Month: November 2022

The final chapter:  “The effects of vessel traffic and ocean noise on gray whale stress hormones”

By Leila S. Lemos, Ph.D., Postdoctoral Associate at Florida International University, former member of the GEMM Lab (Defended PhD. March 2020)

It’s been a long time since I wrote a blog post for the GEMM Lab (more than two years ago!). You may remember me as a former Ph.D. student working with gray whale body condition and hormone variation in association with ambient noise… and so much has happened since then!

After my graduation, since I have tropical blood running in my veins, I literally crossed the entire country in search of blue and sunny skies, warm weather and ocean, and of course different opportunities to continue doing research involving stressors and physiological responses in marine mammals and other marine organisms. It didn’t take me long to start a position as a postdoctoral associate with the Institute of Environment at Florida International University. I have learned so much in these past two years while mainly working with toxicology and stress biomarkers in a wide range of marine individuals including corals, oysters, fish, dolphins, and now manatees. I have started a new chapter in my life, and I am very eager to see where it takes me.

Talking about chapters… my Ph.D. thesis comprised four different chapters and I had published only the first one when I left Oregon: “Intra- and inter-annual variation in gray whale body condition on a foraging ground”. In this study we used drone-based photogrammetry to measure and compare gray whale body condition along the Oregon coast over three consecutive foraging seasons (June to October, 2016-2018). We described variations across the different demographic units, improved body condition with the progression of feeding seasons, and variations across years, with a better condition in 2016 compared to the following two years. Then in 2020, I was able to publish my second chapter entitled “Assessment of fecal steroid and thyroid hormone metabolites in eastern North Pacific gray whales”. In this study, we used gray whale fecal samples to validate and quantify four different hormone metabolite concentrations (progestins, androgens, glucocorticoids, and thyroid hormone). We reported variation in progestins and androgens by demographic unit and by year. Almost a year later, my third chapter “Stressed and slim or relaxed and chubby? A simultaneous assessment of gray whale body condition and hormone variability” was published. In this chapter, we documented a negative correlation between body condition and glucocorticoids, meaning that slim whales were more stressed than the chubby ones.

These three chapters were “relatively easy” to publish compared to my fourth chapter, which had a long and somewhat stressful process (which is funny as I am trying to report stress responses in gray whales). Changes between journals, titles, analyses, content, and focus had to be made over the past year and a half for it to be accepted for publication. However, I believe that it was worth the extra work and invested time as our research definitely became more robust after all of the feedback provided by the reviewers. This chapter, now entitled “Effects of vessel traffic and ocean noise on gray whale stress hormones” was finally published earlier this month at the Nature Scientific Reports journal, and I’ll describe it further below.

Increased human activities in the last decades have altered the marine ecosystem, leaving us with a noisier, warmer, and more contaminated ocean. The noise caused by the dramatic increase in commercial and recreational shipping and vessel traffic1-3 has been associated with negative impacts on marine wildlife populations4,5. This is especially true for baleen whales, whose frequencies primarily used for communication, navigation, and foraging6,7 are “masked” by the noise generated by this watercraft. Several studies have reported alterations in marine mammal behavioral states8-11, increased group cohesion12-14, and displacement8,15 due to this disturbance, however, just a few studies have considered their physiological responses. Examples of physiological responses reported in marine mammals include altered metabolic rate15,16 and variations in stress-related hormone (i.e., glucocorticoids) concentrations relative to vessel abundance and ambient noise17,18. Based on this context and on the scarcity of such assessments, we attempted to determine the effects of vessel traffic and associated ambient noise, as well as potential confounding variables (i.e., body condition, age, sex, time), on gray whale fecal glucocorticoid concentrations.

In addition to the data used in my previous three chapters collected from gray whales foraging off the Oregon coast, we also collected ambient noise levels using hydrophones, vessel count data from the Oregon Department of Fish and Wildlife (ODFW), and wind data from NOAA National Data Buoy Center (NDBC). Our first finding was a positive correlation between vessel counts and underwater noise levels (Fig. 1A), likely indicating that vessel traffic is the dominant source of noise in the area. To confirm this, we also compared underwater noise levels with wind speed (Fig. 1B), but no correlations were found.

Figure 1: Linear correlations between noise levels (daily median root mean square [rms] sound pressure level [SPL] in dB [re 1 μPa]; 50–1000 Hz) recorded on a hydrophone deployed outside the Newport harbor entrance during June to October of 2017 and 2018 and (A) vessel counts in Newport and Depoe Bay, Oregon, USA, and (B) daily median wind speed (m/s) from an anemometer station located on South Beach, Newport, Oregon, USA (station NWPO3). Asterisk indicates significant correlations between SPL and vessel counts in both years.

