you're reading...

Biological oceanography

Millennial algae are not as productive: lazy, or less sea ice opportunities?

Article: Neeley, A. R., Harris, L. A., & Frey, K. E. (2018). Unraveling phytoplankton community dynamics in the northern Chukchi Sea under sea-ice-covered and sea-ice-free conditions. Geophysical Research Letters, 45, 7663–7671. https://doi.org/10.1029/2018GL077684

Arctic sea ice has been on the decline since 1979, and that decline is expected to continue as the atmosphere warms. We’re already seeing how sea ice loss can affect our world, from weather patterns to large-scale ocean circulation to marine life in the Arctic. Despite the growing body of research describing our current predicament, it’s not so easy to predict what will happen when all of the sea ice inevitably disappears from the region.

The importance of life in the Arctic

Many studies focus on the impacts of sea ice loss on the tiniest algae in the marine food web – phytoplankton. These are extremely complex and diverse microscopic ocean plants that use sunlight and nutrients in the water to produce oxygen and energy for larger marine organisms, helping to regulate atmospheric carbon dioxide (the greenhouse gas that enhances global warming). They reside at the base of the marine food web, meaning they feed the tiny critters that feed the fish that feed the larger sea creatures; this makes them one of the most essential parts of marine ecosystems all over the world.

Figure 1: Map showing the locations of 81 sampling sites during the 2011 Climate on EcoSystems and Chemistry of the Arctic Pacific Environment expedition. Colors show the timing of sea ice break-up.

Because there is so much diversity among phytoplankton, specific groups respond differently to environmental conditions. In the Arctic, sea ice provides a cap to the upper ocean that protects it from sunlight and wind – that is, there is no way for the air and sea to interact with each other. This makes for calm, cold, high-nutrient, low-light conditions. When the ice begins to melt into fresh (non-salty) water, the surface becomes stratified – that is, layered by density – from fresh, light water on top to dense, salty water below, which inhibits vertical movement of nutrients. Sunlight at the surface promotes growth of some phytoplankton, but this depletes the surface of nutrients. Stratification prevents nutrients from reaching the surface to replenish their food source. These changes could affect what types of phytoplankton dominate the  ocean surface, and thus how the marine food web operates.

Linking phytoplankton “demographics” to ice conditions

Figure 2: Top – Phytoplankton are differentiated by ice conditions (red: icy, green: low-ice, yellow: no-ice, black: rare types). Closeness to an arrow of an environmental variable – such as light, ice presence, temperature, salinity, and nutrients (silica Si, dissolved inorganic nitrogen DIN, phosphorus P) – indicates how much each type is affected by it. Bottom – Phytoplankton are differentiated by depth shallower or deeper than 25 meters, or 82 feet (red/blue squares: shallower/deeper under ice, red/blue circles: shallower/deeper with no ice).

Dr. Aimee Neeley of the NASA Goddard Space Flight Center led a study that aims to understand how changes in environmental conditions due to sea ice loss affect phytoplankton populations. A research expedition to the Chukchi Sea in 2011 (north of Alaska – see Figure 1) provided data used to address the question of how phytoplankton might respond to an Arctic with little to no sea ice. Dr. Neeley’s team linked observed phytoplankton “demographics” to environmental conditions that may be controlling them, such as water movement, sunlight, nutrients, temperature, and salt content.

They measured environmental conditions at each of the 81 stations, and overlaid them with satellite data of sea ice cover to examine possible relationships. Bottles of water samples were examined under a microscope to identify the types of phytoplankton present at each site and at discrete depths down to 200 meters (about 656 feet). By doing this, they were able to separate communities of phytoplankton based on the conditions in which they thrived (see Figure 2). They further differentiated the phytoplankton into three groups based on the amount of ice present – ice cover, fragmented melting ice, and ice-free. Phytoplankton who thrive in icy conditions possessed similar characteristics, particularly a high carbon biomass – basically, the amount of carbon phytoplankton consume to turn into fuel for larger organisms. Low-and-no-ice phytoplankton tended to be smaller and have low carbon biomass. For organisms that rely on phytoplankton for nutrition, this shift from ice cover to ice-free is akin to visiting the grocery store to buy nutritious food but only finding candy. Although candy is delicious, how long could you really live off of it?

Using observations to predict the future

Dr. Neeley’s team contributed essential observations to the body of work needed to help predict phytoplankton response to an Arctic system with little to no sea ice – an inevitable outcome of a warmer climate. By differentiating these creatures based on their presence under different sea ice conditions, ice cover could be used by computer models to help predict their demographics, and from them, their effects on marine food webs and carbon in the atmosphere. Looks like the millennial phytoplankton problem is more than just plain laziness!


No comments yet.

Post a Comment


  • by oceanbites 2 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 3 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 4 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 5 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 5 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 7 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 8 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 9 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 9 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 9 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 10 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 11 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 11 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com