A massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the equatorial Pacific Ocean

The seeding of an expanse of surface waters in the equatorial Pacific Ocean with low concentrations of dissolved iron triggered a massive phytoplankton bloom which consumed large quantities of carbon dioxide and nitrate that these microscopic plants cannot fully utilize under natural conditions. These and other observations provide unequivocal support for the hypothesis that phytoplankton growth in this oceanic region is limited by iron bioavailability.

Net community production, Thorium-234 activity and particle flux during the Southern Ocean iron fertilization experiment LOHAFEX

A closed eddy core in the Subantarctic Atlantic Ocean was fertilized twice with two tons of iron (as FeSO4), and the 300 km**2 fertilized patch was studied for 39 days to test whether fertilization enhances downward particle flux into the deep ocean. Chlorophyll a and primary productivity doubled after fertilization, and photosynthetic quantum yield (FV/FM) increased from 0.33 to >0.40. Silicic acid (<2 µmol/L) limited diatoms, which contributed <10% of phytoplankton biomass. Copepods exerted high grazing pressure. This is the first study of particle flux out of an artificially fertilized bloom with very low diatom biomass. Net community production (NCP) inside the patch, estimated from O2:Ar ratios, averaged 21 mmol POC/m**2/d, probably ±20%. 234Th profiles implied constant export of ~6.3 mmol POC/m**2/d in the patch, similar to unfertilized waters. The difference between NCP and 234Th-derived export partly accumulated in the mixed layer and was partly remineralized between the mixed layer and 100 m. Neutrally buoyant sediment traps at 200 and 450 m inside and outside the patch caught mostly <1.1 mmol POC/m**2/d, predominantly of fecal origin; flux did not increase upon fertilization. Our data thus indicate intense flux attenuation between 100 and 200 m, and probably between the mixed layer and 100 m. We attribute the lack of fertilization-induced export to silicon limitation of diatoms and reprocessing of sinking particles by detritus feeders. Our data are consistent with the view that nitrate-rich but silicate-deficient waters are not poised for enhanced particle export upon iron addition.

Left to right: Sharon Ewe and Calvin Liu applying Florida Bay sediments to dwarf mangrove forest as part of a fertilization experiment, Taylor Slough

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

Left to right: Sharon Ewe and Calvin Liu applying Florida Bay sediments to dwarf mangrove forest as part of a fertilization experiment, Taylor Slough

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

Responses of seagrass communities to fertilization along a gradient of relative availability of nitrogen and phosphorus in a carbonate environment

Patterns of relative nutrient availability in south Florida suggest spatial differences regarding the importance of nitrogen (N) and phosphorus (P) to benthic primary producers. We did a 14-month in situ fertilization experiment to test predictions of N and P limitation in the subtropical nearshore marine waters of the upper Florida Keys. Six sites were divided into two groups (nearshore, offshore) representing the endpoints of an N: P stoichiometric gradient. Twenty-four plots were established at each site with six replicates of each treatment (1N, 1P, 1N1P, control), for a total of 144 experimental plots. The responses of benthic communities to N and P enrichment varied appreciably between nearshore and offshore habitats. Offshore seagrass beds were strongly limited by nitrogen, and nearshore beds were affected by nitrogen and phosphorus. Nutrient addition at offshore sites increased the length and aboveground standing crop of the two seagrasses, Thalassia testudinum and Syringodium filiforme, and growth rates of T. testudinum. Nutrient addition at nearshore sites increased the relative abundance of macroalgae, epiphytes, and sediment microalgae. N limitation of seagrass in this carbonate system was clearly demonstrated. However, added phosphorus was retained in the system more effectively than N, suggesting that phosphorus might have important long-term effects on these benthic communities. The observed species-specific responses to nutrient enrichment underscores the need to monitor all primary producers when addressing questions of nutrient limitation and eutrophication in seagrass communities.