We also investigated noise levels by the hour of the day (Fig. 2), and we found that noise levels peaked between 6 and 8 am most days, coinciding with the peak of vessels leaving the harbor to get to fishing grounds. Another smaller peak is seen at 12 pm, which may represent “half-day fishing charter” vessels returning to the harbor. In contrast, wind speeds (in the lower graph) peaked between 3 and 4 pm, thus confirming the absence of correlation between noise and wind and providing more evidence that noise levels are dominated by the vessel activity in the area. 

Figure 2: Median noise levels (root mean square sound pressure levels—SPLrms) for each hour of each day recorded on a hydrophone (50–10,000 Hz) deployed outside the Newport harbor entrance during June to October of 2017 (middle plot) and 2018 (upper plot), and hourly median noise level (SPL) against hourly median wind speed (lower plot) from an anemometer station located on South Beach, Newport, Oregon, USA (station NWPO3) over the same time period.

Finally, we assessed the effects of vessel counts, month, year, sex, whale body condition, and other hormone metabolites on glucocorticoid metabolite (GCm; “stress”) concentrations. Since we are working with fecal samples, we needed to consider the whale gut transit time and go back in time to link time of exposure (vessel counts) to response (glucocorticoid concentrations). However, due to uncertainty regarding gut transit time in baleen whales, we compared different time lags between vessel counts and fecal collection. The gut transit time in large mammals is ~12 hours to 4 days3,19,20, so we investigated the influence of vessel counts on whale “stress hormone levels” from the previous 1 to 7 days. The model with the most influential temporal scale included vessel counts from previous day, which showed a significant positive relationship with GCm (the “stress hormone level”) (Fig. 3).

Figure 3: The effect of vessel counts in Newport and Depoe Bay (Oregon, USA) on the day before fecal sample collection on gray whale fecal glucocorticoid metabolite (GCm) concentrations.

Thus, the “take home messages” of our study are:

  1. The soundscape in our study area is dominated by vessel noise.
  2. Vessel counts are strongly correlated with ambient noise levels in our study area.
  3. Gray whale glucocorticoid levels are positively correlated with vessel counts from previous day meaning that gray whale gut transit time may occur within ~ 24 hours of the disturbance event.

These four chapters were all very important studies not only to advance the knowledge of gray whale and overall baleen whale physiology (as this group is one of the most poorly understood of all mammals given the difficulties in sample collection21), but also to investigate potential sources for the unusual mortality event that is currently happening (2019-present) to the Eastern North Pacific population of gray whales. Such studies can be used to guide future research and to inform population management and conservation efforts regarding minimizing the impact of anthropogenic stressors on whales.

I am very glad to be part of this project, to see such great fruits from our gray whale research, and to know that this project is still at full steam. The GEMM Lab continues to collect and analyze data for determining gray whale body condition and physiological responses in association with ambient noise (Granite, Amber and Diamond projects). The gray whales thank you for this!

Cited Literature

1. McDonald, M. A., Hildebrand, J. A. & Wiggins, S. M. Increases in deep ocean ambient noise in the Northeast Pacific west of San Nicolas Island, California. J. Acoust. Soc. Am. 120, 711–718 (2006).

2. Kaplan, M. B. & Solomon, S. A coming boom in commercial shipping? The potential for rapid growth of noise from commercial ships by 2030. Mar. Policy 73, 119–121 (2016).

3. McCarthy, E. International regulation of underwater sound: establishing rules and standards to address ocean noise pollution (Kluwer Academic Publishers, 2004).

4. Weilgart, L. S. The impacts of anthropogenic ocean noise on cetaceans and implications for management. Can. J. Zool. 85, 1091–1116 (2007).

5. Bas, A. A. et al. Marine vessels alter the behaviour of bottlenose dolphins Tursiops truncatus in the Istanbul Strait, Turkey. Endanger. Species Res. 34, 1–14 (2017).

6. Erbe, C., Reichmuth, C., Cunningham, K., Lucke, K. & Dooling, R. Communication masking in marine mammals: a review and research strategy. Mar. Pollut. Bull. 103, 15–38 (2016).

7. Erbe, C. et al. The effects of ship noise on marine mammals: a review. Front. Mar. Sci. 6 (2019).

8. Sullivan, F. A. & Torres, L. G. Assessment of vessel disturbance to gray whales to inform sustainable ecotourism. J. Wildl. Manag. 82, 896–905 (2018).

9. Pirotta, E., Merchant, N. D., Thompson, P. M., Barton, T. R. & Lusseau, D. Quantifying the effect of boat disturbance on bottlenose dolphin foraging activity. Biol. Conserv. 181, 82–89 (2015).

10. Dans, S. L., Degrati, M., Pedraza, S. N. & Crespo, E. A. Effects of tour boats on dolphin activity examined with sensitivity analysis of Markov chains. Conserv. Biol. 26, 708–716 (2012).

11. Christiansen, F., Rasmussen, M. & Lusseau, D. Whale watching disrupts feeding activities of minke whales on a feeding ground. Mar. Ecol. Prog. Ser. 478, 239–251 (2013).

