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- Define eutrophication and explain how human behaviors lead to eutrophication.
- Explain how algae blooms are detrimental to aquatic ecosystems.
- Explain how zooplankton might impact algae blooms caused by cultural eutrophication.
- Predict the effects of changes in an aquatic ecosystem using a computer model
A SlideShare element has been excluded from this version of the text. You can view it online here: pb.libretexts.org/bio2lm/?p=160
An ecosystem is defined as an association of life and the physical environment. Ecosystems take into account both living organisms and the nonliving components like water, soil, light, etc. Ecosystems can be either terrestrial (dessert, forest, grassland) or aquatic (coral reef, pond, estuary).
Within ecosystems scientists study energy transformations. Energy typically enters the ecosystem from the sun, is transferred to photosynthetic organisms (primary producers) and then to organisms that need to eat others for energy, the consumers or heterotrophs. An ecosystem will typically have several levels of consumers. The transfer of energy from organism to organism can be illustrated through trophic levels. A trophic level includes all organisms the same number of transfer steps away from the energy input into an ecosystem. A simple trophic level diagram for a forest ecosystem is illustrated below. Notice the photosynthetic organisms like plants are on the first trophic level, one step away from the energy source. The squirrel is a primary consumer (eating plants directly) but on the second tropic level two steps away from the primary energy source. At each step along the pathway some energy is lost as heat. Therefore at higher tropic levels there are fewer organisms (as noted by the pyramid shape) and most ecosystems support no more than four or five total trophic levels.
Ecosystems are changing due to human behaviors. Humans negatively impact natural ecosystems through activities such as deforestation, hunting, and pollution. Today’s lab focuses on the impact of eutrophication on aquatic ecosystems. Through eutrophication bodies of water acquire extremely high concentrations of nutrients. The source of these nutrients can be natural or artificial. Humans cause cultural eutrophication through behaviors like run off from agricultural fields, wastewater from sewage treatment plants, and excel detergents running into bodies of water. The excess nutrients fuel photosynthesis causing an increased growth in algae, a photosynthetic primary producer protist, and an algae bloom. During the bloom the algae cover the surface of the water. When the algae die, decomposers in the ecosystem break down the protists using up the oxygen available in the aquatic environment through respiration. As oxygen levels decrease (hypoxia), fish die, and the balance of the ecosystem is destroyed.
In an effort to understand ecosystems and human impact on ecosystems scientists often use models. Modeling of ecosystems serves two main functions. First, the model represents scientist’s best understanding of the relationships/functions that define the ecosystem. Second, models allow scientists to investigate questions that would be impossible to pursue in reality.
Ecosystem models fall into two categories, analytical models and simulation models. Analytical models use math to explain simple linear relationships. Simulation models, more widely used, are used to illustrate complex non linear relationships in ecosystems. Since the natural ecosystem has numerous interactions between living and non living components ecosystem models must simplify this real world situation. Models incorporate only the most important components or group similar components in an effort to effectively represent the ecosystem in a straightforward fashion.
This lab will utilize the Silver Spring model, an analytical model, developed by H. T. Odum in 1957. Silver Springs is a real aquatic ecosystem located in central Florida. Odum developed his model to illustrate energy flow through the different trophic levels. The main organisms in Sliver Sping organized by trophic level are:
- First trophic level: Eelgrass and algae are the main photosynthetic organisms.
- Second trophic level: Invertebrates, turtles, and fish are the herbivores.
- Third tropic level: Both fish and invertebrates are carnivores and prey upon the herbivores.
- Fourth tropic level: The top carnivores consist of gar and bass, which eat the other fish species at lower trophic levels.
- Decomposers: Bacteria and crayfish are the main decomposers.
The Silver Springs model is on Blackboard as an Excel file. The general model structure is pictured on the next page. Odum’s model contains five state variables representing energy inputs into the four tropic levels and the decomposers. Flux rates describe the addition/removal of energy to/from the various parts of the system and the rate of transfer of energy between the components of the system. In the Excel file you can change the initial values (X) of any or all of the state variables and coefficients (P), and control the length of time simulated. Following a simulation “run” you will be easily able to view graphs of the state variables or community respiration versus time. To change the initial values, simply type over the current value and press return. Use the model to investigate the scenarios below:
We will use the model in two different scenarios in today’s lab, to understand eutrophication and to determine the impact of bread on the ecosystem.
To understand more about eutrophication, you will conduct a laboratory experiment (Part 1) and use the Silver Springs computer model (Part 2)
One potential way to decrease cultural eutrophication is by having higher trophic level organisms consume the algae. We will investigate this possibility using Daphnia, a zooplankton that feeds on green algae, and an alga species called Chorella. Although the information we gain from this activity is useful, it is an over simplification as to what might really occur in the aquatic environment.
We will use a colorimeter to measure the algae population. A colorimeter measures absorbance, the amount of light that is absorbed by a solution rather than the amount of light that can pass through. As the algae population increases (number of algae cells), the absorbance will also increase. It is a direct relationship.
- Obtain two cuvettes and a transfer pipette.
- Fill one cuvette with distilled water. This cuvette is the blank
- Place the blank into the colorimeter and zero it. This provides a baseline measure for the experiment. Save the blank cuvette for later use.
- Using the disposable pipette, fill the second cuvette with the Chorella algae. Use the pipette to try and disperse the algae evenly throughout the cuvette.
- Add 10 daphnia to the cuvette and immediately measure the absorbance using the colorimeter. Record your reading in the table below.
