Recent News...

Zehria floridana, a newly described genus and species of cyanobacteria. (Image credit: Mares et al., 2019)

Meet Zehria! A newly described genus of marine N2-fixing cyanobacteria is named in honor of Professor Zehr

April 2019

Jeffrey Johansen (John Carroll University) and colleagues disentangled the phylogeny of Cyanothece-like organisms and described two new genera of cyanobacteria, including Zehria, in a recent article in the Journal of Phycology.

 

Mareš, Jan, Jeffrey R. Johansen, Tomáš Hauer, Jan Zima Jr, Stefano Ventura, Oana Cuzman, Bruno Tiribilli, and Jan Kaštovský. "Taxonomic resolution of the genus Cyanothece (Chroococcales, Cyanobacteria), with a treatment on Gloeothece and three new genera, Crocosphaera, Rippkaea, and Zehria." Journal of phycology (2019). 

See UCSC press release here

Graduate student Katie Harding and colleagues demonstrate cyanobacterial N2 fixation in cold Arctic waters

December 2018

 

See UCSC press release here

Prof. Zehr elected 2018 AAAS Fellow

November 2018

 

See UCSC announcement here

Read a more integrative view and detailed description of the Zehr’s lab work aboard the Falkor here.
Eddy Exploration & Ecosystem Dynamics
Schmidt Ocean Institute
R/V Falkor

Ana Cabello and Rosie Gradoville, April-May 2018

 

The main objective of this cruise was to characterize the deep chlorophyll maximum within the center of eddy fields in the North Pacific Subtropical Gyre using long-range autonomous underwater vehicles (LRAUVs). These self-driving vehicles collect information about water temperature, chemistry, and chlorophyll and also are able to collect and preserve seawater samples at sea to study the microorganisms present. In parallel, our group was performing diel sampling every 3-6 hours from CTD casts, nitrogen fixation incubations on free drifting arrays, and deck-board experiments. These experiments all explored the diversity and activity of nitrogen-fixing bacteria, with special focus on UCYN-A. During the diel sampling we collected DNA, RNA and CARD-FISH samples at different depths to compare UCYN-A transcriptional activity and cell-division rates between surface and deep populations. Our incubation experiments investigated how UCYN-A cell-specific carbon and nitrogen fixation rates vary with depth (from 5 to 125m), and also tested whether UCYN-A is fixing nitrogen during the natural dark period.

Zehrites

Zehrites

SIO

SIO

SIO

SIO

CTD ops

CTD ops

CTD ops

CTD ops

Britt

Britt

Zehrites

Zehrites

Ana & Brittany

Ana & Brittany

CTD crew

CTD crew

Ana

Ana

Matt

Matt

CTD sampling

CTD sampling

CTD ops

CTD ops

pump deployment

pump deployment

Britt

Britt

Incubations

Incubations

Incubation crew

Incubation crew

R/V Gordon Sproul

R/V Gordon Sproul

R/V Gordon Sproul

R/V Gordon Sproul

Core cast crew

Core cast crew

Incubations!

Incubations!

Incubations!

Incubations!

SIO

SIO

deck ops

deck ops

deck ops

deck ops

Catalina Island

Catalina Island

deck ops

deck ops

sunset

sunset

What is UCYN-A doing in a coastal shelf ecosystem?
SP1729 R/V Gordon Sproul 

Kendra Turk-Kubo, Ana Cabello, Britt Henke, Brittany Stewart, and honorary Zehr Lab member Jenna Spakeen (VIMS) in collaboration with Matt Mills and Arrigo Lab members (Stanford), October 2017

This was the second of two cruises scheduled this year off the coast of Baja. Our objectives for both cruises were to track growth rates, bulk and cell-specific N2 fixation, nitrate uptake rates, CO2 fixation, and metabolic activities of UCYN-A1 and UCYN-A2 in coastal waters. We also conducted core casts at each station to measure environmental variables including POC/PON, chl a, nutrients (N, P, Si) and take samples to characterize the microbial community composition (DNA/RNA/FCM/CARD-FISH).

