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Where does breathable oxygen on Earth come from?

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Why the ALOHA site for studying the ocean?

Deep water (> 4000 m)
Upwind from the Hawaiian islands
Sufficient distance from coastal influences
Close enough for short duration cruise (financially and logistically feasible)
Longest span of data on phytoplankton

Why the Mauna Loa site for studying the atmosphere?

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HOT – DOGS portal

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HOT – DOGS portal

Testable Question?

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HOT – DOGS portal

Many steps – many challenges

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What are the “take aways” here?

End Part 1

Raw data from HOT-DOGS at the ALOHA station shows where the measurable Chloropigment (a proxy for phytoplankton) is at its maximum.

Limiting variables include: Temperature 22-23C and depth 150 m.

This is the context where a maximum population of phytoplankton lives.

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Where to next?

What did we accomplish in Part 1?

Part 2

Let’s get familiar with the ALOHA area using:��a) eWOCE section plots�b) ODV scatter plots�c) cross-metric comparisons� (including time series)

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Part 2a – eWOCE section plots �(student work example)

What can we learn about who may live in the ocean in the top 200 meters?

Think about environmental conditions (abiotic) as a context for living phytoplankton.

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Section plots, from ALOHA site CTD bottle data

How do the trends you see influence the phytoplankton who live in this environment?

Do phytoplankton experience the same environment at the top of the water (5m) column and the bottom of the water column (200m)?

Part 2b – ODV section plots �(student work example)

Student examples using ODV Applied Problem: Examining a Time Series in ODV: HOT_Instructions to create section plots, from ALOHA site CTD bottle data. These are visualizations of time series data* for the top 200 m of ocean. [*Using HOT_Bottle Data 1988-2008.odv packaged/conditioned by Jennings & Bercovici (2017)]

Questions to elevate thinking:

How do the trends you see influence the phytoplankton who live in this environment? Do phytoplankton experience the same environment at the top of the water (5m) column and the bottom of the water column (200m)?

Scientists are still exploring, but some relationships can be proven using knowledge from basic organic chemistry class: pH influences the ability of the phytoplankton to absorb chemicals (nutrients) dissolved in the water column and influence decomposition rates as well. Temperature and salinity create —context —the boundary that limits where the phytoplankton can live. Nutrients, as they become available cause blooms (phytoplankton need specific amounts of light and nutrients to bloom) which increases the phytoplankton population. Light for photosynthesis reaches to about 200m, and is greatest at 5m. Nutrients arrive and change through seasonal variations and upwelling patterns in the water column—which can be measured using the CTD. Temperature influences how much of each nutrient remains dissolved in the water column for phytoplankton to absorb.

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Part 2c – Excel time series plot

(student work)

Over 27 years the Chloropigment maximum increased about 0.75 ug/L.

Looking at the

ALOHA area using:

Chloropigment cross-metric comparison with time

Next use Logger Pro and ODV to look into other metrics (abiotic conditions)

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Part 2d – Logger Pro plots

each with a different cross metric

(student work)

	fluorescence	salinity
Name	quadratic	sine
Equation	-6.5x^2+.0024x+.44	.08sin(.05x+2.06)+35.23
Correlation	.32	.57
RMSE	.184	.084

Student examples of plots using the same raw data set from HOT-DOGS at ALOHA station.

At Left: “Chloropigment ( fluor) versus time” and At Right: “Salinity versus time”

Salinity shows 6 month variation with high in December and low in June. (correlates to a seasonal variation in the bloom of phytoplankton) The same raw data set shows a slight increase in Chloropigment (fluor) in December-January. Students should consider the relationship they learned about earlier in this lesson -- phytoplankton populations are limited by salinity—this relationship sets a boundary for where phytoplankton may live, but we don’t know from this data why they live (salinity does not cause the bloom, only limits where it can occur). Students can generate “testable questions” to try to learn more about where the phytoplankton for how long and why. They can consider other limiting relationships by examining other cross metric relationships.

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Final – Composition of a drop of sea water

(student work examples)

Pre – instruction

Post – instruction

How to assess