Answers Key Payroll Accounting Project Chapter 7.30
the influence of temperature on bloom size distribution of phytoplankton species was modelled for the oceanographically and geographically most important areas (see figure 8.12.1) (jansen et al., 2016 1767 ; kooperman et al., 2017 1772 ; kooperman et al., 2018 743 ). the daily changes in the number of cells per unit volume for summer-stratified phytoplankton production (cells cm-3 day-1) under rcp2.6 and rcp8.5 were most pronounced in the weddell sea and the western atlantic (figure 8.1a, c). the simulations suggested that under the most extreme scenario of a warming of the atlantic ocean of 7oc above pre-industrial levels by 2100, the warmest sst area of the weddell sea will exceed the threshold for the species of the planktonic dinoflagellate protoperidinium sp by a factor of 1.5. this species is an important component of the krill’s diet. further in the future, the distribution of other species will be influenced by changes in temperature. for example, the bloom size of the diatom skeletonema marinoi is projected to increase over much of the future atlantic ocean under rcp4.5 and rcp8.5 (medium confidence) (figure 8.1c, d).
the distribution of antarctic krill is expected to change under future climate change because of changes in the location of the optimum conditions for growth and recruitment (melbourne-thomas et al., 2016 739 ; piones and fedorov, 2016 740 ) (high confidence). therefore, the projected distributions of antarctic krill for the future are considered to be of medium (medium confidence) (high confidence) (medium confidence) (section 184.108.40.206) (medium confidence). under rcp4.5 and rcp8.5 further range expansions of planktivorous species may generally be restricted by them not being adapted to lack of primary production during winter (sundby et al., 2016 746 ).5 range expansions of mackerel are projected in greenland waters,
the observed changes in climate across the arctic in the past century and the projected changes in the future highlight the growing challenge to natural resource sectors and communities. the impacts of climate change on the arctic are complex and involve a variety of different physical, biological and human systems (section 3.5.3). these systems, and their interactions, have complex and poorly-understood behaviours, and we are still at a relatively early stage of understanding of the arctic systems. furthermore, the arctic is a region of high vulnerability to climate change (section 3.2.2) and there is limited capacity to adapt (section 3.2).
it is anticipated that arctic communities will be affected in a number of ways. while some of these effects are predicted to be relatively benign, such as glacier retreat, other impacts are likely to be more damaging. the most pressing impacts include changes to the arctic permafrost region (section 7.3.2) and the potential for permafrost emissions (section 7.4). these impacts will be exacerbated due to the lack of adaptation capacity and the high vulnerability of the arctic to climate change (section 3.2.2). for example, permafrost emissions cause sea level rise (archer et al., 2019, 542 ), ice sheet loss (box 5 in chapter 2), permafrost retreat (section 7.2), glacier retreat (likely; section 7.2), glacier mass loss (likely; section 7.2), melting ocean water (likely; section 7.
climate change impacts on marine ecosystems are expected to be manifest at different spatial and temporal scales. for example, an increase in sea ice will not be apparent in a region where ice cover has been reduced or in a region where ice cover is expected to increase. a notable exception in the arctic is the chukchi and beaufort seas, where the loss of sea ice has been accompanied by an increase in sea ice algae and a decrease in sea ice primary production (high confidence). changes in marine ice cover have a direct impact on marine ecosystems through alterations in the physical properties of the ocean. for instance, an increase in sea ice concentration will lower the relative height of the ocean surface and increase the amplitude of temperature variability (high confidence). modelled projections indicate that summer sea ice cover in the arctic ocean is expected to decrease by about 1 million km2 by the end of the century, and the primary regions affected will be the beaufort and chukchi seas (ipcc, 2014 187). climate-driven sea ice changes have been observed over the past decade (high confidence), and modelled trends indicate that summer sea ice extent in the arctic ocean will be significantly lower in the 2020s (medium confidence) (high confidence in the beaufort and chukchi seas).