Research faculty member Dr. Diana Steller leads innovative rhodolith research project

The picturesque harbors of Catalina Island are the perfect habitat for rare coral-like red algae known as rhodoliths. Like corals, these algae form calcium carbonate ‘skeletons’ that grow in spherical branching patterns. Then in the gentle wave action of semi-protected harbors, the rhodoliths roll around on the ocean floor like tumbleweeds, forming into spheres, with pockets of open space between the branches.

“They form living layers that look like pink golf balls covering the ocean floor,” explains SJSU/MLML research faculty member Dr. Diana Steller, who led a recent California Sea Grant-funded project on Catalina’s rhodolith beds. “Rhodoliths form a structured habitat on what is otherwise normally soft sediment bottoms—a complex matrix of shapes and sizes for things to find refuge in."

"And because they form a hard structure that's heterogeneous, a lot of organisms can settle, survive better and live there. They act often as nursery grounds, and/or habitat for holdfast of different species,” she adds.

Learn more about Dr. Steller’s fascinating research in new story from California Sea Grant.

Five SJSU/MLML faculty members receive funding from California Sea Grant & CSU COAST

Three new SJSU/MLML research projects are officially Sea Grant-funded! California Sea Grant has announced funding for a total of seven new research projects led by early-career faculty members throughout the state. The one-year projects focus on two key areas of California Sea Grant’s strategic plan: sustainable fisheries & aquaculture, and coastal resilience. This year, a new partnership with the CSU Council on Ocean Affairs, Science & Technology (COAST) provided non-federal match to new CSU faculty members whose research focuses on supporting the state of California’s highest priority marine, coastal and coastal watershed related needs for scientific information.

SJSU/MLML faculty will serve as PIs on the following three projects:

  • Chemical oceanographer Dr. Maxime Grand and co-PI research faculty member Dr. Luke Gardner will lead a new project focused on quantifying volatile bromocarbon emissions from seaweed aquaculture in California.
  • Invertebrate ecologist Dr. Amanda Kahn and co-PIs Dr. Kerstin Wasson and Dr. Luke Gardner will investigate the use of energetics and metabolism to enhance Olympia oyster aquaculture and outplanting success.
  • Ichthyologist Dr. Scott Hamilton and phycologist Dr. Michael Graham will serve as co-PIs on a new project led by SJSU professor Dr. Maya deVries investigating whether co-culture of seaweeds and shellfish improves shell integrity in farmed red abalone.

Congratulations to all our SJSU/MLML faculty members and their collaborators on these exciting new ventures! Learn more about all seven newly funded research projects here.

Thesis Defense by Daniel Gossard – December 18th Livestream

 

"Epiphyte-host dynamics between Pyropia and Nereocystis in central California"
A Thesis Defense by Daniel J. Gossard

The Phycology Lab

MLML Live-Stream | December 18, 2020 at 1 pm

Dan didn't really care for seaweeds until he started working at a seaweed farm in 2016 and everything changed. He realized that the complexity of these (primarily) sessile organisms requires lifetimes of study to even marginally understand, and that they're much more interesting than fish ever could be. His appreciation for the ecology of seaweeds grew as he realized that seaweeds can play an important foundational role for ecosystems. As seaweed biogeographic distributions have been known to rely on ocean temperatures, how will this foundational role change in reaction to a changing climate? What will be the trophic consequences? Can seaweeds potentially mitigate greenhouse (CO2 and methane) emissions? The answer is yes, but can the application be scaled in practical purposes on a global scale? Is seaweed farming a sustainable and scalable US industry that can alleviate the country's import deficit, feed livestock and fertilize fields, and be used as a biological filter to mediate industrial runoff alleviating the effects of eutrophication? (Yes). Despite all these pressing issues related to seaweeds, Dan chose to study an esoteric algal epiphyte for his Master's thesis. After graduating, Dan hopes to continue research in the fields of seaweed ecology and/or aquaculture.

