l Junco Panorama

Welcome to the Sachs Lab

School of Oceanography

Ocean Sciences Building, Rooms 544, 546 & 547 

University of Washington 

Paleoclimatology & Organic Geochemistry Research




Tools & Techniques



Research Projects

    We study the natural variations that occurred in Earth's climate in the pre-industrial age, with a focus on the tropics, the heat engine of the climate system. This provides a baseline against which more recent changes caused by human activities can be assessed. Because satellites, thermometers, rain gauges and and the like did not exist or were not widely used prior to the start of the Industrial Age about 150 years ago we must develop indirect means to reconstruct the climate of that time.

    Our lab specializes in developing a relatively new class of climate proxies based on the hydrogen and carbon isotope ratios of molecular fossils left behind by microalgae and mangroves. We put much effort into testing and calibrating these new measures of rainfall and salinity by growing phytoplankton cultures and mangrove trees under controlled conditions in our lab so that we can estimate these parameters in the past with precision.

  • Tropical Climate & Hydrology Since the Last Glacial Maximum
    • Tropical Pacific climate changes during the last 2,000 years
    • Holocene changes in the Intertropical Convergence Zone (ITCZ)
    • Paleohydrologic reconstructions from molecular & isotopic changes in tropical Pacific lake, bog & ocean sediments
    • El Ni_o-Southern Oscillation variations since the last glacial maximum
    • SST reconstructions from alkenones in Eastern Equatorial Pacific sediments


      • Galapagos 2004 - El Junco Lake, San Cristobal Island
      • Galapagos 2008 - Isabela & Floreana Lakes & Lagoons
      • Christmas (Kiritimati) & Washington (Teraina) Islands 2005
      • Palau 2004
      • Panama Basin 2005
      • Clipperton Atoll 2008
      • Marshall Islands 2009
      • Kosrae, FSM 2009
      • Nauru 2010
      • Brisbane River 2010
      • Kosrae 2010
      • Wallis & Futuna 2011
      • Fiji 2011
      • Solomon Islands 2011
      • Kosrae 2011
      • Yap, Chuuk, Pohnpei & Guam 2012
      • Palau 2013
      • Hainan Island, China 2016
      • Galapagos 2016
      • Palau 2016

      • Phytoplankton Continuous cultures


    • Mangrove Cultures

        We are growing mangroves in order to quantify the hydrogen and carbon isotope fractionation during lipid synthesis across a range of salinities.  This research was motivated by graduate student Nemiah Ladd's observation that hydrogen isotope ratios in lipids from the leaves of the gray mangrove, Avicennia marina, decreased as salinity increased in the Brisbane River (SE Queensland, Australia).  This is opposite the fractionation response observed in phytoplankton, whose lipids are characterized by an increase in their deuterium-to-hydrogen ratio as salinity increases (see our studies from Christmas Island and the Chesapeake Bay).  We would like to quantify this response with controlled experiments  with a variety of mangrove species so that we can calibrate a paleosalinity proxy from mangrove lipids in sediment cores.  These experiments are being performed by graduate student Nemiah Ladd with assistance from UW Biology undergraduate June Landenburger.
        Our first mangroves were planted in our lab in July, 2011 with propagules of Rhizophera apiculata that we collected in Pohnpei, Micronesia.  The figure on the left shows the outside of 3 of the growing tanks, covered with plastic to maintain high humidity.  There is a mock tidal cycle with two high and two low tides per day.  The figure on the right shows the inside of the 15 PSU salinity tank on October 3, 2011.  The largest plants are Rhizophera apiculata.  There are also Rhizophera mangle and Laguncularia racemosa plants growing in this tank, from propagules and seeds from Florida.  If you look closely you can also see some Xylocarpus granatum seeds that have roots, but no shoots yet.  These were collected in Kosrae, Micronesia in September, 2011.

ttp://faculty.washington.edu/jsachs/lab/www/Research/Mangrove_Cultures_UW/Mangrove_tents_sm.jpg  ttp://faculty.washington.edu/jsachs/lab/www/Research/Mangrove_Cultures_UW/Mangrove_S15_tank_sm.jpg

       In order to expand the number of plants and salinities we could maintain, and better control temperature and humidity, we moved our mangrove experiments to the University of Washington Botany Greenhouse in mid-2012.  As of December, 2012 we have 6 species of mangroves growing at 6 different salinities (see below images).
The large number of species are required in order to evaluate the mechanisms responsible for hydrogen isotope fractionation in mangrove lipids as a function of salinity since three different strategies for managing salt are employed by mangroves, alone or in combination.  The images below are from October 11, 2012.  Below left you can see tall shoots of Heritiera littoralis (from Honolulu, HI) and young Rhizophera apiculata (from Pohnpei, FSM) plants.  Below right you can see shoots of Xylocarpus granatum amongst young Rhizophera apiculata plants, both of which were collected in Pohnpei, Micronesia in August 2012.