12. Bejder, L., Samuels, A., Whitehead, H. & Gales, N. Interpreting short-term behavioural responses to disturbance within a longitudinal perspective. Anim. Behav. 72, 1149–1158 (2006).

13. Nowacek, S. M., Wells, R. S. & Solow, A. R. Short-term effects of boat traffic on Bottlenose dolphins, Tursiops truncatus, in Sarasota Bay, Florida. Mar. Mammal. Sci. 17, 673–688 (2001).

14. Bejder, L., Dawson, S. M. & Harraway, J. A. Responses by Hector’s dolphins to boats and swimmers in Porpoise Bay, New Zealand. Mar. Mammal Sci. 15, 738–750 (1999).

15. Lusseau, D. Male and female bottlenose dolphins Tursiops spp. have different strategies to avoid interactions with tour boats in Doubtful Sound. New Zealand. Mar. Ecol. Prog. Ser. 257, 267–274 (2003).

16. Sprogis, K. R., Videsen, S. & Madsen, P. T. Vessel noise levels drive behavioural responses of humpback whales with implications for whale-watching. Elife 9, e56760 (2020).

17. Ayres, K. L. et al. Distinguishing the impacts of inadequate prey and vessel traffic on an endangered killer whale (Orcinus orca) population. PLoS ONE 7, e36842 (2012).

18. Rolland, R. M. et al. Evidence that ship noise increases stress in right whales. Proc. R. Soc. B Biol. Sci. 279, 2363–2368 (2012).

19. Wasser, S. K. et al. A generalized fecal glucocorticoid assay for use in a diverse array of nondomestic mammalian and avian species. Gen. Comp. Endocrinol. 120, 260–275 (2000).

20. Hunt, K. E., Trites, A. W. & Wasser, S. K. Validation of a fecal glucocorticoid assay for Steller sea lions (Eumetopias jubatus). Physiol. Behav. 80, 595–601 (2004).

21. Hunt, K. E. et al. Overcoming the challenges of studying conservation physiology in large whales: a review of available methods. Conserv. Physiol. 1, cot006–cot006 (2013).

A dominant language for scientific communication can streamline the process of science, but it also can create barriers and inequality

Dr. Alejandro A. Fernández Ajó, Postdoctoral Scholar, Marine Mammal Institute – OSU Department of Fisheries, Wildlife, & Conservation Sciences, Geospatial Ecology of Marine Megafauna (GEMM) Lab.

The English language is recognized as the international language of science (Gordin, 2015); I believe this is a useful convention that allows scientists to communicate ideas and gain access to global scientific literature regardless of their origin or native tongue. However, this avenue for sharing knowledge is open only for those proficient in English, and many scientists and users of scientific information, such as policy makers and conservationists, communicate on a daily basis in languages other than English. This inevitably creates barriers to the transfer of knowledge between communities, potentially impacting conservation and management because scientific knowledge is often unavailable in local languages.

Although in non-English speaking countries, local journals are receptive to publishing scientific research in languages other than English (i.e., their local language), oftentimes these local journals are perceived as low-quality and have a relatively low impact factor, making publishing in such journals less attractive to scientists. Therefore, readers with language barriers only have access to limited studies and are often unaware of the most significant research, even when the research is conducted in their region. This situation can result in a void of information relevant for environmental policies and conservation strategies. Ensuring that research findings are available in the local language of the region in which the research is conducted is an important step in science communication, but one that is often neglected.

In addition, scientists with English as a Foreign Language (EFL) confront the added challenge of navigating a second language while writing manuscripts, preparing and presenting oral presentations, and developing outreach communications (Ramirez-Castaneda, 2020). For example, EFL researchers have reported that one of the primary targets of criticism for their manuscripts under review is often the quality of their English rather than the science itself (Drubin and Kellogg, 2012). In academia, most job interviews and PhD applications are conducted in English; and grant and project proposals are often required to be written in English, which can be particularly challenging and can impact the allocation of resources for research and conservation in non-English speaking regions.

I am from Argentina, and I am a native Spanish speaker. I am fortunate to have started learning English at an early age and continue practicing with international collaborations and traveling abroad. Being able to communicate in English has opened many doors for me, but I recognize that I am in a privileged position with respect to many Argentinians and South Americans in general, where the majority of the population receives minimal training in English and bilingualism with English is very low. Thus, socioeconomic status can influence English proficiency, which then determines scientific success and access to knowledge. I believe that the scientific community should be aware of these issues and work towards improving equality in the process of research collaborations. Providing opportunities for students, and enhancing the availability of scientific knowledge for non-English speaking communities, particularly when the research is relevant for such communities.

In this picture I am with an international group of Fulbright scholars during the Spring International Language Program at the University of Arkansas. This is on of many activities organized by the Fulbright program to create bridges across cultures and languages.