Thesis Abstract:

Epiphytism is widespread in the marine environment across macroalgal taxa. However, despite being geographically ubiquitous, many unique epiphyte-host interactions remain poorly understood. Radiation within the bladed Bangiales (Rhodophyta), presumably brought on by a heteromorphic life history coupled with exceptional tolerance of stressors, led to many subtidal species of Pyropia occupying the epiphytic subtidal niche with their annual gametophyte stage. Pyropia nereocystis is a northeastern Pacific species that has evolved to primarily epiphytize the annual kelp Nereocystis luetkeana, which has a large latitudinal range from central California to the Aleutian Islands. There is a complete lack of tested hypotheses regarding the spatial and temporal dynamics of this epiphyte-host interaction and a lack of understanding of whether environmental heterogeneity drives recruitment and growth of Pyropia. I tested three aspects of Pyropia-Nereocystis epiphyte-host dynamics in the southern extent of the host’s range: (1) spatial and temporal variation in epiphtyte presence as a function host canopy densities at five sites for two cohorts; (2) empirical tests of the effects of depth on growth of gametophyte and sporophyte (conchocelis) life history stages through transplantation experiments; and (3) evaluation of the effects of depth and host characteristics on the recruitment and biomass of the ephiphyte over two seasons.

Pyropia epiphytism exhibited a shift in presence on Nereocystis that was attributed to an increase in the proportion of hosts that were epiphytized over the first two sampling periods. These dynamics differed interannually as a function of Nereocystis density. Additionally, testing the coefficient of variation of densities of epiphytized versus non-epiphytized Nereocystis over time (for sampling periods where Pyropia was present) indicated greater clumping of unepiphytized Nereocystis and more regularly arranged epiphytized Nereocystis. Pyropia gametophyte transplants showed no significant differences in growth when transplanted below their primary habitat (on the upper portions of Nereocystis stipes), but Pyropia conchocelis transplants showed a significant positive correlation between growth (change in area occupied) and depth. Intraregional environmental heterogeneity was reflected in significant intraregional differences among Nereocystis host characteristics that affected Pyropia recruitment. Additionally, significant associations between Nereocystis stipe characteristics and Pyropia's lower limit and abundance (biomass) were present for epiphytized Pyropia and their Nereocystis hosts. Nereocystis holdfast depth did not set the lower limit of Pyropia recruitment, but the PC (principal component) associated with longer host apophyses were correlated with a deeper Pyropia recruitment lower limit. Pyropia abundance in the upper meter was a strong predictor of Pyropia biomass on the whole Nereocystis stipe, but only during the peak period of Pyropia abundance. Furthermore, Pyropia abundance was positively correlated with the surface area of Nereocystis, hosts with longer stipes and more cylindrical apophyses, and thresholded by hosts characterized by greater SL:HD (stipe length:holdfast depth). These results suggest that the distribution of epiphytism of Nereocystis is more regular than it is clumped, gametophyte growth is not limited by depth, and that conchocelis can grow successfully depths at least up to 20 m. Additionally, in the presence of environmental heterogeneity, Pyropia may be regulated by Nereocystis stipe characteristics relating to host apophyses, stipe surface area, and ecological effects experienced by individual Nereocystis. The epiphyte-host interaction between the macroscopic stages of these heteromorphic algae highlights: (1) Nereocystis mediates Pyropia's persistence on a cohort sub-population scale, (2) Nereocystis likely influences Pyropia's abundance and lower limit by interactions on an individual host scale, and (3) Pyropia persists in the face of interannual hetereogeneity of host Nereocystis persistence.