    • Field Studies: Yap, Chuuk, Pohnpei & Guam (2012), Station ALOHA Cruise, R/V Thomas G. Thompson (2012), NE Pacific Cruise, R/V Point Sur (2012), Brisbane River (2010), Saline Lakes of Canada's Western Great Plains & Utah's Great Salt Lake (2007), Cargill-Newark Salt Works (2008)Christmas Island (2005), Chesapeake Bay (2006)
    • Publications:

  • El Niño & Peru Upwelling from Mollusks

        JISAO Postdoctoral Fellow, Matthieu Carré (now CNRS Charg_s de Recherche at Univ. of Montpellier, France), is using oxygen and carbon stable isotopes in mollusk shells from middens along the coast of Peru to reconstruct the history of upwelling and El Ni_o during the Holocene.

  • Paleoceanography
    • Deep ocean oxygen, carbon storage & the biological pump
    • Sea surface temperatures
    • Holocene cooling of the Northwest Atlantic Ocean
    • The origin of fine particles in sediment drifts


    • Eastern Mediterranean sapropels
    • Nitrogen & carbon isotopes in chlorophyll


Julian Sachs - Professor of Oceanography

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/matthew_wolhowe-20160419033948.png-20160419033948_smsq.jpgMatthew Wolhowe - NSF Postdoctoral Fellow

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Ashley_Maloney_crop.jpgAshley Maloney - Graduate Student, UW Program on Climate Change Fellow, Global Change IGERT Fellow

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/jiwoonpark-1-20161114040444_smsq.jpgJiwoon Park - Graduate Student

Tess Clinkingbeard - Graduate Student

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Becci_Danford_Palau_IMG_1126.jpgBecci Danford - Undergraduate Student

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/PollySobeck_Palau_IMG_0842.jpgPolly Sobeck - Undergraduate Student

Amanda Witt - Undergraduate Student

Lab Alumni

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Josh_Gregersen_photo.JPGJosh Gregersen - Research Scientist/Engineer 3

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Lauren-Brandkamp_photo.jpgLauren Brandkamp - Research Scientist/Engineer 1

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Alyssa_Leaving_Clipperton_small.jpgAlyssa Atwood - Graduate Student, NSF Graduate Fellow, DOE Graduate Fellow (PhD 2015. Presently NOAA Postdoctoral Fellow at UC-Berkeley & Georgia Tech.)

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Nemiah_Kosrae_8-7-09_3.jpgNemiah Ladd - Graduate Student, NSF Graduate Fellow (PhD 2014. Presently NSF Postdoctoral Fellow at EAWAG, Switzerland)

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Tessa_Photo.jpgTessa McGee - Graduate Student (MS 2016)

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Marta_Headshot_sm.jpgMarta Wolfshorndl - Graduate Student (MS 2016)

elson_WebCrop_1.jpg Dan Nelson - Graduate Student (PhD 2014. Currently Postdoc at Univ. Basel, Switzerland)

Kathleen Hemeon - Research Aide I, Phytoplankton Specialist

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Julie_Richey_mini.jpgDr. Julie Richey - NOAA Postdoctoral Fellow

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Avery_photo_crop.jpg Dr. Avery Cook Shinneman - Postdoctoral Investigator

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Ines_Mugler_photo.jpg Dr. Ines Mügler - Humboldt Postdoctoral Fellow

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Orest_photo_06.jpgDr. Orest Kawka - Lab Manager / Research Scientist II

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Amanda_Chomos_2010.jpgAmanda Chomos, Laboratory Assistant

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/JHou.jpg Dr. Juzhi Hou - UW PCC Postdoctoral Fellow

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Matthieu_Carre_photo_adj.jpgDr. Matthieu Carre - JISAO Postdoctoral Fellow

rittany_photo.pngBrittany Demianew - Research Scientist I

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Valerie_5-21-06.jpgDr. Valerie Schwab - Swiss NSF Postdoctoral Fellow