Baltic Room

Baltic Room

middle of the night in Nome

middle of the night in Nome

Nome Harbor

Nome Harbor

R/V Sikuliaq

R/V Sikuliaq

R/V Sikuliaq

R/V Sikuliaq

Leaving Nome

Leaving Nome

R/V Sikuliaq

R/V Sikuliaq

The team

The team

dimming

dimming

CTD ops

CTD ops

CTD ops

CTD ops

Beaufort Sea

Beaufort Sea

Beaufort Sea

Beaufort Sea

Incubations

Incubations

finally, night-ish

finally, night-ish

returning to land

returning to land

Nome, from sea

Nome, from sea

charter from Barrow to Nome

charter from Barrow to Nome

BARC

BARC

Small boat ops

Small boat ops

Small boat ops

Small boat ops

thermokarst

thermokarst

sunset

sunset

BARC

BARC

R/V Ukpik

R/V Ukpik

Sampling at the edge

Sampling at the edge

Are there Diazotrophs in the Arctic?
Field operations out of BARC &
R/V Sikuliaq

Kendra Turk-Kubo, Britt Henke, Katie Harding, 

August-September 2017

This was our second trip to the Arctic to investigate the spatial extent of nitrogen fixation and which diazotroph species may be active in the Beaufort and Chukchi Sea (Arctic Ocean). Led by Rachel Sipler (VIMS), a team of researchers from VIMS, UCSC, and GIT have come together to study this enigma. 

Follow the blog: https://thedynamicarctic.com

And hear an interview with K. Turk-Kubo about our research: 

https://thedynamicarctic.com/2017/08/16/diazotrophs-in-the-arctic/

cruise track

cruise track

gradients cruise.com

gradients cruise.com

CTD deployment

CTD deployment

Sunset from the R/V Langseth

Sunset from the R/V Langseth

Gradients 2.0 cruise in the North Pacific, from the Subtropical Gyre (21°N) to the Subarctic Gyre (43°N). 
R/V Langseth 

Rosie Gradoville and Brittany Stewart, May-June 2017

This cruise tracked the gradients in diversity and biogeochemistry in the North Pacific on a transect from the Subtropical Gyre to the Subarctic Gyre. We steamed north from Honolulu and mapped out the “transition zone” between the two gyres. Then, we turned around and sailed back to Hawaii, collecting samples at stations aimed at characterizing all three regions. The Zehr lab collected samples for DNA, RNA, and fluorescence in situ hybridization (FISH) in order to explore the diversity, abundance, and activity of nitrogen-fixing bacteria along this transect.

 
The team

The team

R/V Gordon Sproul

R/V Gordon Sproul

R/V Gordon Sproul

R/V Gordon Sproul

IMG_9054

IMG_9054

Incubators

Incubators

CTD control room

CTD control room

CTD control room

CTD control room

Core team!

Core team!

Meredith operating the winch

Meredith operating the winch

Meredith operating the winch

Meredith operating the winch

Meredith operating the winch

Meredith operating the winch

Deployed!

Deployed!

Leona

Leona

CTD deployment

CTD deployment

CTD deployment

CTD deployment

The team!

The team!

What is UCYN-A doing in a coastal shelf ecosystem?
SP1714 R/V Gordon Sproul 

Kendra Turk-Kubo, Mary Hogan, Katie Harding, and honorary Zehr Lab members Meredith McPherson (UCSC) and Jenna Spakeen (VIMS) in collaboration with Matt Mills and Arrigo Lab members (Stanford), May 2017

Our objective on this cruise were to track growth rates, bulk and cell-specific N2 fixation, nitrate uptake rates, CO2 fixation, and metabolic activities of UCYN-A1 and UCYN-A2 in coastal waters. We also conducted core casts at each station to measure environmental variables including POC/PON, chl a, nutrients (N, P, Si) and take samples to characterize the microbial community composition (DNA/RNA/FCM/CARD-FISH).

While off the coast of Baja California, we encountered a storm - the seas were high and the boat was small. See the videos to the left! 