Fortunately, there are several examples pointing towards improving equality in the scientific process, access to knowledge, and opportunities for EFL communities in STEM careers. Several journals are now accepting, or considering to accept the publication of papers in multiple languages. One example of this is the journal Integrative Organismal Biology, which provides the option for publishing the paper abstract in multiple languages. In our recent publication, “Male Bowhead Whale Reproductive Histories Inferred from Baleen Testosterone and Stable Isotopes,” we provided an abstract in five different languages, including Inuktitut, one of primary languages of indigenous groups in the area. And, international exchange programs like the Fulbright Foreign Student Program, of which I was a beneficiary between 2018-2020, enable graduate students and young professionals from abroad to study and conduct research in the United States.

In an effort to contribute to addressing these problems, I am working with a group of colleagues from Argentina (María Constanza (Kata) Marchesi and Tomas Marina) to develop graduate level coursework that will be offered at the Universidad Nacional de la Patagonia in Puerto Madryn, Argentina, with the objective to enable students to learn effective communication using English in the scientific environment. Unfortunately, these types of programs focused on EFL proficiency for STEM students are currently rare in Argentina, but my hope is that our work can spur the creation of additional programs for EFL students in STEM across the region.

I want to finish this post with the acknowledgement of the huge support I have form the GEMM Lab, which welcomes diversity, equity, and inclusivity, and promotes a culture of anti-racism, transparency, and acceptance (See the GEMM Lab DEI statement here).

Did you enjoy this blog? Want to learn more about marine life, research and conservation? Subscribe to our blog and get weekly updates and more! Just add your name into the subscribe box below!

References and Additional Readings

Gordin, M. D. (2015). Scientific Babel : How Science Was Done Before and After Global English. Chicago, IL: University of Chicago Press.

Ramírez-Castañeda V (2020) Disadvantages in preparing and publishing scientific papers caused by the dominance of the English language in science: The case of Colombian researchers in biological sciences. PLoS ONE 15(9): e0238372. https://doi.org/10.1371/journal.pone.0238372

Drubin, D. G., and Kellogg, D. R. (2012). English as the universal language of science: opportunities and challenges. Mol. Biol. Cell 23:1399. doi: 10.1091/mbc.E12-02-0108

Amano, T., González-Varo, J. P., & Sutherland, W. J. (2016). Languages are still a major barrier to global science. PLoS Biology, 14(12), e2000933. https://doi.org/10.1371/journal.pbio.2000933

Marden, E., Abbott, R. J., Austerlitz, F., Ortiz-Barrientos, D., Rieseberg, L. H. (2021). Sharing and reporting benefits from biodiversity research. Molecular Ecology, 30(5), 1103–1107. https://doi.org/10.1111/mec.15702

Márquez, M. C., & Porras, A. M. (2020). Science communication in multiple languages Is critical to Its effectiveness. Frontiers in Communication, 5(May). https://doi.org/10.3389/fcomm.2020.00031

Ramírez-Castañeda V (2020) Disadvantages in preparing and publishing scientific papers caused by the dominance of the English language in science: The case of Colombian researchers in biological sciences. PLoS ONE 15(9): e0238372. https://doi.org/10.1371/journal.pone.0238372

Trisos, C. H., Auerbach, J., & Katti, M. (2021). Decoloniality and anti-oppressive practices for a more ethical ecology. Nature Ecology and Evolution, 5(9), 1205–1212. https://doi.org/10.1038/s41559-021-01460-w

Woolston, C, & Osório, J. (2019). When English is not your mother tongue. Nature 570, 265-267. https://doi.org/10.1038/d41586-019-01797-0

Letter to the Editor of Marine Mammal Science: Enhancing the impact and inclusivity of research by embracing multi-lingual science communication (2022) DOI: 10.13140/RG.2.2.29934.08001 http://dx.doi.org/10.13140/RG.2.2.29934.08001

Leal, J. S., Soares, B., Franco, A. C. S., de Sá Ferreira Lima, R. G., Baker, K., & Griffiths, M. (2022). Decolonizing ecological research: a debate between global North geographers and global South field ecologists. https://doi.org/10.31235/osf.io/wbzh2

A mosaic of interconnected nearshore dynamics in Port Orford

Allison Dawn, GEMM Lab Master’s student, OSU Department of Fisheries, Wildlife and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab 

In last week’s blog, GEMM Lab postdoc Dawn Barlow discussed the uncertain future of upwelling response to climate change and how findings from the Shanks et al., 2009 “Paradigm lost? . . .” study implies that nearshore systems are likely decoupled from offshore upwelling processes. In a follow up to that paper, Shanks and co-authors found that the heterogeneity of coastline morphology (i.e., rocky or sandy) across several Oregon nearshore study sites explained zooplankton retention differences. Indeed, not only are there differences between offshore and nearshore upwelling dynamics, but there are also site-specific factors to consider when it comes to understanding changes in zooplankton retention along the Oregon coast (Shanks et. al, 2010).