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Dirk_5-21-06.jpgDr. Dirk Sachse - Humboldt Postdoctoral Fellow

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Rienk_Palau_Coring.jpgDr. Rienk Smittenberg - Comer Postdoctoral Fellow

Dr. Katharina Pahnke - Comer Postdoctoral Fellow

Dr. Zhaohui Zhang - Comer Postdoctoral Fellow

Jessie Kneeland - Graduate Student

Casey Saenger - Graduate Student

Former Undergraduate Researchers

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Colton_Skavicus_photo.jpg Colton Skavicus - Undergraduate Student

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Kesley_Price_photo.jpg  Kesley Price - Undergraduate Student

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Elise_Baldwin_new.jpg  Elise Baldwin - Undergraduate Student

Samantha Hing - Undergraduate Student

Cyrena Thibodeau - Undergraduate Student

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Johnny Huynh.jpgJohnny Huynh - UW Oceanography Undergraduate, Mary Gates Scholar

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Lauren-Brandkamp_photo.jpgLauren Brandkamp - UW Oceanography Undergraduate

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Chris_Paschall_photo.jpg Chris Paschall - UW Oceanography Undergraduate

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/June_Landenburger_IMG_0324_2.JPG  June Landenburger - UW Biology Undergraduate

Ryan D'Jay - UW Oceanography Undergraduate

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/conor_myhrvold_headshot_sm.jpg Conor Myhrvold - Princeton Undergrad., MIT Science Writing Graduate Student

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Tory_replant_mangrove_Kos2010_IMG_2175.jpg Tory Johnson - UW Undergraduate

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Thien-Y_Le-photo_IMG_5106_sm.jpg Thien-Y, Le - UW Undergraduate

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Jake_Zaragoza_sm.jpgJake Zaragoza - JISAO Summer Intern / Gonzaga Univ. Undergraduate

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Kyle_photo_sga%20banquet_crop.jpgKyle Thomas - Texas Southern University Undergraduate, NOAA/JISAO Intern

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Fran_Lib_tree_7-22-09.jpgFran Janny - UW Undergraduate

eff1_OrangeFilter_PinkWater_GSLn.JPGJeff Bowman - Levinson & Mary Gates Scholar

Jane Lee
Eric Battisti
Brittany Demianew
Carie Frantz

Evan Howard
Brittany Kimball
Daniel Luksic
Jen Nomura

Former High School Interns

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/David_Golub_DSC04307_sm2.jpg David Golub - Interlake High School Gifted Student Intern

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Nathan3_sm.jpgNathan Kato - Interlake High School Gifted Student Intern

Lab Photos
(We like to snowboard & ski!)

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Palau2016_afterTalk_IMG_0264.jpg  Koror, Palau -- October 2016

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/LabSkiTrip_StevensPass_19March2014_sm.jpg  Stevens Pass - March 19, 2014
L to R:  Lei, Marta, Tessa, Ashley, Nemiah, Julian

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Mt_Baker_25March2012_highmed.jpg  Mount Baker - March 25, 2012
L to R:  Dan, Ashley, Julian, Josh

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Sachs_Lab_Ski_Trip_29Mar2011_sm.jpg  Crystal Mountain - March 29, 2011
L to R:  Julian, Dan, Avery, Julie, Mat, Ashley

 ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Ashley_Julie_on_Shenda_11-2-10.jpg Ashley & Julie on SHENDA - Nov 2, 2010

rystal Mountain, 3/15/10Crystal Mountain - March 15, 2010
L to R:  Alyssa, Julian, Dan, Nemiah, Sarah, Jesse

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Crystal_Mt_Rainier_lab_ski_4-5-09.jpgCrystal Mountain - April 5, 2009
L to R:  Julian, Dan, Mt. Rainier, Alyssa, Orest

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Mt_Baker_Dan_Alyssa_Julian_3-31-08.jpgMt. Baker Powder Day - March 31, 2008
L to R:  Alyssa, Julian, Dan

t_Baker_4-11-07.jpgMt. Baker Powder Day - April 11, 2007
L to R:  Orest, Rienk, Valerie, Matthieu, Julian, Dirk

ttp://faculty.washington.edu/jsachs/lab/www/Research/people/Steven's Pass Powder Day - March 9, 2006
L to R: Luzzi, Valerie, Julian, Dirk, Rienk




l Junco Panorama

Galapagos:  September 2004

El Junco: Sole Freshwater Lake in Galapagos

Photo Highlights

Coring Videos

Genovesa: Hypersaline Lake



Palau:  May-June 2004


Introduction, Setting & Marine Lakes, Palau Landscapes, Animals of Palau (Coconut Crab! 1 2 3 4 5), El Nino, Coring Spooky Lake, Biomarkers in Spooky LakeClear Lake, Hell Hole, Jellyfish & Coring Ongeim'l Tketau ('Tourist or Jellyfish Lake'), El Nino History from Ongeim'l Tketau Biomarkers, Molecular Thermometry in Ongeim'l Tketau, Conclusion



