Fujita R.,Environmental Defense Fund |
Moxley J.H.,Environmental Defense Fund |
Van Leuvan T.,Environmental Defense Fund |
Leumer A.,Environmental Defense Fund |
And 3 more authors.
Marine Policy | Year: 2013
Ocean policies around the world increasingly emphasize the importance of maintaining resilient ocean ecosystems, communities, and economies. To maintain and restore the resilience of healthy marine ecosystems in practice, specific management objectives with metrics and a policy framework for how to apply them will be needed. Here we present a concept for doing this, based on evidence that marine ecosystems transition from desirable to less desirable states in response to a number of physical, chemical, and biological drivers. More empirical and synthesis research will be necessary to develop quantitative metrics of resilience and thresholds between ecosystem states for specific ecosystems; however, suggestions are provided here for how to manage for resilience when insufficient data and knowledge are available for quantification. A summary of thresholds for biotic and abiotic drivers of ecosystem state drawn from the literature is also provided as a guide to management. © 2012 Elsevier Ltd.
Bracken M.E.S.,Northeastern University |
Bracken M.E.S.,University of California at Davis |
Menge B.A.,Oregon State University |
Foley M.M.,Center for Ocean Solutions |
And 3 more authors.
Marine Ecology Progress Series | Year: 2012
Filter-feeding invertebrates consume phytoplankton and detritus and therefore serve as important mediators of the exchange of materials from nearshore pelagic to intertidal benthic ecosystems. Here, we evaluated the linkages between nearshore and intertidal systems on temperate rocky reefs on the coasts of Oregon, USA, and New Zealand's South Island. We used differences in the concentrations of both nearshore particulate organic carbon and chlorophyll a (chl a), a proxy for phytoplankton availability, at different sites in Oregon and New Zealand to evaluate the influences of suspended particulate organic material (POM) quality and quantity on the rates of carbon inputs associated with intertidal mussels (Mytilus californianus in Oregon and Mytilus galloprovincialis in New Zealand). We also analyzed the carbon stable isotope ratios (δ13C) of intertidal mussels and nearshore POM to examine changes in mussel growth in carbon relative to changes in their potential food sources along gradients of POM quality (i.e. carbon-to- chlorophyll ratios, C:chl a). In both Oregon and New Zealand, the δ13C in mussel tissues did not change along a gradient of food quality, whereas the δ13C of the POM declined as food quality declined (i.e. C:chl a increased), suggesting that mussels were selectively consuming high-quality food. We also found that the availability of phytoplankton, a high-quality component of the POM, was a better predictor of mussel growth in carbon (mg C g-1 d-1) than the total concentration of particulate organic carbon, which includes both higher-quality phytoplankton and lower-quality detrital material. Our results highlight the necessity of considering POM quality while evaluating the role of filter-feeders as mediators of carbon inputs into intertidal systems. © Inter-Research 2012.
News Article | November 30, 2015
In the spring of 2010, a lone gray whale was spotted off the Mediterranean coast of Israel, an event that sparked international interest for an important reason: It was the first North Atlantic sighting of a gray whale, a species nowadays restricted to the Pacific Ocean, in about 200 years. The case is just one example in a recent spate of animals turning up in places they don’t belong — generally, either Pacific species showing up in the Atlantic, or vice versa. Northern gannets, a North Atlantic species, have been spotted off the coast of California several times in recent years, for instance, while several Pacific species of auks, a type of diving bird, have recently been observed in the Atlantic. It’s a perplexing — yet apparently increasing — trend. And while animals do occasionally wander outside of their ranges, scientists are starting to believe that the recent flurry of movements between the Atlantic and Pacific ocean basins are early evidence of yet another consequence of climate change. They’re arguing that as sea ice continues to melt in the Arctic, passageways are opening for certain animals — heretofore restricted by the ice — to start moving through, enabling them to cross into new territories. This is the focus of a new paper, released Monday in the journal Global Change Biology, that explores the recent uptick in what the authors refer to as “faunal exchange,” or the movement of wildlife between the Atlantic and Pacific ocean basins, via the Arctic. Such movements are likely to be made possible by the opening up of passageways, including the famed Northwest Passage, a shipping route through the Arctic currently largely blocked by sea ice. Marine mammals, such as whales or seals, are often physically prevented