I spend a lot of time thinking about what drives the variability in abundance and distribution of zooplankton prey of gray whales at our Port Orford study site over our long-term study period (2015-2022). For this blog, I want to briefly touch on a few interconnected dynamics in this nearshore PCFG gray whale foraging site that may affect their prey availability. Specifically, the interplay between shoreline topography, temperature, and habitat complexity. 

Interplay between shoreline morphology and thermal fronts

Several years before the “Paradigm lost? . . .” paper, Shanks led a study that investigated how holoplankton (a group of plankton in which mysids and amphipods belong) retention varies across three sites near Cape Arago and one site in Port Orford (Shanks et a., 2003). Here the authors noted that the Port Orford Bight causes an “upwelling shadow”, which is a region of water protected from upwelling-favorable winds. This shadow results in a small-scale warm water feature in the lee of the Port Orford Bight, which may serve as an important retention and recirculation zone for primary productivity (Graham et al., 1997). Discovering this “upwelling shadow” was not the intention of this paper, so the depth and breadth of the warm water plume within our study area has yet to be mapped (see Figure 1 for another West Coast example). However, “upwelling shadows” can act as convergence zones associated with greater zooplankton biomass (Morgan & Fisher, 2010; Ryan et al., 2010, Woodson et al., 2007) and thus may be an important feature to consider in our spatial analyses of drivers of prey availability to gray whales in our Port Orford study region.

Figure 1. Example of an “upwelling shadow” in Monterey Bay. Remotely sensed oceanographic convergent zones (top panel) and sea surface temperature (SST; lower panel) changes over time: a) Sept 8th 2003, b) Sept 2nd 2004, c) Sept 26th 2004, and d) May 31st 2005. Each time period demonstrates that the lee side of Point Año Nuevo is consistently warmer than the surrounding area. Figure source: Ryan et al., 2020.

Habitat complexity: rugosity and kelp

Not only could the unique shoreline in Port Orford contribute to zooplankton aggregations, but the subtidal marine environment is characterized by a range of unique habitat types: rocky reef, kelp beds, and sandy bottom habitat. Structural habitat complexity has been well documented in coral reef systems to be strongly linked with zooplankton prey availability and biodiversity of planktonic grazers (Richardson et al., 2017; Darling et al., 2017; Kuffner et al., 2007; Gladstone, 2007). Structural complexity can be measured in various ways, but quantifying rugosity (or surface “roughness”) is a widely accepted approach. However, only a few studies have demonstrated predator response to rugose habitats in Oregon nearshore rocky reefs (Rasmuson et al., 2021), and there is a dearth of knowledge linking rugosity to marine mammal predation (Cimino et al., 2020). 

Rugosity serves several purposes in the marine environment. A rugose habitat creates micro-habitats for predator evasion, provides greater surface area for kelp recruitment (Cruz et al., 2014; Toohey et al., 2007), and generates turbulence that circulates vital micronutrients for filter-feeding zooplankton and ultimately drives foraging effort at fine scales (Ottersen et al., 2010). 

Figure 2. Example images of habitat rugosity as measured by SCUBA transects. A) High-relief coral habitat with B) quantified depth (m) over transect seconds (10 seconds = 1 meter) and C) Low-relief coral habitat with D) quantified depth (m) over transect seconds (10 seconds = 1 meter). Figure source: Dustan et al., 2013.

Rugosity-generated turbidity might also help explain the zooplankton abundance variation we see across our sampling stations in Port Orford. In Lisa’s recent work showing evidence for a trophic cascade, a decline in bull kelp is overall strongly linked to a decline in zooplankton and gray whale foraging in Port Orford. However, there are sampling stations that, despite a significant loss in kelp, still had an abundance of mysids and hosted gray whale feeding activity in 2021 and 2022. Could this mean that those rocky reef stations, which are more rugose than the sandy bottom habitats, produced enough turbulence to support zooplankton prey? This hypothesis is consistent with several studies that found kelp abundance becomes less relevant with increasing habitat complexity (Trebilco et al., 2016; Anderson, 1994; Choat & Ayling et al., 1987; Larson, 1984). 

There certainly may be other physical or oceanographic factors that create turbidity at these stations. However, as my REU mentee Zoe Sax has been investigating, we think that turbidity could be a metric of primary productivity, which supports zooplankton growth. 

Figure 3 is a map of the average secchi disk values, which provide us with a measure of turbidity (the deeper we see the disk the less turbidity) in 2021 at our 12 sampling stations and their relation to kelp cover. 

