Sea Urchin Embryogenesis as Bioindicators of Marine Pollution in Impact Areas of the Sea of Japan/East Sea and the Sea of Okhotsk

Abstract

The embryogenesis of the sea urchin sand dollar Scaphechinus mirabilis was used as bioindicators of seawater quality from the impact areas of the Sea of Japan/East Sea (Peter the Great Bay) and the Sea of Okhotsk (northwestern shelf of Sakhalin Island and western shelf of Kamchatka Peninsula). Fertilization membrane formation, first cleavage, blastula formation, gastrulation, and 2-armed and 4-armed pluteus formation have been analyzed and a number of abnormalities were calculated. Number of embryogenesis anomalies in sand dollar larvae exposed to sea water from different stations in Peter the Great Bay corresponds to pollution level at each area. The Sea of Okhotsk is the main fishing area for Russia. Anthropogenic impact on the marine ecosystem is caused by fishing and transport vessels mainly. But two shelf areas are considered as "hot spots" due to oil and gas drilling. Offshore oil exploitation on the northeastern Sakhalin Island has been started and at present time oil is being drill on oil-extracting platforms continuously. Significant reserves of hydrocarbons are prospected on western Kamchatka shelf, and exploitation drilling in this area was intensified in 2014. A higher number of abnormalities at gastrula and pluteus stages (19-36%) were detected for the stations around oil platforms near Sakhalin Island. On the western Kamchatka shelf number of abnormalities was 7-21%. Such anomalies as exogastrula, incomplete development of pairs of arms were not observed at all; only the delay of development was registered. Eggs, embryos, and larvae of sea urchins are the suitable bioindicators of early disturbances caused by marine pollution in impact ecosystems.

Environmental impact of submerged and emerged breakwaters

“…Sea urchins are important herbivores on coral reefs, since they play an important role in maintaining the coral-algae balance. The embryogenesis of the sea urchin is a suitable bioindicator of seawater and sedimentation quality in impacted ecosystems ( Lukyanova et al., 2017 ). The presence of sea urchins can significantly influence breakwaters and the dynamics of reef benthic communities by enhancing topographic complexity and minimizing algae and sediment settlement ( McClanahan and Muthiga, 2013 ).…”

Genome-Wide SNP Discovery and Population Genetic Analysis of Mesocentrotus nudus in China Seas

“…The high edible and medicinal values of M. nudus have greatly stimulated the consumption demand, which has led to serious overfishing of wild sea urchins ( Andrew et al, 2002 ; Li and Qi, 2008 ). In addition, the natural habitat of M. nudus , mostly adjacent to the densely populated areas ( Adachi et al, 2020 ), has also been heavily disturbed by human activities including land-sourced pollution, aquaculture pollution, and sea reclamation ( Lukyanova et al, 2017 ; Song and Duan, 2019 ). Under the influence of overfishing and natural habitat loss, the wild population resources of M. nudus are declining rapidly in recent years ( Andrew et al, 2002 ).…”

Spatiotemporal changes caused by the intensive use of sea areas in the liaoning coastal economic zone of China

“…With the increasing restriction of resources and environment, it is difficult to continue the traditional inefficient marine space development activities. In order to solve the problems caused by previous development activities, such as disorderly expansion of reclamation scale, waste of marine resources, decline of productivity of coastal biological resources, deterioration of water quality, siltation of waterway and biological invasion and many other problems [3][4][5][6][7][8]. In the "13th Five-Year Plan", the Chinese government clearly stated that "adhere to land and sea coordination, strengthen the marine economy, scientifically develop marine resources, and protect the marine ecological environment", and clearly defined the overall goal of "build China into a maritime power ", and the activities and forms of marine space development are being reconstructed.…”