An Introduction to the Hawaii Ocean Time-series (HOT) program

and Station ALOHA

Marine Microplankton EcologyOCN 626

• 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

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

James Watt

Historical Highlights Leading to HOT

1986-1988Vertical

Transport and

Exchange (VERTEX)program

1988US 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)

October 1988

First research cruise to Station ALOHA

(A Long-term Oligotrophic

Habitat Assessment)

December 1998

100 cruises to Station ALOHA

August 2008204

Cruises to Station ALOHA

1954Stommel and Sutcliffe begin bimonthly measurements at Hydrostation “S” 28 km SE of Bermuda

1961Menzel and Ryther publish 3 years of biogeochemical

measurements at Station S

1979Coastal Zone Color

Scanner (CZCS)is launched

1987Global Ocean Flux

Study begins

1976Keeling publishes ~18 year record of atmospheric CO2 measurements

at Mauna Loa, Hawaii

Station ALOHA and the North Pacific Subtropical Gyre (NPSG)

ALOHA

NPSGNPSG

15°N to 35°N135°E to 135°W

One of the largest

ecosystems on the planet

Station ALOHA 4800 m deep

HOTBATS

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)

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

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.

Data Types• 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

HOT-DOGS

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)

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

http://hahana.soest.hawaii.edu/hot/hot-dogs/interface.html