Effects of an oil spill on the soft-bottom macrofauna of Arthur Harbour, Antarctica compared with long-term natural change

Hyland, Jeffrey L.; Laur, David R.; Jones, Jeffrey; Shrake, Jay; Cadian, Donald; Harris, Leslie H.

doi:10.1017/s0954102094000052

“…The reduced sedimentation allows greater light penetration and causes minimal smothering, so that the seabed supports a diverse community of plants and animals, including suspension feeders and predators. There is some evidence that this model is applicable to benthic communities adjacent to Antarctic glaciers (Hyland et al 1994), but there are currently very few field observations relating to sedimentation effects and no field manipulations of sedimentation rates.…”

Section: Sedimentationmentioning

confidence: 99%

Likely responses of the Antarctic benthos to climate‐related changes in physical disturbance during the 21st century, based primarily on evidence from the West Antarctic Peninsula region

Smale¹,

Barnes²

2008

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Disturbance has always shaped the evolution and ecology of organisms and nowhere is this more apparent that on the iceberg gouged continental shelves of the Antarctic Peninsula (AP). The vast majority of currently described polar biodiversity occurs on the Southern Ocean shelf but current and projected climate change is rapidly altering disturbance intensities in some regions. The AP is now amongst the fastest warming and changing regions on earth. Seasonal sea ice has decreased in time and extent, most glaciers in the region have retreated, a number of ice shelves have collapsed, and the surface waters of the seas west of the AP have warmed. Here, we review the influences of disturbance from ice, sedimentation, freshening events, wave action and humans on shallow water benthic assemblages, and suggest how disturbance pressures will change during the 21st century in the West Antarctic Peninsula (WAP) and Scotia Arc region. We suggest that the intensity of ice scouring will increase in the region over the next few decades as a result of decreased winter sea ice periods and increased ice loading into coastal waters. Thus, the most frequently disturbed environment on earth will become more so, which will lead to considerable changes in community structure and species distributions. However, as ice fronts retreat past their respective grounding lines, sedimentation and freshening events will become relatively more important. Human presence in the region is increasing, through research, tourism, and resource exploitation, which represents a considerable threat to polar biodiversity over the next century. Adapting to or tolerating multiple, changing environmental stressors will be difficult for a fauna with typically slow generation turnovers that has evolved largely in isolation. We suggest that intensifying acute and chronic disturbances are likely to cause significant changes in ecosystem structure, and probably a considerable loss of polar marine biodiversity, over relatively short timescales.

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“…Changes in benthic community structure are likely to vary considerably from place to place, as they do now, but for those sites subjected to increased disturbance of any form some generalisations can be made. Perhaps crucially, from the limited number of reports available, it seems that the same suite of species (this is particularly true for polychaetes) are associated with early stages of postdisturbance recovery, regardless whether the initial disturbance was from ice scouring (Gerdes et al 2003, Smale et al 2007a, anchor ice (Lenihan and Oliver 1995), sedimentation (Hyland et al 1994) or pollution (Lenihan andOliver 1995, Conlan et al 2004). Thus, these same circum-Antarctic pioneers are likely to become dominant at sites where disturbance pressures intensify.…”

Section: Discussionmentioning

confidence: 99%

“…Even so, some predictions concerning the response of benthos to changing sedimentation rates and disturbance frequencies at retreating glacier termini can be tentatively made. Assemblages proximal to retreating ice fronts are very likely to be species poor and characterised by short-lived mobile taxa as a result of high sediment deposition, freshwater inflow and ice disturbance intensity (Syvitski et al 1989, Hyland et al 1994. As glaciers retreat, sediment deposition within a few kilometres of the ice front remains high, and the benthos is held at a relatively early successional stage.…”

Section: Future Scenarios and Likely Benthic Responsementioning

confidence: 99%

Likely responses of the Antarctic benthos to climate-related changes in physical disturbance during the 21st century, based primarily on evidence from the West Antarctic Peninsula region

Smale¹,

Barnes²

2008

View full text Add to dashboard Cite

Disturbance has always shaped the evolution and ecology of organisms and nowhere is this more apparent that on the iceberg gouged continental shelves of the Antarctic Peninsula (AP). The vast majority of currently described polar biodiversity occurs on the Southern Ocean shelf but current and projected climate change is rapidly altering disturbance intensities in some regions. The AP is now amongst the fastest warming and changing regions on earth. Seasonal sea ice has decreased in time and extent, most glaciers in the region have retreated, a number of ice shelves have collapsed, and the surface waters of the seas west of the AP have warmed. Here, we review the influences of disturbance from ice, sedimentation, freshening events, wave action and humans on shallow water benthic assemblages, and suggest how disturbance pressures will change during the 21st century in the West Antarctic Peninsula (WAP) and Scotia Arc region. We suggest that the intensity of ice scouring will increase in the region over the next few decades as a result of decreased winter sea ice periods and increased ice loading into coastal waters. Thus, the most frequently disturbed environment on earth will become more so, which will lead to considerable changes in community structure and species distributions. However, as ice fronts retreat past their respective grounding lines, sedimentation and freshening events will become relatively more important. Human presence in the region is increasing, through research, tourism, and resource exploitation, which represents a considerable threat to polar biodiversity over the next century. Adapting to or tolerating multiple, changing environmental stressors will be difficult for a fauna with typically slow generation turnovers that has evolved largely in isolation. We suggest that intensifying acute and chronic disturbances are likely to cause significant changes in ecosystem structure, and probably a considerable loss of polar marine biodiversity, over relatively short timescales.

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“…There was a larger proportion of animals in the top 5 cm of sediment vs. deeper (5-10 cm) at stations further from the wellhead, and communities were significantly different among impact areas in the surface sediments but not the deeper sediments. Dorvilleidae, a polychaete family often associated with hydrocarbons (Hyland et al, 1994;Washburn et al, 2016), was responsible for the largest amount of dissimilarity between stations close to the wellhead and further away. Several other taxa were classified as sensitive or tolerant to the deepsea blowout by comparing their distributions among impact and nonimpact zones.…”

Section: Soft-bottom Community Responsementioning

confidence: 99%