Annual report 2005 - North Pacific Marine Science Organization (PICES). Fourteenth meeting, Vladivostok, Russia, September 29-October 9, 2005

Report of Opening Session (pdf 0.07 Mb) Report of Governing Council (pdf 0.2 Mb) Report of the Finance and Administration Committee (pdf 0.07 Mb) Reports of Science Board and Committees Science Board inter-sessional meeting (pdf 0.07 Mb) Science Board (pdf 0.1 Mb) Biological Oceanography Committee (pdf 0.2 Mb) Fishery Science Committee (pdf 0.04 Mb) Marine Environmental Quality Committee (pdf 0.06 Mb) MONITOR Technical Committee (pdf 0.05 Mb) Physical Oceanography and Climate Committee (pdf 0.06 Mb) Technical Committee on Data Exchange (pdf 0.04 Mb) Reports of Sections, Working and Study Groups Section on Ecology of harmful algal blooms in the North Pacific (pdf 0.03 Mb) Section on Carbon and Climate Working Group 18 on Mariculture in the 21st century - The intersection between ecology, socio-economics and production (pdf 0.06 Mb) Working Group 19 on Ecosystem-based management science and its application to the North Pacific (pdf 0.03 Mb) Reports of the Climate Change and Carrying Capacity Program Implementation Panel on the CCCC Program (pdf 0.04 Mb) CFAME Task Team (pdf 0.04 Mb) MODEL Task Team (pdf 0.04 Mb) Reports of Advisory Panels Advisory Panel on Iron Fertilization Experiment in the Subarctic Pacific Ocean (pdf 0.04 Mb) Advisory Panel on Marine Birds and Mammals (pdf 0.03 Mb) Advisory Panel on Micronekton Sampling Inter-Calibration experiment (pdf 0.05 Mb) Summary of Scientific Sessions and Workshops (pdf 0.2 Mb) Membership List (pdf 0.07 Mb) List of Participants (pdf 0.07 Mb) List of Acronyms (pdf 0.03 Mb)

Annual report 2004 - North Pacific Marine Science Organization (PICES). Thirteenth meeting, Honolulu, Hawaii, U.S.A., October 14-24, 2004

Report of Opening Session (pdf 0.07 Mb) Report of Governing Council (pdf 0.2 Mb) Report of the Finance and Administration Committee (pdf 0.08 Mb) Reports of Science Board and Committees Science Board inter-sessional meeting (pdf 0.05 Mb) Science Board (pdf 0.1 Mb) Biological Oceanography Committee (pdf 0.1 Mb) Fishery Science Committee (pdf 0.04 Mb) Marine Environmental Quality Committee (pdf 0.04 Mb) Physical Oceanography and Climate Committee (pdf 0.04 Mb) Technical Committee on Data Exchange (pdf 0.04 Mb) Reports of Sections, Working and Study Groups Harmful Algal Blooms Section (pdf 0.03 Mb) Working Group 17 on Biogeochemical data integration and synthesis (pdf 0.03 Mb) Working Group 18 on Mariculture in the 21st century - The intersection between ecology, socio-economics and production (pdf 0.06 Mb) Study Group on Ecosystem-based management science and its application to the North Pacific (pdf 0.04 Mb) Reports of the Climate Change and Carrying Capacity Program Implementation Panel on the CCCC Program (pdf 0.04 Mb) BASS Task Team (pdf 0.04 Mb) CFAME Task Team (pdf 0.04 Mb) MODEL Task Team (pdf 0.04 Mb) MONITOR Task Team (pdf 0.03 Mb) REX Task Team (pdf 0.04 Mb) Reports of Advisory Panels Advisory Panel on Continuous Plankton Recorder Survey in the North Pacific (pdf 0.4 Mb) Advisory Panel on Iron Fertilization Experiment in the Subarctic Pacific Ocean (pdf 0.03 Mb) Advisory Panel on Marine Birds and Mammals (pdf 0.04 Mb) Advisory Panel on Micronekton Sampling Inter-Calibration experiment (pdf 0.04 Mb) Summary of Scientific Sessions and Workshops (pdf 0.2 Mb) Membership List (pdf 0.07 Mb) List of Participants (pdf 0.09 Mb) List of Acronyms (pdf 0.03 Mb)

Annual report 2003 - North Pacific Marine Science Organization (PICES). Twelfth meeting, Seoul, Republic of Korea, October 9-18, 2003