 

 
In the News...
Gordon and Betty Moore Foundation awards Himadri Pakrasi (InCEES/WUStl) and Prof. Zehr funding to study the symbiotic relationship between oceanic cyanobacteria and microalgae 

January 2017

Read the press release:

https://incees.wustl.edu/2017/01/26/1-million-grant-awarded-to-i-cares-director-and-ucsc-professor/

Link to the Pakrasi Lab:

https://sites.wustl.edu/photosynthbio/

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Prof. Zehr invited to give Plenary talk at The Third Xiamen Symposium on Marine Environmental Sciences

Xiamen, China, January 9-11, 2017

 

http://mel.xmu.edu.cn/conference/3XMAS/

 
Arctic Research Cruise, R/V Sikuliaq, September 3-29, 2016

 

Katie Harding, September 2016

We visited the Arctic to investigate the spatial extent of nitrogen fixation and which diazotroph species may be active in the Beaufort and Chukchi Sea (Arctic Ocean). Led by Rachel Sipler (VIMS), a team of researchers from VIMS, UCSC, and GIT have come together to study this enigma. 

Follow the blog: https://thedynamicarctic.wordpress.com/

And read up on our research goals: 

https://thedynamicarctic.wordpress.com/2016/08/31/an-arctic-fixation/

 
The team

The team

Trace metal clean ziplock bags

Trace metal clean ziplock bags

Termite in bed

Termite in bed

Sunset 2

Sunset 2

Pump watch view

Pump watch view

Sunset

Sunset

Krill

Krill

Leaving Honolulu

Leaving Honolulu

Incubation babies lined up

Incubation babies lined up

Incubators on a sunny day

Incubators on a sunny day

Filtering for CARD-FISH in the dead box

Filtering for CARD-FISH in the dead box

Fitration setup

Fitration setup

Filtering for Chl a

Filtering for Chl a

Calm seas

Calm seas

3000 m foam cups

3000 m foam cups

Baby

Baby

CTD on deck

CTD on deck

Gradients cruise KOK1606, Transect northbound to 37°N along 158°W

 

Hanna Farnelid and Brittany Stewart, April-May 2016

Our objectives during the Gradients cruise were to characterize diazotroph diversity and abundances across the transition zone region between the North Pacific Subtropical Gyre and the Subpolar Gyre. Along the cruise tract, diazotroph diversity and community composition will be analyzed using nifH amplicon sequencing, quantitative PCR (qPCR) targeting known diazotrophs, and fluorescence in situ hybridization (FISH) targeting the unicellular symbiont UCYN-A. We also conducted mixing experiments between different water masses to simulate what happens in the transition zone.  We had an eventful cruise with a termite swarm (!) and a toilet flooding but seas were mainly calm.

 
women @ sea

women @ sea

ready to deploy

ready to deploy

in situ array recovery

in situ array recovery

in situ array recovery

in situ array recovery

in situ array bottles

in situ array bottles

safety @ sea

safety @ sea

CTD recovery

CTD recovery

CTD recovery

CTD recovery

CTD recovery

CTD recovery

CTD @ dusk

CTD @ dusk

sunset

sunset

sunset

sunset

sunset

sunset

sunset

sunset

diamond head

diamond head

returning to land

returning to land

tug assist

tug assist

SCOPE cruise KM1605, North Pacific Subtropical Gyre

 

Mary Hogan and Kendra Turk-Kubo, March 2015

 

Our research group had several objectives for this cruise: 1) Investigate diazotroph growth rates under various nutrient, light, trace metal and temperature regimes; and 2) Investigate diazotroph grazing rates under different light and temperature regimes.

 
Prof. Zehr in the News:
'This is how scientists will save the Baltic Sea'

 

http://mobil.unt.se/uppland/uppsala/sa-ska-forskarna-radda-ostersjon-3848114.aspx

 
R/V KOK (UH)

R/V KOK (UH)

Secured and ready for transit

Secured and ready for transit

Britt and the CTD rosette

Britt and the CTD rosette

Bird's eye view of the Niskins

Bird's eye view of the Niskins

Filtering station

Filtering station

Filtering!

Filtering!

Preparing for Array deployment

Preparing for Array deployment

Incubation Array deployment

Incubation Array deployment

Incubation Array Recovery

Incubation Array Recovery

Incubation Array Recovery

Incubation Array Recovery

Incubation Array Recovery

Incubation Array Recovery

Incubation Array recovery

Incubation Array recovery

Incubation Array Recovery

Incubation Array Recovery

Deckboard incubations

Deckboard incubations

Filtering in the air castle...

Filtering in the air castle...

...is challenging!

