Special Issue "The Effects of Hypoxia on Marine Food Webs and Ecosystems"

A special issue of Diversity (ISSN 1424-2818). This special issue belongs to the section "Marine Diversity".

Deadline for manuscript submissions: closed (30 November 2019).

Special Issue Editor

Dr. Julie Keister
Website
Guest Editor
School of Oceanography, University of Washington, Seattle, USA
Interests: biological oceanography, mesozooplankton, community ecology, climate change, food webs, copepods, euphausiids, bio-physical coupling, biogeography

Special Issue Information

Dear Colleagues,

Hypoxia (low dissolved oxygen) is a growing concern for marine ecosystems as the global climate warms and coastal waters are increasingly influenced by anthropogenic eutrophication. In many regions, the spatial and temporal extent as well as the intensity of hypoxia is expanding. The effects of hypoxia on marine ecosystems are expressed through direct effects on the growth and survival of populations and indirect effects on communities and food webs, nutrients, carbon cycling, and energy flow. In regions of moderate or ephemeral hypoxia, subtle shifts in species habitat use and distributions can alter predator–prey overlap and encounter rates. Under intense or chronic oxygen depletion, trophic interactions, species composition, and diversity can be dramatically affected through species-specific differences in hypoxia tolerance. Differential changes in movement and escape behaviors, hypoxia avoidance, or the use of hypoxic refuges can lead to large changes in predator–prey interactions. Short- or long-term physiological adaptations of individuals to hypoxia can alter biomass and energy flow on the community scale. These changes can have dramatic ecosystem consequences with ramifications for fisheries and the societies that depend on them. ­­

This Special Issue is designed to bring together new information, syntheses, and reviews of the impacts of hypoxia on the world’s estuaries, oceans, and societies through its effects on marine organisms, communities, and food webs—information that is critically needed to better manage and preserve our future marine resources.

Dr. Julie Keister
Guest Editor

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • De-oxygenation
  • Anthropogenic eutrophication
  • Climate change
  • Disturbance
  • Habitat loss
  • Trophic structure
  • Predator–prey interactions
  • Physiological effects.

Published Papers (7 papers)