Last year was a low kelp year, but Mill Rocks still had a few bull kelp canopies. In Mill Rocks where there was rocky reef with kelp, we see secchi values were low (meaning turbidity was high). This is in contrast to the areas in the sandy bottom regions (no kelp, low rugosity: specifically MR16, TC4, TC6, and TC10) with the lightest values, meaning low turbidity. 

Then, in Tichenor Cove specifically, we see that station TC1 has very little kelp but high turbidity; interestingly this site was a favored foraging spot for gray whales in 2021 and happens to be the closest station to the “upwelling shadow” I described earlier. I hope to conduct rugosity measurements in the near future so we can investigate these linkages further.

Figure 3. Map of two study sites, Tichenor Cove and Mill Rocks, with twelve sampling stations in Port Orford, OR and their average secchi disk values (meters) in 2021. Kelp abundance shown in light green polygons. 

Conclusion

This focus on topography, temperature, and habitat complexity to understand zooplankton variation does not discount that upwelling is an important factor for Oregon nearshore ecology. Menge & Menge 2013 found that upwelling accounted for ~50% of ecological variance in rocky intertidal regions. However, these findings occurred across large spatial areas of about 100 km, while our TOPAZ  sampling in Port Orford is on a much finer scale. Variation in ecological patterns at different, hierarchical scales are well-documented (Levin, 1992; Ottersen et al., 2010). Uncovering the “mosaic of processes”, as Shanks et al., 2003 describes, that drives nearshore zooplankton dynamics is equally challenging as it is fascinating, and I look forward to sharing more results from my Master’s work soon.

Did you enjoy this blog? Want to learn more about marine life, research and conservation? Subscribe to our blog and get weekly updates and more! Just add your name into the subscribe box below!

References

Anderson, T. W. (1994). Role of macroalgal structure in the distribution and abundance of a temperate reef fish. Marine ecology progress series. Oldendorf, 113(3), 279-290.

Choat, J. H., & Ayling, A. M. (1987). The relationship between habitat structure and fish faunas on New Zealand reefs. Journal of experimental marine biology and ecology, 110(3), 257-284.

Darling, E. S., Graham, N. A., Januchowski-Hartley, F. A., Nash, K. L., Pratchett, M. S., & Wilson, S. K. (2017). Relationships between structural complexity, coral traits, and reef fish assemblages. Coral Reefs, 36(2), 561-575.

Dustan, P., Doherty, O., & Pardede, S. (2013). Digital reef rugosity estimates coral reef habitat complexity. PloS one, 8(2), e57386.

Gladstone, W. (2007). Selection of a spawning aggregation site by Chromis hypsilepis (Pisces: Pomacentridae): habitat structure, transport potential, and food availability. Marine Ecology Progress Series, 351, 235-247.

Graham, W. M., & Largier, J. L. (1997). Upwelling shadows as nearshore retention sites: the example of northern Monterey Bay. Continental Shelf Research, 17(5), 509-532.

Kuffner, I. B., Brock, J. C., Grober-Dunsmore, R., Bonito, V. E., Hickey, T. D., & Wright, C. W. (2007). Relationships between reef fish communities and remotely sensed rugosity measurements in Biscayne National Park, Florida, USA. Environmental biology of fishes, 78(1), 71-82.

LARSON, R. J., & DeMARTINI, E. E. (1984). SAN ONOFRE, CALIFORNIA. Fishery Bulletin, 82(1-2), 37.

Levin, S. A. (1992). The problem of pattern and scale in ecology. Ecology, 73(6), 1943-1967.

Londoño Cruz et al. (2014) Londoño Cruz E, Mesa-Agudelo LAL, Arias-Galvez F, Herrera-Paz DL, Prado A, Cuellar LM, Cantera J. Distribution of macroinvertebrates on intertidal rocky shores in Gorgona Island, Colombia (Tropical Eastern Pacific) Revista de Biología Tropical. 2014;62(1):189–198. doi: 10.15517/rbt.v62i0.16275

Menge, B. A., & Menge, D. N. (2013). Dynamics of coastal meta-ecosystems: the intermittent upwelling hypothesis and a test in rocky intertidal regions. Ecological Monographs, 83(3), 283-310.

Morgan, S. G., & Fisher, J. L. (2010). Larval behavior regulates nearshore retention and offshore migration in an upwelling shadow and along the open coast. Marine Ecology Progress Series, 404, 109-126.

Ottersen, G., Kim, S., Huse, G., Polovina, J. J., & Stenseth, N. C. (2010). Major pathways by which climate may force marine fish populations. Journal of Marine Systems, 79(3-4), 343-360.

Rasmuson, L. K., Blume, M. T., & Rankin, P. S. (2021). Habitat use and activity patterns of female deacon rockfish (Sebastes diaconus) at seasonal scales and in response to episodic hypoxia. Environmental Biology of Fishes, 104(5), 535-553.

Richardson, L. E., Graham, N. A., Pratchett, M. S., & Hoey, A. S. (2017). Structural complexity mediates functional structure of reef fish assemblages among coral habitats. Environmental Biology of Fishes, 100(3), 193-207.