- Remove the cuvette from the colorimeter and allow it to sit, undisturbed for 30 minutes.
- After 30 minutes, place the blank cuvette (with distilled water) back into the colorimeter. Use the blank to re-zero the machine.
- Remove the blank cuvette and put the algae/Daphnia cuvette into the colorimeter. Measure the absorbance and record your reading in the table below.
|Table 1: Colorimeter data of Daphnia feeding on Chorella|
|Before feeding (time zero)|
- How did the absorbance change from time 0 to time 30 minutes? Did the absorbance increase, decrease, or stay the same?
- What does the absorbance value change tell you about the concentration of the Chorella? Did it increase, decrease, or stay the same?
- What does the absorbance value chance tell you about the behavior of the Daphnia? Did they consume Chorella? How do you know?
- In a real aquatic ecosystem, do you think zooplankton could decrease the impact of cultural eutrophication and algae blooms? Explain why or why not.
Now that you have observed trophic interactions and cultural eutrophication in a lab experiment, apply that knowledge to the computer model. Use the model to analyze the sensitivity of the Silver Springs ecosystem to cultural eutrophication. Remember that alga is a photosynthetic producer on the first trophic level. The Daphnia would be one of the herbivores in the environment on the second trophic level. Change the levels in the model to simulate a eutrophication situation. View the graphs to see how the different trophic level populations change through the simulation.
Based on your findings with the model, answer the following questions:
- What is the maximum number of producers the ecosystem can support before higher trophic levels begin to decline?
- What happens to community respiration in the simulated algae bloom? Does it increase, decrease, or stay the same?
- What happens to the decomposer population in the simulated algae bloom? Does it increase, decrease, or stay the same? Why?
- Which group of carnivores (which trophic level) is more greatly impacted by the algae bloom? Why do you think this is the case?
Eutrophication is not the only way that human activities affect aquatic ecosystems. Tourism in the Silver Spring area has grown lately as a result of more of vacationers visiting Central Florida. When visiting Silver Spring, tourists enjoy feeding the ducks. But, the ducks are gaining weight and becoming dependent on the tourists as a food source disrupting the normal food chain in the environment. Some environmental organizations have voiced displeasure regarding the dependence of ducks on bread handouts from visitors to the lake. Is it feasible to stop feeding the ducks or have they become too reliant on the tourists and the bread handouts?
Use the model to analyze the sensitivity of long-term duck populations to an increase or decrease in bread input. There is a separate variable for bread and the ducks would be on the second trophic level as herbivores. View the graphs to see how the different trophic level populations change through the simulation.
Based on your findings with the model, answer the following questions:
- Is an elimination of bread feasible? Why or why not?
- How would the system respond to increasing levels of tourism, assuming bread levels also increased? What trophic levels are most impacted by increased levels of bread?
- What is the role of bread in the system, and how does its presence or absence impact the ecology of Silver Springs?
- What would be your suggestion to the managing board of Silver Springs? Should they completely eliminate the tourists feeding the ducks? Why or why not?
What is eutrophication?
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VIDEO: What is eutrophication? Here's an overview in one minute. Transcript
Eutrophication is a big word that describes a big problem in the nation's estuaries. Harmful algal blooms, dead zones, and fish kills are the results of a process called eutrophication — which occurs when the environment becomes enriched with nutrients, increasing the amount of plant and algae growth to estuaries and coastal waters.
Sixty-five percent of the estuaries and coastal waters in the contiguous U.S. that have been studied by researchers are moderately to severely degraded by excessive nutrient inputs. Excessive nutrients lead to algal blooms and low-oxygen (hypoxic) waters that can kill fish and seagrass and reduce essential fish habitats. Many of these estuaries also support bivalve mollusk populations (e.g., oysters, clams, scallops), which naturally reduce nutrients through their filter-feeding activities.
Eutrophication sets off a chain reaction in the ecosystem, starting with an overabundance of algae and plants. The excess algae and plant matter eventually decompose, producing large amounts of carbon dioxide. This lowers the pH of seawater, a process known as ocean acidification. Acidification slows the growth of fish and shellfish and can prevent shell formation in bivalve mollusks. This leads to a reduced catch for commercial and recreational fisheries, meaning smaller harvests and more expensive seafood.
Did you know?
In September 2017, New York Governor Andrew M. Cuomo announced a $10.4 million effort to improve Long Island's water quality and bolster the economies and resiliency of coastal communities by restoring native shellfish populations to coastal waters. The state plans to establish five new sanctuary sites in Suffolk and Nassau Counties to transplant seeded clams and oysters, and to expand public shellfish hatcheries in the two counties through a dedicated grant program. Eutrophication has had significant economic impacts on Long Island Sound, where commercial shellfisheries have lost millions of dollars annually since 1985. Recent projections indicate that without intervention, the Sound could lose all of its seagrass beds by 2030, and that two-thirds of the Sound could lack enough oxygen for fish to survive.
In recent years, NOAA's National Centers for Coastal Ocean Science (NCCOS), in collaboration with NOAA's Northeast Fisheries Science Center, has enlisted estuaries' indigenous residents, namely, bivalve mollusks, to help slow and, in some cases, reverse the process of eutrophication, since they efficiently remove nutrients from the water as they feed on phytoplankton and detritus.
