|Installed pH and O2 sensor|
By Dr. Jan Freiwald, Reef Check California Director
California sits at the frontlines of accelerating changes to the ocean such as acidification and hypoxia (low oxygen) due to global climate change. Governments are starting to realize that the costs of climate change will be huge. Rising global temperatures cause warmer ocean waters and elevated carbon dioxide (CO₂) levels in the atmosphere lead to increased CO₂ uptake by the ocean. In fact, over 90% of the heat that is trapped by increasing greenhouse gasses and 30% of the CO₂ produced by fossil fuels is absorbed by the ocean, resulting in a faster rate of ocean acidification than has ever been seen in earth’s history. Both of these processes occur on a global scale, but they are not happening uniformly across the globe. Some areas of the ocean are warming faster or becoming more acidic than others. Recent studies show that the North American West Coast will be affected by these changes earlier and more strongly than will other regions of the world. Increasing temperatures and acidity will fundamentally impact marine life along our coast. Not only will calcifying organisms such as shellfish have difficulty forming their shells, but acidification will also change how animals behave grow and survive. It is impossible to predict the exact consequences, but it is clear fisheries and aquaculture will be impacted and so will the people who depend on them. Some of these consequences are already apparent, for instance, oyster farms along the U.S. West Coast have already experienced massive economic losses and even several have relocated to Hawaii where waters are less acidic. Fisheries will be impacted as species move when waters get too warm or as individuals get disoriented, can’t feed or reproduce due to increasing acidity. California’s fisheries generate $25 billion and support over 150,000 jobs1. If they are impacted by climate change the effects will reverberate through coastal communities leading to job losses and drastic consequences for the wider economy.
Local ocean conditions, species’ physiological responses and ecological feedback mechanisms will modify the effects of acidification and warming as they percolate through the ecosystem. But in order to understand the local impacts of these global changes, we need to study them on the scale of individual reefs and kelp forests. Reef Check has been tracking the health of kelp forest ecosystems along the California coast for over a decade now as part of the state’s Marine Protected Area (MPA) monitoring program. Inside MPAs where human impacts such as fishing are restricted, it is possible to assess the ecological effects of climate change in the absence of other human impacts and on a relatively small scale so that we can improve our understanding of how local conservation measures can mitigate global climate change. In 2017, Reef Check California began collaborating with Dr. Kristy Kroeker’s Lab at the University of California Santa Cruz and researchers at the Monterey Bay Aquarium Research Institute (MBARI) to study climate change at locations and scales that are relevant to California’s nearshore rocky reefs and kelp forests.
We have installed very accurate instruments measuring temperature, ocean pH and dissolved oxygen in kelp forests at Reef Check sites ranging from Mendocino County to southern California. We have installed pH and oxygen sensors in remote locations such as Point Arena (Mendocino County), the Big Sur Coast, Catalina Island and even in Ensenada, Mexico where little climate change research has been done. In addition, we have installed temperature sensors at most of our reef monitoring sites. Over the next few years, we expect to see water temperatures increase, water to become more acidic, and local low oxygen zones to become more common.
The instruments that measure pH are custom built at MBARI and have to withstand California’s harsh ocean conditions year round. Installing them is not an easy task. In order to measure the changes directly in the kelp forest, we have to attach the sensors to the rocky reef seafloor. To do this, we send teams of divers, equipped with underwater pneumatic drills and lots of stainless steel hardware, out to the reef. While one diver drills holes into the rock, others swim back and forth to supply the scuba tanks needed to operate the air powered drill. Then, everyone screws stainless steel bolts into the rock to which the instrument is attached. Once all the bolts are tightened the sensor is calibrated and then ready to collect pH, oxygen and temperature data every 15 minutes. All of the information is stored in the instrument and downloaded when we return to the reef after a few months. The temperature probes can be installed during Reef Check surveys and record temperature every few minutes for over a year with high accuracy. They will be retrieved during our annual reef surveys. We have hired Kate Vylet to be our Climate Change Research Coordinator and to integrate this work with our citizen science monitoring. For 2018, we are looking forward to training our citizen scientists how to retrieve the data and service the sensors.
This project, funded by the California Ocean Protection Council, will feed into the state’s marine management and climate change readiness plans. We are increasing opportunities for public participation in climate change research by involving Reef Check California’s large network of volunteer citizen scientists in this project. In the long run, the integration of this project with our MPA monitoring program will ensure the longevity of our new climate change research and save California money. This work will improve our ability to judge the effectiveness of the state’s MPA network and better track the impacts of climate change on kelp forest ecosystems and associated fisheries.
|Installing sensor on reef||Sensor on the beach||On the boat|