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Research

Open AccessArticle
Effects of Short-Duration and Diel-Cycling Hypoxia on Predation of Mussels and Oysters in Two Tributaries of the Chesapeake Bay
Diversity 2020, 12(3), 87; https://doi.org/10.3390/d12030087 - 26 Feb 2020
Abstract
Although the effects of persistent hypoxia have been well established, few studies have explored the community-level effects of short-duration and diel-cycling hypoxia, for example on predator–prey interactions. Consumer stress models predict that mobile predators will flee hypoxia, while prey stress models predict that [...] Read more.
Although the effects of persistent hypoxia have been well established, few studies have explored the community-level effects of short-duration and diel-cycling hypoxia, for example on predator–prey interactions. Consumer stress models predict that mobile predators will flee hypoxia, while prey stress models predict that sessile species, unable to avoid hypoxic water, will be more susceptible to predation. To test these hypotheses, we studied the effects of diel-cycling hypoxia on predation of the hooked mussel, Ischadium recurvum, and eastern oyster, Crassostrea virginica, in field experiments in two Chesapeake Bay, USA tributaries. We conducted a complementary laboratory experiment that tested the impact of short-duration hypoxia on predation of the two bivalve species by the ecologically and commercially important blue crab, Callinectes sapidus. Although we did not observe a significant effect of diel-cycling hypoxia on predation in the field, we did observe an effect of short-duration hypoxia in the laboratory. Callinectes sapidus exhibited depressed feeding rates and reduced preference for I. recurvum in hypoxic conditions. In both field and lab results, we observed a strong preference of predators for I. recurvum over C. virginica, indicating that the relatively understudied mussel I. recurvum merits greater consideration as a part of estuarine food webs. Full article
(This article belongs to the Special Issue The Effects of Hypoxia on Marine Food Webs and Ecosystems)
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Open AccessArticle
Respiration by the Opportunistic Spionid Polychaete Streblospio gynobranchiata during Adjustment to and Recovery from Moderate Hypoxia
Diversity 2020, 12(2), 73; https://doi.org/10.3390/d12020073 - 12 Feb 2020
Abstract
Understanding the capacity of estuarine organisms to acclimate to stressful conditions provides insights into how communities cope within fluctuating environments. The opportunistic spionid polychaete, Streblospio gynobranchiata Rice and Levin, 1998, regularly experiences intermittent moderate hypoxia within shallow sedimentary habitats. To better understand fine-scale [...] Read more.
Understanding the capacity of estuarine organisms to acclimate to stressful conditions provides insights into how communities cope within fluctuating environments. The opportunistic spionid polychaete, Streblospio gynobranchiata Rice and Levin, 1998, regularly experiences intermittent moderate hypoxia within shallow sedimentary habitats. To better understand fine-scale adjustments by this opportunistic species to short-term moderate hypoxia, the aerobic respiration response of three size classes was examined over a 12 h period and after 24 h of exposure to moderate hypoxia (i.e., 20% air saturation) at 25 °C. In addition, the capacity to resume standard respiration was examined over a 12 h period following a 24 h period of exposure to moderate hypoxia. Mass-specific respiration varied with body size during both exposure and recovery from hypoxia. Small worms switched from an oxyregulating to an oxyconforming strategy within 6 h of exposure to moderate hypoxia at 25 °C. After 24 h of hypoxia exposure, small worms hypo-regulated at 81% of the preceding 24 h normoxic reference level. By contrast, medium and large worms hyper-regulated during the first 12 h exposure period, but hypo-regulated at 70% and 79% of the preceding 24 h normoxic reference levels after 24 h of hypoxia exposure. Fluctuations in respiration levels during the recovery period revealed a temporal recovery pattern implying cycling energetic processes. The recovery pattern also indicated some respiration overshoot to compensate for oxygen debt. The timing of the cycling recovery pattern also differed with body size. The ability of S. gynobranchiata to dynamically adjust its metabolic response to low oxygen stress underscores the ecologically important role of tolerant organisms within estuarine benthic habitats subject to recurrent diel or intermittent hypoxia. Full article
(This article belongs to the Special Issue The Effects of Hypoxia on Marine Food Webs and Ecosystems)
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Open AccessArticle
Species Composition and Distribution of Jellyfish in a Seasonally Hypoxic Estuary, Hood Canal, Washington
Diversity 2020, 12(2), 53; https://doi.org/10.3390/d12020053 - 29 Jan 2020
Abstract
Seasonal hypoxia (≤2 mg dissolved oxygen L−1) can have detrimental effects on marine food webs. Recent studies indicate that some jellyfish can tolerate low oxygen and may have a competitive advantage over other zooplankton and fishes in those environments. We assessed [...] Read more.
