Combatting carbon:

With carbon dioxide (CO2) emissions continuing to rise, it is more important than ever to find strategies to dampen the effects that carbon is having on our atmosphere, oceans and living organisms, including creating innovative ways to remove and/or sequester the carbon we are putting into the world. Researchers from UC Santa Barbara’s Department of Ecology, Evolution, and Marine Biology are attempting to do just that by studying how phytoplankton respond to a potential marine alkalinization treatment. The treatment would consist of artificially increasing the ocean’s pH in order to combat the effects of ocean acidification, a process by which carbon reacts with water to produce carbonic acid (H2CO3), which then breaks into hydrogen ions (H+) and bicarbonate ions (HCO3-). As acidification becomes more widespread, the proliferating H+ ions can react with carbonate ions (CO32-), which when prolonged can have drastic impacts on marine life, particularly those species which rely on the carbonate ions to produce their shells. 

Essentially, the UCSB researchers’ idea is to add a sort of ‘antacid’ to the ocean, a mixture that would convert CO2 into other, less harmful carbon compounds. Doctoral student James Gately, the lead author on the team’s recent paper in ScienceAdvances, says that their goal is to simply speed up a naturally occurring geologic process; when the ocean’s acidity is lowered, its capacity to store more carbon increases. The study consisted of observing the physiological and ecological effects of an alkaline treatment on two ‘phytoplankton functional group representatives,’ Emiliania huxleyi and Chaetoceros. Both of these species move great amounts of compounds like carbonate and silica through the ecosystem as they construct their exoskeletons. Therefore, the loss of or decreased functionality of either species could spell disaster for the ecosystem as a whole. The researchers, however, found that when both E. huxleyi and Chaetoceros were exposed to amounts of CO2 mimicking current levels, combined with the alkaline treatment, neither were significantly affected. While future studies of potential impacts on other marine organisms are necessary, this study has shown that alkalinization treatments are a promising, if short-term, carbon-dioxide removal strategy.

Susceptible seas:

Researchers at UC Santa Barbara’s National Center for Ecological Analysis & Synthesis (NCEAS), along with colleagues from UCSB’s Bren School for Environmental Science, UC Santa Cruz’s Department of Ecology and Evolutionary Biology, and the Scripps Institute of Oceanography, among others, have recently published their findings from a study conducted on the effects of marine heatwaves on ecological communities, both within and outside of marine protected areas (MPAs). The study, co-led by UCSB’s Joshua Smith, Jennifer Caselle, and Kerry Nickols, was part of a 10-year project dedicated to monitoring California’s MPA network, and happened to span the deadly heat wave of 2014-2016, the largest marine heatwave on record to date. The team’s efforts focused on rocky intertidal, reef and kelp forest habitats, and consisted of performing species counts and measurements of the proportional cover of invertebrates and macroalgae in order to quantify remaining biomass, and thus the extent of the heat wave’s damage. They ultimately found that, with the exception of the rocky intertidal zones, there is no significant difference in community susceptibility to heat stress between areas protected from fishing and those which are not. While this news is without doubt disheartening, it will continue to be crucial to protect and maintain MPAs for other reasons, including the ability to monitor how marine communities react to heat waves in the long term and to discern whether MPAs may facilitate recovery, as well as to continue to be able to study the effects of climate change without the presence of fishing or other human interference. 

Tuna trouble:

A recent paper by lead-author Diva Amon of UC Santa Barbara’s Marine Science Institute and colleagues discusses the recent finding that with the escalating effects of climate change, the distribution of multiple tuna species will shift significantly, ultimately leading to overlap with areas currently designated for deep-sea mining. Approximately two thirds of Earth’s oceans are considered to be the “high seas,” or areas beyond national jurisdiction (ABNJ), with ABNJ resources, both living and nonliving, being under the control of the International Seabed Authority (ISA). The ISA is an intergovernmental agency responsible for both the governance of any activities relating to minerals, as well as the regulation of the protection and management of ABNJ fisheries resources. Additionally, the implementation of rules regarding fisheries, particularly those of “economically-important highly-migratory fish stocks” is primarily the responsibility of regional fisheries management organizations. The paper highlights the Clarion-Clipperton Zone (CCZ), a large marine area near Hawaii, in the eastern Pacific. The CCZ hosts an impressive amount of biodiversity, due to several abiotic factors such as high oxygen concentrations and mineral deposits, which make it a choice habitat for many fish species, including many species of tuna. 

However, the CCZ is also particularly attractive to deep-sea mining companies, which aim to extract “polymetallic nodules” from the sea floor in order to use them in the production of iron and steel, among other things. In the near future, rising marine temperatures will drive shifts in distribution of the fish leading to increased overlap between the fisheries and mining zones. Deep-sea mining in the CCZ is currently only in the exploration phase, but if it is permitted to transition into the exploitation phase, it could have significant environmental consequences, including harmful plumes of sediment and increased concentrations of metals in the water column. Current issues of monitoring and controlling the CCZ include gaps in scientific knowledge, the remoteness of the site and multi-sectoral governance resulting in the inability to have a unified approach to conservation and management. It is clear that more research is needed on the environmental aspects of the spatial overlap between deep-sea mining and fisheries, but the paper’s authors also advocate for changes in mining regulation in order to ensure the sustainable co-existence of all stakeholders.