3. Phytoplankton and Primary Production Ch. 3 Phytoplankton and Primary Production 1. Systematic treatment 1. Diatoms (돌말류) 2. Dinoflagellates (와편모조류) 3. Other phytoplankton 2. Photosynthesis and primary production 1. Methods of measuring biomass and primary productivity 3. Radiation and photosynthesis 4. The effects of nutrients on growth rate 5. Physical controls of primary production 1. Oceanic gyres and rings 2. Continental convergence and divergence 3. Planetary frontal systems 4. Shelf-break fronts 5. River-plume fronts 6. Island mass effect and Langmuir frontal zones 6. Global phytoplankton productivity Marine Biology

1. Phytoplankton Groups (Table 3.1) 2. Special Adaptations for a Cyanobacteria Planktonic Existence Nitrogen Fixation; Symbioses Size; Sinking Chrysophyta Adjustments to Unfavorable Chrysophyceae Environmental Conditions Coccolithophores; Silicoflagellates 3. Primary Production in the Sea Bacillariophyceae (Diatoms) Standing Crop vs. Turnover Rate Size Gross vs. Net Primary Productivity Anatomy and Frustule Measurements of Primary Production Reproduction Light and Dark Bottle Technique Global Distribution and Significance Use of Satellites Dinophyta Factors That Affect Primary Production Characteristics; Reproduction The Concept of Limiting Factors Bioluminescence Grazing; Light Blooms; Red Tides and other Toxic Photosynthetic Pigments Dinophytes Nutrient Requirements; Nutrient Other Phytoplankton Regeneration Chlorophyta Marine Snow; Microbial Loops Convective Mixing; Upwelling  Table 3.1 A taxonomic survey of the marine phytoplankton  Phytoplankton  From the Top of the World to the Bottom of the Food Web” is a wonderful summary of all things phytoplanktonic. Visit the From the Top of the World to the Bottom of the Food Web web site  The Monterey Bay Aquarium Research Institute’s Phytoplankton page is an excellent resource for the study of all marine plants (not just those that are microscopic). Visit the Marine Flora web site  Provided by the Biology Department of Raymond Walters College, this Interactive Plankton Key is very helpful for students working with phytoplankton or zooplankton! Visit the Plankton Key web site Table 3.1 A taxonomic survey

 Cyanophyceae  Xanthophyceae (황록조) (Cyanobacteria)  Eustigmatophyceae (남조; 남세균식물강) (진정안점편모조)  Rhodophyceae (홍조)  Prymnesiophyceae (착편모조; 석회비늘편모조)  Cryptophyceae (은편모조)  Euglenophyceae (유글레나조)  Chrysophyceae (황갈조)  Prasinophyceae (담록조)  Bacillariophyceae  (녹조) (Diatomophyceae) (돌말) Chlorophyceae  Pyrrophyceae (Dinophyceae)  Raphidophyceae (와편모조) (침편모조; 라피도조)

Most primary production in the sea is accomplished by phytoplankton, unicellular, photosynthetic organisms. Hence, marine primary producers are fundamentally different from terrestrial producers. 3.1 Systematic treatment Planktonic unicellular algae; phytoplankton 1. Diatoms: Bacillariophyceae  Frustule, diatomaceous ooze  Pennate (깃돌말) and centric forms (중심돌말)  Flotation mechanism  Remain in lighted surface – photosynthesis  Small size  general morphology  Frictional drag  The ratio of cell surface area to volume  Colony or chain formation  Ionic regulation  Oil  0-30 m day-1  Turbulence of surface water 3.1 Systematic treatment (cont.)

1. Diatoms (cont.)  Reproduction  Asexual division  sexual reproduction  Auxospore (증대포자)  Resting spore (휴면포자)  Morphology  Girdle view (narrow, borad), valve view  Epitheca, Hypotheca, valve surface, valve mantle, girdle, epicingulum. Hypocingulum,  Central nodule, terminal nodule, raphe, central nodule, central pore,  Axial area, central area  costae DIATOMS - web info

 Diatoms  What is a diatom?  Diatom Ecology: the central Centrales  Centrales: radially symmetric; dominate marine planktonic communities.  Pennales: bilaterally symmetric; benthic marine and fresh water communities.  Anatomy and morphology.  Siliceous cell walls.  Reproduction  Geologic record and evolution: what you can tell from an old diatom shell.  Industry and economic uses.  Introduction to Bacillariophyta (The Diatoms)  Fossil Record  Life History and Ecology  Systematics  More on Morphology 3.1 Systematic treatment (cont.)

