//
you're reading...

Biodiversity

If the benthos could talk: the value of long-term biodiversity monitoring

Journal source: Hale et al. 2018, Six decades of change in pollution and benthic invertebrate biodiversity in a southern New England estuary, Marine Pollution Bulletin 133: 77-87, https://doi.org/10.1016/j.marpolbul.2018.05.019.

The surface waters often obscure our view of the bottom, or benthic, habitats, but while out of sight, these systems can serve as a time capsule of human stressors that have caused reductions in biodiversity and altered species composition. Biodiversity, the number of different types of organisms living in an ecosystem, is the cornerstone of ecosystem functioning and the services they provide to people. Benthic (bottom habitat) biodiversity directly benefits humans because the different invertebrates living there.  For instance, mussels help filter water which aids in water quality, while various shrimps, snails, and crabs form an important component of the diets of commercially harvested seafood.

(Featured image) Microphotograph of typical benthic animals. Microphotograph taken by G. Carter, April 2000. Photo via Wikimedia Commons.

Marine benthic communities around the world have experienced biodiversity loss because of many different human activities, such as dredging, overfishing, pollution inputs, and watershed development. Estuaries, where freshwater inflows from surrounding lands meet the ocean, receive upstream pollution discharges and runoff from impervious surfaces and agriculture. Estuaries share linkages with the land and sea, and their benthic communities can be used to monitor changes in biodiversity and link observed changes with human activities.

In the presented study, Hale and colleagues from the U.S. Environmental Protection Agency (EPA) National Health and Environmental Effects Research Laboratory explored six decades of change in the benthic invertebrate communities of Narragansett Bay. The researchers also sought to link changes in benthic invertebrate biodiversity to anthropogenic impacts, such as eutrophication and sediment contamination.

Narragansett Bay is a northeastern U.S. estuary in Rhode Island and Massachusetts. The bay’s benthic communities support ecosystem functions and services such as shellfish production and shoreline protection. The bay is surrounded by a large watershed with over 1.9 million people, a high degree of urbanization, and waste water treatment facilities (WWTF) that discharge effluent into streams that flow into the estuary.

Map of Narragansett Bay study area. Yellow stars indicate the reference site (North Jamestown) and known impacted site (Spar Island) used for comparison of biodiversity in this study. Map via Google Maps.

To analyze changes in the bay, the researchers used benthic monitoring data from the EPA’s national coastal assessment programs and other long-term studies on Narragansett Bay. These programs used standardized protocols for sample collection and analysis, collected concurrent physical and chemical data from the water column and the sediments. The sample collection made it possible for the authors to compare biodiversity across several decades. Included in this dataset was one reference site in Narragansett Bay called North Jamestown that is minimally influenced by land use and WWTW discharge. Reference (or control) sites are important to use as a stable comparison for other sites that may be more susceptible to human impacts. To complement the reference site, the authors chose one impacted site called Spar Island in Mt Hope Bay. This site has experienced a number of human changes from watershed development and combined sewer overflows (CSOs). For each year of available data, the authors calculated benthic invertebrate diversity and related long-term trends in biodiversity to water column measurements, such as nitrogen concentrations, which can indicate pollution inputs.

What did they find?

After compiling 60 years of data from previous studies and examining biodiversity trends with relevant water quality measurements, the authors found significant changes had occurred in the benthic invertebrate communities of Narragansett Bay. While community composition changed, the authors noted that biodiversity throughout the bay did not respond drastically to human stressors, except for Spar Island, which showed a distinct drop in biodiversity from the 1970s to the 2000s. The authors also found that changes in community composition were linked to patterns of eutrophication, hypoxia (oxygen depletion), and sediment contaminants, such as petroleum products and heavy metals. By comparing community composition across decades, the authors could look at species that dominated the bay. The authors found that the species that dominated and contributed to decadal changes in community composition had small body sizes and short life cycles, such as the polychaete Mediomastus ambiseta. These life history characteristics allow these species to respond more rapidly to fluctuating habitat conditions; for example, small amphipods can colonize patches of good quality benthic habitat if other areas are too low in dissolved oxygen.

An amphipod, a prevalent member of benthic marine communities. Photo via Wikimedia Commons.

 

While biodiversity may not have declined with increasing human stressors, as originally expected, it began to show a weak upward trend beginning in 2005, which the authors attribute to the 50% reduction in total nitrogen inputs from WWTFs that empty their effluent into the bay. However, several more years of benthic monitoring in the bay will be necessary to determine if this upward trend continues as more efforts are made to reduce nutrient inputs to the estuary.

The bigger picture

This study was able to use long-term benthic monitoring data to determine if changes in biodiversity could be related to historical and present human influences on Narragansett Bay. This study, among others, sheds light on the value of historical data for identifying ecological patterns and linking them with anthropogenic stressors. While benthic monitoring is important, there is a need for multiple research groups to use standard sampling methods so that more studies can apply Hale and colleagues’ approach to other marine ecosystems. Biodiversity, an important feature of marine ecosystems, is also a useful tool for humans to help guide management and restoration efforts in complex habitats.

Discussion

One Response to “If the benthos could talk: the value of long-term biodiversity monitoring”

  1. An interesting and very important study, and well presented in your synopsis. Your concluding “The bigger picture” summary is especially on-target about using comparable methodologies, and should be required reading for researchers. A very concisely written article – well done.

    Posted by Ray Buckley | November 7, 2018, 12:32 pm

Post a Comment

Instagram

  • 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 5 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 6 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 8 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