from moving through the Arctic by sea ice, which gets in the way of their swimming or prohibits them from coming up to breathe. And seafaring birds, while capable of flying over the frozen ocean, frequently choose not to do so because the ice prevents them from diving for fish. But as passageways open up in the melting ice, these animals become more free to move about as they please. Such exchange could cause a variety of ecosystem-level changes down the road, the authors of the new paper argue, such as the potential for dramatic changes to food webs. The paper bases its argument on the growing list of recent examples — the gray whales, the gannets and the auks, as well as unusual sightings of other birds and mammals, such as bowhead whales and shearwaters. “Animals on occasion get lost and they show up in strange places — ‘birds have wings’ is the saying,” said the paper’s lead author, the aptly named Seabird McKeon, a research scientist with the Smithsonian Institution’s National Museum of Natural History. “There are some species that are more prone to vagrancy than others, and so we do have this backdrop of motion.” However, he added, “when we’re talking about this exchange, and when the exchange starts becoming noticeable,” that’s when it becomes apparent that a pattern — likely caused by some other, external factor — is emerging. “Some people might feel that this paper is not loaded down with evidence — they’re basically talking about 10 or 20 species that have been seen out of their geographic range — but they make a good point,” said Larry Crowder, science director for Stanford University’s Center for Ocean Solutions, who was not involved with the paper. “If there hasn’t been a gray whale in the Atlantic in 200 years and now there is one, that’s a change,” he said, adding, “They certainly didn’t overreach.” In fact, Kristin Laidre, a principal scientist at the University of Washington’s Polar Science Center (who was also not involved with the paper), said that the ideas presented in the paper have been floating around the scientific community for some time. “I think in the kind of ecological studies that consider the consequences of ice loss, the idea that species in the Pacific may become more connected with species in the Atlantic [or vice versa] isn’t really a new idea,” she said. Laidre was the lead author on a recent paper in Conservation Biology that explored the conservation status of Arctic marine mammals in light of the increasing effects of climate change in the region. The paper touches on the potential for increased movement of animals in the Arctic — and many of the species discussed in that paper also appear in McKeon’s new paper, where he and his colleagues have compiled a list of marine mammals and birds that they expect will move increasingly between the Atlantic and Pacific ocean basins in the future. The list includes bird species such as Arctic terns, common eiders, Atlantic puffins and short-tailed shearwaters and mammals such as beluga whales, ringed seals and Atlantic white-sided dolphins. Altogether, the list contains dozens of species, including both polar species, which typically inhabit open waters above the Arctic Circle, and what the authors refer to as ice-edge species, which live south of the Arctic sea ice. While no one can say for sure yet what consequences these types of movements could have, McKeon and his colleagues discuss a number of possible outcomes in the paper. It’s important to note that these outcomes are all speculative for the time being. However, scientists can look at past examples of other faunal exchanges to get a sense of what could happen in the future. One example the authors point to is the Great American Biotic Interchange, which occurred several million years ago when the isthmus of Panama formed, allowing land animals a bridge to cross between North and South America. As the authors note, the fossil record indicates that in this case, mammals from North America invaded South America and outcompeted many of the native species there for resources. This type of outcome is a potential concern with species crossing from the Pacific to the Atlantic, and vice versa. Additionally, introducing new predators into an area where they didn’t previously exist can “change food web dynamics profoundly,” Laidre pointed out, noting that the killer whale is a recent prime example. As the authors wrote in the paper, killer whales recently “expanded into ice-free areas of Hudson Bay where they were documented preying upon Arctic marine mammals including beluga (Delphinapterus leucas), narwhal (Monodon monoceros), bowhead, and at least four species of seal.” There could be genetic changes within migrating populations, as well, as they move and mix with one another. One consequence could be an increase in hybridization, whereby some species or subspecies could eventually be genetically phased out of existence, suggested Ryan Terrill, a Ph.D. candidate at Louisiana State University’s Museum of Natural Sciences, who