2. Dinoflagellates (Pyrrophyceae)  Unicellular; Two flagella  Autotrophic, heterotrophic, mixotrophic  Theory of multiserial endosymbiosis  Desmophyceae (정단와편모류), desmokont  Dinophyceae (측와편모류), dinokont  Morphology  Theca, naked:  Epicheca (anterial), hypotheca (posterial), girdle  Theca: plates and pores and/or spines  Armoured (thecate); anarmoured (naked, non-thecate)  Apical plate, intercalary plate, precingular plate, girdle plate, postcingular plate, antaptical plate  Transverse groove (cingulum), longitudinal groove (sulcus)  Transverse flagellum, longitudinal flagellum 3.1 Systematic treatment (cont.)

2. Dinoflagellates (cont.)  Reproduction  Asexual division  Dividing obliquely to form two cell of equal size  New half  Bloom in summer or autumn  Lower light and nutrient-impoverished water  Vertical migration  Sexual reproduction  Cysts 3.1 Systematic treatment (cont.)

2. Dinoflagellates (cont.)  Phytoplankton blooms  Red tides → Harmful algal blooms (HABs)  Anoxic conditions  Toxin: saxitoxin, okadaic acid, domoic acid (diatom)  Paralytic shellfish poisoning (PSP); diarrhetic shellfish poisoning (DSP), ciguatera fish poisoning (CFP), neurotic shellfish poisoning (NSP)  Amnesic shellfish poisoning (ASP)  Cyanobacterial toxin poisoning 3.1 Systematic treatment (cont.)

3. Other phytoplankton Coccolothophorids (Prymnesiophyceae) Coccolith Emiliania bloom Isochrysis, Phaeocystis Silicoflagellates (Chrysophyceae) Golden-brown algae Small, naked, flagellated phytoplankton

Cyanobacteria (Cyanophyceae) Nitrogen fixation Oscillatoria (Trichodesmium) Synechococcus Prochlorophytes

Pennate ======

3.2 Photosynthesis and primary production Primary producer; primary production Photosynthesis vs respiration

6CO2 + 6H2O ⇔ C6H12O6 + 6O2 Solar energy and photosynthesis Light harvesting complex Chlorophyll a Accessory pigments (carotenes, xanthophylls, phycobilins) Light reaction and dark reaction

ATP, NADPH2

 The reduction of CO2 by NADPH2 and require the chemical energy of ATP to produce the end product of high-energy carbohydrates and other organic compounds.  Nitrogen, phosphorus, silicon, vitamin (auxotrophic)

Photosynthetic reactions

 Light reaction

 ATP, NADPH2

 Dark recation

 Reduction of CO2 by NADPH2 and ATP

 Reduction of NO3 Photosystems I and II

PS I uses light to drive a cyclical electron flux to reduce NADP. PS II used light energy to release an electron from the electron donator (H2O) and to generate a charge separation. Photosynthesis versus Light Intensity (P/I curve)

At low light intensities the photosystems are Pmax light limited and their activity increases with rising light intensity. At higher light intensity the photosystem becomes = α saturated and finally strong light inhibits photosynthesis and can damage the photosynthetic apparatus. Ic Ik Phytoplankton can adapt K1 to different light intensities.

Characteristic values of P/I-curves: Pmax (max. photosynthetic rate); Ik (light intensity at saturation); K1 (half saturation constant); α (initial rise of P/I curve) Light adaptation Three types of P/I curves:

1: strongly shade P (3) max adapted with low IK values

Pmax(2) 2: shade adapted

with similar IK but higher Pmax values Pmax(1) than type 1 3: high light adapted with less photosynthetic efficiency at low light intensity. 3.2 Photosynthesis and primary production

1. Methods of measuring biomass and primary productivity Standing stock  The number of organisms per unit area or per unity volume of water at the moment of sampling  Cell counts of preserved phytoplankton Biomass  The total weight (total number x average weight) of all organisms in a given area or volume. Cell count  Direct observation  Electronic counting  Cell volume  Chlorophyll content  Acetone extraction (spectrophotometer, HPLC)  Fluorescence 3.2 Photosynthesis and primary production

1. Methods of measuring biomass and primary productivity (cont.) 14 14 - C method – radioactive bicarbonate (H CO3 ) Rate of production = {(RL – RD) x W}/ R x t  Unit: mg C m-3 h-1  In terms of the amount of carbon fixed in the water column under a square meter of surface per day  mg C m-2 h-1  Chlorophyll a measurement of biomass  Measure of growth rate in units of time  mg C per mg chlorophyll a per hour  Assimilation index  Lost: exudation Chlorophyll concentration  Fluorescence  Remote sensing General process of primary production

Measurement of primary production can be done by

14 different methods: CO2 1) oxygen production 2) CO2 uptake 3) biomass increase

The most common method is the determination of CO2 uptake using radioactively labeled (14C) bicarbonate. The radioactivity incorporated into the new biomass is measured.

