Impacts of bottom fishing on the sediment infaunal community and biogeochemistry of cohesive and non-cohesive sediments Trawling impacts on ecosystem processes
Impacts of bottom fishing on the sediment infaunal community and biogeochemistry of cohesive and non-cohesive sediments Trawling impacts on ecosystem processes
复制标题
底层捕捞对沉积物动物群落以及粘性和非粘性沉积物生物地球化学的影响拖网捕捞对生态系统过程的影响
DOI：
10.1002/lno.10354
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发表时间：
2016
影响因子：
4.5
通讯作者：
Sciberras M
中科院分区：
文献类型：
--
作者：
Sciberras M
底拖网捕捞活动十分广泛，对海底生态系统有很大影响。通过测量底栖动物群落的变化和它们介导的生物地球化学过程，我们调查了扇贝疏浚对沙子和水獭拖网对泥浆的影响。我们假设，由于捕鱼的生物地球化学的变化将是较大的泥大型底栖动物介导的过程预计将发挥更大的作用，比在沙子中的流体动力学介导的氧化还原系统。我们采样底栖动物，沉积物孔隙水营养盐，氧气，叶绿素a（Chl a），表观氧化还原电位不连续层，有机碳和氮含量在砂和泥的捕捞强度梯度。捕鱼对海洋地球化学的影响在泥上比在沙上更强，其中海洋地球化学似乎更强烈地受到潮流和波浪的影响。在泥，拖网增加沉积物表面叶绿素a和铵浓度超过5厘米的深度，但降低铵和硅酸盐浓度在上层沉积物。动物和生物扰动潜力对土壤地球化学的影响在泥和沙生境中都非常有限。我们的研究结果表明，水獭拖网捕捞可能会通过沉积物再悬浮和有机物埋藏到深处来影响有机物的再矿化和营养循环，而不是通过海底群落生物扰动潜力的损失。总之，我们的假设，拖网对海洋地球化学的影响较大的泥支持，但这些影响是介导的底栖动物的变化的假设不支持。这些结果意味着，对泥质沉积物上拖网捕捞的管理应得到更优先的重视。使用底拖渔具捕鱼是对海洋底栖生态系统造成物理干扰的主要来源。几十年来，大多数大陆架和深海的大部分区域一直被底层捕捞密集开发（Halpern等人，2008年; Puig等人，2012年）。随着渔网、桁、拖网门、链和挖泥船在海床上通过，沉积物表面受到扰动，20-50%的常驻生物群（如双壳类、穴居甲壳类、造管多毛类和棘皮动物）被破坏或移走（Jennings和Kaiser，1998年; Kaiser等人，2006年）。以往的研究表明，底鱼捕捞导致底栖次级生产减少，并改变了
Bottom-trawl fisheries are wide-spread and have large effects on benthic ecosystems. We investigate the effect of scallop dredging on sand and otter trawling on mud by measuring changes in the infaunal community and the biogeochemical processes which they mediate. We hypothesize that changes in biogeochemistry due to fishing will be larger in mud where macrofauna-mediated processes are expected to play a greater role, than in sand where hydrodynamics mediate the redox system. We sampled benthic infauna, sediment porewater nutrients, oxygen, chlorophyll a (Chl a), apparent redox potential discontinuity layer, organic carbon and nitrogen content over a gradient of fishing intensity in sand and mud. The effects of fishing on biogeochemistry were stronger on mud than on sand, where biogeochemistry appeared to be more strongly influenced by tidal currents and waves. On mud, trawling increased sediment-surface Chl a and ammonium concentration beyond 5 cm depth, but decreased ammonium and silicate concentration in the upper sediment layers. The effects of fauna and bioturbation potential on biogeochemistry were very limited in both mud and sand habitats. Our results suggests that otter trawling may be affecting organic-matter remineralization and nutrient cycling through sediment resuspension and burial of organic matter to depth rather than through the loss of bioturbation potential of the benthic community. In conclusion, our hypothesis that the effects of trawling on biogeochemistry are larger in mud is supported, but the hypothesis that these effects are mediated by changes in the infauna is not supported. These results imply that management of trawling on muddy sediments should have higher priority.Fishing with bottom towed fishing gear is a major source of physical disturbance for marine benthic ecosystems. Large parts of most shelf and deep seas have been intensively exploited by bottom fishing for decades (Halpern et al. 2008; Puig et al. 2012). As nets, beams, trawl doors, chains and dredges pass over the seabed, the sediment surface is disturbed and 20–50% of the resident biota (eg, bivalves, burrowing crustaceans, tube-building polychaetes, and echinoderms) is damaged or removed (Jennings and Kaiser 1998; Kaiser et al. 2006). Previous studies have shown that bottom fishing results in a decrease in benthic secondary production, as well as changes in the community structure and size composition of