served as a peer reviewer on the paper. On the other hand, this type of mixing could add genetic diversity to small subpopulations, which could be a good thing, said Laidre. In general, Laidre said, the effects of the exchange will not necessarily be all negative. “It’s more of a big baseline shift,” she said. And McKeon noted, “Populations of animals have been moving as long as there have been populations of animals.” So it’s not necessarily a good idea to try and stop them. The key, he said, is rather to increase the monitoring of wildlife as they move about in the Arctic to better understand which species are ending up where and how they might be affecting their environment. This information can help inform conservation tactics moving forward, including the need for updated international conservation agreements. “As the Arctic opens, environmental protections may be undermined,” said Kirsten Oleson, an assistant professor of ecological economics at the University of Hawaii and a co-author on the paper. “We haven’t really thought about protecting fauna in the Arctic because it’s been so remote and there’s been so little access to the area. But as the access increases and these animals are moving through the newly liquified waters, then new environmental protections may need to be put in place.” For instance, as animals move around and their surrounding ecosystems correspondingly adjust, humans may need to alter certain behaviors in order to avoid harming an already shifting and vulnerable environment. “The paper stressed a lot about shifts in food webs of oceanic organisms, but not too much shifts in threats from humans,” Crowder pointed out. “If you have a lot of ships moving through the Northwest Passage, you’re also likely to have the potential for ship strikes of whales, which hasn’t been an issue because shipping [in the Arctic] has been pretty limited.” In general, it’s fair to say that faunal exchange between the Atlantic and Pacific will largely be a “wait-and-see” kind of situation. Scientists seems to agree that it’s already beginning to occur, and will only increase as more passages open up in the Arctic — but its exact effects remain to be seen. Nevertheless, the phenomenon represents yet another — and little talked-about — consequence of anthropogenic climate change, one with potential far-reaching and large-scale implications for the world’s ecosystems. “Inasmuch as we have created the situation, these are natural responses to changing global patterns,” McKeon said. “And so our responsibility, if anything, is to allow species to adjust and to adapt to a changing world in the same way that we are attempting to adjust and adapt to a changing world.”
Krenz C.,Oregon State University |
Menge B.A.,Oregon State University |
Freidenburg T.L.,MPA Monitoring Enterprise |
Lubchenco J.,Oregon State University |
And 3 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2011
Through bottom-up inputs and larval transport, benthic-pelagic links can have an important effect on benthic community structure. Recent work on community structure of northeast Pacific rocky shores has focused on latitudinal differences in recruitment of intertidal invertebrates as a driver of variation in community structure. Recruitment differences are associated with a transition in upwelling near Cape Blanco in southern Oregon. Here we examine the transition in recruitment along an unstudied gap on the northern California and Oregon coasts, document a latitudinal gradient in bottom-up factors, and examine if major coastal promontories associated with upwelling plumes potentially separate benthic-pelagic coupling into regions. We monitored the recruitment of intertidal invertebrates, chlorophyll a concentrations in coastal waters, and the growth rates of mussels at numerous sites along the northern California and Oregon coasts. The transition in recruitment of intertidal invertebrates from north to south changed from very high levels north of Cape Blanco, to intermediate levels between Capes Blanco and Mendocino, to very low levels south of Cape Mendocino. The specific shape of the recruitment cline varied among species. Chlorophyll a concentrations and mussel growth rates were higher north of Cape Blanco than south of Cape Blanco, indicating that bottom-up factors may also drive regional differences in rocky shore community structure. Distinctive timing between regions of recruitment and plankton pulses suggests that benthic-pelagic coupling may be somewhat independent between these regions, which are separated by major coastal promontories. Our results highlight the large variability in spatially coupled ecosystems along the northern California and Oregon coasts that drive the latitudinal gradient in rocky shore community structure in the northeast Pacific. © 2011 Elsevier B.V.
Hazen E.L.,Southwest Fisheries Science Center |
Hazen E.L.,University of Hawaii at Manoa |
Jorgensen S.,Monterey Bay Aquarium Research Institute |
Rykaczewski R.R.,Princeton University |
And 10 more authors.