A groundbreaking modeling project in Long Island Sound showed that the oyster aquaculture industry in Connecticut provides $8.5 – $23 million annually in nutrient reduction benefits. The project also showed that reasonable expansion of oyster aquaculture could provide as much nutrient reduction as the comparable investment of $470 million in traditional nutrient-reduction measures, such as wastewater treatment improvements and agricultural best management practices.
The NOAA scientists used aquaculture modeling tools to demonstrate that shellfish aquaculture compares favorably to existing nutrient management strategies in terms of efficiency of nutrient removal and implementation cost. Documenting the water quality benefits provided by shellfish aquaculture has increased both communities' and regulators' acceptance of shellfish farming, not only in Connecticut but across the nation. In Chesapeake Bay, for example, nutrient removal policies include the harvesting of oyster tissue as an approved method, and in Mashpee Bay, Massachusetts, cultivation and harvest of oysters and clams are part of the official nutrient management plan.
Eutrophication weakens stabilizing effects of diversity in natural grasslands
Studies of experimental grassland communities have demonstrated that plant diversity can stabilize productivity through species asynchrony, in which decreases in the biomass of some species are compensated for by increases in others. However, it remains unknown whether these findings are relevant to natural ecosystems, especially those for which species diversity is threatened by anthropogenic global change. Here we analyse diversity-stability relationships from 41 grasslands on five continents and examine how these relationships are affected by chronic fertilization, one of the strongest drivers of species loss globally. Unmanipulated communities with more species had greater species asynchrony, resulting in more stable biomass production, generalizing a result from biodiversity experiments to real-world grasslands. However, fertilization weakened the positive effect of diversity on stability. Contrary to expectations, this was not due to species loss after eutrophication but rather to an increase in the temporal variation of productivity in combination with a decrease in species asynchrony in diverse communities. Our results demonstrate separate and synergistic effects of diversity and eutrophication on stability, emphasizing the need to understand how drivers of global change interactively affect the reliable provisioning of ecosystem services in real-world systems.
Biological Magnification vs. Bioaccumulation
It’s important to note that there is a significant difference between biomagnification and bioaccumulation. Although some may use the words interchangeably, they actually describe different scenarios in an organism.
Biological magnification specifically refers to increasing concentration of materials in each higher link in the food chain. However, bioaccumulation examines the increased presence of a particular substance inside a single organism.
While the two processes may be interconnected, for the purpose of this article it’s important to differentiate the terminology to understand the real-life examples and practice.
We thank Amber Erickson, Lisa Whitehouse, and Suzanne Ankerstjerne for chemical and analytical assistance and Adam Heathcote for his contributions to site selection and sampling design. Lakes in this study occupy indigenous lands of the Meskwaki, Sauk, Ho-Chunk, Ioway, and Dakota, forcibly ceded in multiple treaties between 1824 and 1853 (http://www.iowahild.com/index.html). The Meskwaki Nation currently resides on 7000 acres in Meskwakenuk in Tama County, IA. This study was funded by a Grant from the National Science Foundation to John A. Downing, DEB-1021525.
This project models a real world scenario and ecological issue: eutrophication, which results in bodies of water that are depleted of oxygen and are in a sense &ldquodead&rdquo. The goal of the project is that the student becomes aware of a real ecological issue and how humans can inadvertently create damage to the natural environment. The student will also research and understand the far reaching effects of this issue and how we can work to prevent it.
- What is eutrophication?
- What is an algal bloom and what are the environmental effects of an algal bloom?
- What are examples of point source pollution and non-point source pollution?
- How do fertilizers, phosphates, nitrates, etc. lead to oxygen depletion in the water?
- What are the long term effects of a body of water being depleted of oxygen?
- What is the experimental control in your experiment? What are some of the variables to consider in your project?
Eutrophication occurs when extra nutrients are added to a body of water. The algae or plant life in the body of water grows at a very fast rate or &ldquoblooms&rdquo. As the plants grow they begin to deplete the oxygen dissolved in the water. The other living things in the water requiring this oxygen begin to die off. Eventually the body of water cannot sustain life and it becomes a &ldquodead&rdquo body of water. Eutrophication is mainly caused by fertilizer runoff from intensive farming practices, and improper sewage treatment. As the need for food rises with the country&rsquos population we become dependent on farming practices different than those that have been traditionally used. This includes using more fertilizer on our crops to increase production. Chemical fertilizers are full of soluble phosphates and nitrates that run off of the land during heavy rains and irrigation. The chemicals make their way into bodies of water where they cause algal and plant blooms, hence eutrophication. When sewage runs into waterways the decomposers in the waste use the oxygen in the water and this also leads to eutrophication. In order to prevent this from happening we need to be more careful about what we use to fertilize crops and how we handle our sewage. Natural fertilizers like manure decompose more slowly so that the nutrients are not washed away quickly in run off water like the chemical fertilizers. We need to treat sewage properly before it makes its way back into the water cycle.
The materials for this project can be found at the grocery store, an aquarium supply shop and around the home.
Global Trends and Patterns
Phytoplankton production is both the foundation of most marine food webs that support provisioning services and a source of excess organic matter that often leads to coastal eutrophication. Today, coastal eutrophication is a global problem (Figure 2), especially in the northern hemisphere, along the western margins of the Atlantic and Pacific Oceans, and in European coastal waters (Howarth, 2008 Nixon, 2009 Rabalais et al., 2009, 2010 Cloern and Jassby, 2010 Cloern et al., 2014).