Seasonal hypoxia (≤2 mg dissolved oxygen L−1) can have detrimental effects on marine food webs. Recent studies indicate that some jellyfish can tolerate low oxygen and may have a competitive advantage over other zooplankton and fishes in those environments. We assessed community structure and distributions of cnidarian and ctenophore jellyfish in seasonally hypoxic Hood Canal, WA, USA, at four stations that differed in oxygen conditions. Jellyfish were collected in June through October 2012 and 2013 using full-water-column and discrete-depth net tows, concurrent with CTD casts to measure dissolved oxygen (DO). Overall, southern, more hypoxic, regions of Hood Canal had higher abundances and higher diversity than the northern regions, particularly during the warmer and more hypoxic year of 2013. Of fifteen species identified, the most abundant—the siphonophore Muggiaea atlantica and hydrozoan Aglantha digitale—reached peak densities > 1800 Ind m−3 and 38 Ind m−3, respectively. M. atlantica were much more abundant at the hypoxic stations, whereas A. digitale were also common in the north. Vertical distributions explored during hypoxia showed that jellyfish were mostly in the upper 10 m regardless of the oxycline depth. Moderate hypoxia seemed to have no detrimental effect on jellyfish in Hood Canal, and may have resulted in high population densities, which could influence essential fisheries and trophic energy flow. Full article
(This article belongs to the Special Issue The Effects of Hypoxia on Marine Food Webs and Ecosystems)
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Open AccessArticle
Historical Shifts in Benthic Infaunal Diversity in the Northern Gulf of Mexico since the Appearance of Seasonally Severe Hypoxia
Diversity 2020, 12(2), 49; https://doi.org/10.3390/d12020049 - 28 Jan 2020
Abstract
Severe and persistent bottom-water hypoxia (≤2 mg O2 L−1) occurs on the Louisiana/Texas continental shelf from mid-May through mid-September over a large area (up to 23,000 km2 in mid-summer). Benthic infauna are less mobile than demersal organisms and become [...] Read more.
Severe and persistent bottom-water hypoxia (≤2 mg O2 L−1) occurs on the Louisiana/Texas continental shelf from mid-May through mid-September over a large area (up to 23,000 km2 in mid-summer). Benthic infauna are less mobile than demersal organisms and become stressed by the low dissolved oxygen; benthic community composition, abundance, diversity, and biomass become altered. From the 1950s to the early 1970s, when sediment core indicators identified the initiation and subsequent worsening of dissolved oxygen conditions, there were no hydrographic data or benthic infaunal studies within the current area of frequent bottom-water hypoxia. This study highlights the impacts of severe hypoxia on benthic macroinfaunal communities and how they may have changed from less-hypoxic periods. Polychaetes were and are the dominant taxa in the available studies, but polychaete species richness in summer is now curtailed severely beginning with our 1985–1986 data. Species richness of polychaetes in summer hypoxia (1985–1986 and 1990–1991) was about 60% less than comparable taxa in 1972–1973. Abundance of polychaetes was much less in summer than spring, and recent infaunal biomass in summer was only 15% of what was found in spring. The result is less prey for demersal penaeid shrimp and fishes. Over the period of our comparison, infaunal feeding modes shifted from subsurface deposit feeders and surface deposit feeders to primarily surface deposit feeders (i.e., 95.5% of all polychaetes). Most were opportunistic, hypoxia tolerant, and recruited in high numbers following hypoxia abatement, some in fall and winter but most in spring. As benthic communities succumb to the stress of severe and continued seasonal low oxygen, they occupy the few upper centimeters of the sediment profile above the redox discontinuity layer with negative feedbacks to the water column by way of altered biogeochemical processes. Full article
(This article belongs to the Special Issue The Effects of Hypoxia on Marine Food Webs and Ecosystems)
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Open AccessArticle
Fewer Copepods, Fewer Anchovies, and More Jellyfish: How Does Hypoxia Impact the Chesapeake Bay Zooplankton Community?
Diversity 2020, 12(1), 35; https://doi.org/10.3390/d12010035 - 17 Jan 2020
Abstract
To understand dissolved oxygen deficiency in Chesapeake Bay and its direct impact on zooplankton and planktivorous fish communities, six research cruises were conducted at two sites in the Chesapeake Bay from spring to autumn in 2010 and 2011. Temperature, salinity, and dissolved oxygen [...] Read more.
To understand dissolved oxygen deficiency in Chesapeake Bay and its direct impact on zooplankton and planktivorous fish communities, six research cruises were conducted at two sites in the Chesapeake Bay from spring to autumn in 2010 and 2011. Temperature, salinity, and dissolved oxygen were measured from hourly conductivity, temperature, and depth (CTD) casts, and crustacean zooplankton, planktivorous fish and gelatinous zooplankton were collected with nets and trawls. CTD data were grouped into three temperature groups and two dissolved oxygen-level subgroups using principal component analysis (PCA). Species concentrations and copepod nonpredatory mortalities were compared between oxygenated conditions within each temperature group. Under hypoxic conditions, there usually were significantly fewer copepods Acartia tonsa and bay anchovies Anchoa mitchilli, but more bay nettles Chyrsaora chesapeakei and lobate ctenophores Mnemiopsis leidyi. Neutral red staining of copepod samples confirmed that copepod nonpredatory mortalities were higher under hypoxic conditions than under normoxia, indicating that the sudden decline in copepod concentration in summer was directly associated with hypoxia. Because comparisons were made within each temperature group, the effects of temperature were isolated, and hypoxia was clearly shown to have contributed to copepod decreases, planktivorous fish decreases, and gelatinous zooplankton increases. This research quantified the direct effects of hypoxia and explained the interactions between seasonality and hypoxia on the zooplankton population. Full article
