative mesozooplankton and microzooplankton grazing impacts. 
The research proposed here addresses major objectives of the SBI-II 
program: ?Assessment of relative importance of top-down as 
compared to bottom-up controls over pelagic-benthic coupling and 
carbon partitioning among different trophic levels? and 
?Assessment of food web changes consequent o the impacts of 
changing ice cover and hydrographic parameters on biogeochemical 
fluxes.? This project will provide rate measurements for 
microzooplankton and mesozooplankton grazing ad reproduction, 
parameters that were identified as high priority for the seasonal 
process cruises in the SBI Phase II Implementation Plan. We will fully 
collaborate with, and make our data available to, other SBI 
investigators.


data_set_title: SBI MIcrozooplankton Stocks
data_set_summary: SHERR SBI Microzooplankton abundance, 
biomass, and community composition for initial samples collected 
for a subset of dilution and mesozooplankton grazing experiments 
carried out during 2002 and 2004 SBI process cruises. Initial 
seawater samples included experiments set up in shelf, slope, and 
basin regions of the SBI study area (Campbell et al. submitted, Sherr 
et al. submitted).
data_format: MS Excel 5.1 worksheet
data_structure: Headers of worksheet columns:
Experiment type, experiment number, SBI station location, SBI 
station number, N Lat, W Long, Bottom depth (m), Sample depth 
(m), Initial chl-a (ug/l), Total protist biomass(ug C/l), Total ciliate 
biomass (ug C/l), Total Heterotrophic dinoflagellate (Hdino) 
biomass (ug C/l), Armored Hdino biomass (ug C/l), Non-armored 
Hdino biomass (ug C/l)




parameters: microzooplankton biomass, micrograms of carbon per 
liter
collection_methods: Two hundred ml subsamples for determination 
of microzooplankton biomass and abundance were preserved with 
10% (2002) or 5% (2004) final concentration acid Lugol solution for 
inverted microscopy.  From 50 to 100 ml of Lugol-preserved 
samples were settled for a minimum of 24 hours and then the 
whole slide inspected by inverted light microscopy.  All ciliate and 
dinoflagellate cells in each sample were counted, sized, and 
categorized into general taxonomic groups. Samples preserved for 
epifluorescence microscopy were inspected to determine whether 
dinoflagellates counted in Lugol-preserved samples were 
heterotrophic or autotrophic. The biovolume of each enumerated 
cell was determined using algorithms for spherical, conical, and 
ellipsoidal shapes.  Cell biomass was estimated using the algorithm 
of Menden-Deuer and Lessard (2000).
collection_period_start: 20020530
collection_period_end: 200408017
seasonal_measurements: spring and summer
temporal_resolution: weekly
study_location: Western Arctic Ocean
geog_coordinates: 71oN - 74oN; 151oW - 161oW
spatial_resolution: upper 50 m of water column, several km to 10's 
of km in study area
refs_about_data: Menden-Deuer, S., Lessard, E. 2000. Carbon to 
volume relationships for dinoflagellates, diatoms, and other protist 
plankton. Limnology and Oceanography 45, 569-579
refs_using_data: Campbell, R.G., E. B. Sherr, C. J. Ashjian, S. 
Plourde, B. F. Sherr, V. Hill, D. A. Stockwell. Mesozooplankton prey 
preference and grazing impact in the Western Arctic Ocean. Deep-
Sea Research II, submitted Jan 2007.

Sherr, E.B., Sherr, B.F., Hartz, A.J. Microzooplankton grazing impact 
in the Western Arctic Ocean. Deep-Sea Research II, submitted Nov-
2006.

related_URLs: 
http://bioloc.coas.oregonstate.edu/SherrLab/Arcticresearch.html

http://bioloc.coas.oregonstate.edu/SherrLab/Microplankton%20ima
ges.html


transfer_medium: email attachment,
data_volume_mb: 0.042

agree: Agree
first_name0: Barry
last_name0: Sherr
middle_initial0: F
organization0: COAS-Oregon State University
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