1. Hawaii Ocean Time-series (HOT) program Marine Microplankton Ecology
An Introduction to the
Hawaii Ocean Time-series (HOT) program
and Station ALOHA
Marine Microplankton Ecology
OCN 626

2. One of the required assignments for OCN 626 is for each of you to give a talk (12 minutes) and write a report on a microbially-relevant aspect of the HOT program.
Some examples:
Dynamics of primary production
A comparison of plankton biomass at Station ALOHA and at BATS (Sargasso Sea)
Temporal variability in the diversity of photosynthetic plankton

3. HOT and Station ALOHA
Hawaii Ocean Time series (HOT) began as a central component of the Joint Global Ocean Flux Study in 1988.
Continuous time series record of biogeochemical and physical oceanographic properties at study site Station ALOHA
(22°45’N, 158°W)
Station ALOHA is occupied for 1 week every month

4. Historical Highlights Leading to HOT
1979
Coastal Zone Color Scanner (CZCS)
is launched
October 1988
First research cruise to Station ALOHA
(A Long-term Oligotrophic Habitat Assessment)
Vertical Transport and Exchange (VERTEX)
program
August 2008
204 Cruises to
Station ALOHA
1961
Menzel and Ryther publish 3 years of biogeochemical measurements at Station S
1987
Global Ocean Flux Study begins
1976
Keeling publishes ~18 year record of atmospheric CO2 measurements at Mauna Loa, Hawaii
December 1998
100 cruises to Station ALOHA
1988
US National Science Foundation grants to D. Karl (U. Hawaii) and A. Knap (BBSR) for establishment of two deep-ocean time series stations
(HOT and BATS)
1954
Stommel and Sutcliffe begin bimonthly
measurements at Hydrostation “S”
28 km SE of Bermuda
James Watt

5. Station ALOHA and the North Pacific Subtropical Gyre (NPSG)
15°N to 35°N
135°E to 135°W
One of the largest
ecosystems on the planet
ALOHA
NPSG
Station ALOHA 4800 m deep

6. HOT
BATS

7. Characteristic features of the subtropical gyre habitats
Very low nutrient concentrations
Light penetrates deep into the upper ocean
Deep chlorophyll maximum
Small plankton
Very rapid nutrient recycling
Very important to global carbon cycle (by virtue of their enormous size)

9. Objectives of the HOT program (circa 1996)
Understand seasonal and interannual variability in rates of production and particle export.
Determine the mechanisms and rates of nutrient input and recycling in the upper 200 m of the water column.
Measure time varying concentrations of CO2 in the upper ocean and estimate annual air-sea gas fluxes

11. HOT Program Highlights (specific to marine microbiology)
Bacteria are predominate photosynthetic organisms (Prochlorococcus and Synechococcus).
Climate-dependence to plankton biomass and productivity.
Higher than anticipated rates of primary production
(> 14 mol C m-2 yr-1).
Archaea numerically dominate mesopelagic (> 200 m) plankton assemblages.

12. HOT-DOGS Data Types Data Modules CTD: Seabird sensor package
Bottle: 24-place rossette and 12L niskin bottles
Particle Flux: floating sediment traps
Primary Production : in-situ incubated 14C
Data Modules
Data Extraction: text columns of data
Display: vertical profiles
Standard Depths: summary & comparative plots
Time-Series: integral, means & horizons

13. Partial list of microbially-relevant measurements at Station ALOHA
Temperature, Salinity, Density
dissolved O2, dissolved inorganic carbon, pH
Dissolved inorganic nutrients (nitrate, nitrite, phosphorus, silica)
Particulate nitrogen, carbon, and phosphorus
Pigments
Primary production
Various measures of plankton biomass
Plankton cell abundances (Prochlorococcus, Synechococcus, non-pigmented picoplankton).
Particle export (carbon, nitrogen, phosphorus fluxes)

14. A few ideas for topics…
“Variability in primary production at Station ALOHA”
Data sets available: 14C-bicarbonate assimilation rates, changes in O2
“A comparison of plankton biomass and productivity at Station ALOHA and BATS”
Data sets available: bacterial cell abundances, chlorophyll, primary production, etc.
“Temporal variability in the diversity and biomass of photosynthetic plankton”
Data sets available: HPLC pigment concentrations, flow cytometric cell abundances