(This article belongs to the Special Issue The Effects of Hypoxia on Marine Food Webs and Ecosystems)
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Open AccessArticle
Negative Effects of Diurnal Changes in Acidification and Hypoxia on Early-Life Stage Estuarine Fishes
Diversity 2020, 12(1), 25; https://doi.org/10.3390/d12010025 - 08 Jan 2020
Cited by 1
Abstract
Estuaries serve as important nursery habitats for various species of early-life stage fish, but can experience cooccurring acidification and hypoxia that can vary diurnally in intensity. This study examines the effects of acidification (pH 7.2–7.4) and hypoxia (dissolved oxygen (DO) ~ 2–4 mg [...] Read more.
Estuaries serve as important nursery habitats for various species of early-life stage fish, but can experience cooccurring acidification and hypoxia that can vary diurnally in intensity. This study examines the effects of acidification (pH 7.2–7.4) and hypoxia (dissolved oxygen (DO) ~ 2–4 mg L−1) as individual and combined stressors on four fitness metrics for three species of forage fish endemic to the U.S. East Coast: Menidia menidia, Menidia beryllina, and Cyprinodon variegatus. Additionally, the impacts of various durations of exposure to these two stressors was also assessed to explore the sensitivity threshold for larval fishes under environmentally-representative conditions. C. variegatus was resistant to chronic low pH, while M. menidia and M. beryllina experienced significantly reduced survival and hatch time, respectively. Exposure to hypoxia resulted in reduced hatch success of both Menidia species, as well as diminished survival of M. beryllina larvae. Diurnal exposure to low pH and low DO for 4 or 8 h did not alter survival of M. beryllina, although 8 or 12 h of daily exposure through the 10 days posthatch significantly depressed larval size. In contrast, M. menidia experienced significant declines in survival for all intervals of diel cycling hypoxia and acidification (4–12 h). Exposure to 12-h diurnal hypoxia generally elicited negative effects equal to, or of greater severity, than chronic exposure to low DO at the same levels despite significantly higher mean DO exposure concentrations. This evidences a substantial biological cost to adapting to changing DO levels, and implicates diurnal cycling of DO as a significant threat to fish larvae in estuaries. Larval responses to hypoxia, and to a lesser extent acidification, in this study on both continuous and diurnal timescales indicate that estuarine conditions throughout the spawning and postspawn periods could adversely affect stocks of these fish, with diverse implications for the remainder of the food web. Full article
(This article belongs to the Special Issue The Effects of Hypoxia on Marine Food Webs and Ecosystems)
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Open AccessArticle
Zooplankton Community Response to Seasonal Hypoxia: A Test of Three Hypotheses
Diversity 2020, 12(1), 21; https://doi.org/10.3390/d12010021 - 01 Jan 2020
Cited by 1
Abstract
Several hypotheses of how zooplankton communities respond to coastal hypoxia have been put forward in the literature over the past few decades. We explored three of those that are focused on how zooplankton composition or biomass is affected by seasonal hypoxia using data [...] Read more.
Several hypotheses of how zooplankton communities respond to coastal hypoxia have been put forward in the literature over the past few decades. We explored three of those that are focused on how zooplankton composition or biomass is affected by seasonal hypoxia using data collected over two summers in Hood Canal, a seasonally-hypoxic sub-basin of Puget Sound, Washington. We conducted hydrographic profiles and zooplankton net tows at four stations, from a region in the south that annually experiences moderate hypoxia to a region in the north where oxygen remains above hypoxic levels. The specific hypotheses tested were that low oxygen leads to: (1) increased dominance of gelatinous relative to crustacean zooplankton, (2) increased dominance of cyclopoid copepods relative to calanoid copepods, and (3) overall decreased zooplankton abundance and biomass at hypoxic sites compared to where oxygen levels are high. Additionally, we examined whether the temporal stability of community structure was decreased by hypoxia. We found evidence of a shift toward more gelatinous zooplankton and lower total zooplankton abundance and biomass at hypoxic sites, but no clear increase in the dominance of cyclopoid relative to calanoid copepods. We also found the lowest variance in community structure at the most hypoxic site, in contrast to our prediction. Hypoxia can fundamentally alter marine ecosystems, but the impacts differ among systems. Full article
(This article belongs to the Special Issue The Effects of Hypoxia on Marine Food Webs and Ecosystems)
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