Analysis Of Wood Waste At Attwood Bay Environmental Sciences Essay

After reexamining the ROV and SCUBA transect informations, it is clear that there have been important impacts to the Marine environment caused by the lacrimation of wood at Attwood Bay. This was evidenced by the comparative volumes and distributions of wood waste nowadays on the ocean floor during the 2006 and 2009 site studies.

Datas collected from the 2006 ROV and 2009 SCUBA site studies indicated that the sum of wood waste accumulated at this site has increased since the initial site visit. A greater proportion of the substrate was seeable during the 2006 study as compared to the 2009 picture footage where much of the substrate was wholly covered with wood waste and accordingly its composing could non be determined. This site exhibited low species diverseness and copiousness, in 2006 and 2009 as compared with unimpacted sites. It is good documented that accretions of bark and other woody dust on the ocean floor negatively impacts benthal infaunal and epifaunal diverseness and copiousness ( Kirkpatrick et.al 1998, Pease, 1974, Conlan, K.E. and Ellis, D.V. , 1979. and Jackson, R.G. 1986 ) . Wood waste negatively impacts benthal communities as it is known to leach potentially toxic organic compounds into the H2O, has a high biological O demand and can surround benthal ( peculiarly infaunal ) communities ( Pease, 1974 ) . The exact nature and impacts of wood waste leachates is non to the full understood, nevertheless these lignin-based substances are known to precipitate out in sea H2O, and believed to settle on and negatively impact benthal home grounds ( Duval, 1980 ) . Areas of bark accretion have been found to hold a higher biological O demand than environing deposits whereby take downing the dissolved O content of the superimposed H2O ( Pease, 1974 and Picard, 2002 ) . Many benthal invertebrates ( peculiarly infaunal ) are unable to last in anoxic conditions and therefore are good indexs of alterations in benthal home ground conditions ( Pease, 1974 and Samis et.al. , 1999 ) .

Additionally, wood waste that accumulates on the ocean floor clutters benthic infaunal marine life ( peculiarly pelecypods ) whereby cut downing the populations of quarry species available to larger benthal marauders such as pediculosis pubiss etc. ( Picard, 2003 ) . The deficiency of pelecypods and other seeable infaunal beings ( with the exclusion of tube-dwelling windflowers ) at this site is to be expected given the sum of wood waste screen. A uninterrupted bed of wood waste hinders the colony and enlisting of many benthal beings and can cut down critical shoal nearshore habitat utilised for rise uping juveniles. ( Samis et.al,1999 ) . Many of the species observed in the study pictures were known to be more resilient to wood dust, viz. sea Cucumis sativuss ( Parastichopus californicus ) , assorted sea stars ( viz. Pycnopodia helianthoides ) , brickle stars ( Ophiuoroidea ) and assorted fish species ( Kirkpatrick et.al. 1998 ) . These species are motile and are hence less easy smothered by wood waste accretions and are by and large suspension feeders ( brickle stars ) or detritivores and hence do non trust on a healthy infaunal community for nutrient. It is believed that sea cucumbers ( Parastichopus californicus ) provender on the abundant bug populations populating the bed of wood waste, and Sun stars are general marauders known to feed on sea Cucumis sativuss ( University of Michigan Museum of Biology, 2009 ) . As good, the high frequence of ascertained elephantine swimming sea slug ( Dendronotus flag ) was sensible given that they feed on the tentacles of the tubing brooding windflower ( Pachycerianthus fimbriatus ) and layer their eggs on the tubing. Overall the species copiousness and diverseness at this site was significantly less than comparable home grounds non impacted by logging activities. Reduced available O, coupled with potentially toxic leachates and the surrounding consequence of thick dust screen explains why a decrease in species diverseness and population complexness is observed in countries where water-based logging has occurred, including the Attwood Bay log shit site.

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Past site appraisals conducted for BCTS have shown that deep-water home grounds are by and large the most to a great extent impacted by accretions of bark and other woody dust. Attwood is no exclusion, despite the fact that the shit is comparatively shallow, the impacts of wood waste have still been found to increase with depth ( Figure 5 ) . Severe impacts were found throughout the site get downing between -4 to -6m deepness and go oning beyond the furthest extent of the SCUBA transects. Datas collected from the ROV study showed these impacts widening to ( and probably beyond ) -50m deepness. Based on these observations, and observations at similar log shit sites where impacts to habitat addition with deepness, it is expected that terrible impacts at this site besides continue into deeper H2O. Although unimpacted deep-water home grounds frequently exhibit lower species diverseness and copiousnesss than shallow-water home grounds due to cut down light incursion and primary productiveness ; the species copiousness in deeper countries at this site is still less than one would anticipate to happen in countries which have non been impacted by wood lacrimation activities. Wood waste is transported in the Marine environment by moving ridges, air current and currents and frequently deposited in deep H2O countries ( Kirkpatrick et.al. 1998 ) . Conveyance of woody dust to deeper countries expands the impact country from shallower to deeper H2O. This site is non known to see important current flow and hence reduced current and tidal flushing in deeper countries has resulted in the accretion of beds of wood waste making a smothering cover over the sea floor. The slow dislocation of this deposited wood waste is besides expected to hold increased anoxic conditions for benthal beings, cut downing species diverseness and copiousness. Picard et Al. identified that impacts of wood waste can last many decennaries and even centuries ( 2003 ) . The possible exists for the deep H2O home ground impacts observed in Attwood Bay to be long permanent as these terrible impacts were observed even in 2006 after 7 old ages of inaction at the site ( Price, 2007 ) .

Pulling decisions on whether or non a site is showing marks of recovery is a cardinal outlook of the appraisal procedure. While this piece of information is built-in towards decision-making, & A ; acirc ; ˆ?recovery & A ; acirc ; ˆ™ has yet to be defined due to the limited sum of scientific information available. At present, the criterion technique for log shit appraisals incorporates merely the aggregation of macro-epifaunal information ( i.e. SCUBA and ROV picture footage and still snap ) . While this information has the ability to talk to the more obvious alterations in home ground and recovery, in the absence of more infaunal sampling ( i.e. testing sediment nucleuss for the presence of juvenile pelecypods, polychetes, and other index species ) , decisions drawn on the true province of recovery are limited. Get downing to concentrate more attempt on measuring the infaunal community at a historical log shit site may work to better our apprehension of recovery and finally consequence in better direction procedures.

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