Marine heat waves, climate change, and failed spawning by coastal invertebrates

Abstract

To investigate the timing and intensity of winter spawning by coastal invertebrates, we enumerated embryos in plankton samples collected in daily time series from January to March of 2014 (79 d), 2015 (73 d), and 2016 (74 d). Samples were collected near the mouth of the Coos Bay estuary in Oregon. We enumerated several hundred different morphologically distinct types of embryos and larvae representing at least five phyla. Forty‐three embryo types were abundant enough (abundance > 500 over the time series) to enable statistical analysis. Twenty of these types were identified using genetic barcoding of which there were four nemerteans, four gastropods, four chitons, five polychaetes, and two echinoderms. In winter 2014, hydrographic conditions were similar to average historical values. Conditions in 2015 and 2016 were characterized by marine heat waves (MHWs). In 2015, the “warm blob”—anomalously warm water in the Northeastern Pacific—affected conditions and in 2016, there was a strong El Niño. In 2015 and 2016, winter spawning intensity was orders of magnitude lower than in 2014 and many taxa failed to spawn (11 and 24 in 2015 and 2016, respectively); spawning appears to have been adversely impacted by the MHWs. The MHW of 2015 has been attributed to anthropogenic global climate change while the 2016 El Niño may have been strengthened by climate change. The frequency, intensity, and duration of MHW are projected to increase dramatically with global warming, which may adversely affect reproduction and recruitment by numerous marine taxa.

Benthic estuarine communities' contribution to bioturbation under the experimental effect of marine heatwaves

“…bioturbation to avoid the heat 14 ). At the population level, changes in growth, reproduction 15 , 16 or survival 14 , 17 may be expected. For communities, displacement might occur to avoid adverse temperature and mass mortality 10 , 18 .…”

Dynamic larval dispersal can mediate the response of marine metapopulations to multiple climate change impacts

“…Climate change also involves increasing temperature, which reduces larval development time and may thus reduce PLD (O'Connor et al 2007, Munday et al 2008, Lett et al 2010. During the adult phase, warming temperature may further impact the reproductive phenology of species by shifting the ST (Kerr et al 2014, Shanks et al 2020, reducing reproductive output and increasing adult mortality (Przeslawski et al 2008, Munday et al 2009. Few studies have looked into multiple climate change effects on pelagic traits and ocean currents.…”

Investigation of the effect of climate change on heat waves

“…The output of the general circulation models can be divided into two types: dynamic and scalable. Heat waves are the most important atmospheric disasters, and the annual mortality rate from climatic hazards shows that thermal waves cause the highest mortality rates compared to other climatic events [15][16][17] . Reducing the consequences of heat waves depends on identifying thermal waves, their predictions, discovering ways to reduce their effects on general health and identifying areas that are vulnerable to heat waves [18][19][20][21] .…”