Figure 2. Global distribution of eutrophic coastal marine ecosystems (adapted from Breitburg et al., 2018). Recent coastal surveys by the United States and the European Union found that 78% of U.S coastal waters and 65% of Europe’s Atlantic coastal waters exhibit symptoms of eutrophication.
In five years (1998), surface chlorophyll-a (Chl) 7 concentration increased by 10% in the coastal ocean (Gregg et al., 2005), largely as a consequence of land-based, anthropogenic N inputs (Justić et al., 1995 Jørgensen and Richardson, 1996 IPCC, 2014). Changes in coastal ecosystem states due to coastal eutrophication include:
• The occurrence of dead zones (hypoxic or anoxic 8 ) zones that develop when excess organic matter sinks below the pycnocline 9 where it is metabolized by aerobic, heterotrophic bacteria (cf., Malone et al., 1988). The number of oxygen depleted coastal ecosystems has increased globally from < 5 prior to WWII to today (Vaquer-Sunyer and Duarte, 2008 Altieri and Diaz, 2019 Diaz et al., 2019), a number that may be an underestimate due to under sampling of the coastal ocean, especially in the southern hemisphere (Altieria et al., 2017 Diaz et al., 2019).
• Harmful algal blooms appear to be increasing in frequency, and there is a growing consensus that cultural eutrophication is at least partially responsible (Anderson et al., 2002 Heil et al., 2005 Glibert et al., 2008 Heisler et al., 2008 Glibert, 2017 Glibert and Burford, 2017).
• Habitat loss is a global problem as warm-water coral reefs have declined by at least 50% (D𠆚ngelo and Wiedenmann, 2014 Hoegh-Guldberg et al., 2017), seagrass meadows by 29% (Orth et al., 2006 Waycott et al., 2009 Deegan et al., 2012), and coastal wetlands (mangrove forests and salt marshes) by 30% (Valiela et al., 2009 Deegan et al., 2012). A common theme accompanying these losses is the impact of anthropogenic nutrient loading.
Sources of Anthropogenic Nitrogen
Over half of the DIN input to coastal ecosystems (including 73% of Large Marine Ecosystems 10 ) is related to anthropogenic sources (Galloway et al., 2004 Howarth, 2008 Lee et al., 2016). An average of % anthropogenic N inputs to coastal watersheds is exported to coastal ecosystems (Howarth et al., 1996 Howarth, 1998), and Galloway et al. (2004) predict that export will increase by 40% by 2050 relative to 2000. Nearly half of this increase is projected to be from South Asia, where industrial agriculture and urbanization are expected to show the greatest increases (Howarth and Marino, 2006 Goldewijk et al., 2011 Lee et al., 2016). Ranked in terms of the magnitude of N loading, major 11 anthropogenic sources include:
(i) Synthetic Fertilizers – The largest source of anthropogenic N transported to coastal ecosystems is the use of synthetic fertilizers (Vitousek et al., 1997 Johnson and Harrison, 2015), which has grown exponentially from near zero in 1910 to × 10 9 kg N yr 𠄱 in 2013 (Penuelas et al., 2013 Lu and Tian, 2017). In 2013, southern Asia accounted for 71% of global fertilizer use, followed by North America (11%), Europe (7%), and South America (6%) (Lu and Tian, 2017). Volatilization of ammonia from agriculture fields emits an estimated 10 × 10 9 kg N yr 𠄱 (8% of the N applied) into the atmosphere (Vitousek et al., 1997 Bouwman et al., 2013).
(ii) Combustion of Fossil Fuels – Emissions from the combustion of fossil fuels release an estimated 25 × 10 9 kg N yr 𠄱 (Penuelas et al., 2013) with Asia, Europe, North America and Sub-Saharan Africa accounting for 30, 20, 17, and 12% of emissions, respectively (Lamsal et al., 2011). As well as being a pressure for eutrophication, nitrous oxide is a potent greenhouse gas (Davidson, 2009).
(iii) Legume Agriculture – Industrial agricultural has replaced large areas of natural vegetation with monocultures of legumes (e.g., soybeans) that support symbiotic N2-fixing bacteria. As a result, inputs of N from biological N-fixation to coastal watersheds has increased from negligible to × 10 9 kg yr 𠄱 (Boyer and Howarth, 2008).
(iv) Animal Husbandry – The production of manure has increased rapidly over the last century. Today, agriculture is responsible for over 75% of the NH3 emissions in the United States and Canada, with animal production accounting for > 70% (Aneja et al., 2001 Bittman and Mikkelsen, 2009). Current loads of manure-N are estimated to be ∼ 18 × 10 9 kg N yr 𠄱 , with production hotspots in western Europe, India, northeastern China, and southeastern Australia where emissions to the atmosphere are growing rapidly (Penuelas et al., 2013 Zhang et al., 2017).
(v) Wastewater – Globally, 80% of municipal wastewater is released into the environment untreated (World Water Assessment Programme [WWAP], 2017). The percentage of treated sewage varies regionally from 90% in North America, 66% in Europe, 35% in Asia, 14% in Latin America and the Caribbean, and ρ% in Africa (Selman and Greenhalgh, 2010). Thus, the most prevalent urban source of nutrient pressure is human sewage, which is estimated to have released ∼ 9 휐 9 kg N yr 𠄱 into the environment in 2018 (extrapolated from van Drecht et al., 2009).