DO14C Losses can occur through excretion of dissolved organic compounds (DOC) and respiration. 14CO2 from respiration Measurement of Primary production

A water sample is put into 5 glass bottles, two of which are wrapped in black foil (as dark controls). 14C- bicarbonate is added and the samples are incubated at the environmental light and temperature for a sample chosen time. The algal cells are harvested by Incubation filtration, excess radioactive biocarbonate is removed and the incorporated 14C is Filtration measured. Measurement of filters 3.3 Radiation and photosynthesis

Solar radiation vs photosynthesis Photosynthesis vs light intensity (P vs I curve) ∆P / ∆I (initial slope); Pmax Pg = {Pmax I [I]}/{KI + [I]} Pn = {Pmax I [I - IC]}/{KI + [I - IC]} Light-dependent reaction (light limited) Light saturated Photoinhibited  Half-saturation, KI  Compensation light intensity, IC  The initial slope : the photosynthetic biochemistry of a cell (i.e. the light-dependent reactions), cellular properties, ∆P / ∆I  Pmax : changes in environmental parameters (such as nutrient concentration and temperature, which affect the dark reaction of photosynthesis) 3.3 Radiation and photosynthesis (cont.)

Critical depth (Dcr) The extinction of light in water (k) The compensation depth of light (IC) The average amount of light (ID) in the euphotic zone Eq. 3.4 Eq. 3.5 Eq. 3.6 Photosynthetic rates in the water column are determined by the light available in different water depths (red line).

Phytoplankton in deep waters or under ice are low light adapted.

However, remember that the upper water column is well mixed and algal cells are frequently transported into different water depths. Primary production in the water column When the sample bottles are placed in different water depths, light limitation is occurs in the deep parts of the water column, light saturation in the upper and light inhibition may reduce photosynthesis in the top layers.

Light inhibitionLight inhibition Light saturation

Light limitation depth

Depth of euphotic zone

(from U. Sommer „Biologische Meereskunde. Springer Verlag (1998) 3.3 Radiation and photosynthesis

 Compensation depth; 광합성율 = 호흡율

 Critical depth; 수층 총 생산량 = 수층 총 호흡량

 - Depth limits of phytoplankton 3.4 The effect of nutrients on growth rate

Productivity – the amount of carbon fixed per unit time Assimilation index Growth is expressed as mg of carbon produced per mg of chlorophyll a per hour μt An increase in cell numberl: (X0 + ∆X) = X0e The doubling time (d), generation time (1/d) μt μd Xt = X0e ; Xt / X0 = 2 = e ; d = ln 2/μ = 0.69/μ The effect of nutrient concentration on μ (time-1)

μ = μmax [N] / {KN + [N]} Nutricline  the zone where nutrient concentrations increase rapidly with depth Nitrate, phosphate, silicate, iron and manganese Low enough to be limiting to plant production 3.4 The effect of nutrients on growth rate (cont.)

HNLC areas: iron High nitrate but low chlorophyll concentrations Iron: nitrite reductase and nitrate reductase Subarctic North Pacific, Equatorial Pacific, Antarctic Ocean

Half-saturation concentration (KN ) Maximum growth rate (μmax)

The physico-chemical environmental mosaic Oligotrophic; Eutrophic; Mesotrophic 3.5 Physical controls of primary production

Light and nutrient Wind mixing Latitudinal gradient (light) Front:  relatively narrow regions characterized by large horizontal gradients in variables such as temperature, salinity, and density Eddy-formation: rings and large-scale gyres  Rotational patterns of circulation Mechanism bringing nutrients up to the euphotic zone form deeper water + seasonal wind mixing 1. Oceanic gyres and rings 2. Continental convergence and divergence 3. Planetary frontal systems 4. Shelf-break fronts 5. River-plume fronts 6. Island mass effect and Langmuir frontal zones 3.5 Physical controls of primary production (cont.)

Oceanic gyres and rings • Anticyclonic gyre (clockwise) convergent gyres • Cyclonic gyres (anticlockwise) divergent gyre • Warm core rings (anticyclonic) • Cold core rings (cyclonic) 3.5 Physical controls of primary production (cont.) Continental convergence and divergence • The edge of continents due to wind-driven oceanic circulation • Divergent continental fronts  The Peru Current, California Current  The Canaries Current and Benguela Current  Antarctic Divergence • Convergent continental front  Warm nutrient-poor water • Antarctic Polar Front (Antarctic convergence)  Source of cold deep water • Equatorial upwelling 3.5 Physical controls of primary production (cont.)