Daniel Gossard Presents: Epiphyte-host dynamics between Pyropia and Nereocystis in central California

Thesis Defense by Lindsay Cooper – December 1st Livestream

 

"Compartmentalization & seasonal variability in storage compounds of Pterygophora californica"
A Thesis Defense by Lindsay Cooper

The Phycology Lab

MLML Live-Stream | December 1, 2020 at 12 pm

While other children told their parents they wanted to be ballerinas or firemen, from the get go, Lindsay claimed she would become a marine biologist. That was the only profession she ever wanted to pursue in life. Every year, her birthday request was to visit Sea World and the San Diego Wild Animal Park for the weekend. However, feeling discouraged by counselors who told her there were few career paths in marine science, she pursued a business degree as an undergrad. After enduring several unfulfilling years on this path, she threw all caution to the wind and started over in order to pursue her lifelong passion of marine science. Lindsay received her SCUBA certification and was able to spend a fall semester doing research with the Wrigley Institute of Environmental Science on Santa Catalina Island. This was her first real immersion into the field and opportunity to do independent research. During this program she developed a love for seaweeds and the drive to pursue a graduate degree.

Lindsay joined the MLML Phycology lab in 2013, where she took an active role in hosting the annual Open House and volunteering to help other students with their research. While at Moss Landing, Lindsay has acquired her scientific dive certification, gone on two research trips to Baja California Sur studying rhodolith beds as a living substrate, and conducted a subtidal study of Pterygophora californica population demographics and aging in Stillwater Cove, Carmel Bay. Her thesis research focuses on the effects of biomass loss on the seasonal variability in storage compounds of Pterygophora californica, an important local kelp species.

Thesis Description:

This study investigates the existence of nutrient compartmentalization within the thallus of Pterygophora, whether there were any seasonal effects, and how biomass loss impacted the compartmentalization of nutrients. The results of this subtidal experiment have been a long time coming; it's the second iteration. The first time Lindsay set up the experiment, she was six months into the experiment when two big winter storms hit in a row and ripped almost all of the tags off of her Pterygophora, and dislodged some of the plants. Lindsay had to redesign the tags, and move the experiment to a slightly more protected location in Stillwater Cove. The experiment began in July 2017 and ran for 15 months.

Lindsay Cooper Presents: Compartmentalization & seasonal variability in storage compounds of Pterygophora californica

Professors Michael Graham and Scott Hamilton receive new California Sea Grant funding

SJSU/MLML Professors Michael Graham of our Phycology Lab and Scott Hamilton of our Ichthyology Lab have received new grant funding from California Sea Grant. Their project titled “Assessment of practical methods for re-establishment of northern California bull kelp populations at an ecologically relevant scale” will focus on restoring native seaweed populations and combatting destructive sea urchin overgrowth.

This grant is one of six funded by California Sea Grant as part of their 2020 Kelp Recovery Research Program. Together the grants total $2.1 million and are funded jointly by California Sea Grant and the California Ocean Protection Council, in collaboration with the California Department of Fish and Wildlife.

Read more about Dr. Graham and Dr. Hamilton's new research project here.

German Nature Show, TerraX, film episode on ‘Kelp – What super algae can do’ features MLML experts

German nature show, Terra X, selects MLML for their episode on “Kelp – What super algae can do”. Phycology student, Ann Bishop, shows off her science communication skills by teaching the TerraX audience about bull kelp, the kelp canopy, the kelp forest ecosystem and the importance of kelp habitats to ocean health. Director, Ross Clark, & manager, Kevin O' Connor, of the SJSU/MLML Central Coast Wetlands Group were also interviewed. In the segment, Clark, discusses the most recent “warm blob”, that resulted in a massive purple urchin recruitment, which then decimated the North Pacific kelp forests. O' Connor then gives viewers the scoop on CCWG's latest research to feed cattle with algae. The research aims to reduce methane emissions by up to 90%!