Nature Climate Change | Year: 2013
To manage marine ecosystems proactively, it is important to identify species at risk and habitats critical for conservation. Climate change scenarios have predicted an average sea surface temperature (SST) rise of 1-6°C by 2100 (refs,), which could affect the distribution and habitat of many marine species. Here we examine top predator distribution and diversity in the light of climate change using a database of 4,300 electronic tags deployed on 23 marine species from the Tagging of Pacific Predators project, and output from a global climate model to 2100. On the basis of models of observed species distribution as a function of SST, chlorophyll a and bathymetry, we project changes in species-specific core habitat and basin-scale patterns of biodiversity. We predict up to a 35% change in core habitat for some species, significant differences in rates and patterns of habitat change across guilds, and a substantial northward displacement of biodiversity across the North Pacific. For already stressed species, increased migration times and loss of pelagic habitat could exacerbate population declines or inhibit recovery. The impending effects of climate change stress the urgency of adaptively managing ecosystems facing multiple threats. Copyright © 2013 Macmillan Publishers Limited.
Mach M.E.,University of British Columbia |
Mach M.E.,Center for Ocean Solutions |
Levings C.D.,Northwest Atlantic Fisheries Center |
Chan K.M.A.,University of British Columbia
Estuaries and Coasts | Year: 2016
Nonnative species cause economic and ecological impacts in habitats they invade, but there is little information on how they spread and become abundant. This is especially true for nonnative species in native Zostera marina eelgrass beds in coastal British Columbia, Canada, which play a vital role in estuarine ecosystems. We tested how nonnative species richness and abundance were related to both arrival vectors and environmental factors in northeast Pacific eelgrass. Using correlation tests and generalized linear models, we examined how nonnative macroinvertebrates (benthic, epifaunal, and large mobile) and some algae species were related to arrival vectors (shipping and aquaculture) and environmental factors (climate variables, human population density, and native richness and abundance). We found 12 nonnative species, 50 % with known negative impacts within eelgrass habitats. For benthic organisms, both nonnative richness and abundance were strongly correlated with shellfish aquaculture activities, and not with shipping activity. For epifaunal nonnative richness and abundance, neither vector was significantly correlated. Climate (temperature and salinity) helped explain nonnative richness but not abundance; there was no relationship of nonnative richness or abundance to native species richness and abundance or population density. Results suggest that aquaculture activities are responsible for many primary introductions of benthic nonnative species, and that temperature and salinity tolerances are responsible for post-introduction invasion success. While aquaculture and shipping vectors are becoming increasingly regulated to prevent further international spread of nonnative species, it will be important when managing nonnatives to consider secondary spread from intraregional transport through local shellfish aquaculture and shipping. © 2016 Coastal and Estuarine Research Federation
Micheli F.,Stanford University |
De Leo G.,Stanford University |
Butner C.,Stanford University |
Martone R.G.,Stanford University |
And 2 more authors.
Biological Conservation | Year: 2014
Effective conservation of marine ecosystems requires the assessment and management of cumulative impacts of multiple activities occurring in the ecosystem. Productivity Susceptibility Analysis (PSA) is a widely used tool to assess the potential impacts of fishing activities on marine ecosystems, particularly in data-poor regions. Yet, PSA and other risk-based approaches often do not account for the cumulative effects of multiple fisheries operating in the same region. Here we amend PSA to incorporate multiple fisheries by proposing a new index for cumulative risk assessment, i.e. Aggregated Susceptibility (AS). We applied this extended PSA to 81 species caught in 5 small-scale fisheries along the coast of Baja California, Mexico, and compared the results to the original PSA. Using the original PSA approach, 18 species (22.2%) were scored as high risk, and twenty-five species (31%) are at low risk from all of the fisheries conducted in this region. When the cumulative risk posed by all fisheries is assessed using our proposed methodology, the proportion of species at high risk increases to 38.3%, whereas the proportion of species at low risk decreases to 21%. For 13 species, the high-risk assessment is made only when scores are aggregated. Among the 5 fisheries, the set gillnet fishery has the greatest impact, which accounted for half of the high risk species and should be the focus of further investigation on how to best manage this fishery. Our analysis demonstrates the importance of accounting for the potential cumulative impacts of multiple co-occurring fisheries for the conservation of coastal marine ecosystems, identifies relative risk imposed by multiple fisheries, and provides a tool for a preliminary evaluation of the possible outcomes of management alternatives. © 2014 Elsevier Ltd.
