Heather Welch’s new paper in Nature Communications highlights the difficult road ahead in terms of managing for marine heatwave impacts on top predator species. Another new paper by Alexa Fredston found marine heatwaves were not a dominant driver of demersal fish biomass which begs the question, why not?
A recent paper by Ariza et al. in Nature Climate Change used hierarchical clustering algorithms to group ocean scatterers for examination of how they are predicted to change under different climate scenarios. They found that there was a marked decrease predicted out to 2100 that could be mitigated if CO2 emissions were curbed.
I did a quick write up as well about what this means more broadly for the fields of ocean prediction and what makes this study unique. Hopefully we can have global clearinghouses for these ecological models to parallel the IPCC efforts for climate models.
E.L. Hazen, 2022. Climate change is “heard” in the ocean depths. Nature Climate Change. DOI: 10.1038/s41558-022-01484-5. PDF
Researchers have developed global forecasts that can provide up to a year’s advance notice of marine heatwaves, sudden and pronounced increases in ocean temperatures that can dramatically affect ocean ecosystems.
“We have seen marine heatwaves cause sudden and pronounced changes in ocean ecosystems around the world, and forecasts can help us anticipate what may be coming,” said lead author Michael Jacox, a research scientist at NOAA Fisheries’ Southwest Fisheries Science Center in Monterey, California, and NOAA’s Physical Sciences Laboratory in Boulder, Colorado.
Marine heatwave forecasts will be available online through NOAA’s Physical Sciences Laboratory. The researchers called the forecasts a “key advance toward improved climate adaptation and resilience for marine-dependent communities around the globe.”
M.G. Jacox, M.A. Alexander, D. Amaya, E. Becker, S.J. Bogard, S. Brodie, E.L. Hazen, M. Pozo Buil, and D. Tommasi, 2022. Global seasonal forecasts of marine heatwaves. Nature 604, 486–490. PDF
Read the abstract of the paper below:
Infographic (c) Stephanie Brodie
From 1910 to 1970, humans killed an estimated 1.5 million baleen whales in the frigid water encircling Antarctica. They were hunted for their blubber, baleen – the filtering fringe they have in place of teeth – and meat. One might assume that from the perspective of krill – the tiny shrimp-like creatures the whales feast on – this would be a boon. Yet the krill are at a fraction of their historical biomass.
With these new consumption estimates, the researchers calculated that the early 20th- century abundance of krill in the Southern Ocean was about five times what it is now in order to feed the pre-whaling whale population. This implies a complex role for whales in their ecosystems where the decline or recovery of their populations is strongly tied to overall ecosystem productivity and functioning.
Figure 1. Fieldwork needed to measure whale size, behavior, and the density of the prey they eat. The vertical difference in foraging and feces may redistribute nutrients to keep marine ecosystems flowing.
Where do animals go is not always where animals find food. Using heat increment of feeding, which is the integrated energy from a gulp of food, we can look at not just where animals go but also where they have success in feeding. Shifting distributions in anomalous years may both optimize the physiology and the feeding of these iconic and threatened species.
Out today in Movement Ecology, we show that when generating absences for presence-only data, there are a suite of approaches available to use and the method may not be as important as appropriately sampling the background environment in a way that matches your hypothesis. We explored this both in marine and terrestrial ecosystems using blue whales and African elephants as study species – many of the patterns persisted. One of our major findings was that global models may benefit from background sampling – but when movement is constrained, background sampling should be limited to the environmental niche space of the presences, or other approaches that similarly sample the environmental niche space should be explored. The other big takeaway from the study is that model approach (e.g. generalized additive mixed models vs. boosted regression trees) may be more important than the method of absence generation. Read more at the link below.
E.L. Hazen, B. Abrahms, S. Brodie, G. Carroll, H. Welch, S.J. Bograd, 2021. Where did they not go? Considerations for generating pseudo-absences for telemetry-based habitat models. Movement Ecology 9, 5. DOI: 10.1186/s40462-021-00240-2. PDF
Our paper was published today (2/9/2021) in Global Change Biology titled “Plastic ingestion by marine fish is widespread and increasing.” Rather than starting from scratch, I include an excerpt below from the Conversation piece written by Alex McInturf and Matt Savoca,
“Trillions of barely visible pieces of plastic are floating in the world’s oceans, from surface waters to the deep seas. These particles, known as microplastics, typically form when larger plastic objects such as shopping bags and food containers break down.
Researchers are concerned about microplastics because they are minuscule, widely distributed and easy for wildlife to consume, accidentally or intentionally. We study marine science and animal behavior, and wanted to understand the scale of this problem. In a newly published study that we conducted with ecologist Elliott Hazen, we examined how marine fish – including species consumed by humans – are ingesting synthetic particles of all sizes.”
Savoca, A. McInturf, E.L. Hazen, 2021. Plastic ingestion by marine fish is widespread and increasing. Global Change Biology. DOI: 10.1111/gcb.15533. PDF
Hannah Blondin published her first-year paper on how blue whale ship strike risk changes daily examining diel patterns in whale behavior and AIS data on the same scales. The coarser our resolution of analysis, the greater ship-strike risk. The graphical abstract below provides a good analysis of the findings!
H. Blondin, B. Abrahms, L. Crowder, E.L. Hazen. 2020. Combining high temporal resolution blue whale distribution and vessel tracking data improves estimates of ship strike risk in the Southern California Bight. Biological Conservation. DOI: 10.1016/j.biocon.2020.108757. PDF
A GRIP fellow from our group, Dr. Steph Dodson has published her work with us in Ecological modeling today, titled “Disentangling the biotic and abiotic drivers of emergent migratory behavior using individual-based models.” Using published info on blue whale movement and fine scale models of krill distribution, Steph was able to test whether an IBM could recreate observed movement timing and extent. Interested in more, please read below!
Fig. 2. (a) Model algorithm in pictorial form. The acronym ARS stands for area restricted search. (b) Behavioral states for each model. Arrows indicate possible transitions. (c) Step length and turning angle distributions for all transiting and foraging states. These distributions have been scaled from Bailey et al. (2009) to account for the 6 h time step used in the IBM. A turning angle of 0∘ corresponds to straight in all behavioral states except of the north-south model, where instead 0∘ is due south.
Dodson, B. Abrahms, S.J. Bograd, J. Fiechter, and E.L. Hazen. 2020. Disentangling the biotic and abiotic drivers of emergent migratory behavior using individual-based models. Ecological Modeling. DOI: 10.1016/j.ecolmodel.2020.109225.
Megan’s recent paper uses NOAA’s RREAS cruise data to look at combined krill biomass from net-tows and differences in habitat use between T. Spinifera and E. Pacifica in the California Current. The paper highlights the issues that arise when modeling a species complex rather than individual species habitat preferences. Getting species identification will help partition net tow data in addition to fisheries acoustic measurements of krill biomass moving forward. Krill also had broad scale response to oceanic warming from El Niño events Also not surprising, predictions of high krill biomass corresponded with top predator sightings as well.