(vi) Finfish aquaculture – Annual nutrients inputs to the coastal ocean via finfish aquaculture increased worldwide by a factor of 6 from ∼ 0.43 × 10 9 kg N yr 𠄱 in 1985 to 2.60 × 10 9 kg N yr 𠄱 in 2005 (Strain and Hargrave, 2005). In contrast, the pressure of nutrient enrichment from bivalve aquaculture is generally small to negligible. In fact, bivalve aquaculture is increasingly being used to offset anthropogenic nutrient pressures (Burkholder and Shumway, 2011 Gallardi, 2014).
Globally, nonpoint (diffuse) source inputs (i-iv above) total × 10 9 kg N yr 𠄱 and far exceed point source inputs (v-vi above) of ∼ 10 × 10 9 kg N yr 𠄱 or 5% of the total. Thus, our emphasis here is on inputs from diffuse sources.
River runoff and atmospheric deposition account for most anthropogenic N inputs to coastal ecosystems (Figure 3 Howarth et al., 1996 Green et al., 2004 Howarth, 2008 Jickells et al., 2017) 12 . During the twentieth Century, total riverine inputs of N to the coastal ocean increased from × 10 9 kg N yr 𠄱 to × 10 9 kg N yr 𠄱 (Galloway et al., 2004 Beusen et al., 2016). Globally, there is a significant linear correlation between net anthropogenic N inputs to coastal watersheds and total river borne N export to the coastal ocean (Boyer and Howarth, 2008 Swaney et al., 2012), and we estimate that % of anthropogenic N inputs to coastal watersheds reaches coastal ecosystems.
Figure 3. Nutrient enrichment pathways () via river runoff, storm water runoff (Urban and Residential Runoff) and atmospheric precipitation and effects of anthropogenic nutrient enrichment on phytoplankton biomass (Algal Bloom) and consequences of eutrophication, e.g., oxygen depletion of bottom waters (O2↓) (Source: Hans Paerl, University of North Carolina).
Anthropogenic inputs of N to the atmosphere are derived from the volatilization of NH3 from fertilizer and the combustion of fossil fuels (emission of nitrous oxide). Atmospheric deposition of N to the global ocean increased rapidly during the twentieth Century from a pre-industrial rate of ∼ 22 × 10 9 kg N yr 𠄱 to > 45 × 10 9 kg N yr 𠄱 today (Dentener et al., 2006 Duce et al., 2008). Of this, it is estimated that atmospheric deposition directly to the coastal ocean is on the order of 8 × 10 9 kg N yr 𠄱 (Seitzinger et al., 2010 Ngatia et al., 2019), or about 14% of total anthropogenic inputs to the coastal ocean. However, the relative magnitude of direct atmospheric deposition to coastal ecosystems varies from 𢏅% in waters most heavily impacted by river borne inputs (e.g., the northern Gulf of Mexico) to ≥ 30% in waters with relatively low river borne inputs (e.g., Baltic, western Mediterranean, mid-Atlantic and northeast U.S.-Canadian Atlantic coastal regions) (Paerl et al., 2002 Spokes and Jickells, 2005).
Publications since 2017
52) Simancas-Giraldo SM, Xiang N, Kennedy MM, Nafeh R, Zelli E, Wild C (in press) Photosynthesis and respiration of the soft coral Xenia umbellata respond to warming but not to organic carbon eutrophication. Peer J
51) Tilstra A, Hoeksema B, Wild C (2021) A presumed Lazarus coral: outstanding regeneration capacity of a Goniopora coral exposed to air over several months. Bulletin of Marine Science, DOI: 10.5343/bms.2021.0007
50) El-Khaled YC, Roth F, Rädecker N, Tilstra A, Karcher DB, Kürten B, Jones BH, Voolstra CR, Wild C (2021) Nitrogen fixation and denitrification activity differ between coral- and algae-dominated Red Sea reefs. Scientific Reports 11:11820, DOI: 10.1038/s41598-021-90204-8
49) Tilstra A, Roth F, El-Khaled YC, Pogoreutz C, Rädecker N, Voolstra CR, Wild C (2021) Relative abundance of nitrogen cycling microbes in coral holobionts reflects environmental nitrate availability. Royal Society Open Science 8: 201835, DOI: 10.1098/rsos.201835
48) Roth F, El-Khaled YC, Karcher DB, Rädecker N, Carvalho S, Duarte CM, Silva L, Calleja, MJ, Morán XA, Jones BH, Voolstra CR, Wild C (2021) Nutrient pollution enhances productivity and framework dissolution in algae- but not in coral-dominated reef communities. Marine Pollution Bulletin 168, 112444, DOI: 10.1016/j.marpolbul.2021.112444
47) El-Khaled YC, Nafeh R, Roth F, Rädecker N, Karcher DB, Jones BH, Voolstra CR, Wild C (2021) High plasticity of nitrogen fixation and denitrification of common coral reef substrates in response to nitrate availability. Marine Pollution Bulletin 168, 112430, DOI: 10.1016/j.marpolbul.2021.112430
46) Müller M, Staab CFK, Puk LD, Schoenig EM, Ferse SCA, Wild C (2021) The rabbitfish Siganus virgatus as key macroalgae browser in coral reefs of the Gulf of Thailand. Diversity 13, 123, DOI: 10.3390/d13030123
45) Elías Ilosvay XE, Segovia J, Ferse SCA, Elías W, Wild C (2021) Rapid relative increase of crustose coralline algae following herbivore exclusion in a reef of El Salvador. Peer J9: e10696, DOI: 10.7717/peerj.10696