Kiribati:  June-July 2005


Northern Line Islands:

Christmas Island (Kiritimati)

Washington Island (Teraina)

ttp://faculty.washington.edu/jsachs/lab/www/Research/Chesapeake_Expedition_2006/James_River_Bridge.jpgChesapeake Bay:  May 2006

  • When:  May 18-31, 2006.
  • Who:  Sachs, Sachse, Schwab, Smittenberg
  • Why:  Evaluate D/H variations in algal lipids along a salinity & d18O gradient from 0-30 PSU and -6 to 0‰, respectively.

ttp://faculty.washington.edu/jsachs/lab/www/Research/Chesapeake_Expedition_2006/CB_Gearing_Up_5-21-06.jpgPreparing a Filtration System

ttp://faculty.washington.edu/jsachs/lab/www/Research/Chesapeake_Expedition_2006/CB_River_Water.jpgSuspended Particle Samples


Saline Lakes of Canada's Western Great Plains & Utah's Great Salt Lake:  June 2007

  • When:  June 7-19, 2007
  • Where:  Alberta, Saskatchewan & Utah
  • Who:  Julian Sachs, Jeff Bowman, Chase Stoudt
  • Why:  Test a new molecular indicator of salinity


Clipperton Atoll: March 2008

  • When:  February 23 - March 22, 2008
  • Who:  Julian Sachs, Dan Nelson, Alyssa Atwood, Olivier Cartapanis
  • Why:  Reconstruct the position of the Intertropical Convergence Zone during the last millennium



Galapagos: June 2008

  • When:  June 3-25, 2008
  • Where:  Floreana & Isabela Islands
  • Who:  Julian Sachs, Alyssa Atwood, Dan Nelson, Simon Haberle
  • Why 1:  Core the sediments of lakes & lagoons for Holocene rainfall reconstruction
  • Why 2:  Lead US Congressional Delegation from the House Science & Technology Committee interested in climate change

Marshall Islands: June-July 2009

  • When:  June 15 - August 12, 2009
  • Where:  Throughout the Marshall Islands
  • Who:  Julian Sachs, Alyssa Atwood, Dan Nelson, Nemiah Ladd, Fran Janny, Conor Myhrvold
  • Why:  Core the sediments of lakes, lagoons & bogs for late Holocene rainfall reconstruction

Kosrae, FSM:  August 2009

  • When:  July 30 - August 12, 2009
  • Where:  Kosrae Island, Federated States of Micronesia
  • Who:  Julian Sachs, Alyssa Atwood, Dan Nelson, Nemiah Ladd, Fran Janny, Conor Myhrvold
  • Why:  Core the sediments of mangrove swamps & forests for late Holocene rainfall reconstruction

ttp://faculty.washington.edu/jsachs/lab/www/Research/Nauru_Brisbane_2010/links/Fall and Winter 09-10 124_1.jpgttp://faculty.washington.edu/jsachs/lab/www/Research/Nauru_Brisbane_2010/links/Pandanus Beach.jpgttp://faculty.washington.edu/jsachs/lab/www/Research/Nauru_Brisbane_2010/links/Fall and Winter 09-10 067.jpg

ttp://faculty.washington.edu/jsachs/lab/www/Research/Nauru_Brisbane_2010/links/Muddy Nemiah.jpgttp://faculty.washington.edu/jsachs/lab/www/Research/Nauru_Brisbane_2010/links/Fall and Winter 09-10 044.jpg
Nauru & Brisbane:  February 2010

  • When:  February 11-23, 2010
  • Where 1:  Republic of Nauru, Micronesia
  • Where 2:  Brisbane River Estuary, Queensland, Australia
  • Who:  Julian Sachs and Nemiah Ladd
  • Why 1:  Core the sediments of a lake in Nauru
  • Why 2:  Sample mangroves along a salinity gradient from seawater to freshwater to evaluate lipid and hydrogen isotope changes