Ryan, J. P., Fischer, A. M., Kudela, R. M., McManus, M. A., Myers, J. S., Paduan, J. D., … & Zhang, Y. (2010). Recurrent frontal slicks of a coastal ocean upwelling shadow. Journal of Geophysical Research: Oceans, 115(C12).

Shanks, A. L., McCulloch, A., & Miller, J. (2003). Topographically generated fronts, very nearshore oceanography and the distribution of larval invertebrates and holoplankters. Journal of Plankton Research, 25(10), 1251-1277.

Shanks, A. L., & Shearman, R. K. (2009). Paradigm lost? Cross-shelf distributions of intertidal invertebrate larvae are unaffected by upwelling or downwelling. Marine Ecology Progress Series, 385, 189-204.

Shanks, A. L., Morgan, S. G., MacMahan, J., & Reniers, A. J. (2010). Surf zone physical and morphological regime as determinants of temporal and spatial variation in larval recruitment. Journal of Experimental Marine Biology and Ecology, 392(1-2), 140-150.

Toohey, B. D., Kendrick, G. A., & Harvey, E. S. (2007). Disturbance and reef topography maintain high local diversity in Ecklonia radiata kelp forests. Oikos, 116(10), 1618-1630.

Trebilco, R., Dulvy, N. K., Stewart, H., & Salomon, A. K. (2015). The role of habitat complexity in shaping the size structure of a temperate reef fish community. Marine Ecology Progress Series, 532, 197-211.

Woodson, C. B., Eerkes-Medrano, D. I., Flores-Morales, A., Foley, M. M., Henkel, S. K., Hessing-Lewis, M., … & Washburn, L. (2007). Local diurnal upwelling driven by sea breezes in northern Monterey Bay. Continental Shelf Research, 27(18), 2289-2302.

How will upwelling ecosystems fare in a changing climate?

By Dawn Barlow, Postdoctoral Scholar, OSU Department of Fisheries, Wildlife, and Conservation Sciences, Geospatial Ecology of Marine Megafauna Lab

Global climate change is affecting all aspects of life on earth. The oceans are not exempt from these impacts. On the contrary, marine species and ecosystems are experiencing significant impacts of climate change at faster rates and greater magnitudes than on land1,2, with cascading effects across trophic levels, impacting human communities that depend on healthy ocean ecosystems3.

In the lobby of the Gladys Valley Marine Studies building that we are privileged to work in here at the Hatfield Marine Science Center, a poem hangs on the wall: “The North Pacific Is Misbehaving”, by Duncan Berry. I read it often, each time moved by how he articulates both the scientific curiosity and the personal emotion that are intertwined in researchers whose work is dedicated to understanding the oceans on a rapidly changing planet. We seek to uncover truths about the watery places we love that capture our fascination; truths that are sometimes beautiful, sometimes puzzling, sometimes heartbreaking. Observations conducted with scientific rigor do not preclude complex human feelings of helplessness, determination, and hope.

Figure 1. Poem by Duncan Berry, entitled, “The North Pacific is Misbehaving”.

Here on the Oregon Coast, we are perched on the edge of a bountiful upwelling ecosystem. Upwelling is the process by which winds drive a net movement of surface water offshore, which is replaced by cold, nutrient-rich water. When this water full of nutrients meets the sunlight of the photic zone, large phytoplankton blooms occur that sustain high densities of forage species like zooplankton and fish, and yielding important feeding opportunities for predators such as marine mammals. Upwelling ecosystems, like the California Current system in our back yard that features in Duncan Berry’s poem, support over 20% of global fisheries catches despite covering an area less than 5% of the global oceans4–6. These narrow bands of ocean on the eastern boundaries of the major oceans are characterized by strong winds, cool sea surface temperatures, and high primary productivity that ultimately support thriving and productive ecosystems (Fig. 2)7.

Figure 2. Reproduced from Bograd et al. 2023. Maps showing global means in several key properties during the warm season (June through August in the Northern Hemisphere and January through March in the Southern Hemisphere). The locations of the four eastern boundary current upwelling systems (EBUSs) are shown by black outlines in each panel. (a) 10-m wind speed (colors) and vectors. (b) SST. (c) Dissolved oxygen concentrations at 200-m depth. (d) Concentration of ocean chlorophyll a. Abbreviations: BenCS, Benguela Current System; CalCS, California Current System; CanCS, Canary Current System; HumCS, Humboldt Current System; SST, sea surface temperature.