44) Rädecker N, Pogoreutz C, Bougoure J, Guagliardo P, Raina JP, Pernice M, Cardenas A, Gegner H, Roth F, Wild C, Meibom A, Voolstra CR, (2021) Heat stress destabilizes symbiotic nutrient cycling in corals. Proceedings of the National Academy of Sciences 118(5), DOI: 10.1073/pnas.2022653118
43) Roth F, Rädecker N, Carvalho S, Duarte CM, Saderne V, Anton A, Silva L, Calleja ML, Morán XAG, Voolstra CR, Kürten B, Jones BH, Wild C (2021) High summer temperatures amplify functional differences between coral- and algae-dominated reef communities. Bull Ecol Soc Am 102(1): e01822, DOI:10.1002/bes2.1822
42) Koepper S, Nuryati S, Palm HW, Theisen S, Wild C, Yulianto I, Kleinertz S (2020) Parasite fauna of the white-streaked grouper (Epinephelus ongus) from the Thousand Islands, Java, Indonesia. Acta Parasitologica, DOI: 10.1007/s11686-020-00312-0
41) Koester A, V Migani, N Bunbury, AK Ford, C Sanchez, C Wild (2020) Early trajectories of benthic coral reef communities following the 2015/16 coral bleaching event at remote Aldabra Atoll, Seychelles. Scientific Reports,10:17034. DOI:10.1038/s41598-020-74077-x
40) Ford A , Jouffray JB, Norström A, Moore BR, Nugues MM, Williams G, Bejarano S, Magron F, Wild C, Ferse S (2020) Local human impacts disrupt relationships between benthic reef assemblages and environmental predictors. Frontiers in Marine Science 7:571115, DOI: 10.3389/fmars.2020.571115
39) Roth F, Rädecker N, Carvalho S, Duarte CM, Saderne V, Anton A, Silva L, Calleja ML, Morán XA, Voolstra CR, Kürten B, Jones BH, Wild C (2020) High summer temperatures amplify functional differences between coral- and algal-dominated reef communities. Ecology 102(2), DOI: 10.1002/ecy.3226
38) Elías Ilosvay XE, Contreras-Silva AI, Alvarez-Filip L, Wild C (2020) Reef recovery in the Mexican Caribbean after 2005 mass coral mortality - potential drivers. Diversity12(338), DOI:10.3390/d12090338
37) Guan Y, Hohn S, Wild C, Merico A (2020) Vulnerability of global coral reef habitat suitability to ocean warming, acidification and eutrophication. Global Change Biology 26(10), DOI: 10.1111/gcb.15293
36) Roth F, Karcher D, Rädecker N, Hohn S, Carvalho S, Thomson T, Saalmann F, Voolstra CR, Kurten B, Struck U, Jones B, Wild C (2020) High rates of carbon and dinitrogen fixation suggest a critical role of benthic pioneer communities in energy and nutrient dynamics of coral reefs. Functional Ecology 34(9), DOI: 10.1111/1365-2435.13625
35) El-Khaled YC, Roth F, Tilstra A, Rädecker N, Karcher DB, Kürten B, Jones BH, Voolstra CR, Wild C (2020) In situ eutrophication stimulates dinitrogen fixation, denitrification, and productivity in Red Sea coral reefs. Marine Ecology Progress Series645:55-66, DOI: 10.3354/meps13352
34) Vollstedt SM, Xiang N, Simancas S, Wild C (in press) Organic eutrophication increases resistance of the pulsating soft coral Xenia umbellata to warming. PeerJ8:e9182, DOI: 10.7717/peerj.9182
33) Olischläger M, Wild C (2020) How does the sexual reproduction of marine life respond to ocean acidification? Diversity12(6), 241, DOI:10.3390/d12060241
32) El-Khaled YC, Roth F, Rädecker N, Kharbatia N, Jones BH, Voolstra CR, Wild C (2020) Simultaneous measurements of dinitrogen fixation and denitrification associated with coral reef substrates: advantages and limitations of a combined acetylene assay. Frontiers in Marine Science7:411, DOI: 10.3389/fmars.2020.00411
31) Contreras-Silva A, Tilstra A, Migani V, Thiel A, Pérez-Cervantes E, Estrada-Saldivar N, Elias X, Mott C, Alvarez-Filip L, Wild C (2020) A meta-analysis to assess long-term spatiotemporal changes of benthic coral and macroalgae cover in the Mexican Caribbean. Scientific Reports10:8897, DOI: 10.1038/s41598-020-65801-8
30) Wild C (2020) Ecosystem engineering by different seagrasses in the Caribbean. Marine Biology167:80, DOI: 10.1007/s00227-020-03690-1
29) Karcher DB, Roth F, Carvalho S, El-Khaled YC, Tilstra A, Kürten B, Struck U, Jones BH, Wild C (2020) Nitrogen eutrophication particularly promotes turf algae in coral reefs of the central Red Sea. PeerJ8:e8737, DOI: 10.7717/peerj.8737
28) Tilstra A, El-Khaled YC, Roth F, Rädecker N, Pogoreutz C, Voolstra CR, Wild C (2019) Denitrification aligns with N2 fixation in Red Sea corals. Scientific Reports9, Article number: 19460, DOI: 10.1038/s41598-019-55408-z
27) Tilstra A, PogoreutzC, RädeckerN, ZieglerM, WildC, VoolstraCR (2019) Relative diazotroph abundance in symbiotic Red Sea corals decreases with water depth. Frontiers inMarine Science6:372, DOI: 10.3389/fmars.2019.00372
26) Eich A, Ford AK, Nugues MM, McAndrews RS, Wild C, Ferse SCA (2019) Positive association between epiphytes and competitiveness of the brown algal genus Lobophora against corals. PeerJ 7: e6380, DOI: 10.7717/peerj.6380
