{"id":5591,"date":"2024-02-07T10:25:28","date_gmt":"2024-02-07T17:25:28","guid":{"rendered":"https:\/\/blogs.oregonstate.edu\/gemmlab\/?p=5591"},"modified":"2024-02-07T10:25:28","modified_gmt":"2024-02-07T17:25:28","slug":"its-getting-hot-in-here-studying-the-impacts-of-marine-heatwaves-on-krill-life-blood-of-the-ocean","status":"publish","type":"post","link":"https:\/\/blogs.oregonstate.edu\/gemmlab\/2024\/02\/07\/its-getting-hot-in-here-studying-the-impacts-of-marine-heatwaves-on-krill-life-blood-of-the-ocean\/","title":{"rendered":"It’s getting hot in here: studying the impacts of marine heatwaves on krill, life-blood of the ocean"},"content":{"rendered":"\n

By Kim Bernard<\/a>, Associate Professor, Oregon State University College of Earth, Ocean, and Atmospheric Sciences <\/em><\/p>\n\n\n\n

Euphausiids, commonly known as \u201ckrill\u201d, represent a globally distributed family of pelagic crustacean zooplankton, spanning from tropical to polar oceans. These remarkable organisms inhabit a vast range of marine habitats, from nearshore coastal waters to the expansive open ocean, and from the sea surface to abyssal depths. Notably, they claim the title of the largest biomass among non-domestic animal groups on Earth! Beyond their sheer abundance, euphausiids play a pivotal role in shaping global marine food webs, supporting both economically significant fisheries and extensive populations of marine megafauna.<\/p>\n\n\n\n

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Figure 1: Nyctiphanes australis<\/em>. Photo credit: A. Slotwinski, CSIRO.<\/figcaption><\/figure>\n\n\n\n

As our planet continues to warm, the ongoing and anticipated shifts in the distribution and biomass of krill populations herald potential disruptions to marine ecosystems and food webs globally. Marine heatwaves, which are expected to increase in frequency, intensity, and duration in the coming decades, have a significant impact on global krill populations, with knock-on effects through food webs. At our home-base off the coast of Oregon, a severe marine heatwave in 2014-2016 resulted in altered krill distributions and reduced biomass, causing a suite of ecological implications ranging from decline in salmon health to increased occurrence of whale entanglements in fishing gear (Daly et al. 2017; Santora et al. 2020).<\/p>\n\n\n

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Figure 2: (A) Simrad EK80 transducers (the larger one is a 38kHz transducer, the smaller is a 120kHz transducer) mounted to a pole that gets lowered into the water during our daily surveys. The transducers emit sound waves that bounce off objects, like krill, in the water and return to the instrument\u2019s transceiver, allowing us to map krill within the water column. (B) The acoustic data collected by the echosounder appears in real-time on our computer screen allowing us to find krill that we can then target with the Bongo net. Photo credits: Kim Bernard.<\/figcaption><\/figure>\n<\/div>\n\n\n

Here, off the coast of New Zealand, the krill species Nyctiphanes australis<\/em> (Figure 1) is an important prey item for many marine predators, including slender tuna (Allothunnus fallai<\/em>), Australian salmon (Kahawai, Arripis trutta<\/em>), Jack mackerel (Trachurus declivis<\/em>), short-tailed shearwater (Puffinus tenuirostris<\/em>) (O\u2019Brien 1988), and of course, the reason we are out here, blue whales (Balaenoptera musculus brevicauda<\/em>) (Torres et al. 2020). In a precursor study to the SAPPHIRE project, members of our current research team demonstrated the potential negative impacts that marine heatwaves can have off the coast of New Zealand. During that study, our team noted declines in the abundance and changes in the distribution patterns of Nyctiphanes australis<\/em> during a marine heatwave compared to normal conditions, with subsequent negative impacts on the distribution and behavior of the local New Zealand blue whale population (Barlow et al. 2020). The impetus of the SAPPHIRE project is to improve our understanding of the physiological mechanisms underlying the observed changes in both krill and blue whale populations, with the goal to better predict future changes.<\/p>\n\n\n\n

As a zooplankton ecologist and \u201ckriller\u201d, my role on the SAPPHIRE project is to further our knowledge on the prey, Nyctiphanes australis<\/em>. There are several components to this part of our research: (1) mapping distribution patterns of krill, (2) measuring the quality of krill as prey to whales, and (3) running experiments to test how warming affects krill physiology. To map the krill distribution patterns, we are using active acoustics (Figure 2). To measure the quality of krill, we first need to collect them, and we do that using a Bongo net (Figure 3) that gets towed behind the boat targeting krill we find using the echosounder. <\/p>\n\n\n

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Figure 3: Kim Bernard and Ngatokoa Tikitau empty the contents of one of the Bongo net cod-ends into a bucket to examine the catch. Unfortunately, it was not filled with krill as we had hoped, but rather a gelatinous zooplankton known as Salpa democratica<\/em>. Photo credit: KC Bierlich.<\/figcaption><\/figure>\n<\/div>\n\n\n

Once we have the krill, we\u2019ll flash freeze them in liquid nitrogen and take them back to Oregon where we\u2019ll measure the amount of protein, fats (lipids), and calories each one contains. Finally, for the experiments on temperature effects, we will use live krill collected with the Bongo net placed individually into 1L Nalgene bottles, each outfitted with oxygen sensors so that we can measure the respiration rates of krill at a range of temperatures they would experience during normal conditions and marine heatwaves (Figure 4).<\/p>\n\n\n

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Figure 4: Respiration experiment set-up with two circulating waterbaths in the foreground feeding two temperature treatments in coolers (aka \u201cchilly bins\u201d) behind. Once we catch krill (which has yet to happen), we will use this set-up to test the effects of warming on krill respiration rates. Photo credit: Kim Bernard.<\/figcaption><\/figure>\n<\/div>\n\n

Torres LG, Barlow DR, Chandler TE, Burnett JD.\u00a02020.\u00a0Insight into the kinematics of blue whale surface foraging through drone observations and prey data.\u00a0PeerJ<\/em>\u00a08:e8906\u00a0https:\/\/doi.org\/10.7717\/peerj.8906<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

By Kim Bernard, Associate Professor, Oregon State University College of Earth, Ocean, and Atmospheric Sciences Euphausiids, commonly known as \u201ckrill\u201d, represent a globally distributed family of pelagic crustacean zooplankton, spanning from tropical to polar oceans. These remarkable organisms inhabit a vast range of marine habitats, from nearshore coastal waters to the expansive open ocean, and … Continue reading It’s getting hot in here: studying the impacts of marine heatwaves on krill, life-blood of the ocean<\/span><\/a><\/p>\n","protected":false},"author":10751,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[188686,712807],"tags":[1237832,195384,712836,1310596,200562],"class_list":["post-5591","post","type-post","status-publish","format-standard","hentry","category-current-projects","category-new-zealand-blue-whales","tag-blue-whales","tag-field-work","tag-krill","tag-marine-heatwaves","tag-new-zealand"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/posts\/5591","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/users\/10751"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/comments?post=5591"}],"version-history":[{"count":3,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/posts\/5591\/revisions"}],"predecessor-version":[{"id":5599,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/posts\/5591\/revisions\/5599"}],"wp:attachment":[{"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/media?parent=5591"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/categories?post=5591"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/tags?post=5591"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}