Report of Opening Session (pdf 58 KB) Report of Governing Council Meeting (pdf 244 KB) Report of 2003 interim Governing Council meeting Tenth Anniversary PICES Organization Review Report of the Finance and Administration Committee (pdf 102 KB) 2002 Auditor's report to the Organization Review of PICES Publication Program Reports of Science Board and Committees: Science Board/Governing Council interim meeting (pdf 81 KB) Science Board (pdf 95 KB) Study Group on PICES Capacity Building Biological Oceanography Committee (pdf 65 KB) Advisory Panel on Micronekton sampling gear intercalibration experiment Advisory Panel on Marine birds and mammals Fishery Science Committee (pdf 41 KB) Working Group 16 on Climate change, shifts to fish production, and fisheries management Marine Environmental Quality Committee (pdf 76 KB) Working Group 15 on Ecology of Harmful Algal Blooms (HABs) in the North Pacific Physical Oceanography and Climate Committee (pdf 70 KB) Working Group 17 on Biogeochemical data integration and synthesis Advisory Panel on North Pacific Data Buoy Technical Committee on Data Exchange (pdf 32 KB) Implementation Panel on the CCCC Program (pdf 64 KB) Nemuro Experimental Planning Team (NEXT) BASS Task Team (pdf 35 KB) Advisory Panel on Iron Fertilization Experiment MODEL Task Team (pdf 29 KB) MONITOR Task Team (pdf 30KB) REX Task Team (pdf 25 KB) Documenting Scientific Sessions (pdf 164 KB) List of Participants (pdf 60 KB) List of Acronyms (pdf 21 KB)

Annual report 2002 - North Pacific Marine Science Organization (PICES). Eleventh meeting, Qingdao, People's Republic of China, October 18-16, 2002

Report of Opening Session (pdf 51 KB) Report of Governing Council Meeting(pdf 136 KB) Report of the Finance and Administration Committee (pdf 48 KB) Reports of Science Board and Committees: Science Board (pdf 71 KB) Biological Oceanography Committee (pdf 66 KB) Working Group 14: Effective sampling of micronekton Marine Birds and Mammals Advisory Panel Fishery Science Committee (pdf 36 KB) Working Group 16: Climate change, shifts to fish production, and fisheries management Marine Environmental Quality Committee (pdf 39 KB) Working Group 15: Ecology of Harmful Algal Blooms (HABs) in the North Pacific Physical Oceanography and Climate Committee (pdf 49 KB) North Pacific Data Buoy Advisory Panel Working Group 17: Biogeochemical data integration and synthesis Technical Committee on Data Exchange (pdf 29 KB) Implementation Panel on the CCCC Program (pdf 43 KB) BASS Task Team (pdf 30 KB) Iron Fertilization Experiment Advisory Panel MODEL Task Team (pdf 28 KB) MONITOR Task Team (pdf 34 KB) Summary of Continuous Plankton Recorder activities in 2002 REX Task Team (pdf 21 KB) Documenting Scientific Sessions (pdf 140 KB) List of Participants (pdf 59 KB) List of Acronyms (pdf 21 KB)

Annual report 2001 - North Pacific Marine Science Organization (PICES). Tenth meeting, Victoria, B.C., Canada, October 5-13, 2001

Report of Opening Session (pdf 42 KB) Report of Governing Council Meeting (pdf 89 KB) Reports of Science Board and Committees: Science Board (pdf 88 KB) Study Group on North Pacific Ecosystem Status Report and Regional Analysis Center Biological Oceanography Committee (pdf 57 KB) Working Group 14: Effective sampling of micronekton Advisory Panel on Marine Birds and Mammals Fishery Science Committee (pdf 37 KB) Working Group 16: Climate change, shifts to fish production, and fisheries management Marine Environmental Quality Committee (pdf 62 KB) Working Group 15: Ecology of Harmful Algal Blooms (HABs) in the North Pacific Physical Oceanography and Climate Committee (pdf 34 KB) Working Group 13: CO2 in the North Pacific Technical Committee on Data Exchange (pdf 24 KB) Implementation Panel on the CCCC Program (pdf 39 KB) BASS Task Team (pdf 32 KB) Advisory Panel on Iron Fertilization Experiment MODEL Task Team (pdf 22 KB) MONITOR Task Team (pdf 32 KB) Advisory Panel on Continuous Plankton Recorder Survey in the North Pacific REX Task Team (pdf 21 KB) Report of the Finance and Administration Committee (pdf 53 KB) List of Participants (pdf 67 KB) List of Acronyms (pdf 13 KB)