25) Roth F, Wild C, Carvalho S, Rädecker N, Voolstra CR, Kürten B, Anlauf H, El-Khaled Y, Carolan R, Jones BH (2019) An in situ approach for measuring biogeochemical fluxes in structurally complex benthic communities. Methods in Ecology and Evolution 10(5), DOI: 10.1111/2041-210x.13151
24) Roth F, Saalmann F, Thomson T, Coker D, Villalobos R, Jones BH, Wild C, Carvalho S (2018) Coral reef degradation affects the potential for reef recovery after disturbance. Marine Environmental Research,Volume 142, DOI: j.marenvres.2018.09.022
23) Wizemann A, Nandini SD, Stuhldreier I, Sánchez-Noguera C, Wisshak M, Westphal H, Rixen T, Wild C, Reymond C (2018) Rapid bioerosion in a tropical upwelling coral reef. PloS One13(9):e0202887, DOI: 10.1371/journal.pone.0202887
22) Tilstra A, van Hoytema N, Cardini U, Bednarz VN, Rix L, Naumann MS, Al-Horani FA, Wild C (2018) Effects of water column mixing and stratification on planktonic primary production and dinitrogen fixation on a northern Red Sea coral reef. Frontiers in Microbiology9:2351,DOI: 10.3389/fmicb.2018.02351
21) Bednarz VN, Naumann MS, Cardini U, Van Hoytema N, Rix L, Rshaidat M, Wild C (2018) Contrasting seasonal responses in dinitrogen fixation between shallow and deep-water colonies of the model coral Stylophora pistillata in the northern Red Sea. PloS One13(6): e0199022, DOI: 10.1371/journal.pone.0199022
20) Lee S, Ford AK, Mangubhai S, Wild C, Ferse SCA (2018) Effects of sandfish (Holothuria scabra) removal on shallow-water sediments in Fiji. Peer J6:e4773, DOI 10.7717/peerj.4773
19) Sánchez-NogueraC, StuhldreierI, CortésJ, JiménezC, MoralesA, WildC, RixenT (2018) Natural ocean acidification at Papagayo upwelling system (North Pacific Costa Rica): implications for reef development. Biogeosciences15, 2349–2360, DOI: 10.5194/bg-15-2349-2018
18) Rix L, de Goeij JM, van Oevelen D, Struck U, Al-Horani FA, Wild C, Naumann MS (2018) Reef sponges facilitate the transfer of coral-derived organic matter to their associated fauna via the sponge loop. Marine Ecology Progress Series589:85-96, DOI: 10.3354/meps12443
17) Pogoreutz C, Rädecker N, Cárdenas A, Gärdes A, Wild C, Voolstra CR (2018) Dominance of Endozoicomonas bacteria throughout coral bleaching and mortality suggests structural inflexibility of the Pocillopora verrucosa microbiome. Ecology and Evolution 1–13, DOI: 10.1002/ece3.3830
16) Plass-Johnson JG, Ferse SC, Bednarz VN, Gärdes A, Heiden J, Lukman M, Miñarro S, Schwieder H, Weiand L, Wild C, Reuter H, Teichberg M (2018) Spatio-temporal patterns in the coral reef communities of the Spermonde Archipelago, 2012-2014, II: Fish assemblages display structured variation related to benthic condition. Frontiers in Marine Science 5:36,DOI: 10.3389/fmars.2018.00036
15) Teichberg M, Wild C, Bednarz VN, Kegler HF, Lukman M, et al. (2018) Spatio-temporal patterns in coral reef communities of the Spermonde Archipelago, 2012-2014, I: Comprehensive reef monitoring reveals two indices that reflect changes in reef health. Frontiers in Marine Science 5:33, DOI: 10.3389/fmars.2018.00033
14) Roth F, Stuhldreier I, Sanchez Noguera C, Carvalho S, Wild C (2017) Simulated overfishing and natural eutrophication promote the relative success of a non-indigenous ascidian in coral reefs at the Pacific coast of Costa Rica. Aquatic Invasions, DOI: 10.3391/ai.2017.12.4.02
13) Ford AK, Eich A, McAndrews R, Mangubhai S, Nugues M, Bejarano S, Wild C, Moore BR, Rico C, Ferse SAC (2017) Evaluation of coral reef management effectiveness using conventional versus resilience-based metrics. Ecological Indicators, DOI: 10.1016/j.ecolind.2017.10.002
12) Peiffer F, Bejarano S, de Witte GP, Wild C (2017) Ongoing removals of invasive lionfish in Honduras and their effect on native Caribbean prey fishes.PeerJ 5:e3818, DOI: 10.7717/peerj.3818
11) Tilstra A, Wijgerde T, Dini-Andreote F, Eriksson BK, Salles JF, Pen I, Osinga R, Wild C (2017) Light induced intraspecific variability in response to thermal stress in the hard coral Stylophora pistillata. PeerJ5:e3802, DOI: 10.7717/peerj.3802
10) Cárdenas A, Neave MJ, Haroon MF, Pogoreutz C, Rädecker N, Wild C, Gärdes A, Voolstra CR (2017) Excess labile carbon promotes the expression of virulence factors in coral reef bacterioplankton. The ISME Journal 12, pages59–76(2018), DOI: 10.1038/ismej.2017.142
9) Rädecker N, Pogoreutz C, Wild C, Voolstra CR (2017) Stimulated Respiration and Net Photosynthesis in Cassiopeia sp. during Glucose Enrichment Suggests in hospite CO2 Limitation of Algal Endosymbionts. Frontiers in Marine Science4:267, DOI: 10.3389/fmars.2017.00267
8) Tilstra A, Bednarz VN, Cardini U, van Hoytema N, Al-Rshaidat MM, Wild C (2017) Seasonality affects dinitrogen fixation associated with two common macroalgae from a coral reef in the northern Red Sea. Marine Ecology Progress Series575:69-80, DOI: 10.3354/meps12206