Cargill San Francisco Bay Saltworks:  June 2008

  • When:  June, 2008
  • Where:  San Francisco Bay, CA
  • Who:  Jeff Bowman
  • Why:  Evaluate the influence of salinity on hydrogen isotope fractionation in algal and cyanobacterial lipids

Kosrae, FSM:  August 2010

  • When:  August 24 - September 3, 2010
  • Where:  Kosrae Island, Federated States of Micronesia
  • Who:  Julian Sachs, Nemiah Ladd, Salma Jibril
  • Why:  Core the sediments of estuaries for late Holocene rainfall reconstruction

ttp://faculty.washington.edu/jsachs/lab/www/Research/WALLIS_2011/Lac_Lalolalo_files/shapeimage_9.pngttp://faculty.washington.edu/jsachs/lab/www/Research/WALLIS_2011/Lac_Lalolalo_files/shapeimage_7.pngttp://faculty.washington.edu/jsachs/lab/www/Research/WALLIS_2011/Wallis_Island_files/Screen Shot 2011-11-04 at 3.58.13 PM.jpgttp://faculty.washington.edu/jsachs/lab/www/Research/WALLIS_2011/Scientific_Equipment_files/shapeimage_5.png
Fiji and Wallis & Futuna:  May-June 2011

  • When:  April 20 - June 10, 2011
  • Where:  Wallis Island, Wallis & Futuna. Teveuni and Vanua Balavu Islands, Fiji
  • Who:  Julian Sachs, Julie Richey, Ashley Maloney, Dan Nelson
  • Why:  Core the sediments of lakes for late Holocene rainfall reconstruction

Solomon Islands:  June-July 2011

  • When:  June 10 - July 3, 2011
  • Where:  Tetepare & Rendova Islands, Western Province, Solomon Islands
  • Who:  Dan Nelson, Mat Prebble (ANU), Tim Thomas (U. Otago)
  • Why:  Core the sediments of lakes for late Holocene rainfall reconstruction

Kosrae, FSM:  August 2011

  • When:  August 20 - September 20, 2011
  • Where:  Kosrae Island, Federated States of Micronesia
  • Who:  Julian Sachs, Nemiah Ladd, Conor Myhrvold
  • Why:  Core the sediments of mangrove swamps for late Holocene rainfall reconstruction

R/V Thomas G. Thompson, Station ALOHA:  February 2012

  • When:  Feb. 2012
  • Where:  Stn. ALOHA (22_N, 158_W)
  • Who:  Sachs Lab
  • Why:  Evaluate the influence of nutrient- & light-limited growth rate on hydrogen isotope fractionation in algal lipids

R/V Point Sur, NE Pacific:  July 2012

  • When:  July 2012
  • Where:  NE Pacific (42_N, 152_W)
  • Who:  Sachs Lab
  • Why:  Evaluate the influence of nutrient- & light-limited growth rate on hydrogen isotope fractionation in algal lipids

Yap, Chuuk, Pohnpei & Guam:  August 2012

  • When:  August 2-24, 2012
  • Where:  Federated States of Micronesia islands of Yap, Chuuk & Pohnpei, and Guam
  • Who:  Julian Sachs, Nemiah Ladd
  • Why:  Sample mangroves along salinity & hydrologic gradients to calibrate H & C isotope indicators of rainfall


Tools & Techniques

-Molecular fossils (biomarkers)

Molecular D/H, 13C/12C, 15N/14N

Isotope-Ratio-Monitoring Gas Chromatography - Mass Spectrometry (irmGC-MS)

High-Performance Liquid Chromatography - Mass Spectrometry (HPLC-MS) 

Gas Chromatography - Mass Spectrometry (GC-MS)

Gas Chromatography - FlameIonization Detection (GC-FID)

High-Performance Liquid Chromatography (HPLC)


Publications & Data

Julian Sachs Homepage


Courses Taught

University of Washington

School of Oceanography

UW Program on Climate Change (PCC)

Where we are on the UW Campus

Contact Info:

Julian P. Sachs
University of Washington
School of Oceanography
Box 355351
Seattle, WA 98195-5351

p (206) 221-5630
f (206) 685-3351

For Package Delivery:

Marine Sciences Bldg

1501 NE Boat Street
Room G
Seattle, WA 98195


Last Updated:  August 13, 2014.

Web design by Julian Sachs (jsachs@uw.edu).