Annual report 2000 - North Pacific Marine Science Organization (PICES). Ninth meeting, Hakodate, Hokkaido, Japan, October 20-28, 2000

Report of Opening Session (pdf 42 KB) Report of Governing Council Meetings (pdf 70 KB) Reports of Science Board and Committees: Science Board (pdf 57 KB) Biological Oceanography Committee (pdf 43 KB) Working Group 14: Effective Sampling of Micronekton Advisory Panel on Marine birds and mammals Fishery Science Committee (pdf 31 KB) Working Group 16 on Implications of Climate change to Fisheries Management Marine Environmental Quality Committee (pdf 47 KB) Working Group 8: Practical Assessment Methodology Working Group 15 on Ecology of Harmful Algal Blooms (HABs) in the North Pacific Physical Oceanography and Climate Committee (pdf 41 KB) Working Group 13: CO2 in the North Pacific Implementation Panel on the CCCC Program (pdf 120 KB) BASS Task Team Advisory Panel on Iron Fertilization Experiment MODEL Task Team MONITOR Task Team Advisory Panel on Continuous Plankton Recorder Survey in the North Pacific REX Task Team Technical Committee on Data Exchange (pdf 24 KB) Finance and Administration: Report of the Finance and Administration Committee (pdf 49 KB) Assets on 31st of December, 1999 Income and Expenditures for 1999 Budget for 2001 Report of the Fund-Raising Committee (pdf 20 KB) Composition of the Organization (pdf 27 KB) List of Participants (pdf 94 KB) List of Acronyms (pdf 13 KB)

Report of the 2004 Workshop on In Situ Iron Enrichment Experiments in the Eastern and Western Subarctic Pacific

Foreword 1. BACKGROUND AND OBJECTIVES (pdf, 0.1 Mb) 2. 2004 WORKSHOP SUMMARY (pdf, < 0.1 Mb) 2.1. What have we learned from the enrichment experiments? 2.2 What are the outstanding questions? 2.3 Recommendations for SEEDS-II 3. EXTENDED ABSTRACTS OF THE 2004 WORKSHOP 3.1 Synthesis of the Iron Enrichment Experiments: SEEDS and SERIES (pdf, 0.5 Mb) Iron fertilization experiment in the western subarctic Pacific (SEEDS) by Atsushi Tsuda The response of N and Si to iron enrichment in the Northeast Pacific Ocean: Results from SERIES by David Timothy, C.S. Wong, Yukihiro Nojiri, Frank A. Whitney, W. Keith Johnson and Janet Barwell-Clarke 3.2 Biological and Physiological Responses (pdf, 0.2 Mb) Zooplankton responses during SEEDS by Hiroaki Saito Phytoplankton community response to iron and temperature gradient in the NW and NE subarctic Pacific Ocean by Isao Kudo, Yoshifumi Noiri, Jun Nishioka, Hiroshi Kiyosawa and Atsushi Tsuda SERIES: Copepod grazing on diatoms by Frank A. Whitney, Moira Galbraith, Janet Barwell-Clarke and Akash Sastri The Southern Ocean Iron Enrichment Experiment: The nitrogen uptake response by William P. Cochlan and Raphael M. Kudela 3.3 Biogeochemical Responses (pdf, 0.5 Mb) What have we learned regarding iron biogeochemistry from iron enrichment experiments? by Jun Nishioka, Shigenobu Takeda and W. Keith Johnson Iron dynamics and temporal changes of iron speciation in SERIES by W. Keith Johnson, C.S. Wong, Nes Sutherland and Jun Nishioka Dissolved organic matter dynamics during SEEDS and SERIES experiments by Takeshi Yoshimura and Hiroshi Ogawa Formation of transparent exopolymer particles during the in-situ iron enrichment experiment in the western subarctic Pacific (SEEDS) by Shigenobu Takeda, Neelam Ramaiah, Ken Furuya and Takeshi Yoshimura Atmospheric measurement by Mitsuo Uematsu 3.4 Prediction from Models (pdf, 0.3 Mb) Modelling iron limitation in the North Pacific by Kenneth L. Denman and M. Angelica Peña A proposed model of the SERIES iron fertilization patch by Debby Ianson, Christoph Voelker and Kenneth L. Denman 4. LIST OF PARTICIPANTS FOR THE 2004 WORKSHOP (pdf, < 0.1 Mb) APPENDIX 1 Report of the 2000 Planning Workshop on Designing the Iron Fertilization Experiment in the Subarctic Pacific (pdf, 1 Mb) APPENDIX 2 Terms of Reference for the Advisory Panel on Iron fertilization experiment in the subarctic Pacific Ocean (pdf, < 0.1 Mb) APPENDIX 3 Historical List of Advisory Panel Members on Iron fertilization experiment in the subarctic Pacific Ocean (pdf, < 0.1 Mb) APPENDIX 4 IFEP-AP Annual Reports (pdf, 0.1 Mb) APPENDIX 5 PICES Press Articles (pdf, 0.6 Mb) (194 page document)