7) Pogoreutz C, Rädecker N, Cárdenas A, Gärdes A, Wild C, Voolstra CR (2017) Nitrogen fixation aligns with nifH abundance and expression in two coral trophic functional groups. Frontiers in Microbiology8:1187, DOI: 10.3389/fmicb.2017.01187
6) Pogoreutz C, Rädecker N, Cárdenas A, Gärdes A, Voolstra CR, Wild C (2017) Sugar enrichment provides evidence for a role of nitrogen fixation in coral bleaching. Global Change Biology 23:3838–3848, DOI: 10.1111/gcb.13695
5) Puk LD, Ferse SC, Wild C (2017) Erratum to: Patterns and trends in coral reef macroalgae browsing: a review of browsing herbivorous fishes of the Indo-Pacific. Reviews inFish Biology and Fisheries27(1):287-92, DOI: 10.1007/s11160-016-9439-9
4) Rix L, Goeij JM, Oevelen D, Struck U, Al‐Horani FA, Wild C, Naumann MS (2017) Differential recycling of coral and algal dissolved organic matter via the sponge loop. Functional Ecology31(3):778-89, DOI: 10.1111/1365-2435.12758
3) Ford AK, Van Hoytema NA, Moore BR, Pandihau L, Wild C, Ferse SC (2017) High sedimentary oxygen consumption indicates that sewage input from small islands drives benthic community shifts on overfished reefs. Environmental Conservation44(4): 405-411, DOI: 10.1017/S0376892917000054
2) Lee S, Ferse SCA, Ford A, Wild C, Mangubhai S (2017) Effect of sea cucumber density on the health of reef-flat sediments Fiji's Sea Cucumber Fishery: Advances in Science for Improved Management. Wildlife Conservation Society. Report No. 01/17
1) Kegler HF, Lukman M, Teichberg M, Plass-Johnson J, Hassenrück C, Wild C, Gärdes, A (2017) Bacterial Community Composition and Potential Driving Factors in Different Reef Habitats of the Spermonde Archipelago, Indonesia. Frontiers in Microbiology 8:662, DOI: 10.3389/fmicb.2017.00662
17.1: Ecosystem and Eutrophication Lab - Biology
Welcome to the Aquatic Ecology Laboratory at Washington State University! The Lab is co-directed by Dr. Stephen M. Bollens and Dr. Gretchen Rollwagen-Bollens with an active and diverse research team consisting of graduate students, undergraduate researchers, research technicians and high school science teachers conducting summer research. We are based on the WSU Vancouver campus, located in the Portland Metropolitan Area.
Our research is broadly concerned with the ecology of marine, estuarine and freshwater phytoplankton, zooplankton and fish, and spans the sub-disciplines of behavior, population biology, community ecology and ecosystem dynamics. Our research often has an applied aspect to it, touching upon such areas as conservation biology, restoration ecology, fisheries oceanography, and global change. We employ a wide variety of approaches to “doing science,” including field (observational), modeling and experimental techniques.
Our group is highly collaborative and Dr. Bollens and Dr. Rollwagen-Bollens often co-advise their graduate students. However, each Co-Director is the lead for one or more of the Lab’s current research themes.
Dynamics of Harmful Algal Blooms (Gretchen Rollwagen-Bollens, Lead) We are interested in the biotic and abiotic factors that influence the development, timing, magnitude, and taxonomic composition of harmful algal blooms in freshwater, estuarine and coastal ecosystems. Our recent focus has been on freshwater cyanobacteria blooms in the Columbia River Basin, across a eutrophication gradient. In particular, we have studied the dynamics of cyanobacteria blooms in Vancouver Lake, a large, shallow eutrophic lake that is a highly valued recreational resource in Clark County, WA.
Ecology, Behavior and Impact of Aquatic Invasive Species (Stephen Bollens, Lead) Our research in this area ranges from observational studies of invasive species abundance, distribution and composition in critical freshwater and estuarine habitats of the Pacific Northwest, to experimental programs to investigate the ecological interactions among native and invasive taxa, with particular focus on the impacts of invasive species on at-risk and economically valuable fish and invertebrate species (i.e. salmon and shellfish).
Locations of other recent projects include San Francisco Bay and the coastal ocean off California, Georges Bank/Northwest Atlantic, the Arabian Sea, the equatorial Pacific, the Florida Keys, and the Bering Sea. Our projects have been funded by a wide range of federal and state agencies, including the National Science Foundation (NSF), the Environmental Protection Agency (EPA), the Office of Naval Research (ONR), the National Oceanic and Atmospheric Administration (NOAA), the United States Geological Survey (USGS), and the CALFED Bay/Delta Program. For more detailed information on our current and recent research projects, please visit our Research and Publications pages.
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