Thesis Defense By Cody Dawson – May 7th, 2018

Phenology and the Response to Disturbance of the fucoid, Stephanocystis osmundacea

A Thesis Defense by Cody Dawson

Phycology Lab

Monday, May 7th, 2018 at 4pm

MLML Seminar Room

Cody Dawson is a Master's student in the Phycology Lab under the expert tutelage of Mike Graham. He received his BS in Biology from Humboldt State University where he was mainly working with invertebrates and predator-prey dynamics. Upon joining MLML in 2014, he discovered a love for seaweed which led him to a project surrounding their physiology that would become his life for the next 3 years. With the completion of his MS, he will be moving onto to study the trophic ecology of nearshore ecosystems in the Alaskan Beaufort Sea at the University of Texas at Austin as a part of his PhD.

Thesis Abstract:

Nearshore rocky ecosystems along exposed shorelines experience frequent disturbances due to turbulent swells and wave action. These disturbances directly affect subtidal algal communities that provide biogenic habitat along the coast. This habitat shapes faunal communities by providing refuge through structural complexity. In central California, kelps are the most notable providers of biogenic habitat, but, seasonally, a prolific fucoid, Stephanocystis osmundacea, adds a considerable amount of habitat into the environment. While diminutive and bushy during the winter, this alga produces canopy-forming reproductive fronds during the spring and summer months that add to the biogenic refuge. The purpose behind this study was to understand how the frequency and timing of disturbances affect the physiology of Stephanocystis. This was accomplished by performing manipulations on the reproductive and vegetative tissues of the alga, including: full reproductive removal (-R), haphazard vegetative blade damage (-V), no removal (C), and damage of both reproductive and vegetative structures (-All). Using measurements of changes in total length (cm) as a proxy for biomass allowed for an in situ assessment of the response by the alga. This external response measurement was coupled with stable isotope analysis of internal response using carbon and nitrogen as a bioindication of fitness. Removal of reproductive fronds during spring elicited a dormancy response, while damage to the vegetative tissue reduced growth, possibly by limiting overall photosynthetic capacity. These results suggest that spring frond growth is important to reproductive fitness and removal can stimulate a life history trade-off between reproduction and survival. Winter manipulations elicited no response due to the dormancy period of this species. Enrichment values for ∂C and ∂N were consistent with reported values for other brown algal species but, because of the timing of extraction, the internal chemistry of the individuals rebounded and the ability to detect a response was lost. Both the natural and manipulated populations had similar ∂C and ∂N when separated by tissue and time of year, which indicates that while the alga may be impacted from an external perspective, it will recover internally and stay as a viable part of the reproductive population. Understanding how these seaweeds respond to biomass loss provides a better perspective of disturbance effects on this species and the ecosystem it helps support.

Thesis Defense by Suzanne Christensen – March 19th, 2018

Chemical competition between microscopic stages of Macrocystis pyrifera and five native kelp species: does giant kelp always lose?

A Thesis Defense by Suzanne Christensen

Phycology Lab

Monday, March 19th, 2018 at 12pm

MLML Seminar Room

Suzanne Christensen came to the United States from Sweden in 2004 where she began her educational journey at Foothill College in CA. She transferred to San Jose State University where she was able to attend a few classes at MLML as an undergrad before graduating with a B.S in marine biology in 2010. A year later she joined the MLML community as a graduate student in the Phycology lab. During her time at MLML, Suzanne worked as graduate student assistant for the marine ecology class for one semester and she also worked for the MLML Front Desk for almost all of her time at the laboratories. In addition she also worked for Tenera Environmental for a few months as a research assistant in 2015 before finding out she was about to be a mom. After welcoming the new addition to her family, Suzanne worked part-time at the end of 2016 helping coordinate the Friends of Moss Landing Marine Labs program. She began fulltime employment in 2017 in Santa Cruz, CA, culturing algae and purifying algal pigments that are used to conjugate antibodies.