Because of their importance to human societies, eastern boundary current upwelling systems (EBUSs) have been well-studied over time. Now, scientists around the world who have dedicated their careers to understanding and describing the dynamics of upwelling systems are forced to reckon with the looming question of what will happen to these systems under climate change. The state of available information was recently synthesized in a forthcoming paper by Bograd et al. (2023). These authors find that the future of upwelling systems is uncertain, as climate change is anticipated to drive conflicting physical changes in their oceanography. Namely, alongshore winds could increase, which would yield increased upwelling. However, a poleward shift in these upwelling systems will likely lead to long-term changes in the intensity, location, and seasonality of upwelling-favorable winds, with intensification in poleward regions but weakening in equatorward areas. Another projected change is stronger temperature gradients between inshore and offshore areas, and vertically within the water column. What these various opposing forces will mean for primary productivity and species community structure remains to be seen.

While most of my prior research has centered around the importance of productive upwelling systems for supporting marine mammal feeding grounds8–10, my recent focus has shifted closer to home, to the nearshore waters less than 5 km from the coastline. Despite their ecological and economic importance, nearshore habitats remain understudied, particularly in the context of climate change. Through the recently launched EMERALD project, we are investigating spatial and temporal distribution patterns of harbor porpoises and gray whales between San Francisco Bay and the Columbia River in relation to fluctuations in key environmental drivers over the past 30 years. On a scientific level, I am thrilled to have such a rich dataset that enables asking broad questions relating to how changing environmental conditions have impacted these nearshore sentinel species. On a more personal level, I must admit some apprehension of what we will find. The excitement of detecting statistically significant northward shift in harbor porpoise distribution stands at odds with my own grappling with what that means for our planet. The oceans are changing, and sensitive species must move or adapt to persist. What does the future hold for this “wild edge of a continent of ours” that I love, as Duncan Berry describes?

Figure 4. The view from Cape Foulweather, showing the complex mosaic of nearshore habitat features. Photo: D. Barlow.

Evidence exists that the nearshore realm of the Northeast Pacific is actually decoupled from coastal upwelling processes11. Rather, these areas may be a “sweet spot” in the coastal boundary layer where headlands and rocky reefs provide more stable retention areas of productivity, distinct from the strong upwelling currents just slightly further from shore (Fig. 4). As the oceans continue to shift under the impacts of climate change, what will it mean for these critically important nearshore habitats? While they are adjacent to prominent upwelling systems, they are also physically, biologically, and ecologically distinct. Will nearshore habitats act as a refuge alongside a more rapidly changing upwelling environment, or will they be impacted in some different way? Many unanswered questions remain. I am eager to continue seeking out truth in the data, with my drive for scientific inquiry fueled by my underlying connection to this wild edge of a continent that I call home.

Did you enjoy this blog? Want to learn more about marine life, research, and conservation? Subscribe to our blog and get a weekly alert when we make a new post! Just add your name into the subscribe box below!

References:

1.          Poloczanska, E. S. et al. Global imprint of climate change on marine life. Nat. Clim. Chang. 3, (2013).

2.          Lenoir, J. et al. Species better track climate warming in the oceans than on land. Nat. Ecol. Evol. 4, 1044–1059 (2020).

3.          Hoegh-Guldberg, O. & Bruno, J. F. The impact of climate change on the world’s marine ecosystems. Science (2010). doi:10.1126/science.1189930

4.          Mann, K. H. & Lazier, J. R. N. Dynamics of Marine Ecosystems: Biological-physical interactions in the oceans. Blackwell Scientific Publications (1996). doi:10.2307/2960585

5.          Ryther, J. Photosynthesis and fish production in the sea. Science (80-. ). 166, 72–76 (1969).

6.          Cushing, D. H. Plankton production and year-class strength in fish populations: An update of the match/mismatch hypothesis. Adv. Mar. Biol. 9, 255–334 (1990).

7.          Bograd, S. J. et al. Climate Change Impacts on Eastern Boundary Upwelling Systems. Ann. Rev. Mar. Sci. 15, 1–26 (2023).

8.          Barlow, D. R., Bernard, K. S., Escobar-Flores, P., Palacios, D. M. & Torres, L. G. Links in the trophic chain: Modeling functional relationships between in situ oceanography, krill, and blue whale distribution under different oceanographic regimes. Mar. Ecol. Prog. Ser. 642, 207–225 (2020).

9.          Barlow, D. R., Klinck, H., Ponirakis, D., Garvey, C. & Torres, L. G. Temporal and spatial lags between wind, coastal upwelling, and blue whale occurrence. Sci. Rep. 11, 1–10 (2021).

10.        Derville, S., Barlow, D. R., Hayslip, C. & Torres, L. G. Seasonal, Annual, and Decadal Distribution of Three Rorqual Whale Species Relative to Dynamic Ocean Conditions Off Oregon, USA. Front. Mar. Sci. 9, 1–19 (2022).

11.        Shanks, A. L. & Shearman, R. K. Paradigm lost? Cross-shelf distributions of intertidal invertebrate larvae are unaffected by upwelling or downwelling. Mar. Ecol. Prog. Ser. 385, 189–204 (2009).