PubMed | University of British Columbia, Canadian Institute of Ocean Sciences and Center for Ocean Solutions
Type: Journal Article | Journal: PloS one | Year: 2016
The multi-scalar complexity of social-ecological systems makes it challenging to quantify impacts from human activities on ecosystems, inspiring risk-based approaches to assessments of potential effects of human activities on valued ecosystem components. Risk assessments do not commonly include the risk from indirect effects as mediated via habitat and prey. In this case study from British Columbia, Canada, we illustrate how such indirect risks can be incorporated into risk assessments for seventeen ecosystem components. We ask whether (i) the addition of indirect risk changes the at-risk ranking of the seventeen ecosystem components and if (ii) risk scores correlate with trophic prey and habitat linkages in the food web. Even with conservative assumptions about the transfer of impacts or risks from prey species and habitats, the addition of indirect risks in the cumulative risk score changes the ranking of priorities for management. In particular, resident orca, Steller sea lion, and Pacific herring all increase in relative risk, more closely aligning these species with their at-risk status designations. Risk assessments are not a replacement for impact assessments, but-by considering the potential for indirect risks as we demonstrate here-they offer a crucial complementary perspective for the management of ecosystems and the organisms within.
News Article | October 7, 2016
Pfleger, a graduate student at the time and now a scientist at Oceana, agreed to help a friend track down proof of a living Alabama sturgeon—a fish not seen since 2009. Instead of netting a live sturgeon, though, Pfleger would be hunting for its genes. 'Environmental DNA,' or eDNA, is an emerging technique that lets scientists identify aquatic animals from the minute bits of tissue they leave behind. Early adopters say that the standard trappings of field research—pricey vessels, ship crews, scuba divers and jars of specimens—could one day be replaced by a geneticist and a liter of water. The Alabama sturgeon is a russet-colored, one kilogram (two to three pounds) fish with hard, armor-like scales. The rarest member of the sturgeon family, it's a casualty of the caviar market and the dams that slice up its river habitat. In 2009, researchers lost contact with the only known living Alabama sturgeon when the fish, a male, broke or lost his tracking tag. Despite what Pfleger described as "extreme" search efforts, no other members of his species have been spotted since. Pfleger's task was to find out if any unseen sturgeons might have shed even a single cell—from scales, mucus or excrement—in water sampled from sites across its historic range. For each sample, Pfleger ran through a multi-step process that resulted in a slurry of genes from potentially thousands of species. The process was time-consuming, Pfleger said, but not hard: "If you can bake cookies, you can do genetics." To tell if any of those fragments belonged to an Alabama sturgeon, Pfleger then applied a 'primer'—a compound that only binds to the DNA of a single species. At the beginning, it was slow going. "I ran hundreds of samples with nothing coming up," Pfleger said. "It was sad for multiple reasons: sad for the sturgeon, and sad I that I had to work for multiple hours on end. It was morally defeating." But defeat turned to triumph. One day, a bit of DNA turned up that tested positive for the long-lost sturgeon. A check against a database confirmed the match. After that, 17 additional results came back positive—putting to rest fears that Alabama sturgeon had gone extinct. Since each sample is tied to a specific spot, Pfleger said, sturgeon search parties can now narrow down where to look. The ultimate goal is for officials to capture enough fish to breed them in captivity—and perhaps to identify and remove the most damaging dams. As for eDNA, Pfleger had high praise: "It's the coolest biological tool available right now." So far, eDNA has seen its biggest successes in rivers. Because ocean environments are enormous and complex, marine applications of this technique have lagged. But researchers at the Center for Ocean Solutions in Monterey, California are starting to change this. In 2014, a team there turned to the Monterey Bay Aquarium to see if eDNA could identify the species swimming in the 4.5 million liter (1 million gallon) Open Ocean tank. After sequencing the genetic material in a liter of tank water, they compared the aquarium's list of fish, sharks and turtles to the one they generated. "It turns out we were able to successfully identify all the bony fishes," said Larry Crowder, the science director at the Center for Ocean Solutions. "The first probe we used saw almost everything in the tank." A year later, the team put eDNA to the test in a less controlled environment: Monterey Bay. They pitted trained divers—the current best method for tallying up marine animals and their abundance—against samples of seawater. Environmental DNA again passed with flying colors. "What was remarkable was that there was only one species of fish that the divers saw that the DNA did not pick up," Crowder said. "And the DNA picked up almost twice as many vertebrate