Thesis Abstract:

The giant kelp Macrocystis pyrifera is often considered competitively dominant to other kelp species due to its high productivity. However, on the microscopic level, previous studies found that Macrocystis can be inferior to other kelp species through microscopic interspecies chemical competition. Recruitment failure can be caused by neighboring kelps because there is no species’ specificity in the stereochemistry of the signaling chemical used during reproduction to initiate spermatozoid release; therefore, Macrocystis spermatozoid release is pre-empted by that of its competitors. To date, this interaction has been tested between Macrocystis and only one other kelp taxon, Pterygophora. To test whether Macrocystis is always chemically outcompeted microscopically, I investigated the competitive outcome, by tracking sporophyte production, between Macrocystis and five native kelps using laboratory studies. Tests with Pterygophora californica and Ecklonia arborea showed asymmetric results indicating that Macrocystis was the inferior kelp. Studies using Alaria marginata and Egregia menziesii found symmetric results where both competing species did poorly in the presence of Macrocystis. Lastly, when Macrocystis was settled with Postelsia palmaeformis, there was no significant difference in sporophyte production between polycultures and monocultures for either species. These results indicate that the competitively superior species will vary depending on the specific species interaction . Studying how Macrocystis competes with species microscopically is essential to understanding its recruitment and subsequent population structure which provides the biogenic habitat in the dynamic kelp forest.

Funding:

MLML John H. Martin Scholarship, COAST graduate award, Myers Trust grant, SJSU Graduate Equity Fellowship, H. T. Harvey Memorial Fellowship, and David and Lucille Packard Foundation.

Thesis Defense by Stephan Bitterwolf – November 3rd, 2017

Physiological effects of nitrate, light, and intertidal position on the red seaweeds Mazzaella flaccida and Mazzaella splendens

A Thesis Defense by Stephan A. Bitterwolf

Phycology Lab

Friday, November 3rd at 12pm

MLML Seminar Room

Thesis Abstract:

California’s intertidal seaweeds Mazzaella flaccida and Mazzaella splendens reside in different intertidal zones. The yellow-green M. flaccida is found in the high- and mid-intertidal, while the brown-purple M. splendens is found in the mid- and low-intertidal. These differences in intertidal position and blade color, in addition to minute differences in morphology, are typically used to differentiate these species in the field. However, a reciprocal transplant study by Foster (1982) found that, not only can M. flaccida and M. splendens reside in each other’s zone, but the color of M. splendens can change to the yellow-green of M. flaccida. Thus, Foster (1982) suggested that these two species may be conspecifics. Presently, genetic evidence supports the separation of both species, however, little progress has been made towards determining the cause, mechanism, and impact of this chromatic plasticity on thallus physiology. The present study serves to further our understanding of this chromatic plasticity in Mazzaella through a series of field and laboratory experiments. In the field experiment, 360 individuals (180 of each species, 90 controls and 90 experimental) were reciprocally transplanted within the intertidal zones of 3 central California sites. Thereafter, transplants were monitored monthly from June – October for blade size and presence. In October, all transplants were removed for pigment analysis. In the laboratory experiments pigment concentrations of both species were quantified from seaweeds cultured in reduced or replete irradiances and nitrate concentrations. Differences in blade size, pigment composition, and survival between site, intertidal zone, species, and culture treatment were investigated with 2-way ANOVAs and non-parametric tests. In these experiments: (1) greening was documented only for seaweeds in the culture experiments, (2) survival was greatest in the low intertidal zone, (3) high intertidal seaweeds contained greater photoprotective pigment content, (4) M. flaccida exhibited increased capacity to regulate photoprotective pigments, and 5) M. splendens exhibited increased capacity of phycobilin pigments. The results of this study illustrate how these intertidal seaweeds can survive adverse conditions such as nutrient limitation or increased light stress/desiccation by cannibalizing phycobiliproteins and increasing photoprotective pigments. The differing extent of each species to regulate photoprotective and phycobilin pigments supports their current classification as separate species.

Acknowledgements from Stephan: This work would not have been possible without the support I received from mentors, labmates, students, family, and friends. Thanks all :D!

Funding: NSF GRFP, Myers Trust, and MLML Wave.

CDFW Permit: #13419