A influência da deposição atmosférica da poeira mineral da Patagônia na biomassa fitoplanctônica do setor Atlântico do Oceano Austral

O Oceano Austral é a região oceânica de maior extensão em que os macronutrientes necessários à produção primária permanecem em níveis elevados por todo ano. Essa condição é conhecida como High Nutrient Low Clorophyll (HNLC) e é determinada, em grande parte, pela relativa escassez de micronutrientes, particularmente o ferro. Diversos experimentos comprovaram que a entrada de ferro neste sistema intensifica a produção biológica, aumentando a fixação do carbono e, eventualmente, sua exportação para águas profundas. Este fenômeno recebeu muita atenção nos últimos 20 anos devido a sua possível influencia no clima, via ciclo do carbono. A relação inversa entre concentração de CO2 na atmosfera e o fluxo de poeira mineral observados em registros glaciais da Antártica Central sugere que a deposição atmosférica pode ser uma importante via para o aporte de micronutrientes. Porém, a contribuição da deposição de poeira mineral para a produção primária nesta região permanece para ser demonstrada e seu possível papel no sistema climático ainda não é conclusivo. No caso do setor Atlântico do Oceano Austral, que recebe influência da Patagônia, os baixos fluxos modernos de poeira mineral e a baixa solubilidade do ferro associado à estrutura dos alumíniossilicato levam muitos autores a postular que fontes oceânicas de micronutrientes sejam mais determinantes. Faltam, no entanto, evidências experimentais. Neste trabalho, abordamos o estudo da fertilização do setor Atlântico do Oceano Austral pela poeira da Patagônia utilizando duas ferramentas: (1) o sensoriamento remoto orbital de aerossóis minerais e clorofila-a em escala interanual; e (2) um experimento de fertilização, com poeira da Patagônia, realizado na Passagem de Drake, considerando fluxos estimados para a era moderna e para o último glacial. Após doze dias de bioensaio, os tratamentos de adição de poeira mostraram a elevação da clorofila-a e da abundância de células em níveis acima dos controles. Níveis intermediários e maiores de adição não diferiram entre si na intensidade de resposta biológica, separando-se apenas da menor adição. Esses resultados indicam que a poeira da Patagônia, mesmo nos fluxos atuais, é capaz de prover os micronutrientes escassos na coluna dágua, com potencial para deflagrar aumentos significativos de biomassa. Através da análise por sensoriamento remoto, identificamos uma região de alta correlação entre poeira e clorofila-a, que está localizada entre a Frente Subtropical e a Frente Polar, se estendendo da Argentina ao sul da África. Esta região difere das águas ao sul da Frente Polar pela menor profundidade da camada de mistura, menor concentração de silicatos, baixa biomassa de diatomáceas e, estima-se, maior estresse fisiológico devido à escassez de ferro e menor aporte oceânico deste nutriente. Em conjunto, essas características parecem criar condições que tornam a resposta biológica mais sensível à deposição de poeira mineral. Estes resultados lançam nova luz sobre o controle atual da produção primária na região e sobre a hipótese da regulação climática pelo fitoplâncton no Oceano Austral, mediado pela deposição de poeira da Patagônia.