Planetary frontal systems • Planetary frontal systems  Convergence or divergence of two current systems  The Oyashio and Kuroshio  The Labrador Current (cold) and Gulf stream (warm) 3.5 Physical controls of primary production (cont.) Shelf-break fronts • The edges of continental shelves and other banks • By combination of the sudden shallowing of water across a continental shelf • By the change in current speed across the shelf  Residual oceanic circulation or tidal exchange • R = PE / TED 3 • S = log10 h/CD |U| 3.5 Physical controls of primary production (cont.) River-plume fronts • High nutrient  natural source, agricultural fertilizers and sewage  The flow of the river at the sea surface causes nutrients to be entrained from deeper water upwelling into the surface water 3.5 Physical controls of primary production (cont.) Island mass effect and Langmuir frontal zones • A disturbance in the flow of water caused by the presence of an island resulting in upwelling (island wake effect) • Wind blows steadily across the surface of relatively calm seas 3.5 Physical controls of primary production (cont.)

1. Oceanic gyres and rings 2. Continental convergence and divergence 3. Planetary frontal systems 4. Shelf-break fronts 5. River-plume fronts 6. Island mass effect and Langmuir frontal zones 3.6 Global phytoplankton productivity

1. Season and location  Upwelling areas: > 1 g C m-2 day-1  Subtropical convergent gyres: < 0.1 g C m-2 day-1  Chlorophyll concentrations in surface waters of the global ocean  The primary productivity of the world’s ocean: 40x109 ton C yr-1  Terrestrial ecosystem  Rain forest: 3,500 gC m-2 yr-1  Relatively small areas 2. Latitudinal and seasonal differences  Differences in light and nutrient availability  Biological processes  Self-shading  Grazing activities 3.6 Global phytoplankton productivity

3. Primary productivity vs. standing stock  North Pacific Ocean (50° N): grazing, close phasing  0.5 mg chl a m-3, 50 (winter) -250 (July) mgC m-2 day-1  Atlantic Ocean: spring bloom 0.1-1.0 mg chl a m-3; autumn bloom  Arctic Ocean  Tropical environment 4. Depth – light attenuation  Schematic seasonal depth changes in phytoplankton biomass Seasonal development

Photosynthesis (Pn) depends on the amount of light and phytoplankton biomass (S). In different seasons Pn changes due to changing light (shading by phytoplankton in the water) and changing biomass (less biomass in summer due to low nutrients). In late summer this creates a biomass peak in deep waters (deep chlorophyll maximum) where phytoplankton utilize the nutrient (N) diffusion from below the thermocline and the limiting light. Deep chlorophyll maxima are typical for tropical oceans. 3.7 Summary

1. Phytoplankton taxonomy; autotrophic production; photosynthesis 2. Photosynthesis • light reaction, dark reaction; chlorophyll and accessory pigments; respiration 3. Nutrients • Nitrogen, phosphorus, iron • Vitamins (auxotrophic) 4. Estimation of the total phytoplankton crop • Standing stock or biomass • Cell number, total volume, quantity of chlorophyll a • The rate of primary production 3.7 Summary (cont.)

5. Pmax, compensation intensity (photosynthesis and respiration)

• Gross photosynthesis, net photosynthesis, respiratory loss 6. P vs I curve

• Pmax and KI 7. Critical depth

• Photosynthetic gain throughout the water column

• Respiratory loses

• Depth of water mixing 3.7 Summary (cont.)

8. Growth rates of phytoplankton

• Essential nutrients in seawater

• Oligotrophic

• Eutrophic 9. Response to different concentrations of limiting nutrients

• Maximum growth rates

• Species-specific responses to different light intensities, temperatures, salinities and other parameters

• Phytoplankton species diversity in what appears superficially to be a homogeneous aqueous environment (paradox) 3.7 Summary (cont.)

10. Solar radiation and essential nutrient availability

• Latitude

• Controlling vertical mixing of water 11. Tropical, polar, temperate • Heating stabilizes the water column – low nutrient • Low in solar radiation 12. Latitudinal patterns of primary productivity

• Physical process that lead to nutrients being redistributed

• Gyres and continental upwelling

• Tidal fronts and rings

• Langmuir circulation 3.7 Summary (cont.)

13. Standing stock of phytoplankton in the surface layers of the sea

• Seasonal bloom

• Upwelling

• Total primary productivity of the world productivity 14. Zooplankton grazing

• Growth rates and generation times of the zooplankton

• Coupling with any phytoplankton increase

• Lag in the development of zooplankton relative to increases in phytoplankton biomass 15. Vertical profile of phytoplankton production

• Season and latitude

Global Primary Production

Paul Falkowski and Dorota Kolber, Rutgers University

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