Dead filtering zone

Dead filtering zone

Dead filtering zone

Dead filtering zone

Sunset in the NPSG

Sunset in the NPSG

Sunset in the NPSG

Sunset in the NPSG

Sunrise in the NPSG

Sunrise in the NPSG

Almost home!

Almost home!

Diamond Head

Diamond Head

SCOPE cruise KOK1507, 200 miles N. of Station ALOHA

 

Hanna Farnelid, Britt Henke and Kendra Turk-Kubo, July-August 2015

 

Our research group had several objectives for this cruise: 1) Investigate diazotroph growth rates under various nutrient, light and temperature regimes (K. Turk-Kubo); 2) Investigate particle associated and phytoplankton associated bacteria (H. Farnelid), and 3) Continue cultivation efforts to isolate the UCYN-A symbiont (B.Henke).

 
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Mari1.jpg

Mari1.jpg

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C-MORE/SCOPE cruise C-20, Station ALOHA

 

Maria del Carmen Muñoz-Marin, April 2015

 

During the C-20 cruise, Postdoc Maria del Carmen Muñoz-Marin sampled diel cycles over 3 days for RNA, DNA and CARD-FISH. With these samples she will develop a whole genome array approach for the nitrogen-fixing cyanobacterium UCYN-A1. With this technique, she will try to determine the whole genome transcription patterns related to PSI, energy metabolism and nitrogenase gene expression over light-dark cycles.

 

Moreover, she will study the interaction between the host and the cyanobacterium during light-dark cycles using double CARD-FISH.

 
R/V Ka`imikai-O-Kanaloa (UH)

R/V Ka`imikai-O-Kanaloa (UH)

HOT cruises depart from Snug Harbor in Honolulu. The R/V Ka`imikai-O-Kanaloa (KOK) often transports the science team to Station ALOHA.

Sunrise at Snug Harbor

Sunrise at Snug Harbor

A beautiful February morning in Honolulu.

Departing Snug Harbor

Departing Snug Harbor

The Honolulu Skyline as we depart Snug Harbor.

Last glimpses of land

Last glimpses of land

Oceanographers have large collections of sky/sea shots like this!

UH Cytometry Van

UH Cytometry Van

This van houses a BD Influx cytometer, that our lab has used many times over the years. Many of our most exciting discoveries have been facilitated by this van.

Bridge of the KOK

Bridge of the KOK

Looking towards the bridge of the KOK.

Growth rate incubations

Growth rate incubations

This is where we conduct microcosm incubations with the microbial community at Station ALOHA. This experiment was designed to measure growth and grazing rates of nitrogen fixing microbes.

Incubations

Incubations

These incubations were conducted in cubitainers, so that there was enough volume to sample for molecular work more than once.

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2015-02-24 08.13.54.jpg

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2015-02-26 17.12.27.jpg

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2015-02-27 07.23.30.jpg

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2015-02-27 07.24.16.jpg

HOT-269
Kendra Turk-Kubo and Hanna Farnelid, February 2015
 
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Science_team_New_Horizon_NEMO.jpg

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Nemo_cruise_track.jpg

NEMO Cruise, August 2014
Irina Shilova, Julie Robidart, and colleagues from Stanford, MIT, and the Univeristy of Hawaii

 

In late summer of 2014, the UCSC, Stanford, and UH research team conducted a month long expedition named NEMO (Nutrient Effects on Marine microOrganisms), as a part of our research funded by the NSF Dimensions in Biodiversity program. The objective of the NEMO research cruise was to investigate the role of nitrogen in shaping phytoplankton biodiversity and physiology in the central North Pacific Ocean. Starting from San Diego, CA, they characterized the nutrient rich dynamic waters of the California Current System, followed by an extensive phytoplankton bloom in the middle of North Pacific Ocean, low-nutrient waters and a large Trichodesmium bloom near Hawaii. Through taking various physicochemical and biological measurements along the transect, and conducting nutrient manipulation experiments, they examined how different forms of nitrogenous substrates together with phosphorus and iron alter microbial community structure, physiology and the rates of phytoplankton photosynthesis. 

 

Ocean Sciences Department

1156 High Street

University of California, Santa Cruz, CA 95064

© 2015 by the Zehr Laboratory

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