organisms than the divers recorded." The eDNA samples differed markedly by habitat type—a "quite surprising" result given that some sites were separated by only 60 meters (200 feet). "It turns out that the organisms you see in the eDNA samples are organisms you'd expect to be in those habitats," Crowder said. Because DNA degrades within one or two days in the sea, Crowder added, each sample likely represents an accurate, time-bound snapshot of a location: "Given space and time, this could be a pretty high-resolution technique." Though Crowder conceded that eDNA has "a lot of kinks that need to be worked out," he forecasts big changes ahead. Over the last 10 years, Crowder noted, the cost of eDNA sequencing has plummeted by orders of magnitude. Further declines could make eDNA a game-changer for cash-strapped government agencies and environmental groups. And because the number of DNA strands in a sample is proportional to a species' abundance, further improvements might make eDNA an important tool for telling not just if an animal was present or absent, but how many individuals there were—a big help for managers that need to keep track of endangered whales or commercially valuable fish. "We like to think it might be disruptive," Crowder said. "This is completely different from any approach we've used before." Explore further: Ocean 'dandruff' a new tool for marine biologists More information: Mariah O. Pfleger et al. Saving the doomed: Using eDNA to aid in detection of rare sturgeon for conservation (Acipenseridae), Global Ecology and Conservation (2016). DOI: 10.1016/j.gecco.2016.08.008
News Article | December 22, 2016
In 2017, construction is set to begin on Kinder Morgan's Trans Mountain pipeline expansion, which will carry bitumen from the Alberta oilsands to the BC coast. It's shaping up to be a big year for pipeline projects, with fossil fuel-friendly Donald Trump coming into the White House (he's said he'd like to revive Keystone XL) and two projects, including Kinder Morgan, going ahead in Canada after receiving Prime Minister Justin Trudeau's recent approval. The potential impact of this type of extraction on coastal environments is sorely understudied. Although plenty of research has been done on the impacts of conventional oil spills in coastal environments, the effects of bitumen carried from the oilsands are virtually unknown, according to a new study in the journal Frontiers in Ecology and the Environment. "Why is there so little research on the biological effects of bitumen?" "When we look at [impacts] that are really specific to this particular industry—the oil sands—we know virtually nothing," said lead author Stephanie Green, a postdoctoral fellow at Stanford University's Center for Ocean Solutions, in a phone interview. The oilsands are typically thought of as an "inland industry," she continued, but there are potentially serious "unrealized impacts for the oceans." And with pipelines carrying this stuff directly through coastal environments, we shouldn't ignore them. Bitumen is a mined slurry of crude oil, sand, and clay, but also includes diluting materials to make it flow efficiently through pipelines. Scientists don't know a whole lot about the impact of these dilutents, partly because manufacturers aren't required to fully report their chemical makeup, according to the researchers. "This is something that we're trying to get a handle on," Green said. "Why is there so little research on the biological effects of bitumen?" Read More: The United States of Climate Change Denial This study was a synthesis of more than 9,000 papers that have examined the consequences of oil sands development. It found that, while individual problems like ocean acidification or the impact on wildlife were taken into account, the cumulative effects of more than one of these issues occurring at once haven't been examined in any detail. Green found 15 potential stressors that could arise during the movement of bitumen to the coast Green found 15 potential stressors that could arise during the movement of bitumen to the West Coast and beyond, from the impacts of higher amounts of sea traffic, to the possible movement of non-native species along the proposed pipeline route. "Biologists are particularly worried about the amount of noise pollution in the water that really disrupts things like feeding and the production and behavior of a whole range of marine species," said Green. For example, scientists and conservationists have expressed worry that the Kinder Morgan pipeline could drive an endangered population of orcas off the BC coast to extinction. Trudeau and his current US counterpart, Barack Obama, seem to acknowledge that continued resource extraction will put marine environments under threat. The two recently announced partial bans on drilling for oil in the Arctic, and Trudeau's government unveiled a marine protection plan earlier this year. Even so, Trudeau has said he's ready to play ball with Trump on Keystone XL. Green thinks that more research on the impacts of oilsands development on marine environments is critical—before development plans are made. "Ideally you would have a good understanding of risks to weigh into your decision-making process," she said. Get six of our favorite Motherboard stories every day by signing up for our newsletter.